/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.bluetooth;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Represents a connected or connecting Bluetooth Socket.
 *
 * Currently only supports RFCOMM sockets.
 *
 * RFCOMM is a connection orientated, streaming transport over Bluetooth. It is
 * also known as the Serial Port Profile (SPP).
 *
 * TODO: Consider implementing SCO and L2CAP sockets.
 * TODO: Clean up javadoc grammer and formatting.
 * TODO: Remove @hide
 * @hide
 */
public final class BluetoothSocket implements Closeable {
    private final int mPort;
    private final String mAddress;    /* remote address */
    private final boolean mAuth;
    private final boolean mEncrypt;
    private final BluetoothInputStream mInputStream;
    private final BluetoothOutputStream mOutputStream;

    private int mSocketData;    /* used by native code only */

    /**
     * Construct a secure RFCOMM socket ready to start an outgoing connection.
     * Call #connect on the returned #BluetoothSocket to begin the connection.
     * The remote device will be authenticated and communication on this socket
     * will be encrypted.
     * @param address remote Bluetooth address that this socket can connect to
     * @param port    remote port
     * @return an RFCOMM BluetoothSocket
     * @throws IOException on error, for example Bluetooth not available, or
     *                     insufficient permissions.
     */
    public static BluetoothSocket createRfcommSocket(String address, int port)
            throws IOException {
        return new BluetoothSocket(-1, true, true, address, port);
    }

    /**
     * Construct an insecure RFCOMM socket ready to start an outgoing
     * connection.
     * Call #connect on the returned #BluetoothSocket to begin the connection.
     * The remote device will not be authenticated and communication on this
     * socket will not be encrypted.
     * @param address remote Bluetooth address that this socket can connect to
     * @param port    remote port
     * @return An RFCOMM BluetoothSocket
     * @throws IOException On error, for example Bluetooth not available, or
     *                     insufficient permissions.
     */
    public static BluetoothSocket createInsecureRfcommSocket(String address, int port)
            throws IOException {
        return new BluetoothSocket(-1, false, false, address, port);
    }

    /**
     * Construct a Bluetooth.
     * @param fd      fd to use for connected socket, or -1 for a new socket
     * @param auth    require the remote device to be authenticated
     * @param encrypt require the connection to be encrypted
     * @param address remote Bluetooth address that this socket can connect to
     * @param port    remote port
     * @throws IOException On error, for example Bluetooth not available, or
     *                     insufficient priveleges
     */
    /*package*/ BluetoothSocket(int fd, boolean auth, boolean encrypt, String address, int port)
            throws IOException {
        mAuth = auth;
        mEncrypt = encrypt;
        mAddress = address;
        mPort = port;
        if (fd == -1) {
            initSocketNative();
        } else {
            initSocketFromFdNative(fd);
        }
        mInputStream = new BluetoothInputStream(this);
        mOutputStream = new BluetoothOutputStream(this);
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            close();
        } finally {
            super.finalize();
        }
    }

    /**
     * Attempt to connect to a remote device.
     * This method will block until a connection is made or the connection
     * fails. If this method returns without an exception then this socket
     * is now connected. #close can be used to abort this call from another
     * thread.
     * @throws IOException On error, for example connection failure
     */
    public void connect() throws IOException {
        connectNative(mAddress, mPort, -1);
    }

    /**
     * Closes this socket.
     * This will cause other blocking calls on this socket to immediately
     * throw an IOException.
     */
    public void close() throws IOException {
        closeNative();
    }

    /**
     * Return the address we are connecting, or connected, to.
     * @return Bluetooth address, or null if this socket has not yet attempted
     *         or established a connection.
     */
    public String getAddress() {
        return mAddress;
    }

    /**
     * Get the input stream associated with this socket.
     * The input stream will be returned even if the socket is not yet
     * connected, but operations on that stream will throw IOException until
     * the associated socket is connected.
     * @return InputStream
     */
    public InputStream getInputStream() throws IOException {
        return mInputStream;
    }

    /**
     * Get the output stream associated with this socket.
     * The output stream will be returned even if the socket is not yet
     * connected, but operations on that stream will throw IOException until
     * the associated socket is connected.
     * @return OutputStream
     */
    public OutputStream getOutputStream() throws IOException {
        return mOutputStream;
    }

    private native void initSocketNative();
    private native void initSocketFromFdNative(int fd);
    private native void connectNative(String address, int port, int timeout);
    /*package*/ native void bindListenNative(int port) throws IOException;
    /*package*/ native BluetoothSocket acceptNative(int timeout) throws IOException;
    /*package*/ native int availableNative();
    /*package*/ native int readNative(byte[] b, int offset, int length);
    /*package*/ native int writeNative(byte[] b, int offset, int length);
    /*package*/ native void closeNative();
    private native void destroyNative();
}