using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Timers;

namespace SKMC.Api.Common.Monitor
{
    /// <summary>
    /// 状态锁存管理器, 用于低频的状态判断并锁定
    /// 例如总线连接状态、设备物料状态、是否长时间无人操作等
    /// </summary>
    public class StateLatchManager : IDisposable
    {
        private readonly Dictionary<string, LatchTask> _tasks = new Dictionary<string, LatchTask>();
        private readonly Timer _timer;

        /// <summary>
        /// 监测并锁定的状态
        /// </summary>
        private static readonly int LATCH_VAL = -1;

        public StateLatchManager(int interval = 5000)
        {
            _timer = new Timer(interval);
            _timer.Elapsed += (s, e) => RunAllTasks();
            // 没有限制重入
            _timer.AutoReset = true;
        }

        /// <summary>
        /// 添加任务，支持返回 bool 或可转换为 int 的数值类型
        /// </summary>
        public void AddTask<T>(string key, Func<T> task, Action callback = null, LatchMode mode = LatchMode.OpenMode)
        {
            _tasks[key] = new LatchTask
            {
                Task = task,
                Callback = callback,
                Mode = mode
            };
        }

        /// <summary>
        /// 获取任务信息
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public LatchTask GetTask(string key)
        {
            return _tasks.ContainsKey(key) ? _tasks[key] : null;
        }

        /// <summary>
        /// 获取累计结果
        /// </summary>
        public int GetResult(string key)
        {
            // TODO 如果获取结果的时间戳与当前时间戳差距较大则无效
            return _tasks.ContainsKey(key) ? _tasks[key].LatchResult : 0;
        }

        /// <summary>
        /// 重置任务结果
        /// </summary>
        public void ResetResult(string key)
        {
            if (_tasks.ContainsKey(key))
            {
                _tasks[key].LatchResult = 0;
                _tasks[key].ErrorInfo = null;
                _tasks[key].Initialized = false;
            }
        }

        public void Start() => _timer.Start();
        public void Stop() => _timer.Stop();

        private void RunAllTasks()
        {
            foreach (var task in _tasks)
            {
                if (task.Value.LatchResult != LATCH_VAL && task.Value.ErrorInfo == null)
                {
                    try
                    {
                        var rawResult = task.Value.Task.DynamicInvoke();
                        int result = ConvertToInt(rawResult);

                        if (task.Value.Mode == LatchMode.CloseMode)
                        {
                            if (task.Value.Initialized)
                            {
                                task.Value.LatchResult &= result;
                                task.Value.LatchResult = task.Value.LatchResult == 0 ? -1 : 1;
                            }
                            else
                            {
                                task.Value.LatchResult = result == 0 ? -1 : 1;
                                task.Value.Initialized = true;
                            }
                        }
                        else if (task.Value.Mode == LatchMode.OpenMode)
                        {
                            if (task.Value.Initialized)
                            {
                                task.Value.LatchResult &= result;
                                task.Value.LatchResult = task.Value.LatchResult == 0 ? 1 : -1;
                            }
                            else
                            {
                                task.Value.LatchResult = result == 0 ? 1 : -1;
                                task.Value.Initialized = true;
                            }
                        }
                        if (task.Value.LatchResult == LATCH_VAL)
                        {
                            task.Value.LatchTime = DateTime.Now;
                            task.Value.Callback?.Invoke();
                        }
                    }
                    catch(Exception e)
                    {
                        task.Value.ErrorInfo = $"ErrorInfo: {e.Message}, Datetime: {DateTime.Now}";
                    }
                }
            }
        }

        private int ConvertToInt(object value)
        {
            if (value is bool b)
                return b ? 1 : 0;
            return Convert.ToInt32(value);
        }

        public void Dispose() => _timer?.Dispose();
    }

    public class LatchTask
    {
        /// <summary>
        /// 监测任务
        /// </summary>
        public Delegate Task { get; set; }
        /// <summary>
        /// 是否已初始化
        /// </summary>
        public bool Initialized { get; set; }
        /// <summary>
        /// 当前结果
        /// </summary>
        public int LatchResult { get; set; }
        /// <summary>
        /// 锁存模式
        /// </summary>
        public LatchMode Mode { get; set; }
        /// <summary>
        /// 触发时间
        /// </summary>
        public DateTime LatchTime { get; set; }
        /// <summary>
        /// 异常信息
        /// </summary>
        public string ErrorInfo { get; set; }
        /// <summary>
        /// 触发后回调动作
        /// </summary>
        public Action Callback { get; set; }
    }

    public enum LatchMode
    {
        /// <summary>
        /// 适用常闭模式：11101/11001返回-1，11111返回1
        /// </summary>
        CloseMode,

        /// <summary>
        /// 适用常开模式：00010/00110返回-1，00000返回1
        /// </summary>
        OpenMode
    }

}