using Predictalytics.Application.Interfaces;
using Predictalytics.Domain.Enums;
using Predictalytics.Domain.Interfaces;
using Predictalytics.Infrastructure.Logging;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Predictalytics.Worker.Services;

/// <summary>
/// Background service that periodically syncs market master data (including outcomes/token IDs)
/// from the Gamma API. This builds the lookup table needed to resolve trades to markets.
/// </summary>
public class MarketSyncWorker : BackgroundService
{
    private static DateTime _lastDbError = DateTime.MinValue;
    private readonly IServiceProvider _services;
    private readonly IPlatformStatisticsService _statsService;
    private readonly ILogger<MarketSyncWorker> _logger;

    public MarketSyncWorker(IServiceProvider services, ILogger<MarketSyncWorker> logger, IPlatformStatisticsService statsService)
    { _services = services; _logger = logger; _statsService = statsService; }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("🏛️ MarketSyncWorker started");
        await Task.Delay(5000, stoppingToken); // Let DB initialize

        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                var rateLimiter = _services.GetRequiredService<IRateLimiter>();
                var platformProviders = _services.GetRequiredService<IEnumerable<IPlatformProvider>>();

                foreach (var p in platformProviders.Where(x => x.IsImplemented))
                {
                    try
                    {
                        if (stoppingToken.IsCancellationRequested) break;

                        using var platformCtx = PlatformLogContext.Push(p.PlatformName);
                        int cycleTotalSynced = 0;
                        foreach (var includeClosed in new[] { false, true })
                        {
                            _logger.LogWarning("[{Platform}] Syncing markets (includeClosed={Closed})...", p.PlatformName, includeClosed);

                            int passSynced = 0;
                            int offset = 0;
                            const int batchSize = 1000;

                            while (!stoppingToken.IsCancellationRequested)
                            {
                                // Fresh scope per batch
                                using var scope = _services.CreateScope();
                                var marketRepo = scope.ServiceProvider.GetRequiredService<IMarketRepository>();
                                var provider = scope.ServiceProvider.GetRequiredService<IEnumerable<IPlatformProvider>>()
                                    .First(x => x.Platform == p.Platform);

                                await rateLimiter.WaitAsync(provider.Platform, stoppingToken);
                                var markets = await provider.GetMarketsAsync(batchSize, offset.ToString(), includeClosed, stoppingToken);

                                if (markets.Count == 0) break;

                                await marketRepo.AddOrUpdateRangeAsync(markets, stoppingToken);

                                passSynced += markets.Count;
                                cycleTotalSynced += markets.Count;
                                _statsService.TrackMarketSync(provider.Platform, markets.Count);
                                offset += batchSize;

                                if (passSynced % 500 == 0)
                                    _logger.LogWarning("[{Platform}] Synced {Total} markets so far (includeClosed={Closed})...", p.PlatformName, passSynced, includeClosed);
                            }
                        }

                        // Need a temporary scope for stats
                        using (var scope = _services.CreateScope())
                        {
                            var marketRepo = scope.ServiceProvider.GetRequiredService<IMarketRepository>();
                            var dbCount = await marketRepo.GetCountAsync(stoppingToken);
                            _logger.LogWarning("✅ [{Platform}] Market sync complete. {Synced} synced this cycle, {Total} total in DB",
                                p.PlatformName, cycleTotalSynced, dbCount);
                        }
                    }
                    catch (Exception ex)
                    {
                        _logger.LogError(ex, "Error syncing markets for platform {Platform}", p.PlatformName);
                    }
                }
            }
            catch (OperationCanceledException) { break; }
            catch (Exception ex) when (ex.ToString().Contains("MySqlException") || ex.ToString().Contains("Connection"))
            {
                if (DateTime.UtcNow - _lastDbError > TimeSpan.FromMinutes(10))
                {
                    _logger.LogWarning("⚠️ Database connection lost in MarketSyncWorker. Retrying in 30m. (Error: {Message})", ex.Message);
                    _lastDbError = DateTime.UtcNow;
                }
            }
            catch (Exception ex) { _logger.LogError(ex, "MarketSyncWorker error"); }

            // Run every 30 minutes
            _logger.LogInformation("🏛️ Next market sync in 30 minutes.");
            await Task.Delay(TimeSpan.FromMinutes(30), stoppingToken);
        }

        _logger.LogInformation("🏛️ MarketSyncWorker stopped");
    }
}