using System.Text.Json;
using Managing.Application.Abstractions.Services;
using Managing.Domain.Backtests;
using Managing.Domain.Bots;
using Managing.Domain.MoneyManagements;
using Managing.Domain.Scenarios;
using Managing.Domain.Strategies;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using static Managing.Common.Enums;

namespace Managing.Application.Workers;

/// <summary>
/// Worker for processing bundle backtest requests
/// </summary>
public class BundleBacktestWorker : BaseWorker<BundleBacktestWorker>
{
    private readonly IServiceProvider _serviceProvider;
    private readonly IMessengerService _messengerService;
    private static readonly WorkerType _workerType = WorkerType.BundleBacktest;

    public BundleBacktestWorker(
        IServiceProvider serviceProvider,
        IMessengerService messengerService,
        ILogger<BundleBacktestWorker> logger) : base(
        _workerType,
        logger,
        TimeSpan.FromMinutes(1),
        serviceProvider)
    {
        _serviceProvider = serviceProvider;
        _messengerService = messengerService;
    }

    protected override async Task Run(CancellationToken cancellationToken)
    {
        var maxDegreeOfParallelism = 3;
        using var semaphore = new SemaphoreSlim(maxDegreeOfParallelism);
        var processingTasks = new List<Task>();
        try
        {
            // Create a new service scope to get fresh instances of services with scoped DbContext
            using var scope = _serviceProvider.CreateScope();
            var backtester = scope.ServiceProvider.GetRequiredService<IBacktester>();

            // Get pending bundle backtest requests
            var pendingRequests =
                await backtester.GetBundleBacktestRequestsByStatusAsync(BundleBacktestRequestStatus.Pending);

            foreach (var bundleRequest in pendingRequests)
            {
                if (cancellationToken.IsCancellationRequested)
                    break;

                await semaphore.WaitAsync(cancellationToken);
                var task = Task.Run(async () =>
                {
                    try
                    {
                        await ProcessBundleRequest(bundleRequest, cancellationToken);
                    }
                    finally
                    {
                        semaphore.Release();
                    }
                }, cancellationToken);
                processingTasks.Add(task);
            }

            await Task.WhenAll(processingTasks);

            await RetryUnfinishedBacktestsInFailedBundles(backtester, cancellationToken);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error in BundleBacktestWorker");
            throw;
        }
    }

    private async Task ProcessBundleRequest(BundleBacktestRequest bundleRequest, CancellationToken cancellationToken)
    {
        // Create a new service scope for this task to avoid DbContext concurrency issues
        using var scope = _serviceProvider.CreateScope();
        var backtester = scope.ServiceProvider.GetRequiredService<IBacktester>();

        try
        {
            _logger.LogInformation("Starting to process bundle backtest request {RequestId}", bundleRequest.RequestId);

            // Update status to running
            bundleRequest.Status = BundleBacktestRequestStatus.Running;
            await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);

            // Deserialize the backtest requests as strongly-typed objects
            var backtestRequests =
                JsonSerializer.Deserialize<List<RunBacktestRequest>>(
                    bundleRequest.BacktestRequestsJson);
            if (backtestRequests == null)
            {
                throw new InvalidOperationException("Failed to deserialize backtest requests");
            }

            // Process each backtest request
            for (int i = 0; i < backtestRequests.Count; i++)
            {
                if (cancellationToken.IsCancellationRequested)
                    break;

                try
                {
                    var runBacktestRequest = backtestRequests[i];
                    // Update current backtest being processed
                    bundleRequest.CurrentBacktest = $"Backtest {i + 1} of {backtestRequests.Count}";
                    await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);

                    // Run the backtest directly with the strongly-typed request
                    var backtestId = await RunSingleBacktest(backtester, runBacktestRequest, bundleRequest, i,
                        cancellationToken);
                    if (!string.IsNullOrEmpty(backtestId))
                    {
                        bundleRequest.Results.Add(backtestId);
                    }

                    // Update progress
                    bundleRequest.CompletedBacktests++;
                    await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);

                    _logger.LogInformation("Completed backtest {Index} for bundle request {RequestId}",
                        i + 1, bundleRequest.RequestId);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error processing backtest {Index} for bundle request {RequestId}",
                        i + 1, bundleRequest.RequestId);
                    bundleRequest.FailedBacktests++;
                    await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);
                }
            }

