using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using TeamAAS.Communication;
using TeamAAS.Communication.Config;
using TeamAAS.Communication.Interfaces;
using TeamAAS.FlowEditor;
using TeamAAS.FlowEditor.Execution;
using TeamAAS.FlowEditor.Models;

namespace TeamAAS.FlowEngine.Execution
{
    /// <summary>
    /// 产品运行引擎：把"运行产品"与"心跳触发"真正接上线。
    /// - LoadRunProduct：加载产品的独立运行态流程（与编辑态互不影响）
    /// - RunOnceAsync：执行所有"主流程触发"的流程一次，并更新 RunStatistics
    /// - StartHeartbeat：订阅通讯设备 DataReceivedEvent，按心跳间隔节流触发一次运行
    /// 注意：主程序需先设置 <see cref="Communication"/>（CoreManager.Communication）。
    /// </summary>
    public class FlowRunner
    {
        private static FlowRunner _instance;
        public static FlowRunner Instance => _instance ?? (_instance = new FlowRunner());

        private readonly object _sync = new object();
        private readonly Dictionary<string, DateTime> _lastTrigger = new Dictionary<string, DateTime>();
        private readonly Dictionary<Guid, List<Action<object, string>>> _subscriptions =
            new Dictionary<Guid, List<Action<object, string>>>();

        private FlowRunner() { }

        /// <summary>通讯管理器（由主程序注入 CoreManager.Communication）</summary>
        public CommunicationManager Communication { get; set; }

        /// <summary>运行态流程（从产品文件加载的独立副本）</summary>
        public List<FlowTabItem> RunTabs { get; private set; } = new List<FlowTabItem>();

        /// <summary>当前运行产品名</summary>
        public string RunProductName { get; private set; } = "";

        public bool IsRunning
        {
            get { lock (_sync) return _isRunning; }
            private set
            {
                bool changed;
                lock (_sync)
                {
                    changed = _isRunning != value;
                    _isRunning = value;
                }
                if (changed)
                    RunStateChanged?.Invoke();
            }
        }
        private bool _isRunning;

        private CancellationTokenSource _runCts;

        // 停止后后台循环仍在"排空"本轮（硬件节点无法中途打断），用该标记防止重复启动
        private volatile bool _draining;

        // 运行态流程的磁盘指纹：仅当流程文件变化时才重载，避免高频触发每次读盘反序列化
        private string _runTabsStamp;

        /// <summary>运行状态变化（开始/停止）——供首页按钮、编辑器锁定监听</summary>
        public event Action RunStateChanged;

        /// <summary>产品加载完成（参数：产品名）</summary>
        public event Action<string> ProductLoaded;

        /// <summary>一次运行结束</summary>
        public event Action RunCompleted;

        /// <summary>运行态 RunTabs 被重新加载（RefreshRunTabs 完成）——监控端订阅以自动同步显示</summary>
        public event Action RunTabsRefreshed;

        /// <summary>
        /// 加载产品为运行产品。
        /// </summary>
        public bool LoadRunProduct(string productName)
        {
            if (string.IsNullOrWhiteSpace(productName)) return false;

            // 切换运行产品前必须先停掉当前运行（首页"加载"也依赖此逻辑兜底）
            Stop();

            // 释放旧运行产品的所有插件资源（防止切换后旧插件句柄/连接残留）
            var oldTabs = RunTabs;
            RunTabs = new List<FlowTabItem>();
            ProductManager.DisposeFlowTabs(oldTabs);

            ProductManager.Instance.LoadProductToRun(productName);
            RunProductName = productName;
            RefreshRunTabs();

            RunStatistics.Instance.Log($"运行产品已加载: {productName}（{RunTabs.Count} 个流程）");
            ProductLoaded?.Invoke(productName);
            return true;
        }

        /// <summary>
        /// 重新解析运行态流程：始终从磁盘加载独立副本，编辑态与运行态彻底分离。
        /// 监控端（FlowEditorShellViewModel.IsMonitorMode=true）通过订阅 RunTabsRefreshed
        /// 主动挂接 RunTabs 显示运行状态，不再隐式共享编辑器 FlowTabs。
        /// </summary>
        private void RefreshRunTabs()
        {
            // 重载运行态流程前，先完全释放 Main（含上次产品的各流程与子流程残留），
            // 保证任何加载入口（首页/PLC 序号切换/心跳重载）都从干净的 Main 开始
            ResultRegistry.Main.ClearAllFlows();

            // 运行态流程绑定主页面专用注册表（与产品管理 Debug 注册表隔离）
            var oldTabs = RunTabs;
            RunTabs = ProductManager.Instance.LoadAllFlows(RunProductName, ResultRegistry.Main);

