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

namespace Dfs.WayneChina.HengshanTerminalWrapper
{
    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("Communicator");

        private string loggerAppendix = "HengshanICTerm msgCutter ";
        private readonly SizableWindow<byte> window;
        private State nextState = State.Uninitialized;

        /// <summary>
        /// Constructor
        /// </summary>
        public StateMachineMessageCutter()
        {
            //this.initWindowSize = initWindowSize;
            this.window = new SizableWindow<byte>();
            this.window.OnWindowFull += (data) =>
            {
                switch (nextState)
                {
                    case State.Uninitialized:
                        if (data.First() == 0xFF)
                        {
                            //前导码(0FFH) +长度(0-20H)
                            this.window.NewSize = 2;
                            this.nextState = State.LengthReady;
                            //innerLogger.Debug(this.loggerAppendix + " state is State.Uninitialized and next is 0xFF, switch to LengthReady");
                        }
                        else
                        {
                            this.OnInvalidMessageRead?.Invoke(this, new MessageCutterInvalidMessageReadEventArg()
                            {
                                Message = "invalid byte[0]: 0x" + data.First().ToString("x2") + ", will skip"
                            });
                            this.window.Clear();
                        }
                        break;
                    case State.LengthReady:
                        var lengthByte = this.window.Skip(1).First();
                        if (lengthByte > 0x20)
                        {
                            this.OnInvalidMessageRead?.Invoke(this, new MessageCutterInvalidMessageReadEventArg()
                            {
                                Message = "invalid lengthByte: 0x" + lengthByte.ToString("x2") + ", should <=0x20, still keep it"
                            });
                        }

                        // 1 is header 0xFF, another 1 is XRL
                        this.window.NewSize = lengthByte + 2;
                        this.nextState = State.BodyReady;
                        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();
                        //this.window.NewSize = this.initWindowSize;
                        break;
                    default:
                        throw new ArgumentOutOfRangeException();
                }
            };
        }

        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]);
        }
    }
}