using System;
using System.Text;
using Sog;
using ChewKeongTAN;
using System.Collections.Generic;
using System.Linq;

namespace PlayerOp
{
    public class DynamicExchangeSvc
    {
        //编码字典
        private static string CHAR_INDEXS = "abcdefghijkmnpqrstuvwxyz2345678";

        //现在字符集一共31个，5位就可以表示
        private static int ConvertByteCount = 5;

        private static int MAX_LENGTH = 32;

        //生成时是否校验
        private static bool IS_CHECK = true;

        //默认兑换码长度
        private const int DEFAULT_CODE_LENGTH = 12;

        //默认密码
        private const string DEFAULT_PASSWD = "arpg2020";

        /// 字节：groupId(1) + id(4) + 随机码补齐 + verify(1)
        public static Dictionary<int, string> CreateCodes(int groupId, int codeCount, int seed, string passwrod = DEFAULT_PASSWD, int codeLength = DEFAULT_CODE_LENGTH)
        {
            Dictionary<int, string> dict = new Dictionary<int, string>(); 

            if (codeLength > MAX_LENGTH)
            {
                return dict;
            }
           
            //用伪随机做种，保证每次做出来的数据一致
            var random = new SRandom(seed);

            //八位数据总长度
            int fullLength = codeLength * ConvertByteCount / 8;

            //剩余长度做随机码
            int randCount = fullLength - 6;
            if (randCount <= 0)
            {
                return dict;
            }

            Byte[] passwdBytes = Encoding.UTF8.GetBytes(passwrod);
           
            for (int i = 1; i <= codeCount; i++)
            {
                var bytes = CreateCodeBytes(groupId, randCount, i, fullLength, random, passwdBytes);
                BigInteger bigInteger = new BigInteger(bytes);
                string code = bigInteger.ToStringByCode(CHAR_INDEXS, codeLength);

                if (IS_CHECK)
                {
                    bool ret = VerifyCode(code,  out int checkGroupId, out int checkId, passwrod);

                    if (!ret || checkGroupId != groupId || checkId != i)
                    {
                        TraceLog.Error("DynamicExchangeSvc.CreateCodes Verify fail  groupId {0} id {1} code {2} ", checkGroupId, checkId, code);
                        break;
                    }
                }

                if (dict.ContainsValue(code))
                {
                    TraceLog.Error("DynamicExchangeSvc.CreateCodes repeat code {0} groupId {1} id {2} ", code, groupId, i);
                    break;
                }

                dict.Add(i, code);
            }

            if (dict.Count != codeCount)
            {
                dict.Clear();
            }
            return dict;
        }

        public static bool VerifyCode(string code,  out int groupId, out int id, string passwrod = DEFAULT_PASSWD)
        {
            groupId = 0;
            id = 0;
            BigInteger deCodeBig = new BigInteger(code, CHAR_INDEXS);
            byte[] bytes = deCodeBig.getBytes();
            int fullLength = code.Length * ConvertByteCount / 8;
            byte[] fullBytes = new byte[fullLength];
            for (int i = 1; i <= fullLength; i++)
            {
                if (i <= bytes.Length)
                {
                    fullBytes[fullLength - i] = bytes[bytes.Length - i];
                }
                else
                {
                    fullBytes[fullLength - i] = 0;
                }
                
            }
            int randCount = fullLength - 6;
            //TraceLog.Trace("VerifyCode bytelength {0} code {1}", fullLength, code);
            //解密
            Byte[] passwdBytes = Encoding.UTF8.GetBytes(passwrod);
            for (int i = 0; i < fullBytes.Length; i++)
            {
                fullBytes[i] = (byte) (fullBytes[i] ^ passwdBytes[i % passwdBytes.Length]);
            }

            //异或解密
            //随机码与id异或
            for (int j = 0; j < 5; j++)
            {
                fullBytes[j] = (byte)(fullBytes[j] ^ fullBytes[5 + j % randCount]);
            }

