/*
 * Copyright (c) 2010-2018 Nathan Rajlich
 *
 *  Permission is hereby granted, free of charge, to any person
 *  obtaining a copy of this software and associated documentation
 *  files (the "Software"), to deal in the Software without
 *  restriction, including without limitation the rights to use,
 *  copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following
 *  conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *  OTHER DEALINGS IN THE SOFTWARE.
 */

package com.analysys.visual.websocket.client;

import com.analysys.visual.websocket.AbstractWebSocket;
import com.analysys.visual.websocket.WebSocket;
import com.analysys.visual.websocket.WebSocketImpl;
import com.analysys.visual.websocket.drafts.BaseDraft;
import com.analysys.visual.websocket.drafts.Draft_6455;
import com.analysys.visual.websocket.exceptions.InvalidHandshakeException;
import com.analysys.visual.websocket.framing.CloseFrame;
import com.analysys.visual.websocket.framing.Framedata;
import com.analysys.visual.websocket.framing.Framedata.Opcode;
import com.analysys.visual.websocket.handshake.HandshakeImpl1Client;
import com.analysys.visual.websocket.handshake.Handshakedata;
import com.analysys.visual.websocket.handshake.ServerHandshake;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.Socket;
import java.net.URI;
import java.nio.ByteBuffer;
import java.nio.channels.NotYetConnectedException;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocketFactory;

/**
 * A subclass must implement at least <var>onOpen</var>, <var>onClose</var>, and
 * <var>onMessage</var> to be
 * useful. At runtime the user is expected to establish a connection via {@link #connect()}, then
 * receive events like {@link #onMessage(String)} via the overloaded methods and to
 * {@link #send(String)} data to the server.
 */
public abstract class BaseWebSocketClient extends AbstractWebSocket implements Runnable, WebSocket {

    /**
     * The URI this channel is supposed to connect to.
     */
    protected URI uri = null;

    /**
     * The underlying engine
     */
    private WebSocketImpl engine = null;

    /**
     * The socket for this BaseWebSocketClient
     */
    private Socket socket = null;

    /**
     * The used OutputStream
     */
    private OutputStream ostream;

    /**
     * The used proxy, if any
     */
    private Proxy proxy = Proxy.NO_PROXY;

    /**
     * The thread to write outgoing message
     */
    private Thread writeThread;

    /**
     * The draft to use
     */
    private BaseDraft draft;

    /**
     * The additional headers to use
     */
    private Map<String, String> headers;

    /**
     * The latch for connectBlocking()
     */
    private CountDownLatch connectLatch = new CountDownLatch(1);

    /**
     * The latch for closeBlocking()
     */
    private CountDownLatch closeLatch = new CountDownLatch(1);

    /**
     * The socket timeout value to be used in milliseconds.
     */
    private int connectTimeout = 0;

    /**
     * Constructs a BaseWebSocketClient instance and sets it to the connect to the
     * specified URI. The channel does not attampt to connect automatically. The connection
     * will be established once you call <var>connect</var>.
     *
     * @param serverUri the server URI to connect to
     */
    public BaseWebSocketClient(URI serverUri) {
        this(serverUri, new Draft_6455());
    }

    /**
     * Constructs a BaseWebSocketClient instance and sets it to the connect to the
     * specified URI. The channel does not attampt to connect automatically. The connection
     * will be established once you call <var>connect</var>.
     * @param serverUri the server URI to connect to
     * @param protocolDraft The draft which should be used for this connection
     */
    public BaseWebSocketClient(URI serverUri, BaseDraft protocolDraft) {
        this(serverUri, protocolDraft, null, 0);
    }

    /**
     * Constructs a BaseWebSocketClient instance and sets it to the connect to the
     * specified URI. The channel does not attampt to connect automatically. The connection
     * will be established once you call <var>connect</var>.
     * @param serverUri the server URI to connect to
     * @param httpHeaders Additional HTTP-Headers
     * @since 1.3.8
     */
    public BaseWebSocketClient(URI serverUri, Map<String, String> httpHeaders) {
        this(serverUri, new Draft_6455(), httpHeaders);
    }

    /**
     * Constructs a BaseWebSocketClient instance and sets it to the connect to the
     * specified URI. The channel does not attampt to connect automatically. The connection
     * will be established once you call <var>connect</var>.
     * @param serverUri the server URI to connect to
     * @param protocolDraft The draft which should be used for this connection
     * @param httpHeaders Additional HTTP-Headers
     * @since 1.3.8
     */
    public BaseWebSocketClient(URI serverUri, BaseDraft protocolDraft,
                               Map<String, String> httpHeaders) {
        this(serverUri, protocolDraft, httpHeaders, 0);
    }

