using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using CoreAgent.ProtocolClient.HandlerEventArgs;
using CoreAgent.ProtocolClient.Models;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json.Linq;

namespace CoreAgent.ProtocolClient.Managers
{
    /// <summary>
    /// 消息ID管理器
    /// </summary>
    public class MessageIdManager : IDisposable
    {
        #region 私有字段

        private readonly ILogger<MessageIdManager> _logger;
        private readonly string _clientName;
        private readonly ConcurrentDictionary<long, MessageHandler> _messageHandlers;
        private readonly ConcurrentDictionary<string, MessageHandler> _messageHandlersByName;

        // 使用long类型防止溢出
        private long _generalMessageId;
        private long _logGetMessageId;

        // 状态管理
        private bool _disposed;

        // 性能优化：缓存字符串构建器
        private readonly StringBuilder _logBuilder = new StringBuilder(256);

        #endregion

        #region 事件

        /// <summary>
        /// 日志获取ID变化事件
        /// </summary>
        public event EventHandler<LogGetIdChangedEventArgs>? LogGetIdChanged;

        /// <summary>
        /// 消息处理器清理事件
        /// </summary>
        public event EventHandler<HandlerCleanupEventArgs>? HandlerCleanup;

        #endregion

        #region 属性

        /// <summary>
        /// 当前通用消息ID
        /// </summary>
        public long CurrentGeneralMessageId => Interlocked.Read(ref _generalMessageId);

        /// <summary>
        /// 当前日志获取消息ID
        /// </summary>
        public long CurrentLogGetMessageId => Interlocked.Read(ref _logGetMessageId);

        /// <summary>
        /// 是否已释放
        /// </summary>
        public bool IsDisposed => _disposed;

        /// <summary>
        /// 消息处理器数量
        /// </summary>
        public int MessageHandlerCount => _messageHandlers.Count;

        /// <summary>
        /// 按名称的消息处理器数量
        /// </summary>
        public int NamedMessageHandlerCount => _messageHandlersByName.Count;

        /// <summary>
        /// 总处理器数量
        /// </summary>
        public int TotalHandlerCount => MessageHandlerCount + NamedMessageHandlerCount;

        #endregion

        #region 构造函数

        /// <summary>
        /// 构造函数
        /// </summary>
        public MessageIdManager(string clientName, ILogger<MessageIdManager> logger)
        {
            _clientName = clientName ?? throw new ArgumentNullException(nameof(clientName));
            _logger = logger ?? throw new ArgumentNullException(nameof(logger));

            _messageHandlers = new ConcurrentDictionary<long, MessageHandler>();
            _messageHandlersByName = new ConcurrentDictionary<string, MessageHandler>();

            _generalMessageId = 0;
            _logGetMessageId = -1; // 初始化为-1，表示未开始

            _logger.LogInformation("[{ClientName}] 创建消息ID管理器，初始LogGet ID: {LogGetId}", _clientName, _logGetMessageId);
        }

        #endregion

        #region 公共方法

        /// <summary>
        /// 生成通用消息ID
        /// </summary>
        public long GenerateGeneralMessageId(JObject message, Action<JObject>? callback = null, bool errorHandler = false)
        {
            ThrowIfDisposed();
            ValidateMessage(message);

            var id = GetNextMessageId();
            message["message_id"] = id;

            // 记录log_get消息的发送
            var messageType = message["message"]?.ToString();
            if (messageType == "log_get")
            {
                LogLogGetMessage(id, message);
            }

            // 注册回调处理器
            if (callback != null)
            {
                _messageHandlers[id] = new MessageHandler
                {
                    Callback = callback,
                    ErrorHandler = errorHandler,
                    CreatedAt = DateTime.UtcNow
                };
            }

            _logger.LogDebug("[{ClientName}] 生成通用消息ID: {MessageId}", _clientName, id);
            return id;
        }