            BigInteger big = new BigInteger(fullBytes);
            //TraceLog.Trace("VerifyCode {0}", big.ToString());

            int sum = 0;
            for (int i = 0; i < fullBytes.Length - 1; i++)
            {
                sum += fullBytes[i];
            }

            byte verify = (byte) (sum % Byte.MaxValue);
             
            if (verify != fullBytes[fullBytes.Length - 1])
            {
                return false;
            }
            
            //解id
            groupId =(int)fullBytes[0];
            id = (int)fullBytes[1] << 24 | (int)fullBytes[2] << 16 | (int)fullBytes[3] << 8 | (int)fullBytes[4];
            return true;
        }

        private static byte[] CreateCodeBytes(int groupId, int randCount, int id, int fullLength, SRandom random, Byte[] passwdBytes)
        {
            byte[] randbytes = new byte[randCount];
            for (int j = 0; j < randCount; j++)
            {
                randbytes[j] = (byte)(random.Next() % Byte.MaxValue);
            }

            ByteHapper byteHapper = ByteHapper.CreateBytes(fullLength);
            byteHapper.AppendNumber((byte)groupId).AppendNumber(id).AppendBytes(randbytes);
            byte verify = (byte)(byteHapper.GetSum() % Byte.MaxValue);
            byteHapper.AppendNumber(verify);

            BigInteger big = new BigInteger(byteHapper.bytes);
            //TraceLog.Trace("CreateCodeBytes {0}", big.ToString());

            //随机码与id异或
            for (int j = 0; j < 5; j++)
            {
                byteHapper.bytes[j] = (byte)(byteHapper.bytes[j] ^ byteHapper.bytes[5 + j % randCount]);
            }

            //异或加密
            for (int j = 0; j < byteHapper.bytes.Length; j++)
            {
                byteHapper.bytes[j] = (byte)(byteHapper.bytes[j] ^ passwdBytes[j % passwdBytes.Length]);
            }

            return byteHapper.bytes;
        }

        partial class ByteHapper
        {
            public byte[] bytes;
            private int index;

            private ByteHapper(int capacity)
            {
                bytes = new byte[capacity];
                index = 0;
            }

            public static ByteHapper CreateBytes(int capacity)
            {
                ByteHapper byteHapper = new ByteHapper(capacity);
                return byteHapper;
            }

            public ByteHapper AppendBytes(byte[] arr)
            {
                for (int i = 0; i < arr.Length; i++)
                {
                    bytes[index + i] = arr[i];
                }

                index += arr.Length;
                return this;
            }

            public ByteHapper AppendNumber(byte val)
            {
                bytes[index] = val;
                index++;
                return this;
            }

            public int GetSum()
            {
                int ret = 0;
                for (int i = 0; i < bytes.Length; i++)
                {
                    ret += bytes[i];
                }

                return ret;
            }

            public ByteHapper AppendNumber(int val)
            {
                byte[] arr = Number2byte(val);
                return AppendBytes(arr);
            }

            public ByteHapper AppendNumber(long val)
            {
                byte[] arr = Number2byte(val);
                return AppendBytes(arr);
            }

            public static byte[] Number2byte(int val)
            {
                byte[] arr = new byte[]
                {
                    (byte) ((val >> 24) & 0xFF),
                    (byte) ((val >> 16) & 0xFF),
                    (byte) ((val >> 8) & 0xFF),
                    (byte) (val & 0xFF),
                };
                return arr;
            }

            public static byte[] Number2byte(long val)
            {
                byte[] arr = new byte[]
                {
                    (byte) ((val >> 56) & 0xFF),
                    (byte) ((val >> 48) & 0xFF),
                    (byte) ((val >> 40) & 0xFF),
                    (byte) ((val >> 32) & 0xFF),
                    (byte) ((val >> 24) & 0xFF),
                    (byte) ((val >> 16) & 0xFF),
                    (byte) ((val >> 8) & 0xFF),
                    (byte) (val & 0xFF),
                };
                return arr;
            }

            public static byte[] Number2byte(short val)
            {
                byte[] arr = new byte[]
                {
                    (byte) ((val >> 8) & 0xFF),
                    (byte) (val & 0xFF),
                };
                return arr;
            }
        }
    }
}