diff --git a/config/services.php b/config/services.php
index 26dc08c1..7d6df3f7 100644
--- a/config/services.php
+++ b/config/services.php
@@ -187,12 +187,17 @@ return (function (): array {
 
         PDO::class => [
             'class' => function (): PDO {
-                $dbFile = Config::get('database.file');
-                $changePerm = !file_exists($dbFile);
+                $inTestMode = true === (defined('IN_TEST_MODE') && true === IN_TEST_MODE);
+                $dsn = $inTestMode ? 'sqlite::memory:' : Config::get('database.dsn');
 
-                $pdo = new PDO(dsn: Config::get('database.dsn'), options: Config::get('database.options', []));
+                if (false === $inTestMode) {
+                    $dbFile = Config::get('database.file');
+                    $changePerm = !file_exists($dbFile);
+                }
 
-                if ($changePerm && inContainer() && 777 !== (int)(decoct(fileperms($dbFile) & 0777))) {
+                $pdo = new PDO(dsn: $dsn, options: Config::get('database.options', []));
+
+                if (!$inTestMode && $changePerm && inContainer() && 777 !== (int)(decoct(fileperms($dbFile) & 0777))) {
                     @chmod($dbFile, 0777);
                 }
 
diff --git a/src/Commands/State/ExportCommand.php b/src/Commands/State/ExportCommand.php
index 7840b7a9..c98e9a86 100644
--- a/src/Commands/State/ExportCommand.php
+++ b/src/Commands/State/ExportCommand.php
@@ -563,8 +563,6 @@ class ExportCommand extends Command
             ],
         ]);
 
-        $this->db->singleTransaction();
-
         $requests = [];
 
         foreach ($backends as $backend) {
@@ -601,6 +599,7 @@ class ExportCommand extends Command
             }
         }
 
+        $start = makeDate();
         $this->logger->notice("SYSTEM: Sending '{total}' play state comparison requests.", [
             'total' => count($requests),
         ]);
@@ -614,9 +613,25 @@ class ExportCommand extends Command
             }
         }
 
-        $this->logger->notice("SYSTEM: Sent '{total}' play state comparison requests.", [
-            'total' => count($requests),
-        ]);
+        $end = makeDate();
+        $this->logger->notice(
+            "SYSTEM: Completed '{total}' play state comparison requests in '{time.duration}'s. Parsed '{responses.size}' of data.",
+            [
+                'total' => count($requests),
+                'time' => [
+                    'start' => $start,
+                    'end' => $end,
+                    'duration' => $end->getTimestamp() - $start->getTimestamp(),
+                ],
+                'memory' => [
+                    'now' => getMemoryUsage(),
+                    'peak' => getPeakMemoryUsage(),
+                ],
+                'responses' => [
+                    'size' => fsize((int)Message::get('response.size', 0)),
+                ],
+            ]
+        );
 
         $this->logger->notice("Export mode ended for '{backends}'.", [
             'backends' => implode(', ', array_keys($backends)),
diff --git a/src/Commands/State/ImportCommand.php b/src/Commands/State/ImportCommand.php
index f4135ab1..7f96019f 100644
--- a/src/Commands/State/ImportCommand.php
+++ b/src/Commands/State/ImportCommand.php
@@ -381,8 +381,6 @@ class ImportCommand extends Command
             ],
         ]);
 
-        $this->db->singleTransaction();
-
         foreach ($list as $name => &$backend) {
             $metadata = false;
             $opts = ag($backend, 'options', []);
@@ -472,21 +470,24 @@ class ImportCommand extends Command
 
         $end = makeDate();
 
-        $this->logger->notice("SYSTEM: Completed waiting on '{total}' requests in '{time.duration}s'.", [
-            'total' => number_format(count($queue)),
-            'time' => [
-                'start' => $start,
-                'end' => $end,
-                'duration' => $end->getTimestamp() - $start->getTimestamp(),
-            ],
-            'memory' => [
-                'now' => getMemoryUsage(),
-                'peak' => getPeakMemoryUsage(),
-            ],
-            'responses' => [
-                'size' => fsize((int)Message::get('response.size', 0)),
-            ],
-        ]);
+        $this->logger->notice(
+            "SYSTEM: Completed waiting on '{total}' requests in '{time.duration}'s. Parsed '{responses.size}' of data.",
+            [
+                'total' => number_format(count($queue)),
+                'time' => [
+                    'start' => $start,
+                    'end' => $end,
+                    'duration' => $end->getTimestamp() - $start->getTimestamp(),
+                ],
+                'memory' => [
+                    'now' => getMemoryUsage(),
+                    'peak' => getPeakMemoryUsage(),
+                ],
+                'responses' => [
+                    'size' => fsize((int)Message::get('response.size', 0)),
+                ],
+            ]
+        );
 
         $queue = $requestData = null;
 
diff --git a/src/Libs/DataUtil.php b/src/Libs/DataUtil.php
index a12f3e32..09b9f7c6 100644
--- a/src/Libs/DataUtil.php
+++ b/src/Libs/DataUtil.php
@@ -54,6 +54,11 @@ final readonly class DataUtil implements JsonSerializable, Stringable
         return new self(array_map($callback, $this->data));
     }
 
+    public function filter(callable $callback): self
+    {
+        return new self(array_filter($this->data, $callback, ARRAY_FILTER_USE_BOTH));
+    }
+
     public function with(string $key, mixed $value): self
     {
         return new self(ag_set($this->data, $key, $value));
@@ -71,6 +76,6 @@ final readonly class DataUtil implements JsonSerializable, Stringable
 
     public function __toString(): string
     {
-        return json_encode($this->data);
+        return json_encode($this->jsonSerialize());
     }
 }
diff --git a/src/Libs/Database/DBLayer.php b/src/Libs/Database/DBLayer.php
index 85d5f3ba..349f804d 100644
--- a/src/Libs/Database/DBLayer.php
+++ b/src/Libs/Database/DBLayer.php
@@ -6,13 +6,13 @@ declare(strict_types=1);
 namespace App\Libs\Database;
 
 use App\Libs\Exceptions\DBLayerException;
+use App\Libs\Exceptions\RuntimeException;
 use Closure;
 use PDO;
 use PDOException;
 use PDOStatement;
 use Psr\Log\LoggerAwareInterface;
 use Psr\Log\LoggerAwareTrait;
-use RuntimeException;
 
 final class DBLayer implements LoggerAwareInterface
 {
@@ -20,6 +20,8 @@ final class DBLayer implements LoggerAwareInterface
 
     private const int LOCK_RETRY = 4;
 
+    private int $retry;
+
     private int $count = 0;
 
     private string $driver;
@@ -53,128 +55,207 @@ final class DBLayer implements LoggerAwareInterface
     public const string IS_JSON_EXTRACT = 'JSON_EXTRACT';
     public const string IS_JSON_SEARCH = 'JSON_SEARCH';
 
-    public function __construct(private PDO $pdo)
+    public function __construct(private readonly PDO $pdo, private array $options = [])
     {
         $driver = $this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME);
 
         if (is_string($driver)) {
             $this->driver = $driver;
         }
+
+        $this->retry = ag($this->options, 'retry', self::LOCK_RETRY);
     }
 
+    /**
+     * Execute a SQL statement and return the number of affected rows.
+     * The execution will be wrapped into {@link DBLayer::wrap()} method. to handle database locks.
+     *
+     * @param string $sql The SQL statement to execute.
+     * @param array $options An optional array of options to be passed to the callback function.
+     *
+     * @return int|false The number of affected rows, or false on failure.
+     */
     public function exec(string $sql, array $options = []): int|false
     {
-        try {
-            return $this->wrap(function (DBLayer $db) use ($sql, $options) {
-                $queryString = $sql;
+        $opts = [];
 
-                $this->last = [
-                    'sql' => $queryString,
-                    'bind' => [],
-                ];
-
-                return $db->pdo->exec($queryString);
-            });
-        } catch (PDOException $e) {
-            if ($e instanceof DBLayerException) {
-                throw $e;
-            }
-
-            throw (new DBLayerException($e->getMessage()))
-                ->setInfo($sql, [], $e->errorInfo ?? [], $e->getCode())
-                ->setFile($e->getTrace()[$options['tracer'] ?? 1]['file'] ?? $e->getFile())
-                ->setLine($e->getTrace()[$options['tracer'] ?? 1]['line'] ?? $e->getLine())
-                ->setOptions($options);
+        if (true === ag_exists($options, 'on_failure')) {
+            $opts['on_failure'] = $options['on_failure'];
         }
+
+        return $this->wrap(function (DBLayer $db) use ($sql) {
+            $queryString = $sql;
+
+            $this->last = [
+                'sql' => $queryString,
+                'bind' => [],
+            ];
+
+            return $db->pdo->exec($queryString);
+        }, $opts);
     }
 
-    public function query(string|PDOStatement $sql, array $bind = [], array $options = []): PDOStatement
+    /**
+     * Execute an SQL statement and return the PDOStatement object.
+     *
+     * @param PDOStatement|string $sql The SQL statement to execute.
+     * @param array $bind The bind parameters for the SQL statement.
+     * @param array $options An optional array of options to be passed to the callback function.
+     *
+     * @return PDOStatement The returned results wrapped in a PDOStatement object.
+     */
+    public function query(PDOStatement|string $sql, array $bind = [], array $options = []): PDOStatement
     {
-        try {
-            return $this->wrap(function (DBLayer $db) use ($sql, $bind, $options) {
-                $isStatement = $sql instanceof PDOStatement;
-                $queryString = $isStatement ? $sql->queryString : $sql;
-
-                $this->last = [
-                    'sql' => $queryString,
-                    'bind' => $bind,
-                ];
-
-                $stmt = $isStatement ? $sql : $db->prepare($sql);
-                if (false === ($stmt instanceof PDOStatement)) {
-                    throw new PDOException('Unable to prepare statement.');
-                }
-
-                $stmt->execute($bind);
-
-                if (false !== stripos($queryString, 'SQL_CALC_FOUND_ROWS')) {
-                    if (false !== ($countStatement = $this->pdo->query('SELECT FOUND_ROWS();'))) {
-                        $this->count = (int)$countStatement->fetch(PDO::FETCH_COLUMN);
-                    }
-                }
-
-                return $stmt;
-            });
-        } catch (PDOException $e) {
-            if ($e instanceof DBLayerException) {
-                throw $e;
-            }
-            throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
-                ->setInfo(
-                    (true === ($sql instanceof PDOStatement)) ? $sql->queryString : $sql,
-                    $bind,
-                    $e->errorInfo ?? [],
-                    $e->getCode()
-                )
-                ->setFile($e->getTrace()[$options['tracer'] ?? 1]['file'] ?? $e->getFile())
-                ->setLine($e->getTrace()[$options['tracer'] ?? 1]['line'] ?? $e->getLine())
-                ->setOptions($options);
+        $opts = [];
+        if (true === ag_exists($options, 'on_failure')) {
+            $opts['on_failure'] = $options['on_failure'];
         }
+
+        return $this->wrap(function (DBLayer $db) use ($sql, $bind) {
+            $isStatement = $sql instanceof PDOStatement;
+            $queryString = $isStatement ? $sql->queryString : $sql;
+
+            $this->last = [
+                'sql' => $queryString,
+                'bind' => $bind,
+            ];
+
+            $stmt = $isStatement ? $sql : $db->prepare($sql);
+
+            if (!empty($bind)) {
+                array_map(
+                    fn($k, $v) => $stmt->bindValue($k, $v, is_int($v) ? PDO::PARAM_INT : PDO::PARAM_STR),
+                    array_keys($bind),
+                    $bind
+                );
+            }
+
+            $stmt->execute();
+
+            return $stmt;
+        }, $opts);
     }
 
+    /**
+     * Start a transaction.
+     *
+     * @return bool Returns true on success, false on failure.
+     */
     public function start(): bool
     {
-        if ($this->pdo->inTransaction()) {
+        if (true === $this->pdo->inTransaction()) {
             return false;
         }
 
         return $this->pdo->beginTransaction();
     }
 
+    /**
+     * Commit a transaction.
+     *
+     * @return bool Returns true on success, false on failure.
+     */
     public function commit(): bool
     {
         return $this->pdo->commit();
     }
 
+    /**
+     * Rollback a transaction.
+     *
+     * @return bool Returns true on success, false on failure.
+     */
     public function rollBack(): bool
     {
         return $this->pdo->rollBack();
     }
 
+    /**
+     * Checks if inside a transaction.
+     *
+     * @return bool Returns true if a transaction is currently active, false otherwise.
+     */
     public function inTransaction(): bool
     {
         return $this->pdo->inTransaction();
     }
 
     /**
-     * @return bool
-     * @deprecated Use {@link self::start()} instead.
+     * This method wraps db operations in a single transaction.
+     *
+     * @param Closure<DBLayer> $callback The callback function to be executed.
+     * @param bool $auto (Optional) Whether to automatically start and commit the transaction.
+     * @param array $options (Optional) An optional array of options to be passed the wrapper.
+     *
+     * @return mixed The result of the callback function.
      */
-    public function beginTransaction(): bool
+    public function transactional(Closure $callback, bool $auto = true, array $options = []): mixed
     {
-        return $this->start();
+        $autoStartTransaction = true === $auto && false === $this->inTransaction();
+
+        if ($autoStartTransaction) {
+            $options['on_failure'] = function ($e) {
+                if ($this->inTransaction()) {
+                    $this->rollBack();
+                }
+                throw $e;
+            };
+        }
+
+        return $this->wrap(function (DBLayer $db, array $options = []) use ($callback, $autoStartTransaction) {
+            if (true === $autoStartTransaction) {
+                $db->start();
+            }
+
+            $result = $callback($this, $options);
+
+            if (true === $autoStartTransaction) {
+                $db->commit();
+            }
+
+            $this->last = $db->getLastStatement();
+            return $result;
+        }, $options);
     }
 
-    public function prepare(string $sql, array $options = []): PDOStatement|false
+    /**
+     * Prepare a statement for execution and return a PDOStatement object.
+     *
+     * @param string $sql The SQL statement to prepare.
+     * @param array $options holds options for {@link PDOStatement} options.
+     *
+     * @return PDOStatement The returned results wrapped in a PDOStatement object.
+     */
+    public function prepare(string $sql, array $options = []): PDOStatement
     {
-        return $this->pdo->prepare($sql, $options);
+        $stmt = $this->pdo->prepare($sql, $options);
+
+        if (false === ($stmt instanceof PDOStatement)) {
+            throw new PDOException('Unable to prepare statement.');
+        }
+
+        return $stmt;
     }
 
+    /**
+     * Returns the ID of the last inserted row or sequence value.
+     *
+     * @return string|false return the last insert id or false on failure or not supported.
+     */
     public function lastInsertId(): string|false
     {
         return $this->pdo->lastInsertId();
     }
 
+    /**
+     * Delete Statement.
+     *
+     * @param string $table The table name.
+     * @param array $conditions The conditions to be met. i.e. WHERE clause.
+     * @param array $options The options to be passed to the query method.
+     *
+     * @return PDOStatement The returned results wrapped in a PDOStatement object.
+     */
     public function delete(string $table, array $conditions, array $options = []): PDOStatement
     {
         if (empty($conditions)) {
@@ -188,9 +269,13 @@ final class DBLayer implements LoggerAwareInterface
         $query[] = 'DELETE FROM ' . $this->escapeIdentifier($table, true) . ' WHERE';
         $query[] = implode(' AND ', $cond['query']);
 
-        if (array_key_exists('limit', $options)) {
+        // -- For some reason, the SQLite authors don't include this feature in the amalgamation.
+        // So it's effectively unavailable to most third-party drivers and programs that use the amalgamation
+        // to compile SQLite. As we don't control the build version of SQLite, we can't guarantee that this
+        // feature is available. So we'll just skip it for SQLite.
+        $ignoreSafety = 'sqlite' !== $this->driver || true === (bool)ag($options, 'ignore_safety', false);
+        if (array_key_exists('limit', $options) && $ignoreSafety) {
             $_ = $this->limitExpr($options['limit']);
-
             $query[] = $_['query'];
             $bind = array_replace_recursive($bind, $_['bind']);
         }
@@ -277,7 +362,16 @@ final class DBLayer implements LoggerAwareInterface
         return $this->query(implode(' ', $query), $bind, $options);
     }
 
