postgres backend for vehicle.

External/Implementations/Postgres/VehicleDataAccess.cs

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+using CarCareTracker.External.Interfaces;
+using CarCareTracker.Models;
+using Npgsql;
+using System.Reflection.Metadata.Ecma335;
+using System.Text.Json;
+
+namespace CarCareTracker.External.Implementations
+{
+    public class PGVehicleDataAccess: IVehicleDataAccess
+    {
+        private NpgsqlConnection pgDataSource;
+        public PGVehicleDataAccess(IConfiguration config)
+        {
+            pgDataSource = new NpgsqlConnection(config["POSTGRES_CONNECTION"]);
+            pgDataSource.Open();
+            //create table if not exist.
+            string initCMD = $"CREATE TABLE IF NOT EXISTS app.{tableName} (id INT GENERATED ALWAYS AS IDENTITY primary key, data jsonb not null)";
+            using (var ctext = new NpgsqlCommand(initCMD, pgDataSource))
+            {
+                ctext.ExecuteNonQuery();
+            }
+        }
+        private static string tableName = "vehicles";
+        public bool SaveVehicle(Vehicle vehicle)
+        {
+            var serializedData = JsonSerializer.Serialize(vehicle);
+            if (vehicle.Id == default)
+            {
+                string cmd = $"INSERT INTO app.{tableName} (data) VALUES(CAST(@data AS jsonb)) RETURNING id";
+                using (var ctext = new NpgsqlCommand(cmd, pgDataSource))
+                {
+                    ctext.Parameters.AddWithValue("data", serializedData);
+                    vehicle.Id = Convert.ToInt32(ctext.ExecuteScalar());
+                    return vehicle.Id != default;
+                }
+            } else
+            {
+                string cmd = $"UPDATE app.{tableName} SET data = CAST(@data AS jsonb) WHERE id = @id";
+                using (var ctext = new NpgsqlCommand(cmd, pgDataSource))
+                {
+                    ctext.Parameters.AddWithValue("id", vehicle.Id);
+                    ctext.Parameters.AddWithValue("data", serializedData);
+                    return ctext.ExecuteNonQuery() > 0;
+                }
+            }
+        }
+        public bool DeleteVehicle(int vehicleId)
+        {
+            string cmd = $"DELETE FROM app.{tableName} WHERE id = @id";
+            using (var ctext = new NpgsqlCommand(cmd, pgDataSource))
+            {
+                ctext.Parameters.AddWithValue("id", vehicleId);
+                return ctext.ExecuteNonQuery() > 0;
+            }
+        }
+        public List<Vehicle> GetVehicles()
+        {
+            string cmd = $"SELECT id, data FROM app.{tableName} ORDER BY id ASC";
+            var results = new List<Vehicle>();
+            using (var ctext = new NpgsqlCommand(cmd, pgDataSource))
+            {
+                using (NpgsqlDataReader reader = ctext.ExecuteReader())
+                while (reader.Read())
+                {
+                    Vehicle vehicle = JsonSerializer.Deserialize<Vehicle>(reader["data"] as string);
+                    vehicle.Id = Convert.ToInt32(reader["id"]);
+                    if (string.IsNullOrWhiteSpace(vehicle.ImageLocation))
+                    {
+                            vehicle.ImageLocation = "/defaults/noimage.png";
+                    }
+                    results.Add(vehicle);
+                }
+            }
+            return results;
+        }
+        public Vehicle GetVehicleById(int vehicleId)
+        {
+            string cmd = $"SELECT id, data FROM app.{tableName} WHERE id = @id";
+            Vehicle vehicle = new Vehicle();
+            using (var ctext = new NpgsqlCommand(cmd, pgDataSource))
+            {
+                ctext.Parameters.AddWithValue("id", vehicleId);
+                using (NpgsqlDataReader reader = ctext.ExecuteReader())
+                    while (reader.Read())
+                    {
+                        vehicle = JsonSerializer.Deserialize<Vehicle>(reader["data"] as string);
+                        vehicle.Id = Convert.ToInt32(reader["id"]);
+                        if (string.IsNullOrWhiteSpace(vehicle.ImageLocation))
+                        {
+                            vehicle.ImageLocation = "/defaults/noimage.png";
+                        }
+                    }
+            }
+            return vehicle;
+        }
+    }
+}