using System;
using System.Threading;
using System.Threading.Tasks;
using EventPartnerGather;
using EventPartnerGatherRequests;
using UnityEngine;
using EEventBuildState = EventPartnerGatherRequests.EEventBuildState;


namespace UI.PartnerGather
{
    /// <summary>
    /// 自动匹配控制器
    /// 负责管理自动匹配的生命周期、轮询和状态处理
    /// </summary>
    public class AutoMatchController : IDisposable
    {
        private const bool EnableTraceLogs = false;
        /// <summary>Set true to log each poll cycle (state / IsInMatching / partner count). English only.</summary>
        private const bool EnablePollCycleLogs = false;
        private readonly IAutoMatchManagerContext _manager;
        private CancellationTokenSource _pollCancellation;
        private bool _isMatching;

        private const int PollIntervalSeconds = 10;

        public bool IsMatching => _isMatching;

        public AutoMatchController(IAutoMatchManagerContext manager)
        {
            _manager = manager ?? throw new ArgumentNullException(nameof(manager));
        }

        /// <summary>
        /// Panel re-enabled: if local toggle is still on, sync partners from status then (re)start matching + polling.
        /// Do not clear IsAutoMatchEnabled when status says IsInMatching=false — user may have only closed the panel
        /// (polling was cancelled locally) or the API may not reflect queue state; re-call ControlAutoMatch(true) via StartAutoMatch.
        /// </summary>
        public async Task TryResumeAutoMatch()
        {
            try
            {
                if (!_manager.IsAutoMatchEnabled)
                    return;

                if (_manager.ShouldCloseAutoMatch)
                {
                    _manager.SetAutoMatchEnabled(false);
                    _manager.NotifyAutoMatchStopped();
                    return;
                }

                var response = await _manager.FetchAndProcessAutoMatchStatus(force: true);
                if (response?.IsInMatching == true)
                    ELog($"AutoMatchStateRestored eventId={_manager.EventId}");

                var ok = await StartAutoMatch();
                if (!ok)
                    _manager.SetAutoMatchEnabled(false);
            }
            catch (Exception e)
            {
                LogError($"TryResumeAutoMatchError eventId={_manager.EventId} error={e.Message}");
            }
        }

        /// <summary>
        /// 开启自动匹配
        /// </summary>
        public async Task<bool> StartAutoMatch()
        {
            var eventId = _manager.EventId;
            try
            {
                Trace($"AutoMatchStartRequest eventId={eventId}");
                var response = await _manager.ControlAutoMatch(true);

                if (response.State != EEventBuildState.Success)
                {
                    LogError($"AutoMatchStartFailed eventId={eventId} state={response.State} reason={response.Message}");
                    return false;
                }

                _isMatching = true;
                StartPullMatchResult(eventId);
                ELog($"AutoMatchStarted eventId={eventId}");
                return true;
            }
            catch (Exception e)
            {
                LogError($"AutoMatchStartException eventId={eventId} error={e.Message}");
                return false;
            }
        }

        private void StartPullMatchResult(int eventId)
        {
            _pollCancellation = new CancellationTokenSource();
            _ = PollMatchResult(eventId, _pollCancellation.Token);
        }

        /// <summary>
        /// 停止自动匹配
        /// </summary>
        public async Task StopAutoMatch()
        {
            Trace($"AutoMatchStopRequest eventId={_manager.EventId}");

            if (!_isMatching)
                return;
            try
            {
                ELog($"AutoMatchStopping eventId={_manager.EventId}");
                await _manager.ControlAutoMatch(false);
            }
            catch (Exception e)
            {
                LogError($"AutoMatchStopException eventId={_manager.EventId} error={e.Message}");
            }
            finally
            {
                CancelPollMatchResult();
            }
        }

        public void CancelPollMatchResult()
        {
            Trace($"AutoMatchPollingCancel eventId={_manager.EventId}");

            _pollCancellation?.Cancel();
            _pollCancellation?.Dispose();
            _pollCancellation = null;
            _isMatching = false;
        }

        /// <summary>
        /// 轮询匹配结果
        /// </summary>
        private async Task PollMatchResult(int eventId, CancellationToken cancellationToken)
        {
            while (!cancellationToken.IsCancellationRequested)
            {
                try
                {
                    var bRet = await CheckStopAutoMatch();
                    if (bRet)
                    {
                        break;
                    }
                    
                    var response = await _manager.FetchAndProcessAutoMatchStatus(force: true);
                    var buildState = response?.State;
                    PollCycleLog(
                        $"PollTick eventId={eventId} state={buildState} isInMatching={response?.IsInMatching} partnerCount={response?.Partners?.Count ?? 0}");
                    switch (buildState)
                    {
                        case EEventBuildState.Success:
                            await OnMatchSuccess(response);
                            break;
                        case EEventBuildState.Failed:
                            OnMatchFailed(response);
                            break;
                    }

                    if (buildState == EEventBuildState.Failed)
                        break;

                    // 等待下次轮询
                    await Task.Delay(PollIntervalSeconds * 1000, cancellationToken);
                }
                catch (OperationCanceledException)
                {
                    Trace($"AutoMatchPollingCancelled eventId={eventId}");
                    break;
                }
                catch (Exception e)
                {
                    LogError($"AutoMatchPollingException eventId={eventId} error={e.Message}");
                    await Task.Delay(PollIntervalSeconds * 1000, cancellationToken);
                }
            }

            _isMatching = false;
        }
        
        private async Task OnMatchSuccess(AutoMatchStatusResponse result)
        {
            Trace($"AutoMatchSuccess eventId={_manager.EventId} partnerCount={result?.Partners?.Count ?? 0}");
            await CheckStopAutoMatch();
        }
        
        /// <summary>
        /// 处理匹配失败
        /// </summary>
        private void OnMatchFailed(AutoMatchStatusResponse result)
        {
            var message = result?.Message ?? string.Empty;
            ELog($"AutoMatchFailed eventId={_manager.EventId} state={result?.State} reason={message}");
            _manager.NotifyAutoMatchFailed(message);
            _ = StopAutoMatch();
        }

        
        private async Task<bool> CheckStopAutoMatch()
        {
            Trace($"AutoMatchCheckStop eventId={_manager.EventId}");
            if (_manager.ShouldCloseAutoMatch)
            {
                await StopAutoMatch();
                _manager.NotifyAutoMatchStopped();
                return true;
            }
            return false;
        }

        /// <summary>
        /// 释放资源
        /// </summary>
        public void Dispose()
        {
            Trace($"AutoMatchDispose eventId={_manager.EventId}");
            CancelPollMatchResult();
        }

        #region 日志

        private static void PollCycleLog(string message)
        {
            if (!EnablePollCycleLogs) return;
#if UNITY_EDITOR
            Debug.Log($"<color=cyan>[AutoMatchController] {message}</color>");
#else
            Debug.Log($"[AutoMatchController] {message}");
#endif
        }

        private static void ELog(string message)
        {
#if UNITY_EDITOR
            Debug.Log($"<color=cyan>[AutoMatchController] {message}</color>");
#endif
        }
        [System.Diagnostics.Conditional("UNITY_EDITOR")]
        private static void Trace(string message)
        {
            if (!EnableTraceLogs) return;
            ELog(message);
        }

        private static void LogError(string message)
        {
            Debug.LogError($"<color=red>[AutoMatchController] {message}</color>");
        }

        #endregion
    }
}