-    public function getCount(string $table, array $conditions = [], array $options = []): void
+    /**
+     * Get the count of rows in a table.
+     *
+     * @param string $table The table name.
+     * @param array $conditions The conditions to be met. i.e. WHERE clause.
+     * @param array $options The options to be passed to the query method.
+     *
+     * @return int The number of rows based on the conditions.
+     */
+    public function getCount(string $table, array $conditions = [], array $options = []): int
     {
         $bind = $query = [];
 
@@ -308,8 +402,20 @@ final class DBLayer implements LoggerAwareInterface
         }
 
         $this->count = (int)$this->query(implode(' ', $query), $bind, $options)->fetchColumn();
+
+        return $this->count;
     }
 
+    /**
+     * Update Statement.
+     *
+     * @param string $table The table name.
+     * @param array $changes The changes to be made. i.e. SET clause.
+     * @param array $conditions The conditions to be met. i.e. WHERE clause.
+     * @param array $options The options to be passed to the query method.
+     *
+     * @return PDOStatement The returned results wrapped in a PDOStatement object.
+     */
     public function update(string $table, array $changes, array $conditions, array $options = []): PDOStatement
     {
         if (empty($changes)) {
@@ -341,7 +447,12 @@ final class DBLayer implements LoggerAwareInterface
 
         $query[] = 'WHERE ' . implode(' AND ', $cond['query']);
 
-        if (array_key_exists('limit', $options)) {
+        // -- For some reason, the SQLite authors don't include this feature in the amalgamation.
+        // So it's effectively unavailable to most third-party drivers and programs that use the amalgamation
+        // to compile SQLite. As we don't control the build version of SQLite, we can't guarantee that this
+        // feature is available. So we'll just skip it for SQLite.
+        $ignoreSafety = 'sqlite' !== $this->driver || true === (bool)ag($options, 'ignore_safety', false);
+        if (array_key_exists('limit', $options) && $ignoreSafety) {
             $_ = $this->limitExpr((int)$options['limit']);
 
             $query[] = $_['query'];
@@ -357,6 +468,15 @@ final class DBLayer implements LoggerAwareInterface
         return $this->query(implode(' ', $query), $bind, $options);
     }
 
+    /**
+     * Insert Statement.
+     *
+     * @param string $table The table name.
+     * @param array $conditions Simple associative array of [column => value].
+     * @param array $options The options to be passed to the query method.
+     *
+     * @return PDOStatement The returned results wrapped in a PDOStatement object.
+     */
     public function insert(string $table, array $conditions, array $options = []): PDOStatement
     {
         if (empty($conditions)) {
@@ -387,31 +507,40 @@ final class DBLayer implements LoggerAwareInterface
         return $this->query($queryString, $conditions, $options);
     }
 
+    /**
+     * Quote a string for use in a query.
+     *
+     * @param mixed $text The string to be quoted.
+     * @param int $type Provides a data type hint for drivers that have alternate quoting styles.
+     *
+     * @return string The quoted string.
+     */
     public function quote(mixed $text, int $type = PDO::PARAM_STR): string
     {
         return (string)$this->pdo->quote($text, $type);
     }
 
-    public function escape(string $text): string
-    {
-        return mb_substr($this->quote($text), 1, -1, 'UTF-8');
-    }
-
+    /**
+     * Get the ID generated in the last query.
+     *
+     * @param string|null $name The name of the sequence object from which the ID should be returned.
+     * @return string The generated ID, or empty string if no ID was generated.
+     */
     public function id(string|null $name = null): string
     {
         return false !== ($id = $this->pdo->lastInsertId($name)) ? $id : '';
     }
 
+    /**
+     * Get the number of rows by using {@link DBLayer::getCount()}.
+     *
+     * @return int The total number of rows.
+     */
     public function totalRows(): int
     {
         return $this->count;
     }
 
-    public function close(): bool
-    {
-        return true;
-    }
-
     /**
      * Make sure only valid characters make it in column/table names
      *
@@ -456,11 +585,21 @@ final class DBLayer implements LoggerAwareInterface
         return $text;
     }
 
+    /**
+     * Get the PDO driver name.
+     *
+     * @return string The driver name.
+     */
     public function getDriver(): string
     {
         return $this->driver;
     }
 
+    /**
+     * Get reference to the PDO object.
+     *
+     * @return PDO The PDO object.
+     */
     public function getBackend(): PDO
     {
         return $this->pdo;
@@ -617,10 +756,22 @@ final class DBLayer implements LoggerAwareInterface
                     }
 
                     $eBindName = '__db_ftS_' . random_int(1, 1000);
-                    $keys[] = sprintf(
-                        "MATCH(%s) AGAINST(%s)",
-                        implode(', ', array_map(fn($columns) => $this->escapeIdentifier($columns, true), $opt[1])),
-                        ':' . $eBindName
+
+                    $keys[] = str_replace(
+                        ['(column)', '(bind)', '(expr)'],
+                        [
+                            $eColumnName,
+                            $eBindName,
+                            implode(', ', array_map(fn($columns) => $this->escapeIdentifier($columns, true), $opt[1]))
+                        ],
+                        (function ($driver) {
+                            if ('sqlite' === $driver) {
+                                return "(column) MATCH :(bind)";
+                            }
+                            return "MATCH((expr)) AGAINST(:(bind))";
+                        })(
+                            $this->driver
+                        )
                     );
 
                     $bind[$eBindName] = $opt[2];
@@ -643,7 +794,7 @@ final class DBLayer implements LoggerAwareInterface
                     break;
                 case self::IS_JSON_EXTRACT:
                     if (!isset($opt[1], $opt[2], $opt[3])) {
-                        throw new RuntimeException('IS_JSON_CONTAINS: expects 3 parameters.');
+                        throw new RuntimeException('IS_JSON_EXTRACT: expects 3 parameters.');
                     }
 
                     $eBindName = '__db_je_' . random_int(1, 1000);
@@ -651,7 +802,7 @@ final class DBLayer implements LoggerAwareInterface
                     $keys[] = sprintf(
                         "JSON_EXTRACT(%s, %s) %s %s",
                         $this->escapeIdentifier($column, true),
-                        $opt[1],
+                        $this->escapeIdentifier($opt[1], true),
                         $opt[2],
                         ':' . $eBindName,
                     );
@@ -672,6 +823,14 @@ final class DBLayer implements LoggerAwareInterface
         ];
     }
 
+    /**
+     * Create an IN expression.
+     *
+     * @param string $key column name
+     * @param array $parameters array of values.
+     *
+     * @return array{bind: array<string, mixed>, query: string}, The bind and query.
+     */
     private function inExpr(string $key, array $parameters): array
     {
         $i = 0;
@@ -689,6 +848,13 @@ final class DBLayer implements LoggerAwareInterface
         ];
     }
 
+    /**
+     * Create a GROUP BY expression.
+     *
+     * @param array $groupBy The columns to group by.
+     *
+     * @return array{query: string} The query.
+     */
     private function groupByExpr(array $groupBy): array
     {
         $groupBy = array_map(
@@ -699,6 +865,13 @@ final class DBLayer implements LoggerAwareInterface
         return ['query' => 'GROUP BY ' . implode(', ', $groupBy)];
     }
 
+    /**
+     * Create an ORDER BY expression.
+     *
+     * @param array $orderBy The columns to order by.
+     *
+     * @return array{query: string} The query.
+     */
     private function orderByExpr(array $orderBy): array
     {
         $sortBy = [];
@@ -712,6 +885,14 @@ final class DBLayer implements LoggerAwareInterface
         return ['query' => 'ORDER BY ' . implode(', ', $sortBy)];
     }
 
+    /**
+     * Create a LIMIT expression.
+     *
+     * @param int $limit The limit.
+     * @param int|null $start The start.
+     *
+     * @return array{bind: array<string, int>, query: string} The bind and query.
+     */
     private function limitExpr(int $limit, ?int $start = null): array
     {
         $bind = [
@@ -732,87 +913,85 @@ final class DBLayer implements LoggerAwareInterface
         ];
     }
 
+    /**
+     * Get the last executed statement.
+     *
+     * @return array The last executed statement.
+     */
     public function getLastStatement(): array
     {
         return $this->last;
     }
 
-    public function transactional(Closure $callback): mixed
+    /**
+     * Wraps the given callback function with a retry mechanism to handle database locks.
+     *
+     * @param Closure{DBLayer,array} $callback The callback function to be executed.
+     * @param array $options An optional array of options to be passed to the callback function.
+     *
+     * @return mixed The result of the callback function.
+     *
+     * @throws DBLayerException If an error occurs while executing the callback function.
+     */
+    private function wrap(Closure $callback, array $options = []): mixed
     {
-        $autoStartTransaction = false === $this->inTransaction();
-
-        for ($i = 1; $i <= self::LOCK_RETRY; $i++) {
-            try {
-                if (true === $autoStartTransaction) {
-                    $this->start();
-                }
-
-                $result = $callback($this);
-
-                if (true === $autoStartTransaction) {
-                    $this->commit();
-                }
-
-                $this->last = $this->getLastStatement();
-
-                return $result;
-            } catch (DBLayerException $e) {
-                /** @noinspection PhpConditionAlreadyCheckedInspection */
-                if ($autoStartTransaction && $this->inTransaction()) {
-                    $this->rollBack();
-                }
-
-                //-- sometimes sqlite is locked, therefore attempt to sleep until it's unlocked.
-                if (false !== stripos($e->getMessage(), 'database is locked')) {
-                    // throw exception if happens self::LOCK_RETRY times in a row.
-                    if ($i >= self::LOCK_RETRY) {
-                        throw $e;
-                    }
-                    /** @noinspection PhpUnhandledExceptionInspection */
-                    sleep(self::LOCK_RETRY + random_int(1, 3));
-                } else {
-                    throw $e;
-                }
-            }
+        static $lastFailure = [];
+        $on_lock = ag($options, 'on_lock', null);
+        $errorHandler = ag($options, 'on_failure', null);
+        $exception = null;
+        if (false === ag_exists($options, 'attempt')) {
+            $options['attempt'] = 0;
         }
 
-        /**
-         * We return in try or throw exception.
-         * As such this return should never be reached.
-         */
-        return null;
-    }
-
-    private function wrap(Closure $callback): mixed
-    {
-        for ($i = 0; $i <= self::LOCK_RETRY; $i++) {
-            try {
-                return $callback($this);
-            } catch (PDOException $e) {
-                if (true === str_contains(strtolower($e->getMessage()), 'database is locked')) {
-                    if ($i >= self::LOCK_RETRY) {
-                        throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
-                            ->setInfo($stnt->queryString, $bind, $e->errorInfo ?? [], $e->getCode())
-                            ->setFile($e->getFile())
-                            ->setLine($e->getLine());
-                    }
-
-                    $sleep = self::LOCK_RETRY + random_int(1, 3);
-
-                    $this->logger?->warning("PDOAdapter: Database is locked. sleeping for '{sleep}s'.", [
-                        'sleep' => $sleep
-                    ]);
-
-                    sleep($sleep);
-                } else {
+        try {
+            return $callback($this, $options);
+        } catch (PDOException $e) {
+            $attempts = (int)ag($options, 'attempts', 0);
+            if (true === str_contains(strtolower($e->getMessage()), 'database is locked')) {
+                if ($attempts >= $this->retry) {
                     throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
-                        ->setInfo($stnt->queryString, $bind, $e->errorInfo ?? [], $e->getCode())
                         ->setFile($e->getFile())
                         ->setLine($e->getLine());
                 }
+
+                $sleep = (int)ag($options, 'max_sleep', rand(1, 4));
+
+                $this->logger?->warning("PDOAdapter: Database is locked. sleeping for '{sleep}s'.", [
+                    'sleep' => $sleep
+                ]);
+
+                $options['attempts'] = $attempts + 1;
+                if (null !== $on_lock) {
+                    return $on_lock($e, $callback, $options);
+                }
+
+                sleep($sleep);
+
+                return $this->wrap($callback, $options);
+            } else {
+                $exception = $e;
+                if (null !== $errorHandler && ag($lastFailure, 'message') !== $e->getMessage()) {
+                    $lastFailure = [
+                        'code' => $e->getCode(),
+                        'message' => $e->getMessage(),
+                        'time' => time(),
+                    ];
+                    return $errorHandler($e, $callback, $options);
+                }
+
+                if ($e instanceof DBLayerException) {
+                    throw $e;
+                }
+
+                throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
+                    ->setInfo($this->last['sql'], $this->last['bind'], $e->errorInfo ?? [], $e->getCode())
+                    ->setFile($e->getFile())
+                    ->setLine($e->getLine());
+            }
+        } finally {
+            if (null === $exception) {
+                $lastFailure = [];
             }
         }
-
-        return false;
     }
 }
diff --git a/src/Libs/Database/DatabaseInterface.php b/src/Libs/Database/DatabaseInterface.php
index 0099ea49..cb8a7aa4 100644
--- a/src/Libs/Database/DatabaseInterface.php
+++ b/src/Libs/Database/DatabaseInterface.php
@@ -179,13 +179,6 @@ interface DatabaseInterface
      */
     public function getDBLayer(): DBLayer;
 
-    /**
-     * Enable single transaction mode.
-     *
-     * @return bool
-     */
-    public function singleTransaction(): bool;
-
     /**
      * Wrap queries into single transaction.
      *
diff --git a/src/Libs/Database/PDO/PDOAdapter.php b/src/Libs/Database/PDO/PDOAdapter.php
index f051c28e..b8c0c7de 100644
--- a/src/Libs/Database/PDO/PDOAdapter.php
+++ b/src/Libs/Database/PDO/PDOAdapter.php
@@ -9,16 +9,14 @@ use App\Libs\Database\DatabaseInterface as iDB;
 use App\Libs\Database\DBLayer;
 use App\Libs\Entity\StateInterface as iState;
 use App\Libs\Exceptions\DBAdapterException as DBException;
-use App\Libs\Exceptions\DBLayerException;
 use App\Libs\Options;
 use Closure;
 use DateTimeInterface;
 use PDO;
 use PDOException;
 use PDOStatement;
-use Psr\Log\LoggerInterface;
-use Random\RandomException;
-use RuntimeException;
+use Psr\Log\LoggerInterface as iLogger;
+use Throwable;
 
 /**
  * Class PDOAdapter
@@ -27,21 +25,11 @@ use RuntimeException;
  */
 final class PDOAdapter implements iDB
 {
-    /**
-     * @var int The number of times to retry acquiring a lock.
-     */
-    private const int LOCK_RETRY = 4;
-
     /**
      * @var bool Whether the current operation is in a transaction.
      */
     private bool $viaTransaction = false;
 
-    /**
-     * @var bool Whether the current operation is using a single transaction.
-     */
-    private bool $singleTransaction = false;
-
     /**
      * @var array Adapter options.
      */
@@ -55,20 +43,14 @@ final class PDOAdapter implements iDB
         'update' => null,
     ];
 
-    /**
-     * @var string The database driver to be used.
-     */
-    private string $driver = 'sqlite';
-
     /**
      * Creates a new instance of the class.
      *
-     * @param LoggerInterface $logger The logger object used for logging.
+     * @param iLogger $logger The logger object used for logging.
      * @param DBLayer $db The PDO object used for database connections.
      */
-    public function __construct(private LoggerInterface $logger, private readonly DBLayer $db)
+    public function __construct(private iLogger $logger, private readonly DBLayer $db)
     {
-        $this->driver = $this->db->getDriver();
     }
 
     /**
@@ -83,7 +65,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function insert(iState $entity): iState
     {
@@ -158,12 +139,20 @@ final class PDOAdapter implements iDB
                 );
             }
 
-            $this->execute($this->stmt['insert'], $data);
+            $this->db->query($this->stmt['insert'], $data, options: [
+                'on_failure' => function (Throwable $e) use ($entity) {
+                    if (false === str_contains($e->getMessage(), '21 bad parameter or other API misuse')) {
+                        throw $e;
+                    }
+                    $this->stmt['insert'] = null;
+                    return $this->insert($entity);
+                }
+            ]);
 
