using FastEndpoints;
using Hangfire;
using Npgsql;
using System.Text.Json;
using KArtSell.BuildingBlocks.Time;
using KArtSell.Modules.ModelOperations.Domain;

namespace KArtSell.Host.Features.MarketData;

/// <summary>
/// VS-03 BE: Market Data Ingestion Endpoints
/// POST /api/market/ingest - Trigger data ingestion
/// GET /api/market/ingest/{jobId} - Check job status
///
/// Schedules market data collection from KRX/OpenDart
/// - Idempotent by date range + data source
/// - Returns 202 Accepted (async processing)
/// - Audit trail with correlation ID
/// </summary>

public sealed class IngestionRequest
{
    public string DataSource { get; set; } = "KRX"; // "KRX", "OpenDart", "Stub"
    public string FromDate { get; set; } = "";       // "2026-01-01"
    public string ToDate { get; set; } = "";         // "2026-12-31"
}

public sealed class IngestionResponse
{
    public Guid JobId { get; set; }
    public string Status { get; set; } = "Queued";
    public int ExpectedRowCount { get; set; }
    public DateTime QueuedAt { get; set; }
}

public sealed class IngestionStatusResponse
{
    public Guid JobId { get; set; }
    public string Status { get; set; } = "Running";
    public int RowsProcessed { get; set; }
    public int RowsFailed { get; set; }
    public int RowsSkipped { get; set; }
    public DateTime? CompletedAt { get; set; }
    public int? DurationSeconds { get; set; }
    public string? ErrorMessage { get; set; }
}

public sealed class TriggerIngestionEndpoint : Endpoint<IngestionRequest, IngestionResponse>
{
    private readonly IMarketDataIngestionService _ingestionService;
    private readonly IClock _clock;

    public TriggerIngestionEndpoint(IMarketDataIngestionService ingestionService, IClock clock)
    {
        _ingestionService = ingestionService;
        _clock = clock;
    }

    public override void Configure()
    {
        Post("/api/market/ingest");
        Roles("DataAdmin");
        AllowAnonymous();
    }

    public override async Task HandleAsync(IngestionRequest req, CancellationToken ct)
    {
        if (!DateOnly.TryParse(req.FromDate, out var fromDate))
        {
            ThrowError("Invalid FromDate format. Use YYYY-MM-DD");
        }

        if (!DateOnly.TryParse(req.ToDate, out var toDate))
        {
            ThrowError("Invalid ToDate format. Use YYYY-MM-DD");
        }

        if (fromDate > toDate)
        {
            ThrowError("FromDate must be <= ToDate");
        }

        var correlationId = HttpContext.TraceIdentifier;

        var (jobId, expectedCount) = await _ingestionService.ScheduleIngestionAsync(
            dataSource: req.DataSource,
            fromDate: fromDate,
            toDate: toDate,
            correlationId: correlationId,
            cancellationToken: ct);

        HttpContext.Response.StatusCode = StatusCodes.Status202Accepted;
        HttpContext.Response.ContentType = "application/json";
        await HttpContext.Response.WriteAsync(JsonSerializer.Serialize(new IngestionResponse
        {
            JobId = jobId,
            Status = "Queued",
            ExpectedRowCount = expectedCount,
            QueuedAt = _clock.UtcNow.DateTime,
        }), ct);
    }
}

public sealed class GetIngestionStatusEndpoint : EndpointWithoutRequest<IngestionStatusResponse>
{
    private readonly IMarketDataIngestionService _ingestionService;

    public GetIngestionStatusEndpoint(IMarketDataIngestionService ingestionService)
    {
        _ingestionService = ingestionService;
    }

    public override void Configure()
    {
        Get("/api/market/ingest/{jobId}");
        AllowAnonymous();
    }

    public override async Task HandleAsync(CancellationToken ct)
    {
        var jobIdStr = Route<string>("jobId");
        if (!Guid.TryParse(jobIdStr, out var jobId))
        {
            ThrowError("Invalid job ID format");
        }

        var status = await _ingestionService.GetIngestionStatusAsync(jobId, ct);

        if (status == null)
        {
            ThrowError("Job not found");
        }

        HttpContext.Response.StatusCode = StatusCodes.Status200OK;
        HttpContext.Response.ContentType = "application/json";
        await HttpContext.Response.WriteAsync(JsonSerializer.Serialize(new IngestionStatusResponse
        {
            JobId = status.JobId,
            Status = status.Status,
            RowsProcessed = status.RowsProcessed,
            RowsFailed = status.RowsFailed,
            RowsSkipped = status.RowsSkipped,
            CompletedAt = status.CompletedAt,
            DurationSeconds = status.DurationSeconds,
            ErrorMessage = status.ErrorMessage,
        }), ct);
    }
}

/// <summary>
/// VS-03 Application Handler: Orchestrates ingestion
///
/// Responsibilities:
/// - Schedule ingestion job (Hangfire)
/// - Validate date range
/// - Check idempotency (same date range = no re-run)
/// - Audit logging
/// </summary>

public interface IMarketDataIngestionService
{
    Task<(Guid JobId, int ExpectedRowCount)> ScheduleIngestionAsync(
        string dataSource,
        DateOnly fromDate,
        DateOnly toDate,
        string correlationId,
        CancellationToken cancellationToken);

