using System.Data;
using System.Data.Common;
using Dapper;
using KArtSell.BuildingBlocks.Data;
using KArtSell.BuildingBlocks.Hashing;
using KArtSell.BuildingBlocks.Time;
using KArtSell.Host.Jobs;
using Microsoft.Extensions.Logging;
using Npgsql;
using Xunit;

namespace KArtSell.Integration.Tests;

/// <summary>
/// Outbox/Inbox Crash-Recovery & Audit Reconciliation Tests
/// Covers: Process crashes, idempotency, consumer retries, audit trails
/// Following AGENTS.md v16.0: Failure modes, recovery validation, evidence preservation
/// </summary>
public sealed class OutboxInboxCrashRecoveryTests : IAsyncLifetime
{
    private readonly string _connectionString;
    private readonly NpgsqlDataSource _dataSource;
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly IClock _clock = new SystemClock();
    private readonly ILogger<OutboxPollerJob> _logger = new NoOpLogger<OutboxPollerJob>();

    public OutboxInboxCrashRecoveryTests()
    {
        _connectionString = Environment.GetEnvironmentVariable("KARTSELL_POSTGRES")
            ?? "Host=localhost;Port=5432;Database=kartselldb;Username=kartsell;Password=kartsell4321@!";
        _dataSource = new NpgsqlDataSourceBuilder(_connectionString).Build();
        _connectionFactory = new NpgsqlConnectionFactory(_dataSource);
    }

    public async Task InitializeAsync()
    {
        // Verify database is accessible
        await using var connection = await _dataSource.OpenConnectionAsync();
        await using var cmd = connection.CreateCommand();
        cmd.CommandText = "SELECT 1";
        await cmd.ExecuteScalarAsync();
    }

    public async Task DisposeAsync()
    {
        await _dataSource.DisposeAsync();
    }

    /// <summary>
    /// Gate 2.1: Outbox Durability - Messages survive process crash
    /// Scenario: Process crashes before marking message published.
    /// Recovery: Restart retrieves the unpublished message.
    /// </summary>
    [Fact]
    public async Task CrashRecovery_OutboxMessage_SurvivesProcessCrash()
    {
        // Arrange: Insert unpublished message simulating pre-crash state
        var messageId = Guid.NewGuid();
        var now = _clock.UtcNow;
        const string payload = """{"decision_id":"crash-test"}""";
        var hash = ContentHasher.Sha256(payload);
        var correlationId = Guid.NewGuid().ToString();

        await using (var connection = await _connectionFactory.OpenAsync(CancellationToken.None))
        {
            await connection.ExecuteAsync("""
                INSERT INTO building_blocks.outbox_message
                (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash)
                VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash)
                """,
                new
                {
                    MessageId = messageId,
                    EventType = "CrashTestEvent",
                    PayloadJson = payload,
                    CorrelationId = correlationId,
                    OccurredAt = now.AddMinutes(-2),
                    Hash = hash
                });
        }

        // Simulate process crash: Verify message is still unpublished
        await using (var connection = await _connectionFactory.OpenAsync(CancellationToken.None))
        {
            var published = await connection.QuerySingleOrDefaultAsync<DateTime?>(
                "SELECT published_at FROM building_blocks.outbox_message WHERE message_id = @MessageId",
                new { MessageId = messageId });

            Assert.Null(published);
        }

        // Act: Restart process - query for unpublished messages (what job would retrieve)
        await using (var connection = await _connectionFactory.OpenAsync(CancellationToken.None))
        {
            var unpublished = await connection.QueryAsync<Guid>("""
                SELECT message_id FROM building_blocks.outbox_message
                WHERE published_at IS NULL
                ORDER BY occurred_at ASC
                """);

            // Assert: Message is still retrievable for processing
            Assert.Contains(messageId, unpublished);
        }
    }

    /// <summary>
    /// Gate 2.2: Inbox Idempotency - Duplicate message handling via UNIQUE constraint
    /// Scenario: Same outbox message processed by multiple consumers (concurrent).
    /// Expected: UNIQUE(message_id, consumer) prevents duplicates.
    /// </summary>
    [Fact]
    public async Task CrashRecovery_InboxIdempotency_PreventsDuplicatesByConsumer()
    {
        // Arrange: Create outbox message
        var messageId = Guid.NewGuid();
        var now = _clock.UtcNow;
        const string payload = """{"idempotency":"test"}""";
        var hash = ContentHasher.Sha256(payload);

        await using var connection = await _connectionFactory.OpenAsync(CancellationToken.None);

        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.outbox_message
            (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash, published_at)
            VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash, @Now)
            """,
            new
            {
                MessageId = messageId,
                EventType = "IdempotencyTestEvent",
                PayloadJson = payload,
                CorrelationId = Guid.NewGuid().ToString(),
                OccurredAt = now.AddMinutes(-2),
                Hash = hash,
                Now = now.DateTime
            });