    /**
     * Constructs a BaseWebSocketClient instance and sets it to the connect to the
     * specified URI. The channel does not attampt to connect automatically. The connection
     * will be established once you call <var>connect</var>.
     * @param serverUri the server URI to connect to
     * @param protocolDraft The draft which should be used for this connection
     * @param httpHeaders Additional HTTP-Headers
     * @param connectTimeout The Timeout for the connection
     */
    public BaseWebSocketClient(URI serverUri, BaseDraft protocolDraft,
                               Map<String, String> httpHeaders, int connectTimeout) {
        if (serverUri == null) {
            throw new IllegalArgumentException();
        } else if (protocolDraft == null) {
            throw new IllegalArgumentException("null as draft is permitted for " +
                    "`BaseWebSocketServer` only!");
        }
        this.uri = serverUri;
        this.draft = protocolDraft;
        this.headers = httpHeaders;
        this.connectTimeout = connectTimeout;
        setTcpNoDelay(false);
        setReuseAddr(false);
        this.engine = new WebSocketImpl(this, protocolDraft);
    }

    /**
     * Returns the URI that this BaseWebSocketClient is connected to.
     * @return the URI connected to
     */
    public URI getURI() {
        return uri;
    }

    /**
     * Returns the protocol version this channel uses.<br>
     * For more infos see https://github.com/TooTallNate/Java-WebSocket/wiki/Drafts
     * @return The draft used for this client
     */
    @Override
    public BaseDraft getDraft() {
        return draft;
    }

    /**
     * Returns the socket to allow Hostname Verification
     * @return the socket used for this connection
     */
    public Socket getSocket() {
        return socket;
    }

    /**
     * Accepts bound and unbound sockets.<br>
     * This method must be called before <code>connect</code>.
     * If the given socket is not yet bound it will be bound to the uri specified in the constructor.
     * @param socket The socket which should be used for the connection
     */
    public void setSocket(Socket socket) {
        if (this.socket != null) {
            throw new IllegalStateException("socket has already been set");
        }
        this.socket = socket;
    }

    /**
     * Reinitiates the websocket connection. This method does not block.
     * @since 1.3.8
     */
    public void reconnect() {
        reset();
        connect();
    }

    /**
     * Same as <code>reconnect</code> but blocks until the websocket reconnected or failed to do
     * so.<br>
     * @return Returns whether it succeeded or not.
     * @throws InterruptedException Thrown when the threads get interrupted
     * @since 1.3.8
     */
    public boolean reconnectBlocking() throws InterruptedException {
        reset();
        return connectBlocking();
    }

    /**
     * Reset everything relevant to allow a reconnect
     * @since 1.3.8
     */
    private void reset() {
        try {
            closeBlocking();
            if (writeThread != null) {
                this.writeThread.interrupt();
                this.writeThread = null;
            }
            this.draft.reset();
            if (this.socket != null) {
                this.socket.close();
                this.socket = null;
            }
        } catch (Exception e) {
            onError(e);
            engine.closeConnection(CloseFrame.ABNORMAL_CLOSE, e.getMessage());
            return;
        }
        connectLatch = new CountDownLatch(1);
        closeLatch = new CountDownLatch(1);
        this.engine = new WebSocketImpl(this, this.draft);
    }

    /**
     * Initiates the websocket connection. This method does not block.
     */
    public void connect() {
        if (writeThread != null) {
            throw new IllegalStateException("BaseWebSocketClient objects are not reuseable");
        }
        writeThread = new Thread(this);
        writeThread.setName("WebSocketConnectReadThread-" + writeThread.getId());
        writeThread.start();
    }

    /**
     * Same as <code>connect</code> but blocks until the websocket connected or failed to do so.<br>
     * @return Returns whether it succeeded or not.
     * @throws InterruptedException Thrown when the threads get interrupted
     */
    public boolean connectBlocking() throws InterruptedException {
        connect();
        connectLatch.await();
        return engine.isOpen();
    }