    Task<IngestionJobStatus?> GetIngestionStatusAsync(Guid jobId, CancellationToken cancellationToken);
}

public record IngestionJobStatus(
    Guid JobId,
    string Status,
    int RowsProcessed,
    int RowsFailed,
    int RowsSkipped,
    DateTime? CompletedAt,
    int? DurationSeconds,
    string? ErrorMessage);

public class MarketDataIngestionService : IMarketDataIngestionService
{
    private readonly NpgsqlDataSource _dataSource;
    private readonly IBackgroundJobClient _jobClient;

    public MarketDataIngestionService(NpgsqlDataSource dataSource, IBackgroundJobClient jobClient)
    {
        _dataSource = dataSource;
        _jobClient = jobClient;
    }

    public async Task<(Guid JobId, int ExpectedRowCount)> ScheduleIngestionAsync(
        string dataSource,
        DateOnly fromDate,
        DateOnly toDate,
        string correlationId,
        CancellationToken cancellationToken)
    {
        var jobId = Guid.NewGuid();

        // Check idempotency: Is there already a job for this date range?
        const string checkSql = """
            SELECT job_id FROM market_data.ingestion_jobs
            WHERE data_source = @source
              AND from_date = @fromDate
              AND to_date = @toDate
              AND status IN ('Running', 'Completed')
            LIMIT 1;
            """;

        await using var connection = await _dataSource.OpenConnectionAsync(cancellationToken);
        await using var checkCmd = connection.CreateCommand();
        checkCmd.CommandText = checkSql;
        checkCmd.Parameters.AddWithValue("@source", dataSource);
        checkCmd.Parameters.AddWithValue("@fromDate", fromDate.ToDateTime(TimeOnly.MinValue));
        checkCmd.Parameters.AddWithValue("@toDate", toDate.ToDateTime(TimeOnly.MinValue));

        var existingJobId = await checkCmd.ExecuteScalarAsync(cancellationToken);
        if (existingJobId != null)
        {
            return ((Guid)existingJobId, 0);
        }

        // Estimate row count (rough: days * ~2000 stocks)
        var days = (toDate.DayNumber - fromDate.DayNumber) + 1;
        var expectedCount = days * 2000; // Stub estimate

        // Insert job record
        const string insertSql = """
            INSERT INTO market_data.ingestion_jobs (job_id, data_source, from_date, to_date, status, correlation_id, triggered_by)
            VALUES (@jobId, @source, @fromDate, @toDate, 'Queued', @correlationId, 'API');
            """;

        await using var insertCmd = connection.CreateCommand();
        insertCmd.CommandText = insertSql;
        insertCmd.Parameters.AddWithValue("@jobId", jobId);
        insertCmd.Parameters.AddWithValue("@source", dataSource);
        insertCmd.Parameters.AddWithValue("@fromDate", fromDate.ToDateTime(TimeOnly.MinValue));
        insertCmd.Parameters.AddWithValue("@toDate", toDate.ToDateTime(TimeOnly.MinValue));
        insertCmd.Parameters.AddWithValue("@correlationId", correlationId);

        await insertCmd.ExecuteNonQueryAsync(cancellationToken);

        // Schedule Hangfire job
        _jobClient.Enqueue<IMarketDataIngestionJob>(j =>
            j.ExecuteAsync(jobId, dataSource, fromDate, toDate, correlationId, CancellationToken.None));

        return (jobId, expectedCount);
    }

    public async Task<IngestionJobStatus?> GetIngestionStatusAsync(Guid jobId, CancellationToken cancellationToken)
    {
        const string sql = """
            SELECT job_id, status, rows_processed, rows_failed, rows_skipped, completed_at, duration_seconds, last_error_message
            FROM market_data.ingestion_jobs
            WHERE job_id = @jobId;
            """;

        await using var connection = await _dataSource.OpenConnectionAsync(cancellationToken);
        await using var cmd = connection.CreateCommand();
        cmd.CommandText = sql;
        cmd.Parameters.AddWithValue("@jobId", jobId);

        await using var reader = await cmd.ExecuteReaderAsync(cancellationToken);
        if (!await reader.ReadAsync(cancellationToken))
            return null;

        return new IngestionJobStatus(
            JobId: reader.GetGuid(0),
            Status: reader.GetString(1),
            RowsProcessed: reader.IsDBNull(2) ? 0 : reader.GetInt32(2),
            RowsFailed: reader.IsDBNull(3) ? 0 : reader.GetInt32(3),
            RowsSkipped: reader.IsDBNull(4) ? 0 : reader.GetInt32(4),
            CompletedAt: reader.IsDBNull(5) ? null : reader.GetDateTime(5),
            DurationSeconds: reader.IsDBNull(6) ? null : reader.GetInt32(6),
            ErrorMessage: reader.IsDBNull(7) ? null : reader.GetString(7));
    }
}

/// <summary>
/// Abstraction: Market data ingestion job (Hangfire worker)
/// </summary>

public interface IMarketDataIngestionJob
{
    Task ExecuteAsync(Guid jobId, string dataSource, DateOnly fromDate, DateOnly toDate, string correlationId, CancellationToken ct);
}