        // Insert first inbox record (simulating first consumer)
        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.inbox_message (message_id, consumer, status)
            VALUES (@MessageId, @Consumer1, 'Pending')
            """,
            new { MessageId = messageId, Consumer1 = "Consumer1" });

        // Act: Try to insert duplicate (same message_id, same consumer)
        var exception = await Assert.ThrowsAsync<PostgresException>(async () =>
        {
            await connection.ExecuteAsync("""
                INSERT INTO building_blocks.inbox_message (message_id, consumer, status)
                VALUES (@MessageId, @Consumer1, 'Pending')
                """,
                new { MessageId = messageId, Consumer1 = "Consumer1" });
        });

        // Assert: UNIQUE constraint violation (error code 23505 = unique_violation)
        Assert.Contains("23505", exception.SqlState);
    }

    /// <summary>
    /// Gate 2.3: Inbox Status Transitions - Invalid transitions blocked
    /// Scenario: Process marks message as Processed before processed_at is set.
    /// Expected: Trigger enforces processed_at must be set when status = Processed.
    /// </summary>
    [Fact]
    public async Task CrashRecovery_InboxStatus_EnforcesProcessedAtTimestamp()
    {
        // Arrange: Create outbox message
        var messageId = Guid.NewGuid();
        var now = _clock.UtcNow;
        const string payload = """{"status":"test"}""";
        var hash = ContentHasher.Sha256(payload);

        await using var connection = await _connectionFactory.OpenAsync(CancellationToken.None);

        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.outbox_message
            (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash, published_at)
            VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash, @Now)
            """,
            new
            {
                MessageId = messageId,
                EventType = "StatusTestEvent",
                PayloadJson = payload,
                CorrelationId = Guid.NewGuid().ToString(),
                OccurredAt = now.AddMinutes(-2),
                Hash = hash,
                Now = now.DateTime
            });

        // Insert inbox message in Pending state
        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.inbox_message (message_id, consumer, status)
            VALUES (@MessageId, @Consumer, 'Pending')
            """,
            new { MessageId = messageId, Consumer = "TestConsumer" });

        // Act: Try to mark as Processed without setting processed_at
        var exception = await Assert.ThrowsAsync<PostgresException>(async () =>
        {
            await connection.ExecuteAsync("""
                UPDATE building_blocks.inbox_message
                SET status = 'Processed'
                WHERE message_id = @MessageId
                """,
                new { MessageId = messageId });
        });

        // Assert: Trigger violation (processed_at must be set)
        Assert.Contains("processed_at must be set", exception.Message, StringComparison.OrdinalIgnoreCase);
    }

    /// <summary>
    /// Gate 2.4: Consumer Failure Retry - Failed messages are retrievable for retry
    /// Scenario: Consumer process crashes mid-processing, message marked Failed.
    /// Recovery: Retry job queries Failed messages and retries them.
    /// </summary>
    [Fact]
    public async Task CrashRecovery_ConsumerFailure_FailedMessagesRetrieval()
    {
        // Arrange: Create outbox message
        var messageId = Guid.NewGuid();
        var now = _clock.UtcNow;
        const string payload = """{"retry":"test"}""";
        var hash = ContentHasher.Sha256(payload);
        var errorMsg = "Consumer process crashed before completion";

        await using var connection = await _connectionFactory.OpenAsync(CancellationToken.None);

        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.outbox_message
            (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash, published_at)
            VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash, @Now)
            """,
            new
            {
                MessageId = messageId,
                EventType = "RetryTestEvent",
                PayloadJson = payload,
                CorrelationId = Guid.NewGuid().ToString(),
                OccurredAt = now.AddMinutes(-2),
                Hash = hash,
                Now = now.DateTime
            });

        // Insert inbox message with Failed status
        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.inbox_message (message_id, consumer, status, error_message, attempted_at)
            VALUES (@MessageId, @Consumer, 'Failed', @ErrorMsg, @AttemptedAt)
            """,
            new
            {
                MessageId = messageId,
                Consumer = "RetryConsumer",
                ErrorMsg = errorMsg,
                AttemptedAt = now.DateTime
            });

        // Act: Query for failed messages (to retry)
        var failedMessages = await connection.QueryAsync<(Guid MessageId, string Consumer, string ErrorMessage)>("""
            SELECT message_id, consumer, error_message
            FROM building_blocks.inbox_message
            WHERE status = 'Failed'
            ORDER BY attempted_at DESC
            LIMIT 10
            """);

        // Assert: Failed message is retrievable
        Assert.NotEmpty(failedMessages);
        var failed = failedMessages.First();
        Assert.Equal(messageId, failed.MessageId);
        Assert.Equal("RetryConsumer", failed.Consumer);
        Assert.Contains("crashed", failed.ErrorMessage, StringComparison.OrdinalIgnoreCase);
    }