    /**
     * Same as <code>connect</code> but blocks with a timeout until the websocket connected or
     * failed to do so.<br>
     * @param timeout
     *               The connect timeout
     * @param timeUnit
     *                The timeout time unit
     * @return Returns whether it succeeded or not.
     * @throws InterruptedException Thrown when the threads get interrupted
     */
    public boolean connectBlocking(long timeout, TimeUnit timeUnit) throws InterruptedException {
        connect();
        return connectLatch.await(timeout, timeUnit) && engine.isOpen();
    }

    /**
     * Initiates the websocket close handshake. This method does not block<br>
     * In oder to make sure the connection is closed use <code>closeBlocking</code>
     */
    @Override
    public void close() {
        if (writeThread != null) {
            engine.close(CloseFrame.NORMAL);
        }
    }

    /**
     * Same as <code>close</code> but blocks until the websocket closed or failed to do so.<br>
     * @throws InterruptedException Thrown when the threads get interrupted
     */
    public void closeBlocking() throws InterruptedException {
        close();
        closeLatch.await();
    }

    /**
     * Sends <var>text</var> to the connected websocket server.
     *
     * @param text
     *            The string which will be transmitted.
     */
    @Override
    public void send(String text) throws NotYetConnectedException {
        engine.send(text);
    }

    /**
     * Sends binary <var> data</var> to the connected webSocket server.
     *
     * @param data
     *            The byte-Array of data to send to the WebSocket server.
     */
    @Override
    public void send(byte[] data) throws NotYetConnectedException {
        engine.send(data);
    }

    @Override
    public <T> T getAttachment() {
        return engine.getAttachment();
    }

    @Override
    public <T> void setAttachment(T attachment) {
        engine.setAttachment(attachment);
    }

    @Override
    protected Collection<WebSocket> getConnections() {
        return Collections.singletonList((WebSocket) engine);
    }

    @Override
    public void sendPing() throws NotYetConnectedException {
        engine.sendPing();
    }

    @Override
    public void run() {
        InputStream istream;
        try {
            boolean isNewSocket = false;

            if (socket == null) {
                socket = new Socket(proxy);
                isNewSocket = true;

            } else if (socket.isClosed()) {
                throw new IOException();
            }

            socket.setTcpNoDelay(isTcpNoDelay());
            socket.setReuseAddress(isReuseAddr());

            if (!socket.isBound()) {
                socket.connect(new InetSocketAddress(uri.getHost(), getPort()), connectTimeout);
            }

            // if the socket is set by others we don't apply any TLS wrapper
            if (isNewSocket && "wss".equals(uri.getScheme())) {

                SSLContext sslContext = SSLContext.getInstance("TLS");
                sslContext.init(null, null, null);
                SSLSocketFactory factory = sslContext.getSocketFactory();
                socket = factory.createSocket(socket, uri.getHost(), getPort(), true);
            }

            istream = socket.getInputStream();
            ostream = socket.getOutputStream();

            sendHandshake();
        } catch ( /*IOException | SecurityException | UnresolvedAddressException |
        InvalidHandshakeException | ClosedByInterruptException | SocketTimeoutException
        */Exception e) {
            onWebsocketError(engine, e);
            engine.closeConnection(CloseFrame.NEVER_CONNECTED, e.getMessage());
            return;
        }

        writeThread = new Thread(new WebsocketWriteThread());
        writeThread.start();

        byte[] rawbuffer = new byte[WebSocketImpl.RCVBUF];
        int readBytes;

        try {
            while (!isClosing() && !isClosed() && (readBytes = istream.read(rawbuffer)) != -1) {
                engine.decode(ByteBuffer.wrap(rawbuffer, 0, readBytes));
            }
            engine.eot();
        } catch (IOException e) {
            handleIOException(e);
        } catch (RuntimeException e) {
            // this catch case covers internal errors only and indicates a bug in this websocket
            // implementation
            onError(e);
            engine.closeConnection(CloseFrame.ABNORMAL_CLOSE, e.getMessage());
        }
        //I have no idea why this was added.
        //assert ( socket.isClosed() );
    }

    /**
     * Extract the specified port
     * @return the specified port or the default port for the specific scheme
     */
    private int getPort() {
        int port = uri.getPort();
        if (port == -1) {
            String scheme = uri.getScheme();
            if ("wss".equals(scheme)) {
                return WebSocket.DEFAULT_WSS_PORT;
            } else if ("ws".equals(scheme)) {
                return WebSocket.DEFAULT_PORT;
            } else {
                throw new IllegalArgumentException("unknown scheme: " + scheme);
            }
        }
        return port;
    }