             $entity->id = (int)$this->db->lastInsertId();
         } catch (PDOException $e) {
             $this->stmt['insert'] = null;
-            if (false === $this->viaTransaction && false === $this->singleTransaction) {
+            if (false === $this->viaTransaction) {
                 $this->logger->error(
                     message: "PDOAdapter: Exception '{error.kind}' was thrown unhandled. '{error.message}' at '{error.file}:{error.line}'.",
                     context: [
@@ -193,7 +182,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function get(iState $entity): iState|null
     {
@@ -204,19 +192,7 @@ final class PDOAdapter implements iDB
         }
 
         if (null !== $entity->id) {
-            $stmt = $this->query(
-                r(
-                    'SELECT * FROM state WHERE ${column} = ${id}',
-                    context: [
-                        'column' => iState::COLUMN_ID,
-                        'id' => (int)$entity->id
-                    ],
-                    opts: [
-                        'tag_left' => '${',
-                        'tag_right' => '}'
-                    ],
-                )
-            );
+            $stmt = $this->db->query('SELECT * FROM state WHERE id = :id', ['id' => (int)$entity->id]);
 
             if (false !== ($item = $stmt->fetch(PDO::FETCH_ASSOC))) {
                 $item = $entity::fromArray($item);
@@ -247,7 +223,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function getAll(DateTimeInterface|null $date = null, array $opts = []): array
     {
@@ -271,13 +246,14 @@ final class PDOAdapter implements iDB
             $sql .= ' WHERE ' . iState::COLUMN_UPDATED . ' > ' . $date->getTimestamp();
         }
 
-        if (null === ($opts['class'] ?? null) || false === ($opts['class'] instanceof iState)) {
+        $fromClass = $opts['class'] ?? $this->options['class'] ?? null;
+        if (null === ($fromClass ?? null) || false === ($fromClass instanceof iState)) {
             $class = Container::get(iState::class);
         } else {
-            $class = $opts['class'];
+            $class = $fromClass;
         }
 
-        foreach ($this->query($sql) as $row) {
+        foreach ($this->db->query($sql) as $row) {
             $arr[] = $class::fromArray($row);
         }
 
@@ -286,7 +262,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function find(iState ...$items): array
     {
@@ -305,13 +280,11 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException
      */
     public function findByBackendId(string $backend, int|string $id, string|null $type = null): iState|null
     {
         $key = $backend . '.' . iState::COLUMN_ID;
         $cond = [
-            'id' => $id
         ];
 
         $type_sql = '';
@@ -320,39 +293,33 @@ final class PDOAdapter implements iDB
             $cond['type'] = $type;
         }
 
-        $sql = "SELECT * FROM state WHERE {$type_sql} JSON_EXTRACT(" . iState::COLUMN_META_DATA . ",'$.{$key}') = :id LIMIT 1";
-        $stmt = $this->db->prepare($sql);
-
-        if (false === $this->execute($stmt, $cond)) {
-            throw new DBException(
-                r("PDOAdapter: Failed to execute sql query. Statement '{sql}', Conditions '{cond}'.", [
-                    'sql' => $sql,
-                    'cond' => arrayToString($cond),
-                ]), 61
-            );
-        }
+        $sql = "SELECT * FROM state WHERE {$type_sql} JSON_EXTRACT(" . iState::COLUMN_META_DATA . ",'$.{$key}') = {id} LIMIT 1";
+        $stmt = $this->db->query(r($sql, ['id' => is_int($id) ? $id : $this->db->quote($id)]), $cond);
 
         if (false === ($row = $stmt->fetch(PDO::FETCH_ASSOC))) {
             return null;
         }
 
-        return Container::get(iState::class)::fromArray($row);
-    }
+        $fromClass = $this->options['class'] ?? null;
+        if (null === ($fromClass ?? null) || false === ($fromClass instanceof iState)) {
+            $class = Container::get(iState::class);
+        } else {
+            $class = $fromClass;
+        }
 
+        return $class::fromArray($row);
+    }
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function update(iState $entity): iState
     {
         try {
             if (null === ($entity->id ?? null)) {
-                throw new DBException(
-                    r("PDOAdapter: Unable to update '{title}' without primary key defined.", [
-                        'title' => $entity->getName() ?? 'Unknown'
-                    ]), 51
-                );
+                throw new DBException(r("PDOAdapter: Unable to update '{title}' without primary key defined.", [
+                    'title' => $entity->getName() ?? 'Unknown'
+                ]), 51);
             }
 
             if (true === $entity->isEpisode() && $entity->episode < 1) {
@@ -391,15 +358,21 @@ final class PDOAdapter implements iDB
             }
 
             if (null === ($this->stmt['update'] ?? null)) {
-                $this->stmt['update'] = $this->db->prepare(
-                    $this->pdoUpdate('state', iState::ENTITY_KEYS)
-                );
+                $this->stmt['update'] = $this->db->prepare($this->pdoUpdate('state', iState::ENTITY_KEYS));
             }
 
-            $this->execute($this->stmt['update'], $data);
+            $this->db->query($this->stmt['update'], $data, options: [
+                'on_failure' => function (Throwable $e) use ($entity) {
+                    if (false === str_contains($e->getMessage(), '21 bad parameter or other API misuse')) {
+                        throw $e;
+                    }
+                    $this->stmt['update'] = null;
+                    return $this->update($entity);
+                }
+            ]);
         } catch (PDOException $e) {
             $this->stmt['update'] = null;
-            if (false === $this->viaTransaction && false === $this->singleTransaction) {
+            if (false === $this->viaTransaction) {
                 $this->logger->error(
                     message: "PDOAdapter: Exception '{error.kind}' was thrown unhandled. '{error.message}' at '{error.file}:{error.line}'.",
                     context: [
@@ -429,7 +402,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function remove(iState $entity): bool
     {
@@ -447,19 +419,7 @@ final class PDOAdapter implements iDB
                 $id = $entity->id;
             }
 
-            $this->query(
-                r(
-                    'DELETE FROM state WHERE ${column} = ${id}',
-                    [
-                        'column' => iState::COLUMN_ID,
-                        'id' => (int)$id
-                    ],
-                    opts: [
-                        'tag_left' => '${',
-                        'tag_right' => '}'
-                    ]
-                )
-            );
+            $this->db->query('DELETE FROM state WHERE id = :id', ['id' => (int)$id]);
         } catch (PDOException $e) {
             $this->logger->error(
                 message: "PDOAdapter: Exception '{error.kind}' was thrown unhandled. '{error.message}' at '{error.file}:{error.line}'.",
@@ -488,7 +448,6 @@ final class PDOAdapter implements iDB
 
     /**
      * @inheritdoc
-     * @throws RandomException if an error occurs while generating a random number.
      */
     public function commit(array $entities, array $opts = []): array
     {
@@ -563,7 +522,7 @@ final class PDOAdapter implements iDB
     /**
      * @inheritdoc
      */
-    public function migrateData(string $version, LoggerInterface|null $logger = null): mixed
+    public function migrateData(string $version, iLogger|null $logger = null): mixed
     {
         return (new PDODataMigration($this->db, $logger ?? $this->logger))->automatic();
     }
@@ -618,7 +577,7 @@ final class PDOAdapter implements iDB
     /**
      * @inheritdoc
      */
-    public function setLogger(LoggerInterface $logger): iDB
+    public function setLogger(iLogger $logger): iDB
     {
         $this->logger = $logger;
 
@@ -630,20 +589,6 @@ final class PDOAdapter implements iDB
         return $this->db;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function singleTransaction(): bool
-    {
-        $this->singleTransaction = true;
-
-        if (false === $this->db->inTransaction()) {
-            $this->db->start();
-        }
-
-        return $this->db->inTransaction();
-    }
-
     /**
      * @inheritdoc
      */
@@ -684,7 +629,7 @@ final class PDOAdapter implements iDB
      */
     public function __destruct()
     {
-        if (true === $this->singleTransaction && true === $this->db->inTransaction()) {
+        if (true === $this->db->inTransaction()) {
             $this->db->commit();
         }
 
@@ -755,7 +700,6 @@ final class PDOAdapter implements iDB
      * @param iState $entity Entity get external ids from.
      *
      * @return iState|null Entity if found, null otherwise.
-     * @throws RandomException if an error occurs while generating a random number.
      */
     private function findByExternalId(iState $entity): iState|null
     {
@@ -809,17 +753,7 @@ final class PDOAdapter implements iDB
         $sqlGuids = ' AND ( ' . implode(' OR ', $guids) . ' ) ';
 
         $sql = "SELECT * FROM state WHERE " . iState::COLUMN_TYPE . " = :type {$sqlEpisode} {$sqlGuids} LIMIT 1";
-
-        $stmt = $this->db->prepare($sql);
-
-        if (false === $this->execute($stmt, $cond)) {
-            throw new DBException(
-                r("PDOAdapter: Failed to execute sql query. Statement '{sql}', Conditions '{cond}'.", [
-                    'sql' => $sql,
-                    'cond' => arrayToString($cond),
-                ]), 61
-            );
-        }
+        $stmt = $this->db->query($sql, $cond);
 
         if (false === ($row = $stmt->fetch(PDO::FETCH_ASSOC))) {
             return null;
@@ -827,150 +761,4 @@ final class PDOAdapter implements iDB
 
         return $entity::fromArray($row);
     }
-
-    /**
-     * Executes a prepared SQL statement with optional parameters.
-     *
-     * @param PDOStatement $stmt The prepared statement to execute.
-     * @param array $cond An optional array of parameters to bind to the statement.
-     * @return bool True if the statement was successfully executed, false otherwise.
-     *
-     * @throws PDOException if an error occurs during the execution of the statement.
-     * @throws RandomException if an error occurs while generating a random number.
-     */
-    private function execute(PDOStatement $stmt, array $cond = []): bool
-    {
-        return $this->wrap(fn(PDOAdapter $adapter) => $stmt->execute($cond));
-    }
-
-    /**
-     * Executes a SQL query on the database.
-     *
-     * @param string $sql The SQL query to be executed.
-     *
-     * @return PDOStatement|false The result of the query as a PDOStatement object.
-     *                            It will return false if the query fails.
-     *
-     * @throws PDOException If an error occurs while executing the query.
-     * @throws RandomException If an error occurs while generating a random number.
-     */
-    private function query(string $sql): PDOStatement|false
-    {
-        return $this->wrap(fn(PDOAdapter $adapter) => $adapter->db->query($sql));
-    }
-
-    /**
-     * FOR DEBUGGING AND DISPLAY PURPOSES ONLY.
-     *
-     * @note Do not use it for anything.
-     * @param string $sql
-     * @param array $parameters
-     * @return string
-     *
-     * @internal This is for debugging purposes only.
-     */
-    public function getRawSQLString(string $sql, array $parameters): string
-    {
-        $replacer = [];
-
-        foreach ($parameters as $key => $val) {
-            $replacer['/(\:' . preg_quote($key, '/') . ')(?:\b|\,)/'] = ctype_digit(
-                (string)$val
-            ) ? (int)$val : '"' . $val . '"';
-        }
-
-        return preg_replace(array_keys($replacer), array_values($replacer), $sql);
-    }
-
-    /**
-     * Generates a valid identifier for a table or column.
-     *
-     * @param string $text The input text to be transformed into a valid identifier.
-     * @param bool $quote Indicates whether the generated identifier should be quoted.
-     *                    By default, it is set to true.
-     *
-     * @return string The generated identifier.
-     * @throws RuntimeException If the input text is not a valid ASCII name or does not meet the naming convention requirements.
-     */
-    public function identifier(string $text, bool $quote = true): string
-    {
-        // table or column has to be valid ASCII name.
-        // this is opinionated, but we only allow [a-zA-Z0-9_] in column/table name.
-        if (!\preg_match('#\w#', $text)) {
-            throw new RuntimeException(
-                r("PDOAdapter: Invalid column/table '{ident}'. Column/table must be valid ASCII code.", [
-                    'ident' => $text
-                ])
-            );
-        }
-
-        // The first character cannot be [0-9]:
-        if (\preg_match('/^\d/', $text)) {
-            throw new RuntimeException(
-                r("PDOAdapter: Invalid column/table '{ident}'. Must begin with a letter or underscore.", [
-                        'ident' => $text
-                    ]
-                )
-            );
-        }
-
-        return !$quote ? $text : match ($this->driver) {
-            'mssql' => '[' . $text . ']',
-            'mysql' => '`' . $text . '`',
-            default => '"' . $text . '"',
-        };
-    }
-
-    /**
-     * Wraps the given callback function with a retry mechanism to handle database locks.
-     *
-     * @param Closure $callback The callback function to be executed.
-     *
-     * @return mixed The result of the callback function.
-     *
-     * @throws DBLayerException If an error occurs while executing the callback function.
-     * @throws RandomException If an error occurs while generating a random number.
-     */
-    private function wrap(Closure $callback): mixed
-    {
-        for ($i = 0; $i <= self::LOCK_RETRY; $i++) {
-            try {
-                return $callback($this);
-            } catch (PDOException $e) {
-                if (true === str_contains(strtolower($e->getMessage()), 'database is locked')) {
-                    if ($i >= self::LOCK_RETRY) {
-                        throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
-                            ->setInfo(
-                                ag($this->db->getLastStatement(), 'sql', ''),
-                                ag($this->db->getLastStatement(), 'bind', []),
-                                $e->errorInfo ?? [],
-                                $e->getCode()
-                            )
-                            ->setFile($e->getFile())
-                            ->setLine($e->getLine());
-                    }
-
-                    $sleep = self::LOCK_RETRY + random_int(1, 3);
-
-                    $this->logger->warning("PDOAdapter: Database is locked. sleeping for '{sleep}s'.", [
-                        'sleep' => $sleep
-                    ]);
-
-                    sleep($sleep);
-                } else {
-                    throw (new DBLayerException($e->getMessage(), (int)$e->getCode(), $e))
-                        ->setInfo(
-                            ag($this->db->getLastStatement(), 'sql', ''),
-                            ag($this->db->getLastStatement(), 'bind', []),
-                            $e->errorInfo ?? [],
-                            $e->getCode()
-                        )
-                        ->setFile($e->getFile())
-                        ->setLine($e->getLine());
-                }
-            }
-        }
-
-        return false;
-    }
 }
diff --git a/src/Libs/EnvFile.php b/src/Libs/EnvFile.php
index 9e6f88f3..c86655f2 100644
--- a/src/Libs/EnvFile.php
+++ b/src/Libs/EnvFile.php
@@ -28,6 +28,19 @@ final class EnvFile
         $this->data = parseEnvFile($this->file);
     }
 
