using System;
using System.Linq;
using Edge.Core.Processor.Communicator;

namespace HengShan_Pump_NonIC_Plus
{
    public class StateMachineMessageCutter : IMessageCutter<byte[]>
    {
        public byte[] Message { get; private set; }

        public event EventHandler OnMessageCut;
        public event EventHandler<MessageCutterInvalidMessageReadEventArg> OnInvalidMessageRead;

        static NLog.Logger innerLogger = NLog.LogManager.LoadConfiguration("nlog.config").GetLogger("StateMachineMessageCutter");
        private string loggerAppendix = "HengShan_Pump_NonIC_Plus msgCutter ";

        private readonly SizableWindow<byte> window;
        private State nextState = State.Uninitialized;

        public StateMachineMessageCutter()
        {
            this.window = new SizableWindow<byte>();
            this.window.OnWindowFull += (data) =>
            {
                switch (nextState)
                {
                    case State.Uninitialized:
                        if (data.First() == 0x9F)
                        {
                            //前导码(09FH) + 枪号 + 长度(0-20H)
                            this.window.NewSize = 3;
                            this.nextState = State.LengthReady;
                            innerLogger.Debug(this.loggerAppendix + " state is State.Uninitialized and next is 0x9F, switch to LengthReady");
                        }
                        else
                            ReadInvalidMessage();
                        break;
                    case State.LengthReady:
                        int len = this.window.Skip(2).First();
                        if (len > 0)
                        {
                            this.window.NewSize += len;
                            this.nextState = State.BodyReady;
                            innerLogger.Debug(this.loggerAppendix + " MsgBodyLen caculated with: " + this.window.NewSize);
                        }
                        else
                            ReadInvalidMessage();
                        break;
                    case State.BodyReady:
                        //innerLogger.Debug(this.loggerAppendix + " Fire OnMessageConstructed with innerQueue: " + this.buffer.ToHexLogString());
                        this.Message = this.window.ToArray();
                        var safe = this.OnMessageCut;
                        safe?.Invoke(this, null);
                        this.nextState = State.Uninitialized;
                        this.window.Clear();
                        break;
                    default:
                        throw new ArgumentOutOfRangeException();
                }
            };
        }

        private void ReadInvalidMessage()
        {
            this.nextState = State.Uninitialized;
            this.window.Clear();
        }

        private enum State
        {
            Uninitialized,
            //HeaderSeeking,
            HeaderReady,
            LengthReady,
            BodyReady,
        }

        public void Feed(byte[] next)
        {
            //innerLogger.Debug(this.loggerAppendix + " " + next.ToHexLogString() + " is feed in Window in state: " + nextState);
            for (int i = 0; i < next.Length; i++)
                this.window.Add(next[i]);
        }
    }
}