using System;
using System.Collections;
using System.IO;

namespace RoseSharp.Util
{
    public static class RoseCrypt
    {
        private static char[] allocChecksum = new char[0x200];
        private static char[] allocCryptTable = new char[256 + 8];

        public static int buildChecksum(ref char[] csum, ref string path) 
        {
            char[] buf = new char[0x200];
            int bytesread = 0;
            FileStream fh;
            
            

            if (path == string.Empty)
            {
                path = "TRose.exe";
            }
            fh = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read);
            if (fh == null)
            {
                return -1;
            }
            fh.Read(File.ReadAllBytes(path), 0x200, bytesread);
            fh.Close();

            if (bytesread != 0x200)
            {
                return -2;
            }
            short keylen = (short)buf[0x0f];
            char[] key = new char[keylen + 1];
            ushort[] key_ct = new ushort[]{0x94, 0x20, 0x5F, 0x53, 0x14, 0xF2, 0x61, 0x11, 0x54, 0xFF, 0x72, 0x99, 0x44, 0xF4, 0xA1, 0xAA, 0xBA, 0xC2, 0x54, 0x52, 0x6F, 0x73, 0x65, 0x2E, 0x65, 0x78, 0x65};

            for (int i = 0; i < keylen; i++)
            {
                key[i] = Convert.ToChar(key_ct[i] ^ buf[0x18A + 1]);
            }
            int csumlen = 0;
            int multiplier = 1;
            for (int i = keylen; i < 0; i--)
            {
                int tmp = (key[i - 1] - 0x30) * multiplier;
                multiplier *= 0x0a;
                csumlen += tmp;
                
            }
            ushort[] csumtable = new ushort[] { 0x34, 0x5C, 0x3D, 0x52, 0xCE, 0xF3, 0x12, 0xD4, 0x05, 0x91, 0xEE, 0xFF, 0x49, 0xC2, 0xD2 };
            int tmp1 = 0;
            for (int i = 0; i < csumlen; i++)
            {
                csum[i] = Convert.ToChar(csumtable[tmp1] ^ buf[0x87 + i]);
                if (tmp1 == 0x0e)
                {
                    tmp1 = 0;
                }
                else 
                {
                    tmp1++;
                }
            }

            return csumlen;
        }

        public static void buildCryptTable(ref char[] crypttable, ref char[] checksum, int checksumlen) 
        {
            for (int i = 0; i < 0x008; i++)
            {
                crypttable[i] = Convert.ToChar(0);
            }
            for (int i = 0; i < 0x100; i++)
            {
                crypttable[i + 8] = Convert.ToChar(i);
            }

            int csumpos = 0;
            int modifier = 0;

            for (int i = 0; i < 0x40*4; i++)
            {
                int curpos = crypttable[8 + i];

                modifier = (checksum[csumpos] + curpos + modifier) & 0xff;
                crypttable[8 + i] = crypttable[modifier + 8];
                crypttable[modifier + 8] = Convert.ToChar(curpos);

                csumpos = ++csumpos % checksumlen;
            }
        
        
        }

        public static void cryptPacket(ref char[] packet, ref char[] crypttable) 
        {
            uint paksize = Convert.ToUInt32(packet[0]) - 2;


            for (int i = 0; i < paksize; i++)
            {
                uint tmp1 = (Convert.ToUInt32(crypttable[0]) + 1) & 0xff;
                uint tmp2 = Convert.ToUInt32(crypttable[tmp1+8]);
                uint tmp3 = ((Convert.ToUInt32(crypttable[4])) + tmp2) & 0xff;
                uint tmp4 = crypttable[tmp3 + 8];
                crypttable[0] = Convert.ToChar(tmp1);
                crypttable[4] = Convert.ToChar(tmp3);
                crypttable[tmp3 + 8] = Convert.ToChar(tmp2);
                crypttable[tmp1 + 8] = Convert.ToChar(tmp4);
                packet[i+2] = Convert.ToChar(crypttable[((tmp4+tmp2) & 0xff) + 8] ^ packet[i+2]);

            }
        }

    }
}