using NetMFAPatcher.Utils;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace NetMFAPatcher.utils
{
    class Decryption
    {
        public static byte[] DecryptionKey;
        public static byte MagicChar=54;
        public static void MakeKey(string sTitle, string sCopyright,string sProject)
        {
            var rawKey = "";
            rawKey += sTitle;
            rawKey += sCopyright;
            rawKey += sProject;
            Logger.Log("Combined data "+rawKey,true,ConsoleColor.Yellow);
            var rawKeyPtr = Marshal.StringToHGlobalAnsi(rawKey);

            var ptr = Decryption.make_key_combined(rawKeyPtr, MagicChar);

            byte[] key = new byte[257];
            Marshal.Copy(ptr, key, 0, 256);
            Marshal.FreeHGlobal(rawKeyPtr);

            DecryptionKey = key;
            Logger.Log($"First 16-Bytes of key: {DecryptionKey.GetHex(16)}",true,ConsoleColor.Yellow);
            File.WriteAllBytes($"{Program.DumpPath}\\key.bin", DecryptionKey);          
        }
        

        public static byte[] DecodeMode3(byte[] chunkData, int chunkSize,int chunkId)
        {
            var reader = new ByteIO(chunkData);
            var decompressedSize = reader.ReadUInt32();
            
            var rawData = reader.ReadBytes((int)reader.Size());
            if (chunkId % 2 != 0)
            {
                rawData[0] ^= (byte)(((byte)chunkId & 0xFF) ^ ((byte)chunkId >> 0x8));
            }
            rawData = DecodeChunk(rawData, chunkSize);
            var data = new ByteIO(rawData);
            var compressedSize = data.ReadUInt32();

            return Decompressor.decompress_block(data, (int)compressedSize, (int)decompressedSize);
        }
        public static byte[] DecodeChunk(byte[] chunkData, int chunkSize)
        {
            IntPtr inputChunkPtr = Marshal.AllocHGlobal(chunkData.Length);
            Marshal.Copy(chunkData, 0, inputChunkPtr, chunkData.Length);

            IntPtr keyPtr = Marshal.AllocHGlobal(DecryptionKey.Length);
            Marshal.Copy(DecryptionKey, 0, keyPtr, DecryptionKey.Length);

            var outputChunkPtr = decode_chunk(inputChunkPtr, chunkSize, MagicChar, keyPtr);

            byte[] decodedChunk = new byte[chunkSize];
            Marshal.Copy(outputChunkPtr, decodedChunk,0,chunkSize);

            Marshal.FreeHGlobal(inputChunkPtr);
            Marshal.FreeHGlobal(keyPtr);

            return decodedChunk;
        }



        [DllImport("Decrypter-x64.dll", EntryPoint = "decode_chunk", CharSet = CharSet.Auto)]
        public static extern IntPtr decode_chunk(IntPtr chunkData, int chunkSize, byte magicChar,IntPtr wrapperKey);
        [DllImport("Decrypter-x64.dll", EntryPoint = "make_key", CharSet = CharSet.Auto)]
        public static extern IntPtr make_key(IntPtr cTitle, IntPtr cCopyright, IntPtr cProject, byte magicChar);
        [DllImport("Decrypter-x64.dll", EntryPoint = "make_key_combined", CharSet = CharSet.Auto)]
        public static extern IntPtr make_key_combined(IntPtr data, byte magicChar);      
    }
}