using System.Text.Json;
using KArtSell.BuildingBlocks.Data;
using KArtSell.BuildingBlocks.Hashing;
using KArtSell.BuildingBlocks.Reliability;
using KArtSell.BuildingBlocks.Time;
using Microsoft.Extensions.Logging;

namespace KArtSell.Modules.ModelOperations.TradeExecution;

public class SubmitTradeCommand
{
    public Guid SellDecisionId { get; set; }
    public int Quantity { get; set; }
    public decimal LimitPrice { get; set; }
    public Guid CorrelationId { get; set; }
}

public class SubmitTradeHandler
{
    private readonly ITradeSql _sql;
    private readonly IKisTradeExecutionService _kis;
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly IOutboxWriter _outbox;
    private readonly IClock _clock;
    private readonly ILogger<SubmitTradeHandler> _logger;

    public SubmitTradeHandler(
        ITradeSql sql,
        IKisTradeExecutionService kis,
        IDbConnectionFactory connectionFactory,
        IOutboxWriter outbox,
        IClock clock,
        ILogger<SubmitTradeHandler> logger)
    {
        _sql = sql;
        _kis = kis;
        _connectionFactory = connectionFactory;
        _outbox = outbox;
        _clock = clock;
        _logger = logger;
    }

    public async Task<Guid> HandleAsync(SubmitTradeCommand command, CancellationToken ct = default)
    {
        var trade = Trade.Create(command.SellDecisionId, command.Quantity, command.CorrelationId, _clock.UtcNow.UtcDateTime);
        await _sql.InsertTradeAsync(trade, ct);
        _logger.LogInformation("Created trade: {TradeId}", trade.Id);

        try
        {
            var (orderId, response) = await _kis.ExecuteTradeAsync(
                trade.Id,
                command.Quantity,
                command.LimitPrice,
                command.CorrelationId,
                ct
            );

            trade.MarkSubmitted(orderId, response);
            await _sql.UpdateTradeStatusAsync(trade, response, null, ct);

            await PublishEventAsync(
                "TradeSubmitted",
                new TradeSubmittedEvent
                {
                    TradeId = trade.Id,
                    SellDecisionId = command.SellDecisionId,
                    KisOrderId = orderId,
                    Quantity = command.Quantity,
                    CorrelationId = command.CorrelationId
                },
                command.CorrelationId,
                ct);

            return trade.Id;
        }
        catch (KisTradeExecutionException ex)
        {
            trade.MarkErrored(ex);
            await _sql.UpdateTradeStatusAsync(trade, ex.KisResponse, ex.Message, ct);

            _logger.LogError(
                "Trade submission failed: {TradeId} {Classification}",
                trade.Id, ex.Classification
            );

            throw;
        }
    }

    private async Task PublishEventAsync<T>(string eventType, T @event, Guid correlationId, CancellationToken ct) where T : class
        => await TradeOutboxPublisher.PublishAsync(_connectionFactory, _outbox, _clock, eventType, @event, correlationId, ct);
}

public class PollTradeStatusCommand
{
    public Guid TradeId { get; set; }
    public string KisOrderId { get; set; } = string.Empty;
    public Guid CorrelationId { get; set; }
}

public class PollTradeStatusHandler
{
    private readonly ITradeSql _sql;
    private readonly IKisTradeExecutionService _kis;
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly IOutboxWriter _outbox;
    private readonly IClock _clock;
    private readonly ILogger<PollTradeStatusHandler> _logger;

    public PollTradeStatusHandler(
        ITradeSql sql,
        IKisTradeExecutionService kis,
        IDbConnectionFactory connectionFactory,
        IOutboxWriter outbox,
        IClock clock,
        ILogger<PollTradeStatusHandler> logger)
    {
        _sql = sql;
        _kis = kis;
        _connectionFactory = connectionFactory;
        _outbox = outbox;
        _clock = clock;
        _logger = logger;
    }

    public async Task HandleAsync(PollTradeStatusCommand command, CancellationToken ct = default)
    {
        var trade = await _sql.GetTradeByIdAsync(command.TradeId, command.CorrelationId, ct);
        if (trade == null)
        {
            _logger.LogWarning("Trade not found: {TradeId}", command.TradeId);
            return;
        }

        try
        {
            var (status, executedQty, unitPrice, response) = await _kis.GetOrderStatusAsync(
                command.KisOrderId,
                command.CorrelationId,
                ct
            );

            if (status is "ACCEPTED" or "PARTIAL_FILLED" or "FULLY_FILLED")
            {
                trade.MarkAccepted(response);
                if (status is "PARTIAL_FILLED" or "FULLY_FILLED")
                {
                    trade.MarkFilled(executedQty, unitPrice, response, _clock.UtcNow.UtcDateTime);
                }

                await _sql.UpdateTradeStatusAsync(trade, response, null, ct);

                if (trade.Status is TradeStatus.FullyFilled)
                {
                    await TradeOutboxPublisher.PublishAsync(
                        _connectionFactory,
                        _outbox,
                        _clock,
                        "TradeFilled",
                        new TradeFilledEvent
                        {
                            TradeId = trade.Id,
                            ExecutedQuantity = executedQty,
                            UnitPrice = unitPrice,
                            CorrelationId = command.CorrelationId
                        },
                        command.CorrelationId,
                        ct);
                }

