/*
 *	This file is part of Transdroid <http://www.transdroid.org>
 *
 *	Transdroid is free software: you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation, either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	Transdroid is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with Transdroid.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
package org.transdroid.daemon.Deluge;

import android.support.annotation.NonNull;

import org.transdroid.daemon.DaemonException;
import org.transdroid.daemon.DaemonException.ExceptionType;
import org.transdroid.daemon.DaemonSettings;
import org.transdroid.daemon.util.TlsSniSocketFactory;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.IOException;
import java.net.Socket;
import java.net.UnknownHostException;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.InflaterInputStream;

import se.dimovski.rencode.Rencode;

import static org.transdroid.daemon.Deluge.DelugeCommon.RPC_METHOD_DAEMON_LOGIN;

/**
 * A Deluge RPC API Client.
 */
class DelugeRpcClient implements Closeable {

	private static final int RESPONSE_TYPE_INDEX = 0;
	private static final int RESPONSE_RETURN_VALUE_INDEX = 2;
	private static final int RPC_ERROR = 2;

	private Socket socket;
	private static AtomicInteger requestId = new AtomicInteger();

	void connect(DaemonSettings settings) throws DaemonException {
		try {
			socket = openSocket(settings);
			if (settings.shouldUseAuthentication()) {
				sendRequest(RPC_METHOD_DAEMON_LOGIN, settings.getUsername(), settings.getPassword());
			}
		} catch (NoSuchAlgorithmException e) {
			throw new DaemonException(ExceptionType.ConnectionError, "Failed to open socket: " + e.getMessage());
		} catch (UnknownHostException e) {
			throw new DaemonException(ExceptionType.AuthenticationFailure, "Failed to sign in: " + e.getMessage());
		} catch (IOException e) {
			throw new DaemonException(ExceptionType.ConnectionError, "Failed to open socket: " + e.getMessage());
		} catch (KeyManagementException e) {
			throw new DaemonException(ExceptionType.ConnectionError, "Failed to open socket: " + e.getMessage());
		}
	}

	public void close() {
		try {
			if (socket != null)
				socket.close();
		} catch (IOException e) {
			// ignore
		}
	}

	@NonNull
	Object sendRequest(String method, Object... args) throws DaemonException {
		final byte[] requestBytes;
		try {
			requestBytes = compress(Rencode.encode(new Object[]{new Object[]{requestId.getAndIncrement(), method, args, new HashMap<>()}}));
		} catch (IOException e) {
			throw new DaemonException(ExceptionType.ConnectionError, "Failed to encode request: " + e.getMessage());
		}
		try {
			socket.getOutputStream().write(requestBytes);
			return readResponse();
		} catch (IOException e) {
			throw new DaemonException(ExceptionType.ConnectionError, e.getMessage());
		}
	}

	@NonNull
	private byte[] compress(byte[] bytes) throws IOException {
		ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
		try {
			DeflaterOutputStream deltaterOut = new DeflaterOutputStream(byteOut);
			try {
				deltaterOut.write(bytes);
				deltaterOut.finish();
				return byteOut.toByteArray();
			} finally {
				deltaterOut.close();
			}
		} finally {
			byteOut.close();
		}
	}

	@NonNull
	private Object readResponse() throws DaemonException, IOException {
		final InflaterInputStream inflater = new InflaterInputStream(socket.getInputStream());
		final ByteArrayOutputStream out = new ByteArrayOutputStream();
		final byte[] buffer = new byte[1024];
		while (inflater.available() > 0) {
			final int n = inflater.read(buffer);
			if (n > 0) {
				out.write(buffer, 0, n);
			}
		}
		final byte[] bytes = out.toByteArray();
		final Object responseObject = Rencode.decode(bytes);

		if (!(responseObject instanceof List)) {
			throw new DaemonException(ExceptionType.UnexpectedResponse, responseObject.toString());
		}
		final List response = (List) responseObject;

		if (response.size() < RESPONSE_RETURN_VALUE_INDEX + 1) {
			throw new DaemonException(ExceptionType.UnexpectedResponse, responseObject.toString());
		}

		if (!(response.get(RESPONSE_TYPE_INDEX) instanceof Number)) {
			throw new DaemonException(ExceptionType.UnexpectedResponse, responseObject.toString());
		}
		final int type = ((Number) (response.get(RESPONSE_TYPE_INDEX))).intValue();

		if (type == RPC_ERROR) {
			throw new DaemonException(ExceptionType.UnexpectedResponse, responseObject.toString());
		}

		return response.get(2);
	}

	@NonNull
	private Socket openSocket(DaemonSettings settings) throws NoSuchAlgorithmException, KeyManagementException, IOException {
		if (!settings.getSsl()) {
			// Non-ssl connections
			return new Socket(settings.getAddress(), settings.getPort());
		}
		final TlsSniSocketFactory socketFactory;
		if (settings.getSslTrustKey() != null && settings.getSslTrustKey().length() != 0) {
			socketFactory = new TlsSniSocketFactory(settings.getSslTrustKey());
		} else if (settings.getSslTrustAll()) {
			socketFactory = new TlsSniSocketFactory(true);
		} else {
			socketFactory = new TlsSniSocketFactory();
		}
		return socketFactory.createSocket(null, settings.getAddress(), settings.getPort(), false);

		//		final TrustManager[] trustAllCerts = new TrustManager[]{new IgnoreSSLTrustManager()};
		//		final SSLContext sslContext = SSLContext.getInstance("TLSv1");
		//		sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
		//		return sslContext.getSocketFactory().createSocket(address, port);
	}

}