/* ============================================================================
 * Douglas Thrift's Web Contact License
 *
 * Copyright (C) 2002, Douglas Thrift. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
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 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment:
 *
 *       "This product includes software developed by Douglas Thrift
 *       (http://computers.douglasthrift.net/webcontact.html)."
 *
 *    Alternately, this acknowledgment may appear in the software itself, if
 *    and wherever such third-party acknowledgments normally appear.
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// Windows XP FAQ Poll
//
// Douglas Thrift
//
// IMAPHandler.cpp

#include "IMAPHandler.h"

IMAPHandler::IMAPHandler(const string& server, bool tls)
{
	letter = 'a';
	number = 0;

	this->tls = tls;
	buffer = new char[BUFSIZ + 1];

#ifdef _WIN32
	if (WSAStartup(MAKEWORD(2, 0), &data) != 0)
	{
		error(program + ": WSAStartup");
		exit(1);
	}
#endif // _WIN32

	if ((sock = socket(PF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET)
	{
		error(program + ": Socket");
		exit(1);
	}
	
	sockaddr_in address;
	hostent* host;

	address.sin_family = AF_INET;

	if ((host = gethostbyname(server.c_str())) == NULL)
	{
		error(program + ": Host: " + server, true);
		exit(1);
	}

	address.sin_addr = *((in_addr*)*host->h_addr_list);
	address.sin_port = htons(tls ? 993 : 143);

	if (connect(sock, (sockaddr*)&address, sizeof(sockaddr_in)) ==
		SOCKET_ERROR)
	{
		error(program + ": Connect");
		exit(1);
	}

	if (tls)
	{
		SSL_load_error_strings();
		SSL_library_init();

		char* seed = new char[BUFSIZ + 1];
		time_t moment = time(NULL);
		sprintf(seed, "froofy%sfoofoo", ctime(&moment));

		RAND_add(seed, strlen(seed), 0.007456);

		delete [] seed;

		ctx = SSL_CTX_new(TLSv1_client_method());
		if (ctx == NULL)
		{
			cerr << program << ": SSL CTX New: " <<
				ERR_reason_error_string(ERR_get_error()) << "\n";
			exit(1);
		}

		ssl = SSL_new(ctx);

		if (SSL_set_fd(ssl, sock) == 0)
		{
			cerr << program << ": SSL Set FD: " <<
				ERR_reason_error_string(ERR_get_error()) << "\n";
			exit(1);
		}

		if (int code = SSL_connect(ssl) <= 0)
		{
			error(program + ": SSL Connect", code);
			exit(1);
		}
	}

	getline();
}

IMAPHandler::~IMAPHandler()
{
	if (tls)
	{
		SSL_shutdown(ssl);
		SSL_free(ssl);
		SSL_CTX_free(ctx);
	}

	closesocket(sock);
	
	delete [] buffer;

#ifdef _WIN32
	WSACleanup();
#endif // _WIN32
}

string IMAPHandler::starttls()
{
	string answer = imap("STARTTLS");

	if (success)
	{
		tls = true;

		SSL_load_error_strings();
		SSL_library_init();

		char* seed = new char[BUFSIZ + 1];
		time_t moment = time(NULL);
		sprintf(seed, "froofy%sfoofoo", ctime(&moment));

		RAND_add(seed, strlen(seed), 0.007456);

		delete [] seed;

		ctx = SSL_CTX_new(TLSv1_client_method());
		if (ctx == NULL)
		{
			cerr << program << ": SSL CTX New: " <<
				ERR_reason_error_string(ERR_get_error()) << "\n";
			exit(1);
		}

		ssl = SSL_new(ctx);

		if (SSL_set_fd(ssl, sock) == 0)
		{
			cerr << program << ": SSL Set FD: " <<
				ERR_reason_error_string(ERR_get_error()) << "\n";
			exit(1);
		}

		if (int code = SSL_connect(ssl) <= 0)
		{
			error(program + ": SSL Connect", code);
			exit(1);
		}
	}

	return answer;
}

string IMAPHandler::command()
{
	char buffer[4];
	sprintf(buffer, "%03u", number++);

	string sequence = letter + string(buffer);

	if (number > 999)
	{
		letter++;
		number = 0;
	}

	if (letter > 'z')
	{
		letter = 'a';
	}

	return sequence;
}

string IMAPHandler::imap(const string& imap)
{
	string result;

	string sequence = command();
	putline(sequence + " " + imap);

