using Edge.Core.Parser.BinaryParser;
using Edge.Core.Parser.BinaryParser.MessageEntity;
using Edge.Core.Parser.BinaryParser.Util;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LanTian_Sinopec_PumpIcCardReader
{
    public class Parser : ParserBase
    {
        public Parser() : base(MessageTemplateLookup.Default)
        {
        }

        public override byte[] Serialize(MessageTemplateBase message)
        {
            var bytesWithoutCrc16 = base.Serialize(message).ToList();
            if (message.GetType().GetProperty("CRC16") != null)
            {
                // skip the first of 0xFA.
                var crc16 = bytesWithoutCrc16.Skip(1).ToArray().ComputeChecksumBytesCrc16();
                var processedBody = ProcessDoubleHexFAInMsgBody(bytesWithoutCrc16);
                var processedCrc = ProcessDoubleHexFAInCRC(crc16);
                var _ = processedBody.Concat(processedCrc);
                return _.ToArray();
            }

            return bytesWithoutCrc16.ToArray();
        }

        /// <summary>
        /// 转义字符：0FAH；在数据里每两个 0FAH 替换为一个 0FAH；在目标地址、源地址、帧号/控制、
        ///有效数据长度中不能出现 0FAH，转义字符不计入 CRC 中，CRC 中采用转义。 
        /// </summary>
        /// <param name="original"></param>
        /// <returns></returns>
        public static byte[] ProcessDoubleHexFAInMsgBody(List<byte> original)
        {
            //====record 0xFA position============
            var indexs = new List<int>();
            for (int i = 6; i < original.Count; i++)
            {
                if (original[i] == 0xFA)
                {
                    indexs.Add(i);
                }
            }
            //=====end=====

            if (!indexs.Any()) return original.ToArray();
            var originalLen = original.Skip(4).Take(2).GetBCD();
            //var newLen = (originalLen + indexs.Count).GetBCDBytes(2);
            var newLen = (originalLen).GetBCDBytes(2);
            original[4] = newLen[0];
            original[5] = newLen[1];
            byte[] _ = new byte[original.Count];
            original.CopyTo(_);
            var newList = _.ToList();
            for (int i = 0; i < indexs.Count; i++)
            {
                newList.Insert(indexs[i] + i, 0xFA);
            }

            return newList.ToArray();
        }

        public static byte[] ProcessDoubleHexFAInCRC(byte[] originalCrc)
        {
            var result = new List<byte>();
            result.Add(originalCrc[0]);
            if (originalCrc[0] == 0xFA)
            {
                result.Add(0xFA);
            }
            result.Add(originalCrc[1]);
            if (originalCrc[1] == 0xFA)
            {
                result.Add(0xFA);
            }

            return result.ToArray();
        }
    }
}