using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Text.RegularExpressions;
using BarrageGrab.Modles.BiliProtoEntity;
using BarrageGrab.Proxy.ProxyEventArgs;
using BrotliSharpLib;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace BarrageGrab
{
    /// <summary>
    /// 哔哩哔哩弹幕抓取器
    /// 协议格式: 自定义16字节Big-Endian帧头 + JSON body (body可能为zlib/brotli压缩)
    /// </summary>
    public class BiliBarrageGrab
    {
        // B站直播弹幕WS域名
        // broadcast-msg.chat.bilibili.com (主域名)
        // *-live-comet.chat.bilibili.com (新版comet服务器, 如 zj-cn-live-comet.chat.bilibili.com)
        // live-trace.com (备用)
        // ws.live.bilibili.com (历史域名)
        private readonly Regex biliWsReg = new Regex(@"chat\.bilibili\.com|live-trace\.com|ws\.live\.bilibili\.com", RegexOptions.IgnoreCase);
        private const string BILI_LIVE_HOST = "live.bilibili.com";

        /// <summary>弹幕消息</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliDanmuMsg>> OnChatMessage;
        /// <summary>点赞消息</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliLikeData>> OnLikeMessage;
        /// <summary>礼物消息</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliGiftData>> OnGiftMessage;
        /// <summary>进入直播间/关注消息</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliInteractData>> OnInteractMessage;
        /// <summary>房间统计消息</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliRoomStats>> OnRoomStatsMessage;
        /// <summary>分享消息 (INTERACT_WORD中msg_type=3)</summary>
        public event EventHandler<BiliRoomMessageEventArgs<BiliInteractData>> OnShareMessage;

        public BiliBarrageGrab()
        {
        }

        /// <summary>
        /// 当前认证的房间ID (从AUTH包解析,供消息处理器读取)
        /// </summary>
        public string CurrentRoomId { get; private set; } = "";

        public bool IsBilibiliHost(string hostname)
        {
            if (string.IsNullOrWhiteSpace(hostname)) return false;
            hostname = hostname.Trim().ToLower();
            return biliWsReg.IsMatch(hostname) || hostname == BILI_LIVE_HOST;
        }

        public bool IsBilibiliWebSocket(string uri)
        {
            if (string.IsNullOrWhiteSpace(uri)) return false;
            return biliWsReg.IsMatch(uri);
        }

        /// <summary>
        /// 处理代理收到的B站WS数据
        /// </summary>
        public void HandleWebSocketData(WsMessageEventArgs e)
        {
            var buff = e.Payload;
            if (buff == null || buff.Length == 0) return;

            try
            {
                // 一个WS帧可能包含多个B站数据包,需要循环解析
                ProcessBuffer(buff, 0, buff.Length, e.ProcessName);
            }
            catch (Exception ex)
            {
                if (biliErrCount < 3)
                {
                    Logger.LogError(ex, $"处理B站弹幕数据包时出错:{ex.Message}");
                    biliErrCount++;
                }
                if (biliErrCount == 3)
                {
                    Logger.LogWarn("B站弹幕解析持续失败，已抑制后续错误日志");
                    biliErrCount++;
                }
            }
        }

        /// <summary>
        /// 处理客户端发送的B站WS数据 (解析AUTH认证包提取roomid)
        /// B站客户端连接WS后会发送AUTH包: {uid,roomid,protover,platform,type,key}
        /// </summary>
        public void HandleSentData(WsMessageEventArgs e)
        {
            var buff = e.Payload;
            if (buff == null || buff.Length < BiliSocketFrame.HEADER_SIZE) return;

            try
            {
                BiliSocketFrame frame;
                if (!BiliSocketFrame.TryParse(buff, 0, buff.Length, out frame)) return;

                // 只关注认证请求包 (Operation=7)
                if (frame.Operation != BiliOperation.AUTH) return;

                var payload = BiliSocketFrame.GetPayload(buff, 0, frame);
                if (payload == null || payload.Length == 0) return;

                var json = System.Text.Encoding.UTF8.GetString(payload);
                var jobj = JObject.Parse(json);
                var roomIdToken = jobj["roomid"];
                if (roomIdToken == null) return;

                // roomid可能是整数或字符串
                string roomId = roomIdToken.Type == JTokenType.Integer
                    ? roomIdToken.Value<long>().ToString()
                    : roomIdToken.Value<string>() ?? "";

                if (!string.IsNullOrWhiteSpace(roomId))
                {
                    CurrentRoomId = roomId;
                    Logger.LogInfo($"B站认证包解析成功,当前房间ID: {roomId}");
                }
            }
            catch (Exception ex)
            {
                Logger.LogWarn($"解析B站AUTH认证包失败: {ex.Message}");
            }
        }

        private static int biliErrCount = 0;

