using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using YD_Event.Core.Entities;
using YD_Event.Core.Enum;

namespace YD_Event.Application.Event;

/// <summary>
/// 赛事状态自动更新后台服务
/// 每5分钟执行一次，自动更新赛事状态
/// </summary>
public class EventStatusUpdateService : BackgroundService
{
    private readonly IServiceProvider _serviceProvider;
    private readonly ILogger<EventStatusUpdateService> _logger;
    private readonly PeriodicTimer _timer;

    public EventStatusUpdateService(
        IServiceProvider serviceProvider,
        ILogger<EventStatusUpdateService> logger)
    {
        _serviceProvider = serviceProvider;
        _logger = logger;
        _timer = new PeriodicTimer(TimeSpan.FromMinutes(5));
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("赛事状态自动更新服务已启动，每5分钟执行一次");

        try
        {
            do
            {
                await UpdateEventStatusesAsync(stoppingToken);
            } while (await _timer.WaitForNextTickAsync(stoppingToken));
        }
        catch (OperationCanceledException)
        {
            _logger.LogInformation("赛事状态自动更新服务已停止");
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "赛事状态自动更新服务发生异常");
        }
    }

    private async Task UpdateEventStatusesAsync(CancellationToken stoppingToken)
    {
        try
        {
            _logger.LogDebug("开始执行赛事状态更新...");

            using var scope = _serviceProvider.CreateScope();
            var repository = scope.ServiceProvider.GetRequiredService<ISqlSugarRepository<EventInfo>>();

            var now = DateTime.Now;
            var eventsToUpdate = new List<EventInfo>();

            var allEvents = await repository.AsQueryable()
                .Where(e => !e.DeleteMark && e.Status == AvailabilityStatus.Enable)
                .ToListAsync(stoppingToken);

            foreach (var evt in allEvents)
            {
                var newStatus = CalculateEventStatus(evt, now);
                if (evt.EventStatus != newStatus)
                {
                    evt.EventStatus = newStatus;
                    evt.UpdatedTime = now;
                    eventsToUpdate.Add(evt);
                    _logger.LogInformation("赛事 {EventId}({EventName}) 状态更新: {OldStatus} -> {NewStatus}",
                        evt.Id, evt.EventName, evt.EventStatus, newStatus);
                }
            }

            if (eventsToUpdate.Any())
            {
                await repository.UpdateRangeAsync(eventsToUpdate);
                _logger.LogInformation("成功更新 {Count} 个赛事的状态", eventsToUpdate.Count);
            }
            else
            {
                _logger.LogDebug("没有需要更新状态的赛事");
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "更新赛事状态时发生异常");
        }
    }

    /// <summary>
    /// 根据时间计算赛事状态
    /// </summary>
    /// <param name="evt">赛事信息</param>
    /// <param name="now">当前时间</param>
    /// <returns>计算后的赛事状态</returns>
    public static EventStatus CalculateEventStatus(EventInfo evt, DateTime now)
    {
        if (now < evt.RegistrationStartTime)
        {
            return EventStatus.NotStarted;
        }
        else if (now >= evt.RegistrationStartTime && now <= evt.RegistrationEndTime)
        {
            return EventStatus.Enrolling;
        }
        else if (now > evt.RegistrationEndTime && now < evt.MatchStartTime)
        {
            return EventStatus.RegistrationEnded;
        }
        else if (now >= evt.MatchStartTime && now <= evt.MatchEndTime)
        {
            return EventStatus.Ongoing;
        }
        else if (now > evt.MatchEndTime)
        {
            return EventStatus.Ended;
        }

        return EventStatus.NotStarted;
    }

    public override void Dispose()
    {
        _timer.Dispose();
        base.Dispose();
    }
}