using System;
using System.Threading;
using System.Threading.Tasks;
using FinlyticCore.Services;
using FinlyticTechnicals.Util;
using Microsoft.Extensions.Hosting;

namespace FinlyticTechnicals.Services;

public class TechnicalScannerBackgroundService : BackgroundService
{
    private readonly ITechnicalUniverseManager _universeManager;
    private readonly ITechnicalScoringEngine _scoringEngine;
    private readonly ISettingsService _settingsService;
    private readonly IFinlyticLogger<TechnicalScannerBackgroundService> _logger;

    public TechnicalScannerBackgroundService(
        ITechnicalUniverseManager universeManager,
        ITechnicalScoringEngine scoringEngine,
        ISettingsService settingsService,
        IFinlyticLogger<TechnicalScannerBackgroundService> logger)
    {
        _universeManager = universeManager;
        _scoringEngine = scoringEngine;
        _settingsService = settingsService;
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        await _logger.LogInfoAsync(SettingKeys.TechnicalAnalysisChannel,
            "[TechnicalScanner] Starting Technical Universe Scanner Background Service...");

        // Initial delay for MQTT connections to stabilize
        await Task.Delay(TimeSpan.FromSeconds(10), stoppingToken);

        // Initial synchronization of Universe
        await _universeManager.RefreshFavoritesAsync(stoppingToken);
        await _universeManager.RefreshDiscoveryAsync(stoppingToken);

        DateTime lastFavoritesSyncUtc = DateTime.UtcNow;
        DateTime lastDiscoverySyncUtc = DateTime.UtcNow;

        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                DateTime now = DateTime.UtcNow;

                // 1. Check Periodic Sync Timers
                if (now - lastFavoritesSyncUtc >= TimeSpan.FromMinutes(15))
                {
                    await _universeManager.RefreshFavoritesAsync(stoppingToken);
                    lastFavoritesSyncUtc = DateTime.UtcNow;
                }

                if (now - lastDiscoverySyncUtc >= TimeSpan.FromMinutes(30))
                {
                    await _universeManager.RefreshDiscoveryAsync(stoppingToken);
                    lastDiscoverySyncUtc = DateTime.UtcNow;
                }

                // 2. Retrieve Active Prioritized Scan Universe
                var universe = await _universeManager.GetActiveUniverseAsync(stoppingToken);
                if (universe.Count > 0)
                {
                    await _logger.LogInfoAsync(SettingKeys.TechnicalAnalysisChannel,
                        "[TechnicalScanner] Scanning {Count} assets in active universe across all strategies...", universe.Count);

                    foreach (var entry in universe)
                    {
                        if (stoppingToken.IsCancellationRequested) break;

                        try
                        {
                            var setups = await _scoringEngine.AnalyzeIsinAsync(entry.Isin, entry.Symbol, entry.Source, entry.AddedAtUtc, stoppingToken);
                            if (setups.Count > 0)
                            {
                                await _logger.LogInfoAsync(SettingKeys.TechnicalAnalysisChannel,
                                    "[TechnicalScanner] Found {Count} active setup(s) for ISIN {Isin} (Top Score: {Score:F1})",
                                    setups.Count, entry.Isin, setups[0].QualityScore);
                            }
                        }
                        catch (Exception ex)
                        {
                            await _logger.LogWarningAsync(SettingKeys.TechnicalAnalysisChannel, ex,
                                "[TechnicalScanner] Error analyzing ISIN {Isin}", entry.Isin);
                        }

                        // Gentle throttle between asset analysis runs
                        await Task.Delay(250, stoppingToken);
                    }
                }
                else
                {
                    await _logger.LogInfoAsync(SettingKeys.TechnicalAnalysisChannel,
                        "[TechnicalScanner] Scan universe is currently empty. Waiting for next cycle.");
                }

                // Wait 60 seconds before next full universe evaluation pass
                await Task.Delay(TimeSpan.FromSeconds(60), stoppingToken);
            }
            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
            {
                break;
            }
            catch (Exception ex)
            {
                await _logger.LogErrorAsync(SettingKeys.TechnicalAnalysisChannel, ex,
                    "[TechnicalScanner] Unexpected error in scanner loop. Retrying in 30 seconds.");
                await Task.Delay(TimeSpan.FromSeconds(30), stoppingToken);
            }
        }

        await _logger.LogInfoAsync(SettingKeys.TechnicalAnalysisChannel,
            "[TechnicalScanner] Technical Universe Scanner Background Service stopped.");
    }
}