using System;
using System.Collections.Concurrent;
using System.Threading;
using Microsoft.Extensions.Logging;

namespace CellularManagement.WebSocket.Monitor;

/// <summary>
/// WebSocket 性能监控器
/// 用于收集和记录 WebSocket 连接的性能指标
/// </summary>
public class WebSocketPerformanceMonitor
{
    private readonly ILogger _logger;
    private readonly ConcurrentDictionary<string, ConnectionMetrics> _metrics = new();

    public class ConnectionMetrics
    {
        private long _totalMessages;
        private long _totalBytes;
        private long _processingTime;
        private int _errorCount;

        public long TotalMessages => _totalMessages;
        public long TotalBytes => _totalBytes;
        public long ProcessingTime => _processingTime;
        public long LastMessageTime { get; set; }
        public int ErrorCount => _errorCount;

        public void IncrementMessages() => Interlocked.Increment(ref _totalMessages);
        public void AddBytes(long bytes) => Interlocked.Add(ref _totalBytes, bytes);
        public void AddProcessingTime(long time) => Interlocked.Add(ref _processingTime, time);
        public void IncrementErrors() => Interlocked.Increment(ref _errorCount);
    }

    public WebSocketPerformanceMonitor(ILogger logger)
    {
        _logger = logger;
    }

    /// <summary>
    /// 记录消息处理性能指标
    /// </summary>
    /// <param name="connectionId">连接ID</param>
    /// <param name="messageSize">消息大小</param>
    /// <param name="processingTime">处理时间（毫秒）</param>
    public void RecordMessage(string connectionId, int messageSize, long processingTime)
    {
        var metrics = _metrics.GetOrAdd(connectionId, _ => new ConnectionMetrics());
        metrics.IncrementMessages();
        metrics.AddBytes(messageSize);
        metrics.AddProcessingTime(processingTime);
        metrics.LastMessageTime = DateTime.UtcNow.Ticks;

        if (metrics.TotalMessages % 100 == 0)
        {
            LogMetrics(connectionId, metrics);
        }
    }

    /// <summary>
    /// 记录错误
    /// </summary>
    /// <param name="connectionId">连接ID</param>
    public void RecordError(string connectionId)
    {
        if (_metrics.TryGetValue(connectionId, out var metrics))
        {
            metrics.IncrementErrors();
        }
    }

    /// <summary>
    /// 获取连接的性能指标
    /// </summary>
    /// <param name="connectionId">连接ID</param>
    /// <returns>性能指标</returns>
    public ConnectionMetrics GetMetrics(string connectionId)
    {
        return _metrics.TryGetValue(connectionId, out var metrics) ? metrics : null;
    }

    /// <summary>
    /// 清理连接的性能指标
    /// </summary>
    /// <param name="connectionId">连接ID</param>
    public void ClearMetrics(string connectionId)
    {
        _metrics.TryRemove(connectionId, out _);
    }

    private void LogMetrics(string connectionId, ConnectionMetrics metrics)
    {
        _logger.LogInformation(
            "连接性能指标 - ID: {ConnectionId}, 消息数: {MessageCount}, " +
            "总字节数: {TotalBytes}, 平均处理时间: {AvgProcessingTime}ms, " +
            "错误数: {ErrorCount}",
            connectionId,
            metrics.TotalMessages,
            metrics.TotalBytes,
            metrics.ProcessingTime / metrics.TotalMessages,
            metrics.ErrorCount);
    }
}