            // Update final status and send notifications
            if (bundleRequest.FailedBacktests == 0)
            {
                bundleRequest.Status = BundleBacktestRequestStatus.Completed;
                // Send Telegram message to the user's channelId
                await NotifyUser(bundleRequest);
            }
            else if (bundleRequest.CompletedBacktests == 0)
            {
                bundleRequest.Status = BundleBacktestRequestStatus.Failed;
                bundleRequest.ErrorMessage = "All backtests failed";
            }
            else
            {
                bundleRequest.Status = BundleBacktestRequestStatus.Completed;
                bundleRequest.ErrorMessage = $"{bundleRequest.FailedBacktests} backtests failed";
                // Send Telegram message to the user's channelId even with partial failures
                await NotifyUser(bundleRequest);
            }

            bundleRequest.CompletedAt = DateTime.UtcNow;
            bundleRequest.CurrentBacktest = null;
            await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);

            _logger.LogInformation("Completed processing bundle backtest request {RequestId} with status {Status}",
                bundleRequest.RequestId, bundleRequest.Status);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing bundle backtest request {RequestId}", bundleRequest.RequestId);

            bundleRequest.Status = BundleBacktestRequestStatus.Failed;
            bundleRequest.ErrorMessage = ex.Message;
            bundleRequest.CompletedAt = DateTime.UtcNow;
            await backtester.UpdateBundleBacktestRequestAsync(bundleRequest);
        }
    }

    private async Task NotifyUser(BundleBacktestRequest bundleRequest)
    {
        if (bundleRequest.User?.TelegramChannel != null)
        {
            var message =
                $"⚠️ Bundle backtest '{bundleRequest.Name}' (ID: {bundleRequest.RequestId}) completed with {bundleRequest.FailedBacktests} failed backtests.";
            await _messengerService.SendMessage(message, bundleRequest.User.TelegramChannel);
        }
    }

    // Change RunSingleBacktest to accept RunBacktestRequest directly
    private async Task<string> RunSingleBacktest(IBacktester backtester, RunBacktestRequest runBacktestRequest,
        BundleBacktestRequest bundleRequest,
        int index, CancellationToken cancellationToken)
    {
        if (runBacktestRequest == null || runBacktestRequest.Config == null)
        {
            _logger.LogError("Invalid RunBacktestRequest in bundle (null config)");
            return string.Empty;
        }

        // Map MoneyManagement
        MoneyManagement moneyManagement = null;
        if (!string.IsNullOrEmpty(runBacktestRequest.Config.MoneyManagementName))
        {
            // In worker context, we cannot resolve by name (no user/db), so skip or set null
            // Optionally, log a warning
            _logger.LogWarning("MoneyManagementName provided but cannot resolve in worker context: {Name}",
                (string)runBacktestRequest.Config.MoneyManagementName);
        }
        else if (runBacktestRequest.Config.MoneyManagement != null)
        {
            var mmReq = runBacktestRequest.Config.MoneyManagement;
            moneyManagement = new MoneyManagement
            {
                Name = mmReq.Name,
                Timeframe = mmReq.Timeframe,
                StopLoss = mmReq.StopLoss,
                TakeProfit = mmReq.TakeProfit,
                Leverage = mmReq.Leverage
            };
            moneyManagement.FormatPercentage();
        }

        // Map Scenario
        Scenario scenario = null;
        if (runBacktestRequest.Config.Scenario != null)
        {
            var sReq = runBacktestRequest.Config.Scenario;
            scenario = new Scenario(sReq.Name, sReq.LoopbackPeriod)
            {
                User = null // No user context in worker
            };
            foreach (var indicatorRequest in sReq.Indicators)
            {
                var indicator = new Indicator(indicatorRequest.Name, indicatorRequest.Type)
                {
                    SignalType = indicatorRequest.SignalType,
                    MinimumHistory = indicatorRequest.MinimumHistory,
                    Period = indicatorRequest.Period,
                    FastPeriods = indicatorRequest.FastPeriods,
                    SlowPeriods = indicatorRequest.SlowPeriods,
                    SignalPeriods = indicatorRequest.SignalPeriods,
                    Multiplier = indicatorRequest.Multiplier,
                    SmoothPeriods = indicatorRequest.SmoothPeriods,
                    StochPeriods = indicatorRequest.StochPeriods,
                    CyclePeriods = indicatorRequest.CyclePeriods,
                    User = null // No user context in worker
                };
                scenario.AddIndicator(indicator);
            }
        }