        /// <summary>
        /// 生成日志获取消息ID
        /// </summary>
        public long GenerateLogGetMessageId(JObject message, Action<JObject> callback)
        {
            ThrowIfDisposed();
            ValidateMessage(message);

            if (callback == null)
                throw new ArgumentNullException(nameof(callback));

            // 生成新的消息ID
            var newLogGetId = GetNextMessageId();
            message["message_id"] = newLogGetId;

            // 注册回调处理器
            _messageHandlers[newLogGetId] = new MessageHandler
            {
                Callback = callback,
                ErrorHandler = false,
                CreatedAt = DateTime.UtcNow,
                IsLogGetHandler = true
            };

            // 设置新的LogGet ID
            var oldLogGetId = Interlocked.Exchange(ref _logGetMessageId, newLogGetId);

            // 触发事件
            LogGetIdChanged?.Invoke(this, new LogGetIdChangedEventArgs(oldLogGetId, newLogGetId));

            _logger.LogDebug("[{ClientName}] LogGet ID变化: {OldId} -> {NewId}", _clientName, oldLogGetId, newLogGetId);
            return newLogGetId;
        }

        /// <summary>
        /// 处理消息响应
        /// </summary>
        public bool HandleMessageResponse(JObject response, Action<string>? errorHandler = null)
        {
            ThrowIfDisposed();

            if (response == null)
                return false;

            // 检查消息处理器
            var id = response["message_id"]?.Value<long>();
            if (id.HasValue && _messageHandlers.TryGetValue(id.Value, out var handler))
            {
                return HandleMessageHandler(id.Value, handler, response, errorHandler);
            }

            // 检查按名称的消息处理器
            var name = response["message"]?.ToString();
            if (!string.IsNullOrEmpty(name) && _messageHandlersByName.TryGetValue(name, out var nameHandler))
            {
                return HandleNamedMessageHandler(name, nameHandler, response);
            }

            return false;
        }

        /// <summary>
        /// 设置消息处理器
        /// </summary>
        public void SetMessageHandler(string[] names, MessageHandler handler)
        {
            ThrowIfDisposed();

            if (names == null || names.Length == 0)
                throw new ArgumentException("消息名称不能为空", nameof(names));

            if (handler == null)
                throw new ArgumentNullException(nameof(handler));

            foreach (var name in names)
            {
                if (!string.IsNullOrEmpty(name))
                {
                    _messageHandlersByName[name] = handler;
                }
            }

            _logger.LogDebug("[{ClientName}] 设置消息处理器: {Names}", _clientName, string.Join(", ", names));
        }

        /// <summary>
        /// 取消消息处理器
        /// </summary>
        public void UnsetMessageHandler(string[] names)
        {
            ThrowIfDisposed();

            if (names == null || names.Length == 0)
                return;

            foreach (var name in names)
            {
                if (!string.IsNullOrEmpty(name))
                {
                    _messageHandlersByName.TryRemove(name, out _);
                }
            }

            _logger.LogDebug("[{ClientName}] 取消消息处理器: {Names}", _clientName, string.Join(", ", names));
        }

        /// <summary>
        /// 检查是否为当前日志获取消息
        /// </summary>
        public bool IsCurrentLogGetMessage(long messageId)
        {
            var currentLogGetId = Interlocked.Read(ref _logGetMessageId);
            return messageId == currentLogGetId;
        }

        /// <summary>
        /// 重置日志获取ID
        /// </summary>
        public void ResetLogGetId()
        {
            var oldLogGetId = Interlocked.Exchange(ref _logGetMessageId, -1);
            LogGetIdChanged?.Invoke(this, new LogGetIdChangedEventArgs(oldLogGetId, -1));
            _logger.LogDebug("[{ClientName}] 重置LogGet ID: {OldId} -> -1", _clientName, oldLogGetId);
        }

