using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Protocol376Simulator.Interfaces;

namespace Protocol376Simulator.Services
{
    /// <summary>
    /// 统计服务类，用于收集和报告通信统计信息
    /// </summary>
    public class StatisticsService
    {
        private readonly string _deviceIdentifier;
        private int _totalMessagesSent = 0;
        private int _totalMessagesReceived = 0;
        private int _failedMessages = 0;
        private readonly Dictionary<MessageType, int> _messageTypeStats = new Dictionary<MessageType, int>();
        private readonly List<TimeSpan> _responseTimes = new List<TimeSpan>();
        private DateTime _lastMessageSentTime = DateTime.MinValue;
        private readonly Dictionary<string, int> _errorStats = new Dictionary<string, int>();
        
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="deviceIdentifier">设备标识（用于日志和显示）</param>
        public StatisticsService(string deviceIdentifier)
        {
            _deviceIdentifier = deviceIdentifier;
            
            // 初始化消息类型统计
            foreach (MessageType type in Enum.GetValues(typeof(MessageType)))
            {
                _messageTypeStats[type] = 0;
            }
        }
        
        /// <summary>
        /// 总发送消息数
        /// </summary>
        public int TotalMessagesSent => _totalMessagesSent;
        
        /// <summary>
        /// 总接收消息数
        /// </summary>
        public int TotalMessagesReceived => _totalMessagesReceived;
        
        /// <summary>
        /// 失败消息数
        /// </summary>
        public int FailedMessages => _failedMessages;
        
        /// <summary>
        /// 消息类型统计
        /// </summary>
        public Dictionary<MessageType, int> MessageTypeStats => _messageTypeStats;
        
        /// <summary>
        /// 平均响应时间
        /// </summary>
        public TimeSpan AverageResponseTime => _responseTimes.Count > 0 ? 
            TimeSpan.FromMilliseconds(_responseTimes.Average(t => t.TotalMilliseconds)) : 
            TimeSpan.Zero;
        
        /// <summary>
        /// 最大响应时间
        /// </summary>
        public TimeSpan MaxResponseTime => _responseTimes.Count > 0 ? 
            _responseTimes.Max() : TimeSpan.Zero;
        
        /// <summary>
        /// 最小响应时间
        /// </summary>
        public TimeSpan MinResponseTime => _responseTimes.Count > 0 ? 
            _responseTimes.Min() : TimeSpan.Zero;
        
        /// <summary>
        /// 记录消息发送
        /// </summary>
        public void RecordMessageSent()
        {
            _totalMessagesSent++;
            _lastMessageSentTime = DateTime.Now;
        }
        
        /// <summary>
        /// 记录消息接收
        /// </summary>
        public void RecordMessageReceived()
        {
            _totalMessagesReceived++;
        }
        
        /// <summary>
        /// 记录消息失败
        /// </summary>
        public void RecordMessageFailed()
        {
            _failedMessages++;
        }
        
        /// <summary>
        /// 记录消息类型统计
        /// </summary>
        /// <param name="messageType">消息类型</param>
        public void RecordMessageType(MessageType messageType)
        {
            if (_messageTypeStats.ContainsKey(messageType))
            {
                _messageTypeStats[messageType]++;
            }
        }
        
        /// <summary>
        /// 记录响应时间
        /// </summary>
        /// <param name="responseTime">响应时间</param>
        public void RecordResponseTime(TimeSpan responseTime)
        {
            if (responseTime.TotalMilliseconds > 0)
            {
                _responseTimes.Add(responseTime);
                
                // 保持响应时间列表在合理大小范围内，避免内存泄漏
                if (_responseTimes.Count > 1000)
                {
                    _responseTimes.RemoveAt(0);
                }
            }
        }
        
        /// <summary>
        /// 记录错误统计
        /// </summary>
        /// <param name="errorType">错误类型</param>
        public void RecordError(string errorType)
        {
            if (string.IsNullOrEmpty(errorType))
            {
                return;
            }
            
            if (_errorStats.ContainsKey(errorType))
            {
                _errorStats[errorType]++;
            }
            else
            {
                _errorStats[errorType] = 1;
            }
        }
        
        /// <summary>
        /// 获取统计信息的字符串表示
        /// </summary>
        /// <returns>格式化的统计信息</returns>
        public string GetStatisticsReport()
        {
            var sb = new StringBuilder();
            
            sb.AppendLine($"设备 {_deviceIdentifier} 通信统计：");
            sb.AppendLine($"总发送消息数: {_totalMessagesSent}");
            sb.AppendLine($"总接收消息数: {_totalMessagesReceived}");
            sb.AppendLine($"失败消息数: {_failedMessages}");
            
            if (_responseTimes.Count > 0)
            {
                sb.AppendLine($"平均响应时间: {AverageResponseTime.TotalMilliseconds:F2}毫秒");
                sb.AppendLine($"最大响应时间: {MaxResponseTime.TotalMilliseconds:F2}毫秒");
                sb.AppendLine($"最小响应时间: {MinResponseTime.TotalMilliseconds:F2}毫秒");
            }
            else
            {
                sb.AppendLine("尚未记录响应时间");
            }
            
            sb.AppendLine("消息类型统计：");
            foreach (var type in _messageTypeStats.Where(x => x.Value > 0).OrderByDescending(x => x.Value))
            {
                sb.AppendLine($"  {type.Key}: {type.Value}");
            }
            
            if (_errorStats.Count > 0)
            {
                sb.AppendLine("错误统计：");
                foreach (var error in _errorStats.OrderByDescending(x => x.Value))
                {
                    sb.AppendLine($"  {error.Key}: {error.Value}");
                }
            }
            
            return sb.ToString();
        }
        
        /// <summary>
        /// 重置所有统计数据
        /// </summary>
        public void ResetStatistics()
        {
            _totalMessagesSent = 0;
            _totalMessagesReceived = 0;
            _failedMessages = 0;
            _responseTimes.Clear();
            _lastMessageSentTime = DateTime.MinValue;
            
            foreach (MessageType type in Enum.GetValues(typeof(MessageType)))
            {
                _messageTypeStats[type] = 0;
            }
            
            _errorStats.Clear();
        }
    }
}