        /// <summary>
        /// 递归解析缓冲区中可能包含的多个B站数据包
        /// </summary>
        private void ProcessBuffer(byte[] buffer, int offset, int count, string processName)
        {
            int processed = 0;
            while (processed + BiliSocketFrame.HEADER_SIZE <= count)
            {
                BiliSocketFrame frame;
                if (!BiliSocketFrame.TryParse(buffer, offset + processed, count - processed, out frame))
                {
                    break;
                }

                // 包长超过剩余缓冲区,说明数据不完整,等下次再处理
                if (processed + frame.PacketLength > count)
                {
                    break;
                }

                var payload = BiliSocketFrame.GetPayload(buffer, offset + processed, frame);
                processed += (int)frame.PacketLength;

                // 只处理服务器推送的消息和心跳回复
                if (frame.Operation == BiliOperation.HEARTBEAT_REPLY)
                {
                    // 心跳回复: body是4字节big-endian人气值
                    if (payload != null && payload.Length >= 4)
                    {
                        var online = (long)BiliSocketFrame.ReadUInt32BE(payload, 0);
                        var stats = new BiliRoomStats { Online = online, Watched = 0 };
                        OnRoomStatsMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliRoomStats>(processName, stats));
                    }
                    continue;
                }

                if (frame.Operation != BiliOperation.MESSAGE) continue;

                // 根据协议版本解压
                byte[] jsonBytes;
                switch (frame.ProtocolVersion)
                {
                    case BiliProtocolVersion.PLAIN:
                    case BiliProtocolVersion.PLAIN_AUTH:
                        jsonBytes = payload;
                        break;
                    case BiliProtocolVersion.ZLIB:
                        jsonBytes = ZlibDecompress(payload);
                        break;
                    case BiliProtocolVersion.BROTLI:
                        jsonBytes = BrotliDecompress(payload);
                        break;
                    default:
                        jsonBytes = payload;
                        break;
                }

                if (jsonBytes == null || jsonBytes.Length == 0) continue;

                // 解压后可能仍然是多个数据包 (Zlib/Brotli压缩的通常是合并包)
                if (frame.ProtocolVersion == BiliProtocolVersion.ZLIB ||
                    frame.ProtocolVersion == BiliProtocolVersion.BROTLI)
                {
                    ProcessBuffer(jsonBytes, 0, jsonBytes.Length, processName);
                    continue;
                }

                // 明文JSON: 解析为消息
                DispatchJsonMessage(jsonBytes, processName);
            }
        }

        /// <summary>
        /// 将JSON字节解析为B站消息并触发对应事件
        /// </summary>
        private void DispatchJsonMessage(byte[] jsonBytes, string processName)
        {
            string json;
            try
            {
                json = System.Text.Encoding.UTF8.GetString(jsonBytes);
            }
            catch { return; }

            if (string.IsNullOrWhiteSpace(json)) return;

            JObject jobj;
            try
            {
                jobj = JObject.Parse(json);
            }
            catch { return; }

            var cmdToken = jobj["cmd"];
            if (cmdToken == null) return;
            string cmd = cmdToken.Value<string>();
            if (string.IsNullOrWhiteSpace(cmd)) return;

            // 兼容cmd带数字后缀的版本,如 DANMU_MSG-4b1cb6f3
            int dashIdx = cmd.IndexOf('-');
            if (dashIdx > 0) cmd = cmd.Substring(0, dashIdx);

