using GerstITS.Data.EntityFramework;
using Microsoft.Data.Sqlite;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;

namespace GerstITS.Examples.Transactions.Migrations;

/// <summary>
/// Configures <see cref="ProductDbContext" /> to use a self-contained SQLite in-memory database.
///
/// SQLite is a RELATIONAL provider and therefore supports real ACID transactions, which is what the
/// transaction example needs to show an atomic rollback that actually discards partial work.
///
/// The EF Core InMemory provider (<c>UseInMemoryDatabase</c>) is deliberately NOT used here: it does
/// not support transactions at all - <c>Database.BeginTransaction()</c> raises the
/// <c>TransactionIgnoredWarning</c> - so it cannot demonstrate an atomic rollback. In production the
/// same code runs unchanged against PostgreSQL or SQL Server.
///
/// A single <see cref="SqliteConnection" /> is opened and kept open for the lifetime of the process so
/// the in-memory database is shared across every <see cref="ProductDbContext" /> instance (an in-memory
/// SQLite database only lives as long as its connection is open).
/// </summary>
public sealed class SqliteInMemoryDatabaseConfigurator : DatabaseConfiguratorBase, IDisposable
{
    #region Fields

    private readonly SqliteConnection _connection;

    #endregion

    #region Constructors

    public SqliteInMemoryDatabaseConfigurator(IConfiguration configuration)
        : base(configuration)
    {
        _connection = new SqliteConnection("DataSource=:memory:");
        _connection.Open();
    }

    #endregion

    #region DatabaseConfiguratorBase

    public override void ConfigureModelCreating(ModelBuilder modelBuilder)
    {
        // No relational-specific mapping is required; ProductEntity is mapped by convention.
    }

    protected override void ConfigureDatabase(DbContextOptionsBuilder optionsBuilder, string connectionString)
    {
        optionsBuilder.UseSqlite(_connection);
    }

    #endregion

    #region IDisposable

    public void Dispose()
    {
        _connection.Dispose();
    }

    #endregion
}