	while (true)
	{
		string input = getline();

		if (input.find(sequence + " OK") == 0)
		{
			success = true;
			break;
		}
		else if (input.find(sequence + " NO") == 0 || input.find(sequence +
			" BAD") == 0)
		{
			success = false;
			break;
		}
		else
		{
			result += input + "\r\n";
		}
	}

	return result;
}

string IMAPHandler::imap(const string& imap, const string& args)
{
	string result;

	string sequence = command();
	putline(sequence + " " + imap + " " + args);

	while (true)
	{
		string input = getline();

		if (input.find(sequence + " OK") == 0)
		{
			success = true;
			break;
		}
		else if (input.find(sequence + " NO") == 0 || input.find(sequence +
			" BAD") == 0)
		{
			success = false;
			break;
		}
		else
		{
			result += input + "\r\n";
		}
	}

	return result;
}

string IMAPHandler::imap(const string& imap, const string& args, const string&
	message)
{
	string result;

	string sequence = command();
	putline(sequence + " " + imap + " " + args);
	putline(message);

	while (true)
	{
		string input = getline();

		if (input.find(sequence + " OK") == 0)
		{
			success = true;
			break;
		}
		else if (input.find(sequence + " NO") == 0 || input.find(sequence +
			" BAD") == 0)
		{
			success = false;
			break;
		}
		else
		{
			result += input + "\r\n";
		}
	}

	return result;
}

void IMAPHandler::putline(const string line)
{
	if (debug) cerr << line << "\n";

	sprintf(buffer, "%s\r\n", line.c_str());

	if (tls)
	{
		if (int code = SSL_write(ssl, buffer, strlen(buffer)) <= 0)
		{
			error(program + ": SSL Write", code);
			exit(1);
		}
	}
	else
	{
		if (send(sock, buffer, strlen(buffer), 0) == SOCKET_ERROR)
		{
			error(program + ": Send");
			exit(1);
		}
	}
}

string IMAPHandler::getline()
{
	string line;
	char byte;

	do
	{
		if (tls)
		{
			if (int code = SSL_read(ssl, &byte, 1) <= 0)
			{
				error(program + ": SSL Read", code);
				exit(1);
			}
		}
		else
		{
			if (recv(sock, &byte, 1, 0) == SOCKET_ERROR)
			{
				error(program + ": Recv");
				exit(1);
			}
		}

		if (byte != '\r' && byte != '\n')
		{
			line += byte;
		}
	}
	while (byte != '\n');

	if (debug) cerr << line << "\n";

	return line;
}

void IMAPHandler::error(const string& prefix, bool host)
{
#ifdef _WIN32
	string error;