            // 释放上一轮运行态 Tab（插件 Dispose + Main 注册表清理），
            // 防止每次开始/停止累积一份带相机图像等大对象的旧插件实例
            if (oldTabs != null && oldTabs.Count > 0)
                ProductManager.DisposeFlowTabs(oldTabs);

            RunTabsRefreshed?.Invoke();
            _runTabsStamp = ProductManager.Instance.GetProductFlowStamp(RunProductName);
        }

        /// <summary>
        /// 仅当产品流程文件发生变化（或尚未加载）时才从磁盘重载运行态流程；否则复用内存中的 RunTabs。
        /// 用于高频触发（心跳/事件）路径，避免每次触发都读盘+反序列化+重建插件实例。
        /// </summary>
        private void RefreshRunTabsIfChanged()
        {
            var stamp = ProductManager.Instance.GetProductFlowStamp(RunProductName);
            if (RunTabs != null && RunTabs.Count > 0 && stamp == _runTabsStamp)
                return;
            RefreshRunTabs();
        }

        /// <summary>
        /// 执行一次：并行执行所有"主流程触发"的流程，全部结束后统计结果。
        /// </summary>
        public async Task<bool> RunOnceAsync()
        {
            if (IsRunning || _draining) return false;

            RefreshRunTabsIfChanged();

            var mains = RunTabs.Where(t => t.TriggerType == TriggerType.MainFlow).ToList();
            if (mains.Count == 0)
            {
                RunStatistics.Instance.Log("未加载运行产品或产品中没有主流程");
                return false;
            }

            IsRunning = true;
            _draining = false;
            _runCts = new CancellationTokenSource();
            bool success = true;
            var sw = Stopwatch.StartNew();
            try
            {
                RunStatistics.Instance.Log("开始运行...");
                var tasks = mains.Select(t => ExecuteTabAsync(t, _runCts.Token)).ToArray();
                var results = await Task.WhenAll(tasks);
                success = results.All(r => r);
            }
            finally
            {
                sw.Stop();
                _runCts?.Dispose();
                _runCts = null;
                _draining = false;
                IsRunning = false;
                RunStatistics.Instance.AddRun(success, sw.ElapsedMilliseconds);
                RunCompleted?.Invoke();
            }
            return success;
        }

        /// <summary>
        /// 循环运行：每个"主流程触发"的流程在独立的循环 Task 中运行，互不等待。
        /// 流程 A 慢、流程 B 快时，B 不会被 A 拖住等待；任何一个流程本轮完成立即进入下一轮。
        /// 直到 Stop() 被调用（取消 token）所有循环退出。
        /// </summary>
        public async Task RunLoopAsync()
        {
            if (IsRunning || _draining) return;

            RefreshRunTabs();

            var mains = RunTabs.Where(t => t.TriggerType == TriggerType.MainFlow).ToList();
            if (mains.Count == 0)
            {
                RunStatistics.Instance.Log("未加载运行产品或产品中没有主流程");
                return;
            }

            IsRunning = true;
            _draining = false;
            _runCts = new CancellationTokenSource();
            var token = _runCts.Token;
            RunStatistics.Instance.Log("开始循环运行（点击停止按钮结束）...");
            try
            {
                // 每个流程一个独立循环，互不等待
                var loopTasks = mains.Select(tab => RunSingleTabLoopAsync(tab, token)).ToList();
                await Task.WhenAll(loopTasks);
            }
            finally
            {
                _runCts?.Dispose();
                _runCts = null;
                _draining = false;
                IsRunning = false;
                RunStatistics.Instance.Log("运行已停止");
                RunCompleted?.Invoke();
            }
        }

        /// <summary>
        /// 单个流程的独立循环：完成一轮立即进入下一轮，不等其他流程。
        /// </summary>
        private async Task RunSingleTabLoopAsync(FlowTabItem tab, CancellationToken token)
        {
            while (!token.IsCancellationRequested)
            {
                var sw = Stopwatch.StartNew();
                bool ok = await ExecuteTabAsync(tab, token);
                sw.Stop();
                if (token.IsCancellationRequested) break;
                RunStatistics.Instance.AddRun(ok, sw.ElapsedMilliseconds);

                // 循环间隔：单轮结束后等待用户设置的毫秒数再开始下一轮（最小1ms，防止空流程卡CPU）
                try { await Task.Delay(tab.LoopIntervalMs, token); }
                catch (OperationCanceledException) { break; }
            }
        }

        /// <summary>
        /// 停止循环运行 / 单次运行。
        /// 立即解除"运行中"状态（编辑器解锁、按钮复位）；后台循环在完成本轮后自行结束。
        /// </summary>
        public void Stop()
        {
            _runCts?.Cancel();
            IsRunning = false;