+    /**
+     * Return a new instance of the class with the same file.
+     * This method will not flush the current data into new instance.
+     * You must call persist() method to save the data. before calling this method.
+     *
+     * @param bool $create
+     * @return self
+     */
+    public function newInstance(bool $create = false): self
+    {
+        return new self($this->file, create: $create);
+    }
+
     /**
      * Get the value of a configuration setting.
      *
diff --git a/src/Libs/Router.php b/src/Libs/Router.php
deleted file mode 100644
index 3b37d772..00000000
--- a/src/Libs/Router.php
+++ /dev/null
@@ -1,212 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace App\Libs;
-
-use App\Libs\Attributes\Route\Route;
-use FilesystemIterator;
-use InvalidArgumentException;
-use PhpToken;
-use RecursiveDirectoryIterator;
-use RecursiveIteratorIterator;
-use ReflectionAttribute;
-use ReflectionClass;
-use RuntimeException;
-use SplFileInfo;
-use Throwable;
-
-final readonly class Router
-{
-    /**
-     * @param array $dirs List of directories to scan for php files.
-     */
-    public function __construct(private array $dirs = [])
-    {
-    }
-
-    public function getDirs(): array
-    {
-        return $this->dirs;
-    }
-
-    public function generate(): array
-    {
-        $routes = [];
-
-        foreach ($this->dirs as $path) {
-            array_push($routes, ...$this->scanDirectory($path));
-        }
-
-        usort($routes, fn($a, $b) => strlen($a['path']) < strlen($b['path']) ? -1 : 1);
-
-        return $routes;
-    }
-
-    private function scanDirectory(string $dir): array
-    {
-        $classes = $routes = [];
-
-        /** @var array<SplFileInfo> $files */
-        $files = new RecursiveIteratorIterator(
-            new RecursiveDirectoryIterator($dir, FilesystemIterator::SKIP_DOTS)
-        );
-
-        foreach ($files as $file) {
-            if (!$file->isFile()) {
-                continue;
-            }
-
-            if (!$file->isReadable() || 'php' !== $file->getExtension()) {
-                continue;
-            }
-
-            $class = $this->parseFile((string)$file);
-
-            if (false === $class) {
-                continue;
-            }
-
-            array_push($classes, ...$class);
-        }
-
-        foreach ($classes as $className) {
-            if (!class_exists($className)) {
-                continue;
-            }
-
-            array_push($routes, ...$this->getRoutes(new ReflectionClass($className)));
-        }
-
-        return $routes;
-    }
-
-    protected function getRoutes(ReflectionClass $class): array
-    {
-        $routes = [];
-
-        $attributes = $class->getAttributes(Route::class, ReflectionAttribute::IS_INSTANCEOF);
-
-        $invokable = false;
-
-        foreach ($class->getMethods() as $method) {
-            if ($method->getName() === '__invoke') {
-                $invokable = true;
-            }
-        }
-
-        foreach ($attributes as $attribute) {
-            try {
-                $attributeClass = $attribute->newInstance();
-
-                if (!$attributeClass instanceof Route) {
-                    continue;
-                }
-            } catch (Throwable) {
-                continue;
-            }
-
-            if (false === $invokable && !$attributeClass->isCli) {
-                throw new InvalidArgumentException(
-                    r(
-                        'Trying to route \'{route}\' to un-invokable class/method \'{callable}\'.',
-                        [
-                            'route' => $attributeClass->pattern,
-                            'callable' => $class->getName()
-                        ]
-                    )
-                );
-            }
-
-            $routes[] = [
-                'path' => $attributeClass->pattern,
-                'method' => $attributeClass->methods,
-                'callable' => $class->getName(),
-                'host' => $attributeClass->host,
-                'middlewares' => $attributeClass->middleware,
-                'name' => $attributeClass->name,
-                'port' => $attributeClass->port,
-                'scheme' => $attributeClass->scheme,
-            ];
-        }
-
-        foreach ($class->getMethods() as $method) {
-            $attributes = $method->getAttributes(Route::class, ReflectionAttribute::IS_INSTANCEOF);
-
-            foreach ($attributes as $attribute) {
-                try {
-                    $attributeClass = $attribute->newInstance();
-                    if (!$attributeClass instanceof Route) {
-                        continue;
-                    }
-                } catch (Throwable) {
-                    continue;
-                }
-
-                $call = $method->getName() === '__invoke' ? $class->getName() : [$class->getName(), $method->getName()];
-
-                $routes[] = [
-                    'path' => $attributeClass->pattern,
-                    'method' => $attributeClass->methods,
-                    'callable' => $call,
-                    'host' => $attributeClass->host,
-                    'middlewares' => $attributeClass->middleware,
-                    'name' => $attributeClass->name,
-                    'port' => $attributeClass->port,
-                    'scheme' => $attributeClass->scheme,
-                ];
-            }
-        }
-
-        return $routes;
-    }
-
-    private function parseFile(string $file): array|false
-    {
-        $classes = [];
-        $namespace = '';
-
-        try {
-            $stream = new Stream($file, 'r');
-            $content = $stream->getContents();
-            $stream->close();
-        } catch (InvalidArgumentException $e) {
-            throw new RuntimeException(
-                r('Unable to read \'{file}\'. {error}', [
-                    'file' => $file,
-                    'error' => $e->getMessage(),
-                ])
-            );
-        }
-
-        $tokens = PhpToken::tokenize($content);
-        $count = count($tokens);
-
-        foreach ($tokens as $i => $iValue) {
-            if ($iValue->getTokenName() === 'T_NAMESPACE') {
-                for ($j = $i + 1; $j < $count; $j++) {
-                    if ($tokens[$j]->getTokenName() === 'T_NAME_QUALIFIED') {
-                        $namespace = $tokens[$j]->text;
-                        break;
-                    }
-                }
-            }
-
-            if ($iValue->getTokenName() === 'T_CLASS') {
-                for ($j = $i + 1; $j < $count; $j++) {
-                    if ($tokens[$j]->getTokenName() === 'T_WHITESPACE') {
-                        continue;
-                    }
-
-                    if ($tokens[$j]->getTokenName() === 'T_STRING') {
-                        $classes[] = $namespace . '\\' . $tokens[$j]->text;
-                    } else {
-                        break;
-                    }
-                }
-            }
-        }
-
-        return count($classes) >= 1 ? $classes : false;
-    }
-}
diff --git a/src/Libs/ServeStatic.php b/src/Libs/ServeStatic.php
index c1183c8f..c1157968 100644
--- a/src/Libs/ServeStatic.php
+++ b/src/Libs/ServeStatic.php
@@ -10,11 +10,15 @@ use League\Route\Http\Exception\BadRequestException;
 use League\Route\Http\Exception\NotFoundException;
 use Psr\Http\Message\ResponseInterface as iResponse;
 use Psr\Http\Message\ServerRequestInterface as iRequest;
+use Psr\Log\LoggerAwareInterface;
+use Psr\Log\LoggerAwareTrait;
 use SplFileInfo;
 use Throwable;
 
-final class ServeStatic
+final class ServeStatic implements LoggerAwareInterface
 {
+    use LoggerAwareTrait;
+
     private finfo|null $mimeType = null;
 
     private const array CONTENT_TYPE = [
@@ -39,7 +43,6 @@ final class ServeStatic
     private const array MD_IMAGES = [
         '/screenshots' => __DIR__ . '/../../',
     ];
-    private array $looked = [];
 
     public function __construct(private string|null $staticPath = null)
     {
@@ -59,8 +62,6 @@ final class ServeStatic
      */
     public function serve(iRequest $request): iResponse
     {
-        $requestPath = $request->getUri()->getPath();
-
         if (false === in_array($request->getMethod(), ['GET', 'HEAD', 'OPTIONS'])) {
             throw new BadRequestException(
                 message: r("Method '{method}' is not allowed.", ['method' => $request->getMethod()]),
@@ -68,6 +69,11 @@ final class ServeStatic
             );
         }
 
+        // -- as we alter the static path for .md files, we need to keep the original path
+        // -- do not mutate the original path. as it may be used in other requests.
+        $staticPath = $this->staticPath;
+        $requestPath = $request->getUri()->getPath();
+
         if (array_key_exists($requestPath, self::MD_FILES)) {
             return $this->serveFile($request, new SplFileInfo(self::MD_FILES[$requestPath]));
         }
@@ -75,44 +81,36 @@ final class ServeStatic
         // -- check if the request path is in the MD_IMAGES array
         foreach (self::MD_IMAGES as $key => $value) {
             if (str_starts_with($requestPath, $key)) {
-                $this->staticPath = realpath($value);
+                $staticPath = realpath($value);
                 break;
             }
         }
 
-        $filePath = fixPath($this->staticPath . $requestPath);
+        if (false === ($realBasePath = realpath($staticPath))) {
+            throw new BadRequestException(
+                message: r("The static path '{path}' doesn't exists.", ['path' => $staticPath]),
+                code: Status::SERVICE_UNAVAILABLE->value
+            );
+        }
 
+        $filePath = fixPath($staticPath . $requestPath);
         if (is_dir($filePath)) {
             $filePath = $filePath . '/index.html';
         }
 
         if (!file_exists($filePath)) {
-            $checkIndex = $this->deepIndexLookup($this->staticPath, $requestPath);
-            if (!file_exists($checkIndex)) {
-                throw new NotFoundException(
-                    message: r(
-                        "File '{file}' is not found. {checkIndex} {looked}",
-                        [
-                            'file' => $requestPath,
-                            'checkIndex' => $checkIndex,
-                            'looked' => $this->looked,
-                        ]
-                    ),
-                    code: Status::NOT_FOUND->value
-                );
+            $this->logger?->debug("File '{file}' is not found.", ['file' => $filePath]);
+            $checkIndex = fixPath($staticPath . $this->deepIndexLookup($staticPath, $requestPath));
+            if (false === file_exists($checkIndex) || false === is_file($checkIndex)) {
+                throw new NotFoundException(r("Path '{file}' is not found.", [
+                    'file' => $requestPath,
+                ]), code: Status::NOT_FOUND->value);
             }
             $filePath = $checkIndex;
         }
 
-        if (false === ($realBasePath = realpath($this->staticPath))) {
-            throw new BadRequestException(
-                message: r("The static path '{path}' doesn't exists.", ['path' => $this->staticPath]),
-                code: Status::SERVICE_UNAVAILABLE->value
-            );
-        }
 
         $filePath = realpath($filePath);
-
         if (false === $filePath || false === str_starts_with($filePath, $realBasePath)) {
             throw new BadRequestException(
                 message: r("Request '{file}' is invalid.", ['file' => $requestPath]),
@@ -183,23 +181,21 @@ final class ServeStatic
         // -- paths may look like /parent/id/child, do a deep lookup for index.html at each level
         // return the first index.html found
         $path = fixPath($path);
-
-        if ('/' === $path) {
+        if ('/' === $path || empty($path)) {
             return $path;
         }
 
         $paths = explode('/', $path);
         $count = count($paths);
-        if ($count < 2) {
+        $index = $count - 1;
+
+        if ($index < 2) {
             return $path;
         }
 
-        $index = $count - 1;
-
         for ($i = $index; $i > 0; $i--) {
-            $check = $base . implode('/', array_slice($paths, 0, $i)) . '/index.html';
-            $this->looked[] = $check;
-            if (file_exists($check)) {
+            $check = implode('/', array_slice($paths, 0, $i)) . '/index.html';
+            if (file_exists($base . $check)) {
                 return $check;
             }
         }
diff --git a/src/Libs/Server.php b/src/Libs/Server.php
index 418ad15f..55ebf538 100644
--- a/src/Libs/Server.php
+++ b/src/Libs/Server.php
@@ -16,13 +16,13 @@ use Symfony\Component\Process\Process;
  */
 final class Server
 {
-    public const CONFIG_HOST = 'host';
-    public const CONFIG_PORT = 'port';
-    public const CONFIG_ROOT = 'root';
-    public const CONFIG_PHP = 'php';
-    public const CONFIG_ENV = 'env';
-    public const CONFIG_ROUTER = 'router';
-    public const CONFIG_THREADS = 'threads';
+    public const string CONFIG_HOST = 'host';
+    public const string CONFIG_PORT = 'port';
+    public const string CONFIG_ROOT = 'root';
+    public const string CONFIG_PHP = 'php';
+    public const string CONFIG_ENV = 'env';
+    public const string CONFIG_ROUTER = 'router';
+    public const string CONFIG_THREADS = 'threads';
 
     /**
      * @var array $config The configuration settings for the server
diff --git a/src/Libs/TestCase.php b/src/Libs/TestCase.php
index 8ee72f26..80a3df94 100644
--- a/src/Libs/TestCase.php
+++ b/src/Libs/TestCase.php
@@ -36,6 +36,7 @@ class TestCase extends \PHPUnit\Framework\TestCase
      * @param Throwable|string $exception Expected exception class
      * @param string $exceptionMessage (optional) Exception message
      * @param int|null $exceptionCode (optional) Exception code
+     * @param callable{ TestCase, Throwable}|null $callback (optional) Custom callback to handle the exception
      * @return void
      */
     protected function checkException(
@@ -44,6 +45,7 @@ class TestCase extends \PHPUnit\Framework\TestCase
         Throwable|string $exception,
         string $exceptionMessage = '',
         int|null $exceptionCode = null,
+        callable $callback = null,
     ): void {
         $caught = null;
         try {
@@ -51,13 +53,17 @@ class TestCase extends \PHPUnit\Framework\TestCase
         } catch (Throwable $e) {
             $caught = $e;
         } finally {
+            if (null !== $callback) {
+                $callback($this, $caught);
+                return;
+            }
             if (null === $caught) {
-                $this->fail($reason);
+                $this->fail('No exception was thrown. ' . $reason);
             } else {
                 $this->assertInstanceOf(
                     is_object($exception) ? $exception::class : $exception,
                     $caught,
-                    $reason
+                    $reason . ' ' . $caught->getMessage(),
                 );
                 if (!empty($exceptionMessage)) {
                     $this->assertStringContainsString($exceptionMessage, $caught->getMessage(), $reason);
diff --git a/src/Libs/helpers.php b/src/Libs/helpers.php
index 56732ace..7ca7205a 100644
--- a/src/Libs/helpers.php
+++ b/src/Libs/helpers.php
@@ -7,6 +7,8 @@ use App\Backends\Common\Cache as BackendCache;
 use App\Backends\Common\ClientInterface as iClient;
 use App\Backends\Common\Context;
 use App\Libs\APIResponse;
+use App\Libs\Attributes\Route\Cli;
+use App\Libs\Attributes\Route\Route;
 use App\Libs\Attributes\Scanner\Attributes as AttributesScanner;
 use App\Libs\Attributes\Scanner\Item as ScannerItem;
 use App\Libs\Config;
@@ -27,7 +29,6 @@ use App\Libs\Guid;
 use App\Libs\Initializer;
 use App\Libs\Options;
 use App\Libs\Response;
-use App\Libs\Router;
 use App\Libs\Stream;
 use App\Libs\Uri;
 use App\Listeners\ProcessPushEvent;
@@ -1021,29 +1022,53 @@ if (false === function_exists('generateRoutes')) {
      */
     function generateRoutes(string $type = 'cli', array $opts = []): array
     {
-        $dirs = [__DIR__ . '/../Commands'];
-        foreach (array_keys(Config::get('supported', [])) as $backend) {
-            $dir = r(__DIR__ . '/../Backends/{backend}/Commands', ['backend' => ucfirst($backend)]);
-
-            if (!file_exists($dir)) {
-                continue;
-            }
-
-            $dirs[] = $dir;
-        }
-
-        $routes_cli = (new Router($dirs))->generate();
-
         $cache = $opts[iCache::class] ?? Container::get(iCache::class);
 
+        $routes_cli = $routes_http = [];
+
         try {
+            $dirs = [__DIR__ . '/../Commands'];
+            foreach (array_keys(Config::get('supported', [])) as $backend) {
+                $dir = r(__DIR__ . '/../Backends/{backend}/Commands', ['backend' => ucfirst($backend)]);
+
+                if (!file_exists($dir)) {
+                    continue;
+                }
+
+                $dirs[] = $dir;
+            }
+            foreach (AttributesScanner::scan($dirs, allowNonInvokable: true)->for(Cli::class) as $item) {
+                $routes_cli[] = [
+                    'callable' => $item->getCallable(),
+                    'path' => ag($item->data, 'pattern'),
+                    'method' => ag($item->data, 'methods'),
+                    'middleware' => ag($item->data, 'middleware'),
+                    'host' => ag($item->data, 'host'),
+                    'name' => ag($item->data, 'name'),
+                    'port' => ag($item->data, 'port'),
+                    'scheme' => ag($item->data, 'scheme'),
+                ];
+            }
+
             $cache->set('routes_cli', $routes_cli, new DateInterval('PT1H'));
         } catch (\Psr\SimpleCache\InvalidArgumentException) {
         }
 
-        $routes_http = (new Router([__DIR__ . '/../API']))->generate();
-
         try {
+            $dirs = [__DIR__ . '/../API'];
+            foreach (AttributesScanner::scan($dirs, allowNonInvokable: false)->for(Route::class) as $item) {
+                $routes_http[] = [
+                    'callable' => $item->getCallable(),
+                    'path' => ag($item->data, 'pattern'),
+                    'method' => ag($item->data, 'methods'),
+                    'middleware' => ag($item->data, 'middleware'),
+                    'host' => ag($item->data, 'host'),
+                    'name' => ag($item->data, 'name'),
+                    'port' => ag($item->data, 'port'),
+                    'scheme' => ag($item->data, 'scheme'),
+                ];
+            }
+
             $cache->set('routes_http', $routes_http, new DateInterval('P1D'));
         } catch (\Psr\SimpleCache\InvalidArgumentException) {
         }
diff --git a/src/Model/Base/Traits/UsesBasicRepository.php b/src/Model/Base/Traits/UsesBasicRepository.php
index 934f116f..9096d176 100644
--- a/src/Model/Base/Traits/UsesBasicRepository.php
+++ b/src/Model/Base/Traits/UsesBasicRepository.php
@@ -15,13 +15,9 @@ trait UsesBasicRepository
 {
     use UsesPaging;
 
