using System;
using System.Collections.Generic;

namespace TeamAAS.Logging
{
    /// <summary>
    /// 内存日志总线：AppLogger / PluginLogger 写文件的同时把结构化条目发布到这里，
    /// 实时日志控件（LogView）订阅 <see cref="Published"/> 联动显示，并可用 <see cref="Snapshot"/> 回填历史。
    /// 发布过程吞掉一切异常，绝不影响业务流程。
    /// </summary>
    public static class LogStream
    {
        /// <summary>环形缓冲容量（新控件加载时可回填的最近条目数）。</summary>
        public const int BufferCapacity = 1000;

        private static readonly object Gate = new object();
        private static readonly Queue<LogEntry> Buffer = new Queue<LogEntry>();

        /// <summary>有新日志条目时触发（可能在任意后台线程触发，订阅方自行切 UI 线程）。</summary>
        public static event Action<LogEntry> Published;

        /// <summary>发布一条日志条目：入环形缓冲并通知订阅者。</summary>
        public static void Publish(LogEntry entry)
        {
            if (entry == null) return;

            lock (Gate)
            {
                Buffer.Enqueue(entry);
                while (Buffer.Count > BufferCapacity)
                    Buffer.Dequeue();
            }

            try
            {
                Published?.Invoke(entry);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("[LogStream] publish failed: " + ex.Message);
            }
        }

        /// <summary>返回当前缓冲的快照（最旧→最新），供控件首次加载回填。</summary>
        public static List<LogEntry> Snapshot()
        {
            lock (Gate)
            {
                return new List<LogEntry>(Buffer);
            }
        }

        /// <summary>清空缓冲（不影响已显示在控件里的条目）。</summary>
        public static void Clear()
        {
            lock (Gate)
            {
                Buffer.Clear();
            }
        }
    }
}