using Communicator;
using log4net;
using Parser.BinaryParser.Util;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace WayneChina_IcCardReader_SinoChem
{
public class StateMachineMessageCutter : IMessageCutter<byte[]>
{
public byte[] Message { get; private set; }
public event EventHandler OnMessageCut;
static ILog innerLogger = log4net.LogManager.GetLogger("StateMachineMessageCutter");
private string loggerAppendix = "WayneChina_IcCardReader_SinoChem msgCutter ";
private readonly SizableWindow<byte> window;
private State nextState = State.Uninitialized;
/// <summary>
/// if the 0xFA count is odd, will use round up for count/2.
/// e.g.: 0xFA appeared 2 times, return 1.
/// 0xFA appeared 3 times, return 2, this is considered as window is not big enough to include further 0xFA since they're always even.
/// </summary>
/// <returns></returns>
private int Get0xFAPairCountInWindow(IList<byte> target)
{
return (int)Math.Round(((double)(target.Count(w => w == 0xFA)) / 2), MidpointRounding.AwayFromZero);
}
/// <summary>
/// found all pair(one besides one) of 0xFA in a list, and reduce the pair to a single 0xFA.
/// </summary>
/// <param name="target"></param>
private int Reduce0xFAPair(IList<byte> target, int from)
{
var faAppearedPositions = new List<int>();
for (int i = from; i < target.Count; i++)
{
if (target[i] == 0xFA)
{
faAppearedPositions.Add(i);
i++;
}
}
for (int i = 0; i < faAppearedPositions.Count; i++)
{
target.RemoveAt(faAppearedPositions[i] - i);
}
return faAppearedPositions.Count;
}
/// <summary>
///
/// </summary>
public StateMachineMessageCutter()
{
//通讯数据包格式为：数据包头(0xFA)+源地址(1byte)+有效数据长度(2 bytes)+有效数据+数据校验(2 bytes)
this.window = new SizableWindow<byte>();
this.window.OnWindowFull += (data) =>
{
switch (nextState)
{
case State.Uninitialized:
if (data.First() == 0xFA)
{
// extend to 2 to see if exists extra 0xFA
this.window.NewSize = 2;
this.nextState = State.PrefixReady;
innerLogger.Debug(this.loggerAppendix + " state is State.Uninitialized and next is 0xFF, switch to LengthReady");
}
else
this.window.Clear();
break;
case State.PrefixReady:
if (this.window.Count(h => h == 0xFA) == 1)
{
innerLogger.Debug(this.loggerAppendix + " 1 time of 0xFA in header window, valid starter, switch to LengthReady");
this.nextState = State.LengthReady;
this.window.NewSize = 4;
}
else
{
innerLogger.Debug(this.loggerAppendix + " 2 times of 0xFA in potential header window, drop all and wait...");
// double 0xFA, not a starter.
this.nextState = State.Uninitialized;
this.window.Clear();
}
break;
case State.LengthReady:
//this.DumpWindowToQueue();
try
{
this.window.NewSize += this.window.Skip(2).Take(2).GetBCD();
this.nextState = State.BodyReady;
innerLogger.Debug(this.loggerAppendix + " MsgBodyLen caculated with: " + this.window.NewSize);
}
catch (Exception ex)
{
innerLogger.Debug($"LengthReady: Exception in parsing message length bytes : {ex.ToString()}");
this.nextState = State.Uninitialized;
this.window.Clear();
}
break;
case State.BodyReady:
//innerLogger.Debug(this.loggerAppendix + " Fire OnMessageConstructed with innerQueue: " + this.buffer.ToHexLogString());
if (this.window.All(w => w != 0xFA))
{
innerLogger.Debug(this.loggerAppendix + " MsgBody have NO 0xFA, fastly switch to CrcReady");
/* window size exactly match with MsgBodyLen, indicats there's no 0xFA in body.*/
this.window.NewSize += 2;
this.nextState = State.CrcReady;
}
else
{
try
{
/* window size not match with MsgBodyLen, indicates there's one or more 0xFA in body.*/
var __msgBodyLen = this.window.Skip(2).Take(2).GetBCD();
var faPairCount = Get0xFAPairCountInWindow(this.window.Skip(1).ToList());
if ((this.window.Count - 4) == (__msgBodyLen + faPairCount))
{
//innerLogger.Debug(this.loggerAppendix + " Reduce0xFAPair from raw window: " + this.window.ToHexLogString());
var reducedCount = this.Reduce0xFAPair(this.window, 1);
this.window.NewSize += (2 - reducedCount);
this.nextState = State.CrcReady;
}
else
{
/*extend the window based on 0xFA count in `current` window. NOTE, every extend may include new 0xFA pair.*/
this.window.NewSize += 1;
//innerLogger.Debug(this.loggerAppendix + " Re-extend window size to: " + this.windowSize);
}
}
catch (Exception ex)
{
innerLogger.Debug($"BodyReady: Exception in parsing message length bytes : {ex.ToString()}");
this.nextState = State.Uninitialized;
this.window.Clear();
}
}
break;
case State.CrcReady:
try
{
var _msgBodyLen = this.window.Skip(2).Take(2).GetBCD();
var crcPart = this.window.Skip(4 + _msgBodyLen).ToList();
if (crcPart.Count == 2 && crcPart[0] == 0xFA)
{
innerLogger.Debug(this.loggerAppendix + " Crc[0] is 0xFA, extend windowSize to 3");
this.window.NewSize += 1; return;
}
if (crcPart.Count == 3 && crcPart[2] == 0xFA)
{
innerLogger.Debug(this.loggerAppendix + " Crc[2] is 0xFA, extend windowSize to 4");
this.window.NewSize += 1; return;
}
Enumerable.Repeat("_", (int)Math.Round(((double)(crcPart.Count(w => w == 0xFA)) / 2))).ToList().ForEach(
s =>
{
innerLogger.Debug(this.loggerAppendix + " Removing one 0xFA from Crc part.");
crcPart.Remove(0xFA);
});
this.Message = this.window.Take(4 + _msgBodyLen).ToList().Concat(crcPart).ToArray();
var safe = this.OnMessageCut;
safe?.Invoke(this, null);
this.nextState = State.Uninitialized;
this.window.Clear();
//this.window.NewSize = this.initWindowSize;
}
catch (Exception ex)
{
innerLogger.Debug($"CrcReady: BodyReady: Exception in parsing message length bytes : {ex.ToString()}");
this.nextState = State.Uninitialized;
this.window.Clear();
}
break;
default:
throw new ArgumentOutOfRangeException();
}
};
}
private enum State
{
Uninitialized,
// single 0xFA
PrefixReady,
// 0xFA + 1 byte source address
HeaderReady,
// 0xFA + 1 byte source address + 2 bytes real length
LengthReady,
// 0xFA + 1 byte source address + 2 bytes real length + real data
BodyReady,
// 0xFA + 1 byte source address + 2 bytes real length + real data + 2 bytes CRC
CrcReady,
}
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]);
}
}
}