-    protected DBLayer $db;
-
-    public function __construct(DBLayer $db)
+    public function __construct(private readonly DBLayer $db)
     {
-        $this->init($db);
-
-        $this->db = $db;
+        $this->init($this->db);
 
         if (empty($this->table)) {
             throw new RuntimeException('You must set table name in $this->table');
diff --git a/tests/Database/DBLayerTest.php b/tests/Database/DBLayerTest.php
new file mode 100644
index 00000000..f6f9ba43
--- /dev/null
+++ b/tests/Database/DBLayerTest.php
@@ -0,0 +1,646 @@
+<?php
+/** @noinspection SqlResolve, SqlWithoutWhere */
+
+declare(strict_types=1);
+
+namespace Tests\Database;
+
+use App\Libs\Config;
+use App\Libs\Database\DBLayer;
+use App\Libs\Database\PDO\PDOAdapter;
+use App\Libs\Exceptions\DBLayerException;
+use App\Libs\Exceptions\ErrorException;
+use App\Libs\Exceptions\RuntimeException;
+use App\Libs\Guid;
+use App\Libs\TestCase;
+use Monolog\Handler\TestHandler;
+use Monolog\Logger;
+use PDO;
+use PDOException;
+use Throwable;
+use TypeError;
+
+class DBLayerTest extends TestCase
+{
+    private DBLayer|null $db = null;
+    protected TestHandler|null $handler = null;
+
+    private function createDB(PDO $pdo): void
+    {
+        $pdo->exec('DROP TABLE IF EXISTS "test"');
+        $pdo->exec(
+            <<<SQL
+            CREATE TABLE "test" (
+                "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+                "name" TEXT NULL,
+                "watched" INTEGER NULL DEFAULT 0,
+                "added_at" INTEGER NULL,
+                "updated_at" INTEGER NULL,
+                "json_data" JSON NULL,
+                "nullable" TEXT NULL
+            )
+        SQL
+        );
+        $pdo->exec('DROP TABLE IF EXISTS "fts_table"');
+        $pdo->exec('CREATE VIRTUAL TABLE "fts_table" USING fts5( name, json_data);');
+    }
+
+    public function setUp(): void
+    {
+        $this->handler = new TestHandler();
+        $logger = new Logger('logger');
+        $logger->pushHandler($this->handler);
+        Guid::setLogger($logger);
+
+        if (null === Config::get('database', null)) {
+            Config::init([
+                'database' => ag(require __DIR__ . '/../../config/config.php', 'database', [])
+            ]);
+        }
+
+        $this->db = new DBLayer(new PDO(dsn: 'sqlite::memory:', options: Config::get('database.options', [])));
+        $this->createDB($this->db->getBackend());
+
+        foreach (Config::get('database.exec', []) as $cmd) {
+            $this->db->exec($cmd);
+        }
+    }
+
+    public function test_exec()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->exec('SELECT * FROM movies'),
+            reason: 'Should throw an exception when an error occurs and no on_failure handler is set.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'no such table',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->exec(
+                sql: 'SELECT * FROM movies',
+                options: ['on_failure' => fn(Throwable $e) => throw new ErrorException('Error occurred')]
+            ),
+            reason: 'the on_failure handler should be called when an error occurs.',
+            exception: ErrorException::class,
+            exceptionMessage: 'Error occurred',
+        );
+
+        $this->assertSame(0, $this->db->exec('DELETE FROM test'));
+    }
+
+    public function test_query()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->query(sql: 'SELECT * FROM movies'),
+            reason: 'Should throw an exception when an error occurs and no on_failure handler is set.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'no such table',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->query(
+                sql: 'SELECT * FROM movies',
+                options: ['on_failure' => fn(Throwable $e) => throw new ErrorException('Error occurred')]
+            ),
+            reason: 'the on_failure handler should be called when an error occurs.',
+            exception: ErrorException::class,
+            exceptionMessage: 'Error occurred',
+        );
+
+        $this->checkException(
+            closure: function () {
+                $options = Config::get('database.options', []);
+                $options[PDO::ATTR_ERRMODE] = PDO::ERRMODE_SILENT;
+
+                $pdo = new PDO(dsn: 'sqlite::memory:', options: $options);
+                $db = new DBLayer($pdo);
+
+                foreach (Config::get('database.exec', []) as $cmd) {
+                    $this->db->exec($cmd);
+                }
+
+                (new PDOAdapter(new Logger('test'), $this->db))->migrations('up');
+
+                return $db->query(sql: 'SELECT * FROM test WHERE zid = :id');
+            },
+            reason: 'If PDO error mode is set to silent mode, failing to prepare a statement should still throw an exception.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'Unable to prepare statement.',
+        );
+    }
+
+    public function test_transactions_operations()
+    {
+        $this->db->start();
+        $this->assertTrue($this->db->inTransaction(), 'Should be in transaction.');
+        $this->assertFalse($this->db->start(), 'Should not start a new transaction if we are already in one.');
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        $this->assertSame('1', $this->db->lastInsertId(), 'Should return last insert id.');
+        $this->db->rollBack();
+        $this->assertFalse($this->db->inTransaction(), 'Should not be in transaction.');
+
+        $this->db->start();
+        $this->assertCount(
+            0,
+            $this->db->select('sqlite_sequence')->fetchAll(),
+            'Should not have any records, as we rolled back.'
+        );
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        $this->assertSame('1', $this->db->lastInsertId(), 'Should return last insert id.');
+        $this->db->commit();
+        $this->assertFalse($this->db->inTransaction(), 'Should not be in transaction.');
+        $this->assertCount(
+            1,
+            $this->db->select('sqlite_sequence')->fetchAll(),
+            'Should have one record, as we committed.'
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->transactional(function (DBLayer $db) {
+                $this->db->insert('sqlite_sequence', ['name' => 'test2', 'seq' => 1]);
+                $db->insert('not_set', ['name' => 'test', 'seq' => 1]);
+            }),
+            reason: 'Should throw an exception when trying to commit without starting a transaction.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'no such table',
+        );
+
+        $this->assertCount(
+            1,
+            $this->db->select('sqlite_sequence')->fetchAll(),
+            'Should have one record, as the previous transaction was rolled back.'
+        );
+
+        $ret = $this->db->transactional(function (DBLayer $db) {
+            return $db->insert('sqlite_sequence', ['name' => 'test2', 'seq' => 1]);
+        });
+
+        $this->assertSame(1, $ret->rowCount(), 'Should return the number of affected rows.');
+    }
+
+    public function test_insert()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->insert('test', []),
+            reason: 'Should throw exception if conditions parameter is empty.',
+            exception: RuntimeException::class
+        );
+    }
+
+    public function test_delete()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->delete('test', []),
+            reason: 'Should throw exception if conditions parameter is empty.',
+            exception: RuntimeException::class
+        );
+
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        try {
+            $this->assertSame(
+                1,
+                $this->db->delete('sqlite_sequence', ['name' => 'test'], options: [
+                    'limit' => 1,
+                    'ignore_safety' => true
+                ])->rowCount(),
+                'Should return the number of affected rows.'
+            );
+        } catch (DBLayerException $e) {
+            if (str_contains($e->getMessage(), 'near "LIMIT": syntax error') && 'sqlite' === $this->db->getDriver()) {
+                $this->assertSame(
+                    1,
+                    $this->db->delete('sqlite_sequence', ['name' => 'test'])->rowCount(),
+                    'Should return the number of affected rows.'
+                );
+            } else {
+                throw $e;
+            }
+        }
+    }
+
+    public function test_getCount()
+    {
+        $this->assertSame(
+            0,
+            $this->db->getCount('sqlite_sequence'),
+            'Should return the number of records in the table.'
+        );
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        $total = $this->db->getCount('sqlite_sequence', [
+            'seq' => [DBLayer::IS_HIGHER_THAN_OR_EQUAL, 1]
+        ], options: [
+            'groupby' => ['name'],
+            'orderby' => ['name' => 'ASC'],
+        ]);
+        $this->assertSame(1, $total, 'Should return the number of records in the table.');
+        $this->assertSame($total, $this->db->totalRows(), 'Should return the number of records in the table.');
+
+        $this->db->delete('sqlite_sequence', ['name' => 'test']);
+        $this->assertSame(
+            0,
+            $this->db->getCount('sqlite_sequence'),
+            'Should return the number of records in the table.'
+        );
+    }
+
+    public function test_update()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->update('test', [], ['id' => 1]),
+            reason: 'Should throw exception if conditions parameter is empty.',
+            exception: RuntimeException::class
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->update('test', ['name' => 'test'], []),
+            reason: 'Should throw exception if conditions parameter is empty.',
+            exception: RuntimeException::class
+        );
+
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        $this->assertSame(
+            1,
+            $this->db->update('sqlite_sequence', ['seq' => 2], ['name' => 'test'])->rowCount(),
+            'Should return the number of affected rows.'
+        );
+        try {
+            $this->assertSame(
+                1,
+                $this->db->update('sqlite_sequence', ['seq' => 1], ['name' => 'test'], options: [
+                    'limit' => 1,
+                    'ignore_safety' => true
+                ])->rowCount(),
+                'Should return the number of affected rows.'
+            );
+        } catch (DBLayerException $e) {
+            if (str_contains($e->getMessage(), 'near "LIMIT": syntax error') && 'sqlite' === $this->db->getDriver()) {
+                $this->assertSame(
+                    1,
+                    $this->db->update('sqlite_sequence', ['seq' => 1], ['name' => 'test'])->rowCount(),
+                    'Should return the number of affected rows.'
+                );
+            } else {
+                throw $e;
+            }
+        }
+    }
+
+    public function test_quote()
+    {
+        if ('sqlite' === $this->db->getDriver()) {
+            $this->assertEquals("'test'", $this->db->quote('test'), "Should return 'test'.");
+            $this->assertSame("'''test'''", $this->db->quote("'test'"), "Should return ''''test''''.");
+            $this->assertSame("'\"test\"'", $this->db->quote('"test"'), "Should return '\"test\"'.");
+        }
+    }
+
+    public function test_id()
+    {
+        $this->db->insert('sqlite_sequence', ['name' => 'test', 'seq' => 1]);
+        $this->assertSame('1', $this->db->id('test'), 'Should return the last insert id.');
+        $this->assertSame('1', $this->db->id(), 'Should return the last insert id.');
+    }
+
+    public function test_escapeIdentifier()
+    {
+        $this->checkException(
+            closure: fn() => $this->db->escapeIdentifier(''),
+            reason: 'Should throw exception if the identifier is empty.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'Column/table must be valid ASCII code'
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->escapeIdentifier('😊'),
+            reason: 'Should throw exception if the identifier contains non-ASCII characters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'Column/table must be valid ASCII code.'
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->escapeIdentifier('1foo'),
+            reason: 'Should throw exception if the identifier contains non-ASCII characters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'Must begin with a letter or underscore'
+        );
+
+        $this->assertSame('foo', $this->db->escapeIdentifier('foo'), 'Should return foo if quote is off.');
+
+        if ('sqlite' === $this->db->getDriver()) {
+            $this->assertSame('"foo"', $this->db->escapeIdentifier('foo', true), 'Should return "foo".');
+            $this->assertSame(
+                '""foo"."bar""',
+                $this->db->escapeIdentifier('"foo"."bar"', true),
+                'Should return ""foo"."bar"".'
+            );
+        }
+    }
+
+    public function test_getBackend()
+    {
+        $this->assertInstanceOf(PDO::class, $this->db->getBackend(), 'Should return the PDO instance.');
+    }
+
+    public function test_select()
+    {
+        $this->db->insert('test', [
+            'name' => 'test',
+            'watched' => 1,
+            'added_at' => 1,
+            'updated_at' => 2,
+            'json_data' => json_encode([
+                'my_id' => 1,
+                'my_name' => 'test',
+                'my_data' => [
+                    'my_id' => 1,
+                    'my_name' => 'test',
+                ],
+            ]),
+        ]);
+
+        $this->db->insert('test', [
+            'name' => 'test2',
+            'watched' => 0,
+            'added_at' => 3,
+            'updated_at' => 4,
+            'json_data' => json_encode([
+                'my_id' => 2,
+                'my_name' => 'test2',
+                'my_data' => [
+                    'my_id' => 2,
+                    'my_name' => 'test2',
+                ],
+            ]),
+        ]);
+
+        $data1 = $this->db->select('test', [], ['id' => 1])->fetch();
+        $data2 = $this->db->select('test', [], ['id' => 2])->fetch();
+
+        $this->checkException(
+            closure: fn() => $this->db->select('test', ['id' => 1], ['id' => 1]),
+            reason: 'Should throw TypeError exception if cols value is not a string.',
+            exception: TypeError::class,
+            exceptionMessage: 'must be of type string',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('test', ['*'], ['id'], options: ['count' => true]),
+            reason: 'Should throw exception if conditions parameter is not an key/value pairs.',
+            exception: TypeError::class,
+            exceptionMessage: 'must be of type string',
+        );
+
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], ['id' => 1])->fetch(),
+            'Should return the record with id 1.'
+        );
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], ['id' => 2])->fetch(),
+            'Should return the record with id 2.'
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], ['id' => 2], options: [
+                'orderby' => ['id' => 'DESC'],
+                'limit' => 1,
+                'start' => 0,
+                'groupby' => ['id'],
+            ])->fetch(),
+            'Should return the record with id 2.'
+        );
+    }
+
+    public function test_lock_retry()
+    {
+        /** @noinspection PhpUnhandledExceptionInspection */
+        $random = random_int(1, 100);
+
+        $this->db->transactional(function (DBLayer $db, array $options = []) use ($random) {
+            // -- trigger database lock exception
+            if ((int)ag($options, 'attempts', 0) < 1) {
+                throw new PDOException('database is locked');
+            }
+
+            $db->insert('sqlite_sequence', ['name' => 'test-' . $random, 'seq' => 1]);
+        }, options: [
+            'max_sleep' => 0,
+        ]);
+
+        $this->assertSame(1, $this->db->getCount('sqlite_sequence', ['name' => 'test-' . $random]));
+
+        $this->checkException(
+            closure: function () use ($random) {
+                $this->db->transactional(fn() => throw new PDOException('database is locked'), options: [
+                    'max_sleep' => 0,
+                    'max_attempts' => 1,
+                ]);
+            },
+            reason: 'Should throw an exception when the maximum number of attempts is reached.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'database is locked',
+        );
+        $this->checkException(
+            closure: function () use ($random) {
+                $this->db->transactional(fn() => throw new PDOException('database is locked'), options: [
+                    'max_sleep' => 0,
+                    'max_attempts' => 1,
+                    'on_lock' => fn() => throw new DBLayerException('on_lock called'),
+                ]);
+            },
+            reason: 'Should throw an exception when the maximum number of attempts is reached.',
+            exception: DBLayerException::class,
+            exceptionMessage: 'on_lock called',
+        );
+    }
+
+    public function test_condition_parser()
+    {
+        $this->db->insert('test', [
+            'name' => 'test',
+            'watched' => 1,
+            'added_at' => 1,
+            'updated_at' => 2,
+            'json_data' => json_encode([
+                'my_id' => 1,
+                'my_name' => 'test',
+                'my_data' => [
+                    'my_id' => 1,
+                    'my_name' => 'test',
+                ],
+            ]),
+        ]);
+
+        $this->db->insert('test', [
+            'name' => 'test2',
+            'watched' => 0,
+            'added_at' => 3,
+            'updated_at' => 4,
+            'json_data' => json_encode([
+                'my_id' => 2,
+                'my_name' => 'test2',
+                'my_data' => [
+                    'my_id' => 2,
+                    'my_name' => 'test2',
+                ],
+            ]),
+        ]);
+
+
+        $data1 = $this->db->select('test', [], ['id' => 1])->fetch();
+        $data2 = $this->db->select('test', [], ['id' => 2])->fetch();
+
+        $this->db->insert('fts_table', ['name' => $data1['name'], 'json_data' => $data1['json_data']]);
+        $this->db->insert('fts_table', ['name' => $data2['name'], 'json_data' => $data2['json_data']]);
+
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], [
+                'id' => [DBLayer::IS_LOWER_THAN_OR_EQUAL, 1],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], [
+                'id' => [DBLayer::IS_HIGHER_THAN_OR_EQUAL, 2],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], [
+                'added_at' => [DBLayer::IS_BETWEEN, [1, 2]],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], [
+                'added_at' => [DBLayer::IS_NOT_BETWEEN, [1, 2]],
+            ])->fetch(),
+            'Should return the record with id 2.'
+        );
+
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], [
+                'nullable' => [DBLayer::IS_NULL],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], [
+                'name' => [DBLayer::IS_LIKE, 'test2'],
+            ])->fetch(),
+            'Should return the record with id 2.'
+        );
+
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], [
+                'name' => [DBLayer::IS_NOT_LIKE, 'test2'],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+        $this->assertSame(
+            $data1,
+            $this->db->select('test', [], [
+                'id' => [DBLayer::IS_IN, [0, 1]],
+            ])->fetch(),
+            'Should return the record with id 1.'
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], [
+                'id' => [DBLayer::IS_NOT_IN, [0, 1]],
+            ])->fetch(),
+            'Should return the record with id 2.'
+        );
+
+        try {
+            $this->assertSame(
+                $data2,
+                $this->db->select('test', [], ['json_data' => [DBLayer::IS_JSON_CONTAINS, '$.my_id', 2],])->fetch(),
+                'Should return the record with id 1.'
+            );
+        } catch (DBLayerException $e) {
+            if (str_contains($e->getMessage(), 'no such function') && 'sqlite' === $this->db->getDriver()) {
+                // -- pass as sqlite does not support json_contains
+            } else {
+                throw $e;
+            }
+        }
+
+        $this->checkException(
+            closure: fn() => $this->db->select('test', [], ['json_data' => [DBLayer::IS_JSON_CONTAINS, '$.my_id'],]
+            )->fetch(),
+            reason: 'Should throw an exception when json_contains receives less then expected parameters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'IS_JSON_CONTAINS: expects 2',
+        );
+
+        $this->assertSame(
+            $data2,
+            $this->db->select('test', [], ['json_data' => [DBLayer::IS_JSON_EXTRACT, '$.my_id', '>', 1]])->fetch(),
+            'Should return the record with id 2.'
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('test', [], ['json_data' => [DBLayer::IS_JSON_EXTRACT, '$.my_id', '>']]),
+            reason: 'Should throw an exception when json_extract receives less then expected parameters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'IS_JSON_EXTRACT: expects 3',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('test', [], ['json_data' => ['NOT_SET', '$.my_id', '>']]),
+            reason: 'Should throw exception on unknown operator.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'expr not implemented',
+        );
+
+        $this->assertSame(
+            'test',
+            $this->db->select('fts_table', [], [
+                'name' => [DBLayer::IS_MATCH_AGAINST, ['name'], 'test'],
+            ])->fetch()['name'],
+            'Should return the record with id 2.'
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('fts_table', [], [
+                'name' => [DBLayer::IS_MATCH_AGAINST, ['name']],
+            ])->fetch(),
+            reason: 'Should throw an exception when match against receives less then expected parameters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'IS_MATCH_AGAINST: expects 2',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('fts_table', [], [
+                'name' => [DBLayer::IS_MATCH_AGAINST, 'name', 'test'],
+            ])->fetch(),
+            reason: 'Should throw an exception when match against receives less then expected parameters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'IS_MATCH_AGAINST: expects parameter 1 to be array',
+        );
+
+        $this->checkException(
+            closure: fn() => $this->db->select('fts_table', [], [
+                'name' => [DBLayer::IS_MATCH_AGAINST, ['name'], ['test']],
+            ])->fetch(),
+            reason: 'Should throw an exception when match against receives less then expected parameters.',
+            exception: RuntimeException::class,
+            exceptionMessage: 'IS_MATCH_AGAINST: expects parameter 2 to be string',
+        );
+    }
+
+}
diff --git a/tests/Database/PDOAdapterTest.php b/tests/Database/PDOAdapterTest.php
index 3c09b9c0..ae1158d7 100644
--- a/tests/Database/PDOAdapterTest.php
+++ b/tests/Database/PDOAdapterTest.php
@@ -1,24 +1,25 @@
 <?php
-/** @noinspection PhpUnhandledExceptionInspection */
 
