using Microsoft.Data.SqlClient;
using Microsoft.EntityFrameworkCore;
using ZB.MOM.WW.OtOpcUa.Configuration;

namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests.Harness;

/// <summary>
///     A migrated, throw-away config database on the central SQL Server, for the few ControlPlane behaviours
///     the InMemory provider cannot model (a SQL Server <c>DbUpdateException</c> names the WHOLE statement
///     batch; collation-ordered reads). Same server / credentials / env overrides as
///     <c>Configuration.Tests.SchemaComplianceFixture</c> (<c>OTOPCUA_CONFIG_TEST_SERVER</c>,
///     <c>OTOPCUA_CONFIG_TEST_SA_PASSWORD</c>; default the shared docker host's dev SA), and the same database
///     name shape, so that suite's 24 h orphan reaper also reclaims a database a killed run leaks here.
/// </summary>
public sealed class SqlServerTestDatabase : IDisposable
{
    private const string DefaultServer = "10.100.0.35,14330";
    private const string DefaultSaPassword = "OtOpcUaDev_2026!";

    /// <summary>Gets the connection string of the migrated database.</summary>
    public string ConnectionString { get; }

    private readonly string _databaseName;

    /// <summary>Creates and migrates the database.</summary>
    public SqlServerTestDatabase()
    {
        var server = Environment.GetEnvironmentVariable("OTOPCUA_CONFIG_TEST_SERVER") ?? DefaultServer;
        var saPassword = Environment.GetEnvironmentVariable("OTOPCUA_CONFIG_TEST_SA_PASSWORD") ?? DefaultSaPassword;
        _databaseName = $"OtOpcUaConfig_Test_{DateTime.UtcNow:yyyyMMddHHmmss}_{Guid.NewGuid():N}";
        ConnectionString =
            $"Server={server};Database={_databaseName};User Id=sa;Password={saPassword};TrustServerCertificate=True;Encrypt=False;";
        using var ctx = NewContext();
        ctx.Database.Migrate();
    }

    /// <summary>A new context on the database.</summary>
    /// <returns>The context.</returns>
    public OtOpcUaConfigDbContext NewContext() =>
        new(new DbContextOptionsBuilder<OtOpcUaConfigDbContext>().UseSqlServer(ConnectionString).Options);

    /// <summary>A factory over <see cref="NewContext"/>.</summary>
    /// <returns>The factory.</returns>
    public IDbContextFactory<OtOpcUaConfigDbContext> Factory() => new ContextFactory(this);

    /// <summary>Drops the database (best effort; a leak is reaped by the Configuration suite).</summary>
    public void Dispose()
    {
        try
        {
            SqlConnection.ClearAllPools();
            var master = new SqlConnectionStringBuilder(ConnectionString) { InitialCatalog = "master" }.ConnectionString;
            using var conn = new SqlConnection(master);
            conn.Open();
            using var cmd = conn.CreateCommand();
            cmd.CommandText = @"
DECLARE @sql nvarchar(max);
IF DB_ID(@name) IS NOT NULL
BEGIN
    SET @sql = N'ALTER DATABASE ' + QUOTENAME(@name) + N' SET SINGLE_USER WITH ROLLBACK IMMEDIATE; ' +
               N'DROP DATABASE ' + QUOTENAME(@name) + N';';
    EXEC sp_executesql @sql;
END";
            cmd.Parameters.Add(new SqlParameter("@name", _databaseName));
            cmd.ExecuteNonQuery();
        }
        catch (Exception)
        {
            // Best effort — see the class remarks.
        }
    }

    private sealed class ContextFactory(SqlServerTestDatabase owner) : IDbContextFactory<OtOpcUaConfigDbContext>
    {
        public OtOpcUaConfigDbContext CreateDbContext() => owner.NewContext();
    }
}