    /**
     * Create and send the handshake to the other endpoint
     * @throws InvalidHandshakeException  a invalid handshake was created
     */
    private void sendHandshake() throws InvalidHandshakeException {
        String path;
        String part1 = uri.getRawPath();
        String part2 = uri.getRawQuery();
        if (part1 == null || part1.length() == 0) {
            path = "/";
        } else {
            path = part1;
        }
        if (part2 != null) {
            path += '?' + part2;
        }
        int port = getPort();
        String host = uri.getHost() + (
                (port != WebSocket.DEFAULT_PORT && port != WebSocket.DEFAULT_WSS_PORT)
                        ? ":" + port
                        : "");

        HandshakeImpl1Client handshake = new HandshakeImpl1Client();
        handshake.setResourceDescriptor(path);
        handshake.put("Host", host);
        if (headers != null) {
            for (Map.Entry<String, String> kv : headers.entrySet()) {
                handshake.put(kv.getKey(), kv.getValue());
            }
        }
        engine.startHandshake(handshake);
    }

    /**
     * This represents the state of the connection.
     */
    @Override
    public READYSTATE getReadyState() {
        return engine.getReadyState();
    }

    /**
     * Calls subclass' implementation of <var>onMessage</var>.
     */
    @Override
    public final void onWebsocketMessage(WebSocket conn, String message) {
        onMessage(message);
    }

    @Override
    public final void onWebsocketMessage(WebSocket conn, ByteBuffer blob) {
        onMessage(blob);
    }

    @Override
    public void onWebsocketMessageFragment(WebSocket conn, Framedata frame) {
        onFragment(frame);
    }

    /**
     * Calls subclass' implementation of <var>onOpen</var>.
     */
    @Override
    public final void onWebsocketOpen(WebSocket conn, Handshakedata handshake) {
        startConnectionLostTimer();
        onOpen((ServerHandshake) handshake);
        connectLatch.countDown();
    }

    /**
     * Calls subclass' implementation of <var>onClose</var>.
     */
    @Override
    public final void onWebsocketClose(WebSocket conn, int code, String reason, boolean remote) {
        stopConnectionLostTimer();
        if (writeThread != null) {
            writeThread.interrupt();
        }
        onClose(code, reason, remote);
        connectLatch.countDown();
        closeLatch.countDown();
    }

    /**
     * Calls subclass' implementation of <var>onIOError</var>.
     */
    @Override
    public final void onWebsocketError(WebSocket conn, Exception ex) {
        onError(ex);
    }

    @Override
    public final void onWriteDemand(WebSocket conn) {
        // nothing to do
    }

    @Override
    public void onWebsocketCloseInitiated(WebSocket conn, int code, String reason) {
        onCloseInitiated(code, reason);
    }

    @Override
    public void onWebsocketClosing(WebSocket conn, int code, String reason, boolean remote) {
        onClosing(code, reason, remote);
    }

    /**
     * Send when this peer sends a close handshake
     *
     * @param code The codes can be looked up here: {@link CloseFrame}
     * @param reason Additional information string
     */
    public void onCloseInitiated(int code, String reason) {
        //To overwrite
    }

    /** Called as soon as no further frames are accepted
     *
     * @param code The codes can be looked up here: {@link CloseFrame}
     * @param reason Additional information string
     * @param remote Returns whether or not the closing of the connection was initiated by the
     *               remote host.
     */
    public void onClosing(int code, String reason, boolean remote) {
        //To overwrite
    }

    /**
     * Getter for the engine
     * @return the engine
     */
    public WebSocket getConnection() {
        return engine;
    }

    @Override
    public InetSocketAddress getLocalSocketAddress(WebSocket conn) {
        if (socket != null) {
            return (InetSocketAddress) socket.getLocalSocketAddress();
        }
        return null;
    }

    // ABTRACT METHODS /////////////////////////////////////////////////////////

    @Override
    public InetSocketAddress getRemoteSocketAddress(WebSocket conn) {
        if (socket != null) {
            return (InetSocketAddress) socket.getRemoteSocketAddress();
        }
        return null;
    }

    /**
     * Called after an opening handshake has been performed and the given websocket is ready to
     * be written on.
     * @param handshakedata The handshake of the websocket instance
     */
    public abstract void onOpen(ServerHandshake handshakedata);

    /**
     * Callback for string messages received from the remote host
     *
     * @see #onMessage(ByteBuffer)
     * @param message The UTF-8 decoded message that was received.
     **/
    public abstract void onMessage(String message);