        /// <summary>
        /// 清理过期的消息处理器
        /// </summary>
        public int CleanupExpiredHandlers(int maxAge = 30000) // 默认30秒
        {
            ThrowIfDisposed();

            var now = DateTime.UtcNow;
            var expiredKeys = new List<long>();

            foreach (var kvp in _messageHandlers)
            {
                if (kvp.Value.CreatedAt.AddMilliseconds(maxAge) < now)
                {
                    expiredKeys.Add(kvp.Key);
                }
            }

            var cleanedCount = 0;
            foreach (var key in expiredKeys)
            {
                if (_messageHandlers.TryRemove(key, out _))
                {
                    cleanedCount++;
                }
            }

            if (cleanedCount > 0)
            {
                _logger.LogDebug("[{ClientName}] 清理了 {CleanedCount} 个过期的消息处理器", _clientName, cleanedCount);

                // 触发清理事件
                HandlerCleanup?.Invoke(this, new HandlerCleanupEventArgs(
                    _messageHandlers.Count,
                    _messageHandlersByName.Count,
                    cleanedCount));
            }

            return cleanedCount;
        }

        #endregion

        #region 私有方法

        /// <summary>
        /// 获取下一个消息ID
        /// </summary>
        private long GetNextMessageId()
        {
            var id = Interlocked.Increment(ref _generalMessageId);

            // 检查溢出
            if (id <= 0)
            {
                _logger.LogWarning("[{ClientName}] 消息ID溢出，重置为1", _clientName);
                Interlocked.Exchange(ref _generalMessageId, 1);
                return 1;
            }

            return id;
        }

        /// <summary>
        /// 验证消息对象
        /// </summary>
        private void ValidateMessage(JObject message)
        {
            if (message == null)
                throw new ArgumentNullException(nameof(message));
        }

        /// <summary>
        /// 处理消息处理器
        /// </summary>
        private bool HandleMessageHandler(long id, MessageHandler handler, JObject response, Action<string>? errorHandler)
        {
            // 如果不是通知消息，则移除处理器
            if (response["notification"]?.Value<bool>() != true)
            {
                _messageHandlers.TryRemove(id, out _);
            }

            // 处理错误
            if (response["error"] != null)
            {
                if (!handler.ErrorHandler)
                {
                    errorHandler?.Invoke(response["error"]?.ToString() ?? "未知错误");
                }
                else
                {
                    handler.Callback?.Invoke(response);
                }
                return true;
            }

            // 正常处理
            handler.Callback?.Invoke(response);
            return true;
        }

        /// <summary>
        /// 处理按名称的消息处理器
        /// </summary>
        private bool HandleNamedMessageHandler(string name, MessageHandler handler, JObject response)
        {
            handler.Callback?.Invoke(response);
            return true;
        }

        /// <summary>
        /// 记录LogGet消息
        /// </summary>
        private void LogLogGetMessage(long id, JObject message)
        {
            _logBuilder.Clear();
            _logBuilder.AppendFormat("[{0}] 发送log_get消息: message_id={1}", _clientName, id);

            if (message["timeout"] != null)
                _logBuilder.AppendFormat(", timeout={0}", message["timeout"]);

            if (message["headers"] != null)
                _logBuilder.AppendFormat(", headers={0}", message["headers"]);

            _logBuilder.AppendFormat(", ThreadId={0}", Thread.CurrentThread.ManagedThreadId);

            _logger.LogDebug(_logBuilder.ToString());
        }

        /// <summary>
        /// 检查是否已释放
        /// </summary>
        private void ThrowIfDisposed()
        {
            if (_disposed)
            {
                throw new ObjectDisposedException(nameof(MessageIdManager));
            }
        }

        #endregion

        #region IDisposable

        /// <summary>
        /// 释放资源
        /// </summary>
        public void Dispose()
        {
            if (_disposed) return;

            _disposed = true;

            // 清理所有消息处理器
            _messageHandlers.Clear();
            _messageHandlersByName.Clear();

            _logger.LogInformation("[{ClientName}] 释放消息ID管理器", _clientName);
        }

        #endregion
    }
}