            // 完全释放运行态结果缓存（含各流程与其子流程条目），释放挂住的大对象引用
            try { ResultRegistry.Main.ClearAllFlows(); }
            catch { }

            // 强制全代 GC，确保 LOH 大对象（图像、CogRecord 等）被回收
            GC.Collect(2, GCCollectionMode.Forced, true);
            GC.WaitForPendingFinalizers();
            GC.Collect(2, GCCollectionMode.Forced, true);
        }

        /// <summary>
        /// 按名称执行一个运行态流程（供事件触发等外部场景调用）。
        /// </summary>
        public async Task<bool> RunFlowByNameAsync(string flowName)
        {
            var tab = RunTabs.FirstOrDefault(t => t.Name == flowName);
            if (tab == null)
            {
                AppLogger.Warning($"运行流程不存在: {flowName}", nameof(FlowRunner));
                return false;
            }
            return await ExecuteTabAsync(tab, CancellationToken.None);
        }

        private async Task<bool> ExecuteTabAsync(FlowTabItem tab, CancellationToken token)
        {
            if (tab?.Graph == null) return false;
            var editorVm = tab.EditorVm;
            SetEditorRunning(editorVm, true);
            try
            {
                var executor = new FlowExecutor(tab.Graph);
                var tcs = new TaskCompletionSource<bool>();
                executor.ExecutionCompleted += ok => tcs.TrySetResult(ok);
                await executor.ExecuteAsync(token);
                return await tcs.Task;
            }
            catch (Exception ex)
            {
                AppLogger.Error($"流程执行异常: {tab.Name}", ex, nameof(FlowRunner));
                return false;
            }
        }

        /// <summary>
        /// 在 UI 线程同步编辑器 ViewModel 的 IsRunning，触发 RunFlowCommand 等按钮状态刷新。
        /// </summary>
        private static void SetEditorRunning(FlowEditorViewModel editorVm, bool running)
        {
            if (editorVm == null) return;
            System.Windows.Application.Current?.Dispatcher.Invoke(() =>
            {
                editorVm.IsRunning = running;
            });
        }

        #region 心跳触发

        /// <summary>
        /// 根据全局事件配置订阅通讯设备的数据到达事件，作为产品运行触发器。
        /// 同一设备按 IntervalMs 节流，防止高频数据把执行引擎打爆。
        /// </summary>
        public void StartHeartbeat()
        {
            StopHeartbeat();

            var cfg = GlobalVariableManager.LoadGlobalEventConfig();
            foreach (var hb in cfg.Heartbeats)
            {
                if (hb == null || !hb.Enabled) continue;

                var device = FindDevice(hb);
                if (device == null)
                {
                    AppLogger.Warning($"心跳设备未找到: {hb.DeviceName}", nameof(FlowRunner));
                    continue;
                }

                Action<object, string> handler = (s, data) => OnHeartbeatData(hb);
                device.DataReceivedEvent += handler;

                lock (_sync)
                {
                    if (!_subscriptions.TryGetValue(device.Id, out var list))
                    {
                        list = new List<Action<object, string>>();
                        _subscriptions[device.Id] = list;
                    }
                    list.Add(handler);
                }
            }

            AppLogger.Info($"心跳监听已启动，订阅 {_subscriptions.Count} 个设备", nameof(FlowRunner));
        }

        public void StopHeartbeat()
        {
            lock (_sync)
            {
                foreach (var kvp in _subscriptions)
                {
                    var device = Communication?.Get(kvp.Key);
                    if (device == null) continue;
                    foreach (var handler in kvp.Value)
                        device.DataReceivedEvent -= handler;
                }
                _subscriptions.Clear();
                _lastTrigger.Clear();
            }
        }

        private async void OnHeartbeatData(HeartbeatConfig hb)
        {
            if (hb == null || !hb.Enabled) return;

            var now = DateTime.Now;
            lock (_sync)
            {
                string key = hb.DeviceId.ToString();
                if (_lastTrigger.TryGetValue(key, out var last)
                    && (now - last).TotalMilliseconds < hb.IntervalMs)
                    return;
                _lastTrigger[key] = now;
            }

            await RunOnceAsync();
        }

        private ICommunication FindDevice(HeartbeatConfig hb)
        {
            if (Communication == null) return null;
            if (hb.DeviceId != Guid.Empty)
            {
                var byId = Communication.Get(hb.DeviceId);
                if (byId != null) return byId;
            }
            if (!string.IsNullOrWhiteSpace(hb.DeviceName))
                return Communication.GetByName(hb.DeviceName);
            return null;
        }

        #endregion
    }
}