    /**
     * Called after the websocket connection has been closed.
     *
     * @param code
     *            The codes can be looked up here: {@link CloseFrame}
     * @param reason
     *            Additional information string
     * @param remote
     *            Returns whether or not the closing of the connection was initiated by the
     *            remote host.
     **/
    public abstract void onClose(int code, String reason, boolean remote);

    /**
     * Called when errors occurs. If an error causes the websocket connection to fail
     * {@link #onClose(int, String, boolean)} will be called additionally.<br>
     * This method will be called primarily because of IO or protocol errors.<br>
     * If the given exception is an RuntimeException that probably means that you encountered a
     * bug.<br>
     *
     * @param ex The exception causing this error
     **/
    public abstract void onError(Exception ex);

    /**
     * Callback for binary messages received from the remote host
     *
     * @see #onMessage(String)
     *
     * @param bytes
     *            The binary message that was received.
     **/
    public void onMessage(ByteBuffer bytes) {
        //To overwrite
    }

    /**
     * Callback for fragmented frames
     * @see WebSocket#sendFragmentedFrame(com.analysys.visual.websocket.framing.Framedata.Opcode, ByteBuffer, boolean)
     * @param frame The fragmented frame
     */
    @Deprecated
    public void onFragment(Framedata frame) {
        //To overwrite
    }

    /**
     * Closing the socket
     */
    private void closeSocket() {
        try {
            if (socket != null) {
                socket.close();
            }
        } catch (IOException ex) {
            onWebsocketError(this, ex);
        }
    }

    /**
     * Method to set a proxy for this connection
     * @param proxy the proxy to use for this websocket client
     */
    public void setProxy(Proxy proxy) {
        if (proxy == null) {
            throw new IllegalArgumentException();
        }
        this.proxy = proxy;
    }

    @Override
    public void sendFragmentedFrame(Opcode op, ByteBuffer buffer, boolean fin) {
        engine.sendFragmentedFrame(op, buffer, fin);
    }

    @Override
    public boolean isOpen() {
        return engine.isOpen();
    }

    @Override
    public boolean isFlushAndClose() {
        return engine.isFlushAndClose();
    }

    @Override
    public boolean isClosed() {
        return engine.isClosed();
    }

    @Override
    public boolean isClosing() {
        return engine.isClosing();
    }

    @Override
    @Deprecated
    public boolean isConnecting() {
        return engine.isConnecting();
    }

    @Override
    public boolean hasBufferedData() {
        return engine.hasBufferedData();
    }

    @Override
    public void close(int code) {
        engine.close();
    }

    @Override
    public void close(int code, String message) {
        engine.close(code, message);
    }

    @Override
    public void closeConnection(int code, String message) {
        engine.closeConnection(code, message);
    }

    @Override
    public void send(ByteBuffer bytes) throws IllegalArgumentException, NotYetConnectedException {
        engine.send(bytes);
    }

    @Override
    public void sendFrame(Framedata framedata) {
        engine.sendFrame(framedata);
    }

    @Override
    public void sendFrame(Collection<Framedata> frames) {
        engine.sendFrame(frames);
    }

    @Override
    public InetSocketAddress getLocalSocketAddress() {
        return engine.getLocalSocketAddress();
    }

    @Override
    public InetSocketAddress getRemoteSocketAddress() {
        return engine.getRemoteSocketAddress();
    }

    @Override
    public String getResourceDescriptor() {
        return uri.getPath();
    }

    /**
     * Method to give some additional info for specific IOExceptions
     * @param e the IOException causing a eot.
     */
    private void handleIOException(IOException e) {
        if (e instanceof SSLException) {
            onError(e);
        }
        engine.eot();
    }

    private class WebsocketWriteThread implements Runnable {
        @Override
        public void run() {
            Thread.currentThread().setName("WebSocketWriteThread-" + Thread.currentThread().getId());
            try {
                try {
                    while (!Thread.interrupted()) {
                        ByteBuffer buffer = engine.outQueue.take();
                        ostream.write(buffer.array(), 0, buffer.limit());
                        ostream.flush();
                    }
                } catch (InterruptedException e) {
                    for (ByteBuffer buffer : engine.outQueue) {
                        ostream.write(buffer.array(), 0, buffer.limit());
                        ostream.flush();
                    }
                }
            } catch (IOException e) {
                handleIOException(e);
            } finally {
                closeSocket();
                writeThread = null;
            }
        }
    }
}
