using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
using Google.Protobuf;
using pbr = global::Google.Protobuf.Reflection;

namespace F6
{
    internal delegate Google.Protobuf.IMessage CreateMsg();
    internal delegate void HandlerMsg(Google.Protobuf.IMessage msg);
    internal class HandlerRec
    {
        internal CreateMsg createMsg;
        internal List<HandlerMsg> handlers = new List<HandlerMsg>();
    }

    public class MsgHandler
    {
        public delegate void HandlerDelegate<in T>(T msg);

        private Type cmMsgType;
        private Type smMsgType;
        private Dictionary<int, HandlerRec> handlerHash = new Dictionary<int, HandlerRec>();

        public MsgHandler(Type cmMsgType, Type smMsgType)
        {
            this.cmMsgType = cmMsgType;
            this.smMsgType = smMsgType;
        }

        public int GetCMMsgId(Type type)
        {
            return this.GetPbMsgId(this.cmMsgType, "_" + type.Name);
        }

        public int GetSMMsgId(Type type)
        {
            return this.GetPbMsgId(this.smMsgType, "_" + type.Name);
        }

        public int GetPbMsgId(Type enumType, string msgName)
        {
            foreach (var f in enumType.GetFields())
            {
                var tAttrs = f.GetCustomAttributes(typeof(pbr::OriginalNameAttribute), false);
                if (tAttrs.Length > 0)
                {
                    var tAttr = (pbr::OriginalNameAttribute)tAttrs[0];
                    if (tAttr.Name.Equals(msgName))
                    {
                        var val = Enum.Parse(enumType, f.Name);
                        return Convert.ToInt32(val);
                    }
                }
            }
            return 0;
        }

        public void RegisterHandler<T>(HandlerDelegate<T> handler) where T : IMessage<T> ,new()
        {
            int msgId = this.GetSMMsgId(typeof(T));
            HandlerRec handler1;
            if (!this.handlerHash.TryGetValue(msgId, out handler1))
            { 
                handler1 = new HandlerRec();
                handler1.createMsg += () =>
                {
                    return new T();
                };
                this.handlerHash.Add(msgId, handler1);
            }
            handler1.handlers.Add((Google.Protobuf.IMessage msg) =>
            {
                handler((T)msg);
            });
        }

        public void DispatchMsg(int msgId, byte[] data, int offset, int length)
        {
            HandlerRec handler;
            if (this.handlerHash.TryGetValue(msgId, out handler))
            {
                var msg = handler.createMsg();
                msg = msg.Descriptor.Parser.ParseFrom(data, offset, length);
                foreach (var h in handler.handlers)
                {
                    h(msg);
                }
            }
        }

    }

}