using System;
using System.Threading;
using System.Threading.Tasks;
using FATrace.Com;
using FATrace.Model;
using NLog;

namespace FATrace.OEMApp.Services
{
    public sealed class TimeClearDataService
    {
        private readonly Logger _logger = LogManager.GetCurrentClassLogger();
        private CancellationTokenSource? _cts;
        private Task? _loopTask;
        private TimeSpan _runAt = new TimeSpan(2, 0, 0);
        private int _retentionDays = 365;
        private bool _enabled = true;

        public event Action<string>? Info;

        public void Start()
        {
            if (_cts != null) return;

            try
            {
                _enabled = ConfigHelper.GetBoolOrDefault("DataCleanupEnabled", true);
                var tod = ConfigHelper.GetStringOrDefault("DataCleanupTimeOfDay", "02:00:00");
                if (!TimeSpan.TryParse(tod, out _runAt))
                {
                    _runAt = new TimeSpan(2, 0, 0);
                }
                _retentionDays = Math.Max(1, ConfigHelper.GetIntOrDefault("DataRetentionDays", 365));
            }
            catch { }

            if (!_enabled)
            {
                _logger.Warn("[TimeClear] 已禁用，未启动");
                return;
            }

            _cts = new CancellationTokenSource();
            _loopTask = Task.Run(() => RunAsync(_cts.Token));
            _logger.Info("[TimeClear] 服务已启动，时间点={RunAt}, 保留天数={Days}", _runAt, _retentionDays);
            SafeInfo($"定时清理服务启动，时间点={_runAt}, 保留天数={_retentionDays}");
        }

        public void Stop()
        {
            try { _cts?.Cancel(); } catch { }
            _cts = null;
            _logger.Info("[TimeClear] 服务已停止");
        }

        private async Task RunAsync(CancellationToken token)
        {
            while (!token.IsCancellationRequested)
            {
                try
                {
                    var now = DateTime.Now;
                    var next = GetNextRunTime(now);
                    var delay = next - now;
                    SafeInfo($"距离下一次清理还有 {delay:hh\\:mm\\:ss}，计划时间 {next:yyyy-MM-dd HH:mm:ss}");
                    await Task.Delay(delay, token);
                    await CleanupOnceAsync(token);
                }
                catch (OperationCanceledException)
                {
                    break;
                }
                catch (Exception ex)
                {
                    _logger.Error(ex, "[TimeClear] 后台循环异常");
                    try { await Task.Delay(TimeSpan.FromMinutes(1), token); } catch { }
                }
            }
        }

        private DateTime GetNextRunTime(DateTime now)
        {
            var next = now.Date + _runAt;
            if (next <= now.AddSeconds(1)) next = next.AddDays(1);
            return next;
        }

        private async Task CleanupOnceAsync(CancellationToken token)
        {
            var cutoff = DateTime.Now.AddDays(-_retentionDays);
            _logger.Info("[TimeClear] 开始清理，截止时间: {Cutoff}", cutoff);
            SafeInfo($"开始清理，截止时间: {cutoff:yyyy-MM-dd HH:mm:ss}");

            long delJf = 0, delDl = 0, delRaw = 0, delAct = 0;
            try
            {
                delJf = FSqlContext.FDb.Delete<JellyfinMonitorTask>().Where(a => a.CreateTime < cutoff).ExecuteAffrows();
            }
            catch (Exception ex)
            {
                _logger.Warn(ex, "[TimeClear] 清理 JellyfinMonitorTask 失败");
            }

            try
            {
                delDl = FSqlContext.FDb.Delete<DownloadTask>().Where(a => a.CreateTime < cutoff).ExecuteAffrows();
            }
            catch (Exception ex)
            {
                _logger.Warn(ex, "[TimeClear] 清理 DownloadTask 失败");
            }

            try
            {
                delRaw = FSqlContext.FDb.Delete<OEMRawUse>().Where(a => a.CreateTime < cutoff).ExecuteAffrows();
            }
            catch (Exception ex)
            {
                _logger.Warn(ex, "[TimeClear] 清理 OEMRawUse 失败");
            }

            try
            {
                delAct = FSqlContext.FDb.Delete<VideoAction>().Where(a => a.CreateTime < cutoff).ExecuteAffrows();
            }
            catch (Exception ex)
            {
                _logger.Warn(ex, "[TimeClear] 清理 VideoAction 失败");
            }

            _logger.Info("[TimeClear] 清理完成: JellyfinMonitorTask={Jf}, DownloadTask={Dl}, OEMRawUse={Raw}, VideoAction={Act}", delJf, delDl, delRaw, delAct);
            SafeInfo($"清理完成: Jf={delJf}, Dl={delDl}, Raw={delRaw}, Act={delAct}");

            await Task.CompletedTask;
        }

        private void SafeInfo(string msg)
        {
            try { Info?.Invoke(msg); } catch { }
        }
    }
}