    /// <summary>
    /// Gate 2.5: Audit Reconciliation - All events are tracked with correlation ID
    /// Scenario: Process completes event handling. Audit log should have end-to-end trace.
    /// Expected: Every inbox message has correlation_id linking to outbox message.
    /// </summary>
    [Fact]
    public async Task CrashRecovery_AuditReconciliation_CorrelationIdTracing()
    {
        // Arrange: Create complete event flow
        var messageId = Guid.NewGuid();
        var correlationId = Guid.NewGuid().ToString();
        var now = _clock.UtcNow;
        const string payload = """{"audit":"trace"}""";
        var hash = ContentHasher.Sha256(payload);

        await using var connection = await _connectionFactory.OpenAsync(CancellationToken.None);

        // Insert outbox message
        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.outbox_message
            (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash, published_at)
            VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash, @Now)
            """,
            new
            {
                MessageId = messageId,
                EventType = "AuditTraceEvent",
                PayloadJson = payload,
                CorrelationId = correlationId,
                OccurredAt = now.AddMinutes(-2),
                Hash = hash,
                Now = now.DateTime
            });

        // Insert inbox message (simulating successful processing)
        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.inbox_message
            (message_id, consumer, status, processed_at)
            VALUES (@MessageId, @Consumer, 'Processed', @Now)
            """,
            new
            {
                MessageId = messageId,
                Consumer = "AuditConsumer",
                Now = now.DateTime
            });

        // Act: Reconcile - Verify inbox message links back to outbox via message_id
        var reconciliation = await connection.QuerySingleOrDefaultAsync<(string OutboxCorrelationId, string InboxConsumer, string InboxStatus)?>("""
            SELECT
                o.correlation_id,
                i.consumer,
                i.status
            FROM building_blocks.outbox_message o
            INNER JOIN building_blocks.inbox_message i ON o.message_id = i.message_id
            WHERE o.message_id = @MessageId
            """,
            new { MessageId = messageId });

        // Assert: End-to-end traceability
        Assert.NotNull(reconciliation);
        Assert.Equal(correlationId, reconciliation!.Value.OutboxCorrelationId);
        Assert.Equal("AuditConsumer", reconciliation!.Value.InboxConsumer);
        Assert.Equal("Processed", reconciliation!.Value.InboxStatus);
    }

    /// <summary>
    /// Gate 2.6: Multiple Consumers - Same outbox event routed to multiple consumers
    /// Scenario: One outbox message should create N inbox records (one per consumer).
    /// Expected: Each consumer processes independently (idempotent dedup per consumer).
    /// </summary>
    [Fact]
    public async Task CrashRecovery_MultipleConsumers_IndependentProcessing()
    {
        // Arrange: Create outbox message for multiple consumers
        var messageId = Guid.NewGuid();
        var now = _clock.UtcNow;
        const string payload = """{"broadcast":"multi-consumer"}""";
        var hash = ContentHasher.Sha256(payload);

        await using var connection = await _connectionFactory.OpenAsync(CancellationToken.None);

        await connection.ExecuteAsync("""
            INSERT INTO building_blocks.outbox_message
            (message_id, event_type, schema_version, payload_json, correlation_id, occurred_at, payload_hash, published_at)
            VALUES (@MessageId, @EventType, 1, CAST(@PayloadJson AS jsonb), @CorrelationId, @OccurredAt, @Hash, @Now)
            """,
            new
            {
                MessageId = messageId,
                EventType = "MultiConsumerEvent",
                PayloadJson = payload,
                CorrelationId = Guid.NewGuid().ToString(),
                OccurredAt = now.AddMinutes(-2),
                Hash = hash,
                Now = now.DateTime
            });

        // Insert inbox records for three consumers
        var consumers = new[] { "Consumer1", "Consumer2", "Consumer3" };
        foreach (var consumer in consumers)
        {
            await connection.ExecuteAsync("""
                INSERT INTO building_blocks.inbox_message (message_id, consumer, status)
                VALUES (@MessageId, @Consumer, 'Pending')
                """,
                new { MessageId = messageId, Consumer = consumer });
        }

        // Act: Query inbox records for this message
        var inboxRecords = await connection.QueryAsync<(string Consumer, string Status)>("""
            SELECT consumer, status
            FROM building_blocks.inbox_message
            WHERE message_id = @MessageId
            ORDER BY consumer
            """,
            new { MessageId = messageId });

        // Assert: All three consumers have independent records
        Assert.Equal(3, inboxRecords.Count());
        Assert.Contains("Consumer1", inboxRecords.Select(r => r.Consumer));
        Assert.Contains("Consumer2", inboxRecords.Select(r => r.Consumer));
        Assert.Contains("Consumer3", inboxRecords.Select(r => r.Consumer));
        Assert.All(inboxRecords, r => Assert.Equal("Pending", r.Status));
    }

    // ========== Helper Classes ==========

    private sealed class NoOpLogger<T> : ILogger<T>
    {
        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
        public bool IsEnabled(LogLevel logLevel) => false;
        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter) { }
    }
}