 declare(strict_types=1);
 
 namespace Tests\Database;
 
+use App\Libs\Config;
+use App\Libs\Container;
 use App\Libs\Database\DatabaseInterface as iDB;
 use App\Libs\Database\DBLayer;
 use App\Libs\Database\PDO\PDOAdapter;
 use App\Libs\Entity\StateEntity;
-use App\Libs\Entity\StateInterface;
+use App\Libs\Entity\StateInterface as iState;
 use App\Libs\Exceptions\DBAdapterException as DBException;
 use App\Libs\Guid;
+use App\Libs\Options;
 use App\Libs\TestCase;
 use DateTimeImmutable;
 use Error;
 use Monolog\Handler\TestHandler;
 use Monolog\Logger;
 use PDO;
-use Random\RandomException;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\NullOutput;
@@ -48,32 +49,81 @@ class PDOAdapterTest extends TestCase
         Guid::setLogger($logger);
 
         $this->db = new PDOAdapter($logger, new DBLayer(new PDO('sqlite::memory:')));
+        $this->db->setOptions([
+            Options::DEBUG_TRACE => true,
+            'class' => new StateEntity([]),
+        ]);
+        $this->db->setLogger($logger);
         $this->db->migrations('up');
     }
 
     public function test_insert_throw_exception_if_has_id(): void
     {
-        $this->expectException(DBException::class);
-        $this->expectExceptionCode(21);
-        $item = new StateEntity($this->testEpisode);
-        $this->db->insert($item);
-        $this->db->insert($item);
+        $this->checkException(
+            closure: function () {
+                $item = new StateEntity($this->testEpisode);
+                $this->db->insert($item);
+                $this->db->insert($item);
+            },
+            reason: 'When inserting item with id, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'primary key already defined',
+            exceptionCode: 21,
+        );
+    }
+
+    public function test_insert_conditions(): void
+    {
+        $this->checkException(
+            closure: function () {
+                $item = new StateEntity($this->testEpisode);
+                $item->type = 'invalid';
+                $this->db->insert($item);
+            },
+            reason: 'When inserting item with id, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'Unexpected content type',
+            exceptionCode: 22,
+        );
+        $this->checkException(
+            closure: function () {
+                $item = new StateEntity($this->testEpisode);
+                $item->episode = 0;
+                $this->db->insert($item);
+            },
+            reason: 'When inserting episode item with episode number 0, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'Unexpected episode number',
+        );
     }
 
     public function test_insert_successful(): void
     {
-        $item = $this->db->insert(new StateEntity($this->testEpisode));
+        $item = new StateEntity($this->testEpisode);
+        $item->created_at = 0;
+        $item->updated_at = 0;
+        $item->watched = 0;
+
+        $item = $this->db->insert($item);
         $this->assertSame(1, $item->id, 'When inserting new item, id is set to 1 when db is empty.');
+
+        $item = new StateEntity($this->testMovie);
+        $item->created_at = 0;
+        $item->updated_at = 0;
+        $item->watched = 0;
+        $item->setMetadata([
+            iState::COLUMN_META_DATA_PLAYED_AT => null,
+        ]);
+
+        $item = $this->db->insert($item);
+        $this->assertSame(2, $item->id, 'When inserting new item, id is set to 1 when db is empty.');
     }
 
-    /**
-     * @throws RandomException
-     */
     public function test_get_conditions(): void
     {
         $test = $this->testEpisode;
 
-        foreach (StateInterface::ENTITY_ARRAY_KEYS as $key) {
+        foreach (iState::ENTITY_ARRAY_KEYS as $key) {
             if (null === ($test[$key] ?? null)) {
                 continue;
             }
@@ -104,9 +154,13 @@ class PDOAdapterTest extends TestCase
 
     public function test_getAll_call_without_initialized_container(): void
     {
-        $this->expectException(Error::class);
-        $this->expectExceptionMessage('Call to a member function');
-        $this->db->getAll();
+        $this->db->setOptions(['class' => null]);
+        $this->checkException(
+            closure: fn() => $this->db->getAll(),
+            reason: 'When calling getAll without initialized container, an exception should be thrown.',
+            exception: Error::class,
+            exceptionMessage: 'Call to a member function',
+        );
     }
 
     public function test_getAll_conditions(): void
@@ -133,20 +187,34 @@ class PDOAdapterTest extends TestCase
         );
     }
 
-    public function test_update_call_without_id_exception(): void
+    public function test_update_fail_conditions(): void
     {
-        $this->expectException(DBException::class);
-        $this->expectExceptionCode(51);
-        $item = new StateEntity($this->testEpisode);
+        $this->checkException(
+            closure: fn() => $this->db->update(new StateEntity($this->testEpisode)),
+            reason: 'When updating item without id, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'without primary key',
+            exceptionCode: 51,
+        );
 
-        $this->db->update($item);
+        $this->checkException(
+            closure: function () {
+                $item = new StateEntity($this->testEpisode);
+                $this->db->insert($item);
+                $item->episode = 0;
+                $this->db->update($item);
+            },
+            reason: 'When inserting episode item with episode number 0, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'Unexpected episode number',
+        );
     }
 
     public function test_update_conditions(): void
     {
         $test = $this->testEpisode;
 
-        foreach (StateInterface::ENTITY_ARRAY_KEYS as $key) {
+        foreach (iState::ENTITY_ARRAY_KEYS as $key) {
             if (null === ($test[$key] ?? null)) {
                 continue;
             }
@@ -161,12 +229,23 @@ class PDOAdapterTest extends TestCase
         $this->assertSame($item, $updatedItem, 'When updating item, same object is returned.');
 
         $r = $this->db->get($item)->getAll();
-        $updatedItem->updated_at = $r[StateInterface::COLUMN_UPDATED_AT];
+        $updatedItem->updated_at = $r[iState::COLUMN_UPDATED_AT];
         $this->assertSame(
             $updatedItem->getAll(),
             $r,
             'When updating item, getAll should return same values as the recorded item.'
         );
+
+        $updatedItem->watched = 0;
+        $item->setMetadata([
+            iState::COLUMN_META_DATA_PLAYED_AT => null,
+        ]);
+        $item = $this->db->update($item);
+
+        $this->assertNull(
+            ag($item->getMetadata($item->via), iState::COLUMN_META_DATA_PLAYED_AT),
+            'When watched flag is set to 0, played_at metadata should be null.'
+        );
     }
 
     public function test_remove_conditions(): void
@@ -185,7 +264,7 @@ class PDOAdapterTest extends TestCase
             'When db is not empty, remove returns true if record removed.'
         );
         $this->assertInstanceOf(
-            StateInterface::class,
+            iState::class,
             $this->db->get($item2),
             'When Record exists an instance of StateInterface is returned.'
         );
@@ -205,6 +284,13 @@ class PDOAdapterTest extends TestCase
             $this->db->remove($item3),
             'If record does not have id and/or pointers, return false.'
         );
+
+        $item1 = new StateEntity($this->testEpisode);
+        $this->db->insert($item1);
+        $this->assertTrue(
+            $this->db->remove(new StateEntity($this->testEpisode)),
+            'When removing item with id, return true.'
+        );
     }
 
     public function test_commit_conditions(): void
@@ -218,8 +304,8 @@ class PDOAdapterTest extends TestCase
             'Array<added, updated, failed> with count of each operation status.'
         );
 
-        $item1->guids['guid_anidb'] = StateInterface::TYPE_EPISODE . '/1';
-        $item2->guids['guid_anidb'] = StateInterface::TYPE_MOVIE . '/1';
+        $item1->guids['guid_anidb'] = iState::TYPE_EPISODE . '/1';
+        $item2->guids['guid_anidb'] = iState::TYPE_MOVIE . '/1';
 
         $this->assertSame(
             ['added' => 0, 'updated' => 2, 'failed' => 0],
@@ -230,8 +316,156 @@ class PDOAdapterTest extends TestCase
 
