using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.Testing;
using Microsoft.Extensions.Configuration;
using Npgsql;

namespace ItWorx.KnowledgeHub.IntegrationTests.Infrastructure;

/// <summary>
/// One isolated logical database per test class, on the shared
/// <see cref="PostgresContainerFixture"/> server. Real EF Core
/// migrations run at startup exactly as production does — this is not a mocked or
/// SQLite-backed substitute (docs/22-testing-strategy.md).
/// </summary>
public sealed class KnowledgeHubIntegrationFactory : WebApplicationFactory<Program>, IAsyncLifetime
{
    private readonly PostgresContainerFixture _postgres;
    private readonly IReadOnlyDictionary<string, string?> _additionalConfiguration;
    private readonly string _databaseName = $"test_{Guid.NewGuid():N}";

    private readonly string _attachmentsDirectory =
        Path.Combine(Path.GetTempPath(), "ikh-tests-attachments", Guid.NewGuid().ToString("N"));
    private readonly string _importsDirectory =
        Path.Combine(Path.GetTempPath(), "ikh-tests-imports", Guid.NewGuid().ToString("N"));
    private readonly string _backupsDirectory =
        Path.Combine(Path.GetTempPath(), "ikh-tests-backups", Guid.NewGuid().ToString("N"));
    private readonly string _keysDirectory =
        Path.Combine(Path.GetTempPath(), "ikh-tests-keys", Guid.NewGuid().ToString("N"));

    public KnowledgeHubIntegrationFactory(
        PostgresContainerFixture postgres,
        IReadOnlyDictionary<string, string?>? additionalConfiguration = null)
    {
        _postgres = postgres;
        _additionalConfiguration = additionalConfiguration ?? new Dictionary<string, string?>();
    }

    public async Task InitializeAsync()
    {
        await using var connection = new NpgsqlConnection(_postgres.AdminConnectionString);
        await connection.OpenAsync();
        await using var command = connection.CreateCommand();
        command.CommandText = $"CREATE DATABASE \"{_databaseName}\"";
        await command.ExecuteNonQueryAsync();
    }

    async Task IAsyncLifetime.DisposeAsync()
    {
        // Dispose the hosted TestServer/HttpClient first (base WebApplicationFactory
        // behavior), then drop this test class's isolated database.
        await base.DisposeAsync();


        if (Directory.Exists(_attachmentsDirectory))
        {
            Directory.Delete(_attachmentsDirectory, recursive: true);
        }

        if (Directory.Exists(_importsDirectory))
        {
            Directory.Delete(_importsDirectory, recursive: true);
        }

        if (Directory.Exists(_backupsDirectory))
        {
            Directory.Delete(_backupsDirectory, recursive: true);
        }

        if (Directory.Exists(_keysDirectory))
        {
            Directory.Delete(_keysDirectory, recursive: true);
        }

        try
        {
            await using var connection = new NpgsqlConnection(_postgres.AdminConnectionString);
            await connection.OpenAsync();
            await using (var terminate = connection.CreateCommand())
            {
                terminate.CommandText =
                    "SELECT pg_terminate_backend(pid) FROM pg_stat_activity " +
                    "WHERE datname = @name AND pid <> pg_backend_pid()";
                terminate.Parameters.AddWithValue("name", _databaseName);
                await terminate.ExecuteNonQueryAsync();
            }

            await using var drop = connection.CreateCommand();
            drop.CommandText = $"DROP DATABASE IF EXISTS \"{_databaseName}\"";
            await drop.ExecuteNonQueryAsync();
        }
        catch (NpgsqlException)
        {
            // Best-effort cleanup: the whole container is disposed at the end of the
            // run regardless, so a failure to drop one logical database here is not a
            // correctness problem for the test suite.
        }
    }


    /// <summary>The isolated content-addressed attachment storage root for this test
    /// class, so parallel test classes never share (or race on) blob files.</summary>
    public string AttachmentsDirectory => _attachmentsDirectory;

    /// <summary>The isolated LeafWiki imports mount root for this test class. Tests
    /// write synthetic fixture files here directly (never a real snapshot).</summary>
    public string ImportsDirectory => _importsDirectory;

    /// <summary>The isolated backups root for this test class, so parallel/sequential
    /// test classes never share (or have retention-prune) each other's backups.</summary>
    public string BackupsDirectory => _backupsDirectory;

    protected override void ConfigureWebHost(IWebHostBuilder builder)
    {
        builder.UseContentRoot(
            Path.Combine(
                FindRepositoryRoot().FullName,
                "src",
                "backend",
                "ItWorx.KnowledgeHub.Api"));

        builder.UseEnvironment("IntegrationTest");

        builder.ConfigureAppConfiguration((_, configuration) =>
        {
            var values = new Dictionary<string, string?>
            {
                ["KnowledgeHub:Database:Host"] = _postgres.Host,
                ["KnowledgeHub:Database:Port"] = _postgres.Port.ToString(System.Globalization.CultureInfo.InvariantCulture),
                ["KnowledgeHub:Database:Name"] = _databaseName,
                ["KnowledgeHub:Database:Username"] = PostgresContainerFixture.Username,
                ["KnowledgeHub:Database:Password"] = PostgresContainerFixture.Password,

                ["KnowledgeHub:Paths:Attachments"] = _attachmentsDirectory,
                ["KnowledgeHub:Paths:Imports"] = _importsDirectory,
                ["KnowledgeHub:Paths:Backups"] = _backupsDirectory,
                ["KnowledgeHub:Paths:Keys"] = _keysDirectory
            };

            foreach (var (key, value) in _additionalConfiguration)
            {
                values[key] = value;
            }

            configuration.AddInMemoryCollection(values);
        });
    }

    private static DirectoryInfo FindRepositoryRoot()
    {
        DirectoryInfo? current = new(AppContext.BaseDirectory);

        while (current is not null)
        {
            if (File.Exists(Path.Combine(current.FullName, "global.json"))
                && (File.Exists(Path.Combine(current.FullName, "CLAUDE.md"))
                    || File.Exists(Path.Combine(current.FullName, "PUBLIC_SOURCE_EXPORT.md"))))
            {
                return current;
            }

            current = current.Parent;
        }

        throw new DirectoryNotFoundException("Could not locate the repository root.");
    }
}