                _logger.LogInformation("Trade status updated: {TradeId} -> {Status}", trade.Id, status);
            }
        }
        catch (KisTradeExecutionException ex)
        {
            await _sql.UpdateTradeStatusAsync(trade, ex.KisResponse, ex.Message, ct);

            _logger.LogError("Failed to poll trade status: {TradeId}", trade.Id);
        }
    }
}

public class ConfirmSettlementCommand
{
    public Guid TradeId { get; set; }
    public string KisOrderId { get; set; } = string.Empty;
    public decimal? Commission { get; set; }
    public Guid CorrelationId { get; set; }
}

public class ConfirmSettlementHandler
{
    private readonly ITradeSql _sql;
    private readonly IKisTradeExecutionService _kis;
    private readonly IDbConnectionFactory _connectionFactory;
    private readonly IOutboxWriter _outbox;
    private readonly IClock _clock;
    private readonly ILogger<ConfirmSettlementHandler> _logger;

    public ConfirmSettlementHandler(
        ITradeSql sql,
        IKisTradeExecutionService kis,
        IDbConnectionFactory connectionFactory,
        IOutboxWriter outbox,
        IClock clock,
        ILogger<ConfirmSettlementHandler> logger)
    {
        _sql = sql;
        _kis = kis;
        _connectionFactory = connectionFactory;
        _outbox = outbox;
        _clock = clock;
        _logger = logger;
    }

    public async Task HandleAsync(ConfirmSettlementCommand command, CancellationToken ct = default)
    {
        var trade = await _sql.GetTradeByIdAsync(command.TradeId, command.CorrelationId, ct);
        if (trade == null)
        {
            _logger.LogWarning("Trade not found for settlement: {TradeId}", command.TradeId);
            return;
        }

        try
        {
            var (success, response) = await _kis.ConfirmSettlementAsync(
                command.KisOrderId,
                command.CorrelationId,
                ct
            );

            if (success)
            {
                trade.MarkConfirmed(_clock.UtcNow.UtcDateTime, command.Commission);
                await _sql.UpdateTradeStatusAsync(trade, response, null, ct);

                await TradeOutboxPublisher.PublishAsync(
                    _connectionFactory,
                    _outbox,
                    _clock,
                    "TradeSettled",
                    new TradeSettledEvent
                    {
                        TradeId = trade.Id,
                        NetProceeds = trade.NetProceeds ?? 0,
                        CorrelationId = command.CorrelationId
                    },
                    command.CorrelationId,
                    ct);

                _logger.LogInformation("Trade settlement confirmed: {TradeId}", trade.Id);
            }
        }
        catch (KisTradeExecutionException ex)
        {
            await _sql.UpdateTradeStatusAsync(trade, ex.KisResponse, ex.Message, ct);

            _logger.LogError("Failed to confirm settlement: {TradeId}", trade.Id);
        }
    }
}

public class TradeSubmittedEvent
{
    public Guid TradeId { get; set; }
    public Guid SellDecisionId { get; set; }
    public string KisOrderId { get; set; } = string.Empty;
    public int Quantity { get; set; }
    public Guid CorrelationId { get; set; }
}

public class TradeFilledEvent
{
    public Guid TradeId { get; set; }
    public int ExecutedQuantity { get; set; }
    public decimal UnitPrice { get; set; }
    public Guid CorrelationId { get; set; }
}

public class TradeSettledEvent
{
    public Guid TradeId { get; set; }
    public decimal NetProceeds { get; set; }
    public Guid CorrelationId { get; set; }
}

/// <summary>
/// DEBT-TRADE-001: outbox write happens in its own transaction, separate from the
/// preceding trade status update (which owns its own connection in TradeSql). Not yet
/// atomic with the state transition. See TECH_DEBT_REGISTER.md.
/// </summary>
internal static class TradeOutboxPublisher
{
    public static async Task PublishAsync<T>(
        IDbConnectionFactory connectionFactory,
        IOutboxWriter outbox,
        IClock clock,
        string eventType,
        T @event,
        Guid correlationId,
        CancellationToken ct) where T : class
    {
        var payload = JsonSerializer.Serialize(@event);
        var message = new OutboxMessage(
            Guid.NewGuid(),
            eventType,
            1,
            payload,
            correlationId.ToString(),
            clock.UtcNow,
            ContentHasher.Sha256(payload));

        await using var connection = await connectionFactory.OpenAsync(ct);
        await using var transaction = await connection.BeginTransactionAsync(ct);
        await outbox.AddAsync(connection, transaction, message, ct);
        await transaction.CommitAsync(ct);
    }
}