     public function test_migrations_call_with_wrong_direction_exception(): void
     {
-        $this->expectException(DBException::class);
-        $this->expectExceptionCode(91);
-        $this->db->migrations('not_dd');
+        $this->checkException(
+            closure: fn() => $this->db->migrations('not_dd'),
+            reason: 'When calling migrations with wrong direction, an exception should be thrown.',
+            exception: DBException::class,
+            exceptionMessage: 'Unknown migration direction',
+            exceptionCode: 91,
+        );
+    }
+
+    public function test_commit_transaction_on__destruct(): void
+    {
+        $started = $this->db->getDBLayer()->start();
+        $this->assertTrue($started, 'Transaction should be started.');
+
+        $this->db->getDBLayer()->transactional(function () {
+            $this->db->insert(new StateEntity($this->testEpisode));
+            $this->db->insert(new StateEntity($this->testMovie));
+        }, auto: false);
+
+        $this->assertTrue($this->db->getDBLayer()->inTransaction(), 'Transaction should be still open.');
+        $this->db->__destruct();
+        $this->assertFalse($this->db->getDBLayer()->inTransaction(), 'Transaction should be closed.');
+
+        $this->assertCount(
+            2,
+            $this->db->getAll(),
+            'When transaction is committed, records should be found in db.'
+        );
+    }
+
+    public function test_find(): void
+    {
+        $item1 = new StateEntity($this->testEpisode);
+        $item2 = new StateEntity($this->testMovie);
+        $this->db->insert($item1);
+        $this->db->insert($item2);
+
+        $items = $this->db->find($item1, $item2, new StateEntity([]));
+
+        $this->assertCount(2, $items, 'Only items that are found should be returned.');
+        $this->assertSame($item1->id, array_values($items)[0]->id, 'When items are found, they should be returned.');
+        $this->assertSame($item2->id, array_values($items)[1]->id, 'When items are found, they should be returned.');
+    }
+
+    public function test_findByBackendId(): void
+    {
+        Container::init();
+        Container::add(iState::class, new StateEntity([]));
+
+        $this->db->setOptions(['class' => null]);
+        $item1 = new StateEntity($this->testEpisode);
+        $item2 = new StateEntity($this->testMovie);
+        $this->db->insert($item1);
+        $this->db->insert($item2);
+
+        $item1_db = $this->db->findByBackendId(
+            $item1->via,
+            ag($item1->getMetadata($item1->via), iState::COLUMN_ID),
+            $item1->type,
+        );
+
+        $this->assertCount(0, $item1_db->apply($item1)->diff(), 'When item is found, it should be returned.');
+        $this->assertNull(
+            $this->db->findByBackendId('not_set', 0, 'movie'),
+            'When item is not found, null should be returned.'
+        );
+
+        $this->db->setOptions(['class' => new StateEntity([])]);
+
+        $item2_db = $this->db->findByBackendId(
+            $item2->via,
+            ag($item2->getMetadata($item2->via), iState::COLUMN_ID),
+            $item2->type,
+        );
+        $this->assertCount(0, $item2_db->apply($item2)->diff(), 'When item is found, it should be returned.');
+    }
+
+    public function test_ensureIndex()
+    {
+        $this->assertTrue($this->db->ensureIndex(), 'When ensureIndex is called, it should return true.');
+    }
+
+    public function test_migrateData()
+    {
+        Config::init(require __DIR__ . '/../../config/config.php');
+        $this->assertFalse(
+            $this->db->migrateData(Config::get('database.version')),
+            'At this point we are starting with new database, so migration should be false.'
+        );
+    }
+
+    public function test_maintenance()
+    {
+        Config::init(require __DIR__ . '/../../config/config.php');
+        $this->assertTrue(
+            0 === $this->db->maintenance(),
+            'At this point we are starting with new database, so maintenance should be false.'
+        );
+    }
+
+    public function test_reset()
+    {
+        $this->assertTrue($this->db->reset(), 'When reset is called, it should return true. and reset the db.');
+    }
+
+    public function test_transaction()
+    {
+        $this->db->getDBLayer()->start();
+        $this->checkException(
+            closure: function () {
+                return $this->db->transactional(fn() => throw new \PDOException('test', 11));
+            },
+            reason: 'If we started transaction from outside the db, it shouldn\'t swallow the exception.',
+            exception: \PDOException::class,
+            exceptionMessage: 'test',
+            exceptionCode: 11,
+        );
+        $this->db->getDBLayer()->rollback();
+
+
+        $this->db->getDBLayer()->start();
+        $this->db->transactional(fn($db) => $db->insert(new StateEntity($this->testEpisode)));
+        $this->db->getDBLayer()->commit();
+
+        $this->checkException(
+            closure: function () {
+                return $this->db->transactional(fn() => throw new \PDOException('test', 11));
+            },
+            reason: 'The exception should be thrown after rollback.',
+            exception: \PDOException::class,
+            exceptionMessage: 'test',
+            exceptionCode: 11,
+        );
+    }
+
+    public function test_isMigrated()
+    {
+        Config::init(require __DIR__ . '/../../config/config.php');
+        $db = new PDOAdapter(new Logger('logger'), new DBLayer(new PDO('sqlite::memory:')));
+        $this->assertFalse(
+            $db->isMigrated(),
+            'At this point we are starting with new database, so migration should be false.'
+        );
+        $this->assertTrue(
+            0 === $db->migrations('up'),
+            'When migrations are run, it should return true.'
+        );
+        $this->assertTrue(
+            $db->isMigrated(),
+            'When migrations are run, it should return true.'
+        );
     }
 }
diff --git a/tests/Fixtures/static_data/test.css b/tests/Fixtures/static_data/test.css
new file mode 100644
index 00000000..b0bf9bdf
--- /dev/null
+++ b/tests/Fixtures/static_data/test.css
@@ -0,0 +1,6 @@
+html {
+    background-color: #f0f0f0;
+    font-family: Arial, sans-serif;
+    font-size: 16px;
+    color: #333;
+}
diff --git a/tests/Fixtures/static_data/test.html b/tests/Fixtures/static_data/test.html
new file mode 100644
index 00000000..0d2fedff
--- /dev/null
+++ b/tests/Fixtures/static_data/test.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport"
+          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
+    <meta http-equiv="X-UA-Compatible" content="ie=edge">
+    <title>Document</title>
+</head>
+<body>
+</body>
+</html>
diff --git a/tests/Fixtures/static_data/test.js b/tests/Fixtures/static_data/test.js
new file mode 100644
index 00000000..3caf394d
--- /dev/null
+++ b/tests/Fixtures/static_data/test.js
@@ -0,0 +1 @@
+const testFunc = () => 'test'
diff --git a/tests/Fixtures/static_data/test.json b/tests/Fixtures/static_data/test.json
new file mode 100644
index 00000000..71374789
--- /dev/null
+++ b/tests/Fixtures/static_data/test.json
@@ -0,0 +1,3 @@
+{
+    "test": "test"
+}
diff --git a/tests/Fixtures/static_data/test.md b/tests/Fixtures/static_data/test.md
new file mode 100644
index 00000000..c0b806e1
--- /dev/null
+++ b/tests/Fixtures/static_data/test.md
@@ -0,0 +1 @@
+# Test markdown
diff --git a/tests/Fixtures/static_data/test.woff2 b/tests/Fixtures/static_data/test.woff2
new file mode 100644
index 00000000..9daeafb9
--- /dev/null
+++ b/tests/Fixtures/static_data/test.woff2
@@ -0,0 +1 @@
+test
diff --git a/tests/Fixtures/static_data/test/index.html b/tests/Fixtures/static_data/test/index.html
new file mode 100644
index 00000000..77523a94
--- /dev/null
+++ b/tests/Fixtures/static_data/test/index.html
@@ -0,0 +1 @@
+test_index.html
diff --git a/tests/Fixtures/static_data/test2/test.html b/tests/Fixtures/static_data/test2/test.html
new file mode 100644
index 00000000..9daeafb9
--- /dev/null
+++ b/tests/Fixtures/static_data/test2/test.html
@@ -0,0 +1 @@
+test
diff --git a/tests/Libs/DataUtilTest.php b/tests/Libs/DataUtilTest.php
new file mode 100644
index 00000000..7c9cc9cb
--- /dev/null
+++ b/tests/Libs/DataUtilTest.php
@@ -0,0 +1,205 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Libs;
+
+use App\Libs\DataUtil;
+use App\Libs\TestCase;
+use Nyholm\Psr7\Factory\Psr17Factory;
+use Nyholm\Psr7Server\ServerRequestCreator;
+use Psr\Http\Message\ServerRequestInterface as iRequest;
+
+class DataUtilTest extends TestCase
+{
+    private array $query = ['page' => 1, 'limit' => 10];
+    private array $post = [
+        'foo' => 'bar',
+        'baz' => 'kaz',
+        'sub' => ['key' => 'val'],
+        'bool' => true,
+        'int' => 1,
+        'float' => 1.1
+    ];
+
+    private iRequest|null $request = null;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $factory = new Psr17Factory();
+        $creator = new ServerRequestCreator($factory, $factory, $factory, $factory);
+
+        $this->request = $creator->fromArrays(
+            server: [
+                'REQUEST_METHOD' => 'GET',
+                'SCRIPT_FILENAME' => realpath(__DIR__ . '/../../public/index.php'),
+                'REMOTE_ADDR' => '127.0.0.1',
+                'REQUEST_URI' => '/',
+                'SERVER_NAME' => 'localhost',
+                'SERVER_PORT' => 80,
+                'HTTP_USER_AGENT' => 'WatchState/0.0',
+            ],
+            headers: [
+                'Accept' => 'application/json',
+                'Authorization' => 'Bearer api_test_token',
+            ],
+            cookie: ['test' => 'cookie'],
+            get: $this->query,
+            post: $this->post,
+            files: [
+                'file' => [
+                    'name' => 'test_servers.yaml',
+                    'type' => 'text/plain',
+                    'size' => filesize(__DIR__ . '/../Fixtures/test_servers.yaml'),
+                    'error' => UPLOAD_ERR_OK,
+                    'tmp_name' => __DIR__ . '/../Fixtures/test_servers.yaml',
+                ],
+            ]
+        );
+    }
+
+    public function test_DataUtil_fromArray(): void
+    {
+        $this->assertSame($this->query, DataUtil::fromArray($this->query)->getAll(), 'fromArray() returns all data');
+        $this->assertSame($this->post, DataUtil::fromArray($this->post)->getAll(), 'fromArray() returns all data');
+    }
+
+    public function test_DataUtil_fromRequest(): void
+    {
+        $this->assertSame(
+            $this->post,
+            DataUtil::fromRequest($this->request)->getAll(),
+            'fromRequest() returns all data post data, Default is without query params.'
+        );
+
+        $this->assertSame(
+            $this->post,
+            DataUtil::fromRequest($this->request, includeQueryParams: false)->getAll(),
+            'fromRequest() return only post data, without query params when includeQueryParams is explicitly set to false.'
+        );
+
+        $this->assertSame(
+            array_replace_recursive($this->query, $this->post),
+            DataUtil::fromRequest($this->request, includeQueryParams: true)->getAll(),
+            'fromRequest() returns all data including query params when includeQueryParams is explicitly set to true.'
+        );
+    }
+
+    public function test_DataUtil_get(): void
+    {
+        $obj = DataUtil::fromRequest($this->request, includeQueryParams: true);
+
+        $this->assertSame($this->query['page'], $obj->get('page'), 'get() returns the value of the key if it exists.');
+        $this->assertSame(
+            $this->query['limit'],
+            $obj->get('limit'),
+            'get() returns the value of the key if it exists.'
+        );
+        $this->assertNull($obj->get('not_set'), 'get() returns null if the key does not exist.');
+        $this->assertSame(
+            'default',
+            $obj->get('not_set', 'default'),
+            'get() returns the default value if the key does not exist.'
+        );
+        $this->assertIsArray($obj->get('sub'), 'get() returns an array if the key is an array.');
+        $this->assertIsBool($obj->get('bool'), 'get() returns a boolean if the key is a boolean.');
+        $this->assertIsInt($obj->get('int'), 'get() returns an integer if the key is an integer.');
+        $this->assertIsFloat($obj->get('float'), 'get() returns a float if the key is a float.');
+        $this->assertIsString($obj->get('foo'), 'get() returns a string if the key is a string.');
+        $this->assertSame(
+            ag($this->post, 'sub.key'),
+            $obj->get('sub.key'),
+            'get() returns the value of the key if it exists.'
+        );
+    }
+
+    public function test_dataUtil_has()
+    {
+        $obj = DataUtil::fromRequest($this->request, includeQueryParams: true);
+        $this->assertTrue($obj->has('page'), 'has() returns true if the key exists.');
+        $this->assertTrue($obj->has('limit'), 'has() returns true if the key exists.');
+        $this->assertFalse($obj->has('not_set'), 'has() returns false if the key does not exist.');
+        $this->assertTrue($obj->has('sub'), 'has() returns true if the key is an array.');
+        $this->assertTrue($obj->has('sub.key'), 'has() returns true if the sub.key exists.');
+    }
+
+    public function test_dataUtil_map()
+    {
+        $obj = DataUtil::fromRequest($this->request, includeQueryParams: true);
+        $callback = fn($value) => is_string($value) ? strtoupper($value) : $value;
+        $data = array_replace_recursive($this->query, $this->post);
+        $this->assertSame(
+            array_map($callback, $data),
+            $obj->map($callback)->getAll(),
+            'map() returns the array with the callback applied to each value.'
+        );
+    }
+
+    public function test_dataUtil_filter()
+    {
+        $data = array_replace_recursive($this->query, $this->post);
+        $obj = DataUtil::fromRequest($this->request, includeQueryParams: true);
+        $callback = fn($value, $key) => is_string($value) && $key === 'foo';
+        $this->assertSame(
+            array_filter($data, $callback, ARRAY_FILTER_USE_BOTH),
+            $obj->filter($callback)->getAll(),
+            'filter() returns the array with the callback applied to each value.'
+        );
+    }
+
+    public function test_dataUtil_with()
+    {
+        $obj = DataUtil::fromArray($this->query);
+        $expected = $this->query;
+        $expected['new'] = 'value';
+
+        $this->assertSame(
+            $expected,
+            $obj->with('new', 'value')->getAll(),
+            'with() returns a new DataUtil object with the key and value set.'
+        );
+    }
+
+    public function test_dataUtil_without()
+    {
+        $obj = DataUtil::fromArray($this->query);
+
+        $this->assertSame(
+            ['page' => $this->query['page']],
+            $obj->without('limit')->getAll(),
+            'without() returns a new DataUtil object without the key.'
+        );
+
+        $this->assertSame(
+            $this->query,
+            $obj->without('not_set')->getAll(),
+            'without() returns a new DataUtil object even if the key does not exist with same data.'
+        );
+
+        $this->assertNotSame(
+            spl_object_hash($obj),
+            spl_object_hash($obj->without('not_set')),
+            'without() Any mutation should return a new object. and the spl_object_hash() should not be the same.'
+        );
+
+        $this->assertNotSame(
+            spl_object_id($obj),
+            spl_object_id($obj->without('not_set')),
+            'without() Any mutation should return a new object. and the spl_object_id() should not be the same.'
+        );
+    }
+
+    public function test_dataUtil_jsonSerialize()
+    {
+        $obj = DataUtil::fromArray($this->query);
+        $this->assertSame(json_encode($this->query), json_encode($obj), 'jsonSerialize() returns the data array.');
+    }
+
+    public function test_dataUtil_toString()
+    {
+        $obj = DataUtil::fromArray($this->query);
+        $this->assertSame(json_encode($this->query), (string)$obj, 'jsonSerialize() returns the data array.');
+    }
+
+}
diff --git a/tests/Libs/ServeStaticTest.php b/tests/Libs/ServeStaticTest.php
new file mode 100644
index 00000000..0528e7df
--- /dev/null
+++ b/tests/Libs/ServeStaticTest.php
@@ -0,0 +1,155 @@
+<?php
+/** @noinspection PhpUnhandledExceptionInspection */
+
+declare(strict_types=1);
+
+namespace Tests\Libs;
+
+use App\Libs\Config;
+use App\Libs\Enums\Http\Status;
+use App\Libs\ServeStatic;
+use App\Libs\TestCase;
+use Nyholm\Psr7\ServerRequest;
+
+class ServeStaticTest extends TestCase
+{
+    private ServeStatic|null $server = null;
+    private string $dataPath = __DIR__ . '/../Fixtures/static_data';
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->server = new ServeStatic(realpath($this->dataPath));
+    }
+
+    private function createRequest(string $method, string $uri, array $headers = []): ServerRequest
+    {
+        return new ServerRequest($method, $uri, $headers);
+    }
+
+    public function test_error_responses()
+    {
+        $this->checkException(
+            closure: fn() => $this->server->serve($this->createRequest('GET', '/nonexistent')),
+            reason: 'If file does not exist, A NotFoundException should be thrown.',
+            exception: \League\Route\Http\Exception\NotFoundException::class,
+            exceptionMessage: 'not found',
+            exceptionCode: Status::NOT_FOUND->value,
+        );
+
+        $this->checkException(
+            closure: function () {
+                Config::save('webui.path', '/nonexistent');
+                return (new ServeStatic())->serve($this->createRequest('GET', '/nonexistent'));
+            },
+            reason: 'If file does not exist, A NotFoundException should be thrown.',
+            exception: \League\Route\Http\Exception\BadRequestException::class,
+            exceptionMessage: 'The static path',
+            exceptionCode: Status::SERVICE_UNAVAILABLE->value,
+        );
+
+        $this->checkException(
+            closure: fn() => $this->server->serve($this->createRequest('PUT', '/nonexistent.md')),
+            reason: 'Non-idempotent methods should not be allowed on static files.',
+            exception: \League\Route\Http\Exception\BadRequestException::class,
+            exceptionMessage: 'is not allowed',
+        );
+
+        // -- Check for LFI vulnerability.
+        $this->checkException(
+            closure: fn() => $this->server->serve($this->createRequest('GET', '/../../../composer.json')),
+            reason: 'Should not allow serving files outside the static directory.',
+            exception: \League\Route\Http\Exception\BadRequestException::class,
+            exceptionMessage: 'is invalid.',
+            exceptionCode: Status::BAD_REQUEST->value,
+        );
+
+        // -- Check for invalid root static path.
+        $this->checkException(
+            closure: fn() => (new ServeStatic('/nonexistent'))->serve($this->createRequest('GET', '/test.html')),
+            reason: 'Should throw exception if the static path does not exist.',
+            exception: \League\Route\Http\Exception\BadRequestException::class,
+            exceptionMessage: 'The static path',
+            exceptionCode: Status::SERVICE_UNAVAILABLE->value,
+        );
+
+        $this->checkException(
+            closure: fn() => $this->server->serve($this->createRequest('GET', '/test2/foo/bar')),
+            reason: 'If file does not exist, A NotFoundException should be thrown.',
+            exception: \League\Route\Http\Exception\NotFoundException::class,
+            exceptionMessage: 'not found',
+            exceptionCode: Status::NOT_FOUND->value,
+        );
+
+        $this->checkException(
+            closure: fn() => $this->server->serve($this->createRequest('GET', '/')),
+            reason: 'If file does not exist, A NotFoundException should be thrown.',
+            exception: \League\Route\Http\Exception\NotFoundException::class,
+            exceptionMessage: 'not found',
+            exceptionCode: Status::NOT_FOUND->value,
+        );
+    }
+
+    public function test_responses()
+    {
+        $response = $this->server->serve($this->createRequest('GET', '/test.html'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+        $this->assertEquals('text/html; charset=utf-8', $response->getHeaderLine('Content-Type'));
+        $this->assertEquals(file_get_contents($this->dataPath . '/test.html'), (string)$response->getBody());
+        $this->assertSame(filesize($this->dataPath . '/test.html'), $response->getBody()->getSize());
+
+        // -- test screenshots serving, as screenshots path is not in public directory and not subject
+        // -- to same path restrictions as other files.
+        $response = $this->server->serve($this->createRequest('GET', '/screenshots/add_backend.png'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+        $this->assertEquals('image/png', $response->getHeaderLine('Content-Type'));
+        $this->assertEquals(
+            file_get_contents(__DIR__ . '/../../screenshots/add_backend.png'),
+            (string)$response->getBody()
+        );
+
+        // -- There are similar rules for .md files test them.
+        $response = $this->server->serve($this->createRequest('GET', '/README.md'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+        $this->assertEquals('text/markdown; charset=utf-8', $response->getHeaderLine('Content-Type'));
+        $this->assertEquals(file_get_contents(__DIR__ . '/../../README.md'), (string)$response->getBody());
+
+        // -- Check directory serving.
+        $response = $this->server->serve($this->createRequest('GET', '/test'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+        $this->assertEquals('text/html; charset=utf-8', $response->getHeaderLine('Content-Type'));
+        $this->assertEquals(
+            file_get_contents(__DIR__ . '/../Fixtures/static_data/test/index.html'),
+            (string)$response->getBody()
+        );
+
+        $response = $this->server->serve($this->createRequest('GET', '/test.html', [
+            'if-modified-since' => gmdate('D, d M Y H:i:s T', filemtime($this->dataPath . '/test.html')),
+        ]));
+
+        $this->assertEquals(Status::NOT_MODIFIED->value, $response->getStatusCode());
+
+        // -- check for deep index lookup.
+        $response = $this->server->serve($this->createRequest('GET', '/test/view/action/1'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+        $this->assertEquals('text/html; charset=utf-8', $response->getHeaderLine('Content-Type'));
+        $this->assertEquals(
+            file_get_contents(__DIR__ . '/../Fixtures/static_data/test/index.html'),
+            (string)$response->getBody()
+        );
+
+        $response = $this->server->serve($this->createRequest('GET', '/test/view/1'));
+        $this->assertEquals(Status::OK->value, $response->getStatusCode());
+
+
+        $response = $this->server->serve($this->createRequest('GET', '/test.html', [
+            'if-modified-since' => '$$ INVALID DATA',
+        ]));
+
+        $this->assertEquals(
+            Status::OK->value,
+            $response->getStatusCode(),
+            'If the date is invalid, the file should be served as normal.'
+        );
+    }
+}
diff --git a/tests/Libs/StateEntityTest.php b/tests/Libs/StateEntityTest.php
index 7a21518c..638b9598 100644
--- a/tests/Libs/StateEntityTest.php
+++ b/tests/Libs/StateEntityTest.php
@@ -17,41 +17,28 @@ class StateEntityTest extends TestCase
     private array $testMovie = [];
     private array $testEpisode = [];
 