            switch (cmd)
            {
                case BiliCmd.DANMU_MSG:
                    {
                        var msg = ParseDanmuMsg(jobj);
                        if (msg != null)
                        {
                            OnChatMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliDanmuMsg>(processName, msg));
                        }
                        break;
                    }
                case BiliCmd.SEND_GIFT:
                    {
                        var msg = jobj["data"]?.ToObject<BiliGiftData>();
                        if (msg != null)
                        {
                            OnGiftMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliGiftData>(processName, msg));
                        }
                        break;
                    }
                case BiliCmd.INTERACT_WORD:
                    {
                        var msg = jobj["data"]?.ToObject<BiliInteractData>();
                        if (msg != null)
                        {
                            // msg_type: 1=进入 2=关注 3=分享
                            if (msg.MsgType == 3)
                            {
                                OnShareMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliInteractData>(processName, msg));
                            }
                            else
                            {
                                OnInteractMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliInteractData>(processName, msg));
                            }
                        }
                        break;
                    }
                case BiliCmd.LIKE_INFO_V3_CLICK:
                    {
                        var msg = jobj["data"]?.ToObject<BiliLikeData>();
                        if (msg != null)
                        {
                            OnLikeMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliLikeData>(processName, msg));
                        }
                        break;
                    }
                case BiliCmd.ONLINE_RANK_COUNT:
                    {
                        var count = jobj["data"]?["count"]?.Value<long>() ?? 0;
                        var stats = new BiliRoomStats { Online = count, Watched = 0 };
                        OnRoomStatsMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliRoomStats>(processName, stats));
                        break;
                    }
                case BiliCmd.WATCHED_CHANGE:
                    {
                        var num = jobj["data"]?["num"]?.Value<long>() ?? 0;
                        var stats = new BiliRoomStats { Online = 0, Watched = num };
                        OnRoomStatsMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliRoomStats>(processName, stats));
                        break;
                    }
                case BiliCmd.ROOM_REAL_TIME_MESSAGE_UPDATE:
                    {
                        // 同时包含在线人数和看过人数
                        var online = jobj["data"]?["online"]?.Value<long>() ?? 0;
                        var watched = jobj["data"]?["watched_show"]?["num"]?.Value<long>() ?? 0;
                        var stats = new BiliRoomStats { Online = online, Watched = watched };
                        OnRoomStatsMessage?.Invoke(this, new BiliRoomMessageEventArgs<BiliRoomStats>(processName, stats));
                        break;
                    }
                default:
                    // 未知消息类型忽略
                    break;
            }
        }

        /// <summary>
        /// 解析DANMU_MSG消息: info[1]=内容, info[2]=[uid,uname,isAdmin,rank,?anchor]
        /// </summary>
        private BiliDanmuMsg ParseDanmuMsg(JObject jobj)
        {
            try
            {
                var info = jobj["info"] as JArray;
                if (info == null || info.Count < 3) return null;

                var content = info[1]?.Value<string>() ?? "";
                var userInfo = info[2] as JArray;
                if (userInfo == null || userInfo.Count < 2) return null;

                var msg = new BiliDanmuMsg
                {
                    Content = content,
                    Uid = userInfo[0]?.Value<long>() ?? 0,
                    Uname = userInfo[1]?.Value<string>() ?? "",
                    IsAdmin = userInfo.Count > 2 && userInfo[2]?.Value<int>() == 1,
                    IsAnchor = userInfo.Count > 4 && userInfo[4] != null && userInfo[4].Type != JTokenType.Null
                };
                return msg;
            }
            catch
            {
                return null;
            }
        }

        /// <summary>Zlib解压</summary>
        private byte[] ZlibDecompress(byte[] data)
        {
            if (data == null || data.Length == 0) return null;
            try
            {
                using (var ms = new MemoryStream(data))
                using (var zlib = new DeflateStream(ms, CompressionMode.Decompress))
                using (var outMs = new MemoryStream())
                {
                    // zlib前2字节是header(0x78 0x9c等),DeflateStream需要跳过
                    // 但 .NET Core 2.1+ 的 DeflateStream 可以处理 zlib header, .NET Framework 需要跳过
                    if (data.Length >= 2 && data[0] == 0x78)
                    {
                        ms.Position = 2;
                    }
                    zlib.CopyTo(outMs);
                    return outMs.ToArray();
                }
            }
            catch (Exception ex)
            {
                Logger.LogWarn($"B站Zlib解压失败: {ex.Message}");
                return null;
            }
        }

        /// <summary>Brotli解压 (使用 BrotliSharpLib)</summary>
        private byte[] BrotliDecompress(byte[] data)
        {
            if (data == null || data.Length == 0) return null;
            try
            {
                using (var ms = new MemoryStream(data))
                using (var brotli = new BrotliSharpLib.BrotliStream(ms, CompressionMode.Decompress))
                using (var outMs = new MemoryStream())
                {
                    brotli.CopyTo(outMs);
                    return outMs.ToArray();
                }
            }
            catch (Exception ex)
            {
                Logger.LogWarn($"B站Brotli解压失败: {ex.Message}");
                return null;
            }
        }
    }

    /// <summary>B站消息事件参数</summary>
    public class BiliRoomMessageEventArgs<T> : EventArgs where T : class
    {
        public string Process { get; set; }
        public T Message { get; set; }

        public BiliRoomMessageEventArgs() { }

        public BiliRoomMessageEventArgs(string process, T data)
        {
            this.Process = process;
            this.Message = data;
        }
    }
}