	switch (WSAGetLastError())
	{
	case WSAEACCES:
		error = "Permission denied.";
		break;
	case WSAEADDRINUSE:
		error = "Address already in use.";
		break;
	case WSAEADDRNOTAVAIL:
		error = "Cannot assign requested address.";
		break;
	case WSAEAFNOSUPPORT:
		error = "Address family not supported by protocol family.";
		break;
	case WSAEALREADY:
		error = "Operation already in progress.";
		break;
	case WSAECONNABORTED:
		error = "Software caused connection abort.";
		break;
	case WSAECONNREFUSED:
		error = "Connection refused.";
		break;
	case WSAECONNRESET:
		error = "Connection reset by peer.";
		break;
	case WSAEDESTADDRREQ:
		error = "Destination address required.";
		break;
	case WSAEFAULT:
		error = "Bad address.";
		break;
	case WSAEHOSTDOWN:
		error = "Host is down.";
		break;
	case WSAEHOSTUNREACH:
		error = "No route to host.";
		break;
	case WSAEINPROGRESS:
		error = "Operation now in progress.";
		break;
	case WSAEINTR:
		error = "Interrupted function call.";
		break;
	case WSAEINVAL:
		error = "Invalid argument.";
		break;
	case WSAEISCONN:
		error = "Socket is already connected.";
		break;
	case WSAEMFILE:
		error = "Too many open files.";
		break;
	case WSAEMSGSIZE:
		error = "Message too long.";
		break;
	case WSAENETDOWN:
		error = "Network is down.";
		break;
	case WSAENETRESET:
		error = "Network dropped connection on reset.";
		break;
	case WSAENETUNREACH:
		error = "Network is unreachable.";
		break;
	case WSAENOBUFS:
		error = "No buffer space available.";
		break;
	case WSAENOPROTOOPT:
		error = "Bad protocol option.";
		break;
	case WSAENOTCONN:
		error = "Socket is not connected.";
		break;
	case WSAENOTSOCK:
		error = "Socket operation on non-socket.";
		break;
	case WSAEOPNOTSUPP:
		error = "Operation not supported.";
		break;
	case WSAEPFNOSUPPORT:
		error = "Protocol family not supported.";
		break;
	case WSAEPROCLIM:
		error = "Too many processes.";
		break;
	case WSAEPROTONOSUPPORT:
		error = "Protocol not supported.";
		break;
	case WSAEPROTOTYPE:
		error = "Protocol wrong type for socket.";
		break;
	case WSAESHUTDOWN:
		error = "Cannot send after socket shutdown.";
		break;
	case WSAESOCKTNOSUPPORT:
		error = "Socket type not supported.";
		break;
	case WSAETIMEDOUT:
		error = "Connection timed out.";
		break;
	case WSATYPE_NOT_FOUND:
		error = "Class type not found.";
		break;
	case WSAEWOULDBLOCK:
		error = "Resource temporarily unavailable.";
		break;
	case WSAHOST_NOT_FOUND:
		error = "Host not found.";
		break;
	case WSA_INVALID_HANDLE:
		error = "Specified event object handle is invalid.";
		break;
	case WSA_INVALID_PARAMETER:
		error = "One or more parameters are invalid.";
		break;
//	case WSAINVALIDPROCTABLE:
//		error = "Invalid procedure table from service provider.";
//		break;
//	case WSAINVALIDPROVIDER:
//		error = "Invalid service provider version number.";
//		break;
	case WSA_IO_INCOMPLETE:
		error = "Overlapped I/O event object not in signaled state.";
		break;
	case WSA_IO_PENDING:
		error = "Overlapped operations will complete later.";
		break;
	case WSA_NOT_ENOUGH_MEMORY:
		error = "Insufficient memory available.";
		break;
	case WSANOTINITIALISED:
		error = "Successful WSAStartup not yet performed.";
		break;
	case WSANO_DATA:
		error = "Valid name, no data record of requested type.";
		break;
	case WSANO_RECOVERY:
		error = "This is a non-recoverable error.";
		break;
//	case WSAPROVIDERFAILEDINIT:
//		error = "Unable to initialize a service provider.";
//		break;
	case WSASYSCALLFAILURE:
		error = "System call failure.";
		break;
	case WSASYSNOTREADY:
		error = "Network subsystem is unavailable.";
		break;
	case WSATRY_AGAIN:
		error = "Non-authoritative host not found.";
		break;
	case WSAVERNOTSUPPORTED:
		error = "WINSOCK.DLL version out of range.";
		break;
	case WSAEDISCON:
		error = "Graceful shutdown in progress.";
		break;
	case WSA_OPERATION_ABORTED:
		error = "Overlapped operation aborted.";
		break;
	default:
		error = "Unknown error.";
		break;
	}

	cerr << prefix << ": " << error << "\n";
#else
	if (host)
	{
		herror(prefix.c_str());
	}
	else
	{
		perror(prefix.c_str());
	}
#endif // _WIN32
}

void IMAPHandler::error(const string& prefix, int code)
{
	string error;

	switch (SSL_get_error(ssl, code))
	{
	case SSL_ERROR_NONE:
		error = "The TLS/SSL I/O operation completed.";
		break;
	case SSL_ERROR_ZERO_RETURN:
		error = "The TLS/SSL connection has been closed.";
		break;
	case SSL_ERROR_WANT_READ:
	case SSL_ERROR_WANT_WRITE:
	case SSL_ERROR_WANT_CONNECT:
//	case SSL_ERROR_WANT_ACCEPT:
	case SSL_ERROR_WANT_X509_LOOKUP:
		error = "The operation did not complete.";
		break;
	case SSL_ERROR_SYSCALL:
		if (int err = ERR_get_error() != 0)
		{
			error = ERR_reason_error_string(err);
		}
		else
		{
			switch (code)
			{
			case 0:
				error = "An EOF was observed that violates the protocol.";
				break;
			case -1:
				this->error(prefix);
				return;
			default:
				error = "Unknown error.";
				break;
			}
		}
		break;
	case SSL_ERROR_SSL:
		error = ERR_reason_error_string(ERR_get_error());
		break;
	default:
		error = "Unknown error.";
		break;
	}

	cerr << prefix << ": " << error << "\n";
}