-    private TestHandler|null $lHandler = null;
-    private Logger|null $logger = null;
-
     protected function setUp(): void
     {
         $this->testMovie = require __DIR__ . '/../Fixtures/MovieEntity.php';
         $this->testEpisode = require __DIR__ . '/../Fixtures/EpisodeEntity.php';
-        $this->lHandler = new TestHandler();
-        $this->logger = new Logger('logger', processors: [new LogMessageProcessor()]);
-        $this->logger->pushHandler($this->lHandler);
+        $logger = new Logger('logger', processors: [new LogMessageProcessor()]);
+        $logger->pushHandler(new TestHandler());
     }
 
     public function test_init_bad_type(): void
     {
         $this->testMovie[iState::COLUMN_TYPE] = 'oi';
 
-        try {
-            new StateEntity($this->testMovie);
-        } catch (RuntimeException $e) {
-            $this->assertInstanceOf(
-                RuntimeException::class,
-                $e,
-                'When new instance of StateEntity is called with invalid type, exception is thrown'
-            );
-        }
-
-        try {
-            StateEntity::fromArray($this->testMovie);
-        } catch (RuntimeException $e) {
-            $this->assertInstanceOf(
-                RuntimeException::class,
-                $e,
-                'When ::fromArray is called with invalid type, exception is thrown'
-            );
-        }
+        $this->checkException(
+            closure: fn() => new StateEntity($this->testMovie),
+            reason: 'When new instance of StateEntity is called with invalid type, exception is thrown',
+            exception: RuntimeException::class,
+        );
+        $this->checkException(
+            closure: fn() => StateEntity::fromArray($this->testMovie),
+            reason: 'When ::fromArray is called with invalid type, exception is thrown',
+            exception: RuntimeException::class,
+        );
     }
 
     public function test_init_bad_data(): void
@@ -84,11 +71,16 @@ class StateEntityTest extends TestCase
     public function test_diff_array_param(): void
     {
         $entity = new StateEntity($this->testEpisode);
-        $entity->setMetadata([iState::COLUMN_META_DATA_PLAYED_AT => 4]);
+        $entity->setMetadata([
+            iState::COLUMN_META_DATA_PLAYED_AT => 4,
+            'test' => ['foo' => 'bar'],
+        ]);
 
         $arr = [];
         $arr = ag_set($arr, 'metadata.home_plex.played_at.old', 2);
         $arr = ag_set($arr, 'metadata.home_plex.played_at.new', 4);
+        $arr = ag_set($arr, 'metadata.home_plex.test.old', 'None');
+        $arr = ag_set($arr, 'metadata.home_plex.test.new', ['foo' => 'bar']);
 
         $this->assertSame(
             $arr,
@@ -538,6 +530,16 @@ class StateEntityTest extends TestCase
             $entity->diff(),
             'When apply() is called with fields that contain changed keys, only those fields are applied to current entity.'
         );
+
+        $data1 = $this->testMovie;
+        $data1[iState::COLUMN_ID] = 1;
+        $data2 = $this->testMovie;
+        $data2[iState::COLUMN_ID] = 2;
+
+        $id1 = new StateEntity($data1);
+        $id2 = new StateEntity($data2);
+
+        $this->assertSame(1, $id1->apply($id2)->id, 'When apply() should not alter the object ID.');
     }
 
     public function test_updateOriginal(): void
@@ -588,9 +590,14 @@ class StateEntityTest extends TestCase
             'When setIsTainted() is called with true, isTainted() returns true'
         );
 
-        $this->expectException(\TypeError::class);
-        /** @noinspection PhpStrictTypeCheckingInspection */
-        $entity->setIsTainted('foo');
+        $this->checkException(
+            closure: function () use ($entity) {
+                /** @noinspection PhpStrictTypeCheckingInspection */
+                return $entity->setIsTainted('foo');
+            },
+            reason: 'When setIsTainted() is called with invalid type, exception is thrown',
+            exception: \TypeError::class,
+        );
     }
 
     public function test_isTainted(): void
@@ -641,8 +648,12 @@ class StateEntityTest extends TestCase
 
         unset($this->testMovie[iState::COLUMN_VIA]);
         $entity = new StateEntity($this->testMovie);
-        $this->expectException(RuntimeException::class);
-        $entity->setMetadata([]);
+
+        $this->checkException(
+            closure: fn() => $entity->setMetadata([]),
+            reason: 'When setMetadata() called with empty array, an exception is thrown',
+            exception: RuntimeException::class,
+        );
     }
 
     public function test_getExtra(): void
@@ -686,8 +697,11 @@ class StateEntityTest extends TestCase
 
         unset($this->testMovie[iState::COLUMN_VIA]);
         $entity = new StateEntity($this->testMovie);
-        $this->expectException(RuntimeException::class);
-        $entity->setExtra([]);
+        $this->checkException(
+            closure: fn() => $entity->setExtra([]),
+            reason: 'When setExtra() called with empty array, an exception is thrown',
+            exception: RuntimeException::class,
+        );
     }
 
     public function test_shouldMarkAsUnplayed(): void
@@ -756,6 +770,16 @@ class StateEntityTest extends TestCase
             'When metadata played date is missing, shouldMarkAsUnplayed() returns false'
         );
 
+        // -- Condition 3: no metadata for via.
+        $data1 = $this->testMovie;
+        $data = $this->testMovie;
+        $data[iState::COLUMN_VIA] = 'not_set';
+        $data[iState::COLUMN_WATCHED] = 0;
+        $this->assertFalse(
+            StateEntity::fromArray($data1)->shouldMarkAsUnplayed(StateEntity::fromArray($data)),
+            'When no metadata set for a backend, shouldMarkAsUnplayed() returns false'
+        );
+
         // -- Condition 5: metadata played is false.
         $data = $this->testMovie;
         $data[iState::COLUMN_META_DATA][$this->testMovie[iState::COLUMN_VIA]][iState::COLUMN_WATCHED] = 0;
@@ -845,7 +869,7 @@ class StateEntityTest extends TestCase
 
     public function test_getPlayProgress(): void
     {
-        $testData = ag_set($this->testMovie, 'watched', 0);
+        $testData = ag_set($this->testMovie, iState::COLUMN_WATCHED, 0);
         $testData = ag_set($testData, 'metadata.home_plex.watched', 0);
         $entity = new StateEntity($testData);
         $this->assertSame(
@@ -854,7 +878,7 @@ class StateEntityTest extends TestCase
             'When hasPlayProgress() when valid play progress is set, returns true'
         );
 
-        $testData = ag_set($this->testMovie, 'watched', 0);
+        $testData = ag_set($this->testMovie, iState::COLUMN_WATCHED, 0);
         $testData = ag_set($testData, 'metadata.home_plex.watched', 0);
         $testData = ag_set($testData, 'metadata.test_plex', ag($testData, 'metadata.home_plex', []));
         $testData = ag_set($testData, 'metadata.test.progress', 999);
@@ -865,6 +889,17 @@ class StateEntityTest extends TestCase
             $entity->getPlayProgress(),
             'When hasPlayProgress() when valid play progress is set, returns true'
         );
+
+        $testData[iState::COLUMN_WATCHED] = 1;
+        $entity = new StateEntity($testData);
+        $this->assertSame(0, $entity->getPlayProgress(), 'When entity is watched, getPlayProgress() returns 0');
+
+        $testData = ag_set($this->testMovie, iState::COLUMN_WATCHED, 0);
+        $testData = ag_set($testData, 'metadata.home_plex.watched', 1);
+        $testData = ag_set($testData, 'metadata.test_plex', ag($testData, 'metadata.home_plex', []));
+        $testData = ag_set($testData, 'metadata.test.progress', 999);
+        $entity = new StateEntity($testData);
+        $this->assertSame(0, $entity->getPlayProgress(), 'When entity is watched, getPlayProgress() returns 0');
     }
 
     public function test_context(): void
@@ -960,4 +995,63 @@ class StateEntityTest extends TestCase
             'Quorum will not be met if one of the values is null.'
         );
     }
+
+    public function test_updated_added_at_columns()
+    {
+        $data = $this->testMovie;
+
+        $data[iState::COLUMN_CREATED_AT] = 0;
+        $data[iState::COLUMN_UPDATED_AT] = 0;
+
+        $entity = new StateEntity($data);
+
+        $this->assertSame(
+            $this->testMovie[iState::COLUMN_UPDATED],
+            $entity->updated_at,
+            'When entity is created with updated_at set to 0, updated_at is set to updated date from metadata'
+        );
+
+        $this->assertSame(
+            $this->testMovie[iState::COLUMN_UPDATED],
+            $entity->created_at,
+            'When entity is created with created_at set to 0, created_at is set to updated date from metadata'
+        );
+    }
+
+    public function test_decoding_array_fields()
+    {
+        $data = $this->testMovie;
+
+        $data[iState::COLUMN_PARENT] = 'garbage data';
+        $data[iState::COLUMN_GUIDS] = 'garbage data';
+        $data[iState::COLUMN_META_DATA] = 'garbage data';
+        $data[iState::COLUMN_EXTRA] = 'garbage data';
+
+        $entity = new StateEntity($data);
+
+        $this->assertSame([],
+            $entity->getMetadata(),
+            'When array keys are json decode fails, getMetadata() should returns empty array'
+        );
+
+        $this->assertSame([],
+            $entity->getGuids(),
+            'When array keys are json decode fails, getGuids() should returns empty array'
+        );
+
+        $this->assertSame([],
+            $entity->getParentGuids(),
+            'When array keys are json decode fails, getParentGuids() should returns empty array'
+        );
+
+        $this->assertSame([],
+            $entity->getExtra(),
+            'When array keys are json decode fails, getExtra() should returns empty array'
+        );
+
+        $this->assertSame([],
+            $entity->getPointers(),
+            'When array keys are json decode fails, getPointers() should returns empty array'
+        );
+    }
 }
diff --git a/tests/Libs/envFileTest.php b/tests/Libs/envFileTest.php
new file mode 100644
index 00000000..3fd55912
--- /dev/null
+++ b/tests/Libs/envFileTest.php
@@ -0,0 +1,223 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Libs;
+
+use App\Libs\EnvFile;
+use App\Libs\Exceptions\RuntimeException;
+use App\Libs\TestCase;
+
+class envFileTest extends TestCase
+{
+    private array $data = [];
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->data = [
+            "WS_TZ" => "Asia/Kuwait",
+            "WS_CRON_IMPORT" => "1",
+            "WS_CRON_EXPORT" => "0",
+            "WS_CRON_IMPORT_AT" => "16 */1 * * *",
+            "WS_CRON_EXPORT_AT" => "30 */3 * * *",
+            "WS_CRON_PUSH_AT" => "*/10 * * * *",
+        ];
+    }
+
+    public function test_constructor()
+    {
+        $this->checkException(
+            closure: fn() => new EnvFile('nonexistent.env', create: false),
+            reason: 'If file does not exist, and autoCreate is set to false, an exception should be thrown.',
+            exception: RuntimeException::class,
+            exceptionMessage: "does not exist.",
+        );
+
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertFileExists($tmpFile);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_get()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+                $this->assertEquals($value, $envFile->get($key), "The value of key '{$key}' should be '{$value}'.");
+            }
+
+            $this->assertNull(
+                $envFile->get('nonexistent_key'),
+                "The value of a nonexistent key should be NULL by default."
+            );
+
+            $this->assertSame(
+                'default',
+                $envFile->get('nonexistent', 'default'),
+                "The default value should be returned."
+            );
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_set()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+            }
+            $envFile->persist();
+
+            $envFile = new EnvFile($tmpFile);
+
+            foreach ($this->data as $key => $value) {
+                $this->assertEquals($value, $envFile->get($key), "The value of key '{$key}' should be '{$value}'.");
+            }
+
+            $this->assertNull(
+                $envFile->get('nonexistent_key'),
+                "The value of a nonexistent key should be NULL by default."
+            );
+
+            $this->assertSame(
+                'default',
+                $envFile->get('nonexistent', 'default'),
+                "The default value should be returned."
+            );
+
+            $envFile->set('new_key', true);
+
+            $this->assertTrue(
+                $envFile->get('new_key'),
+                "Due to unfortunate design, the value of key bool 'new_key' should be true. until we persist it."
+            );
+
+            $envFile->persist();
+            $envFile = $envFile->newInstance();
+            $this->assertTrue($envFile->has('new_key'), "The key 'new_key' should exist.");
+            $this->assertSame(
+                '1',
+                $envFile->get('new_key'),
+                "The value of key 'new_key' should be '1' as we cast bool to string."
+            );
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_has()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+            }
+            $envFile->persist();
+
+            $envFile = new EnvFile($tmpFile);
+
+            foreach ($this->data as $key => $value) {
+                $this->assertTrue($envFile->has($key), "The key '{$key}' should exist.");
+            }
+
+            $this->assertFalse($envFile->has('nonexistent_key'), "The key 'nonexistent_key' should not exist.");
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_persist()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+            }
+            $envFile->persist();
+
+            $envFile = new EnvFile($tmpFile);
+            $this->assertSame($this->data, $envFile->getAll(), "The data should be persisted and retrieved correctly.");
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_getAll()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+            }
+            $envFile->persist();
+
+            $envFile = new EnvFile($tmpFile);
+            $this->assertSame($this->data, $envFile->getAll(), "The data should be persisted and retrieved correctly.");
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+
+    public function test_remove()
+    {
+        $tmpFile = sys_get_temp_dir() . '/watchstate_test.env';
+        $key = array_keys($this->data)[0];
+
+        try {
+            $envFile = new EnvFile($tmpFile, create: true);
+            $this->assertEmpty($envFile->get(array_keys($this->data)[0]));
+
+            foreach ($this->data as $key => $value) {
+                $envFile->set($key, $value);
+            }
+
+            $envFile->persist();
+            $envFile->remove($key);
+            $envFile->persist();
+
+            $envFile = new EnvFile($tmpFile);
+            $this->assertNotSame($this->data, $envFile->getAll(), "The key '{$key}' should be been removed.");
+            $this->assertArrayNotHasKey($key, $envFile->getAll(), "The key '{$key}' should be been removed.");
+        } finally {
+            if (file_exists($tmpFile)) {
+                unlink($tmpFile);
+            }
+        }
+    }
+}