        // Map TradingBotConfig
        var backtestConfig = new TradingBotConfig
        {
            AccountName = runBacktestRequest.Config.AccountName,
            MoneyManagement = moneyManagement,
            Ticker = runBacktestRequest.Config.Ticker,
            ScenarioName = runBacktestRequest.Config.ScenarioName,
            Scenario = scenario,
            Timeframe = runBacktestRequest.Config.Timeframe,
            IsForWatchingOnly = runBacktestRequest.Config.IsForWatchingOnly,
            BotTradingBalance = runBacktestRequest.Config.BotTradingBalance,
            IsForBacktest = true,
            CooldownPeriod = runBacktestRequest.Config.CooldownPeriod,
            MaxLossStreak = runBacktestRequest.Config.MaxLossStreak,
            MaxPositionTimeHours = runBacktestRequest.Config.MaxPositionTimeHours,
            FlipOnlyWhenInProfit = runBacktestRequest.Config.FlipOnlyWhenInProfit,
            FlipPosition = runBacktestRequest.Config.FlipPosition,
            Name = $"{bundleRequest.Name} #{index + 1}",
            CloseEarlyWhenProfitable = runBacktestRequest.Config.CloseEarlyWhenProfitable,
            UseSynthApi = runBacktestRequest.Config.UseSynthApi,
            UseForPositionSizing = runBacktestRequest.Config.UseForPositionSizing,
            UseForSignalFiltering = runBacktestRequest.Config.UseForSignalFiltering,
            UseForDynamicStopLoss = runBacktestRequest.Config.UseForDynamicStopLoss
        };

        // Run the backtest (no user context)
        var result = await backtester.RunTradingBotBacktest(
            backtestConfig,
            runBacktestRequest.StartDate,
            runBacktestRequest.EndDate,
            bundleRequest.User, // No user context in worker
            true,
            runBacktestRequest.WithCandles,
            bundleRequest.RequestId // Use bundleRequestId as requestId for traceability
        );

        _logger.LogInformation("Processed backtest for bundle request {RequestId}", bundleRequest.RequestId);
        // Assume the backtest is created and you have its ID (e.g., backtest.Id)
        // Return the backtest ID
        return result.Id;
    }

    private async Task RetryUnfinishedBacktestsInFailedBundles(IBacktester backtester,
        CancellationToken cancellationToken)
    {
        var failedBundles = await backtester.GetBundleBacktestRequestsByStatusAsync(BundleBacktestRequestStatus.Failed);
        foreach (var failedBundle in failedBundles)
        {
            if (cancellationToken.IsCancellationRequested)
                break;

            // Use Results property to determine which backtests need to be retried
            var succeededIds = new HashSet<string>(failedBundle.Results ?? new List<string>());

            // Deserialize the original requests
            var originalRequests =
                JsonSerializer
                    .Deserialize<List<RunBacktestRequest>>(failedBundle.BacktestRequestsJson);
            if (originalRequests == null) continue;

            for (int i = failedBundle.CompletedBacktests; i < originalRequests.Count; i++)
            {
                var expectedId = /* logic to compute expected backtest id for this request */ string.Empty;
                // If this backtest was not run or did not succeed, re-run it
                if (!succeededIds.Contains(expectedId))
                {
                    var backtestId = await RunSingleBacktest(backtester, originalRequests[i], failedBundle, i,
                        cancellationToken);
                    if (!string.IsNullOrEmpty(backtestId))
                    {
                        failedBundle.Results?.Add(backtestId);
                        failedBundle.CompletedBacktests++;
                        await backtester.UpdateBundleBacktestRequestAsync(failedBundle);
                    }
                }
            }

            // If all backtests succeeded, update the bundle status
            if (failedBundle.CompletedBacktests == originalRequests.Count)
            {
                failedBundle.Status = BundleBacktestRequestStatus.Completed;
                failedBundle.ErrorMessage = null; // Clear any previous error
                failedBundle.CompletedAt = DateTime.UtcNow;
                await backtester.UpdateBundleBacktestRequestAsync(failedBundle);

                // Notify user about successful retry
                await NotifyUser(failedBundle);
            }
            else
            {
                _logger.LogWarning("Bundle {RequestId} still has unfinished backtests after retry",
                    failedBundle.RequestId);
            }
        }
    }
}