/*
 * Copyright (c) 2015 The Android Open Source Project
 * Copyright (C) 2015 Samsung LSI
 * Copyright (c) 2008-2009, Motorola, Inc.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * - Neither the name of the Motorola, Inc. nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package javax.obex;

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

import android.util.Log;

/**
 * This class in an implementation of the OBEX ClientSession.
 * @hide
 */
public final class ClientSession extends ObexSession {

    private static final String TAG = "ClientSession";

    private boolean mOpen;

    // Determines if an OBEX layer connection has been established
    private boolean mObexConnected;

    private byte[] mConnectionId = null;

    /*
     * The max Packet size must be at least 255 according to the OBEX
     * specification.
     */
    private int mMaxTxPacketSize = ObexHelper.LOWER_LIMIT_MAX_PACKET_SIZE;

    private boolean mRequestActive;

    private final InputStream mInput;

    private final OutputStream mOutput;

    private final boolean mLocalSrmSupported;

    private final ObexTransport mTransport;

    public ClientSession(final ObexTransport trans) throws IOException {
        mInput = trans.openInputStream();
        mOutput = trans.openOutputStream();
        mOpen = true;
        mRequestActive = false;
        mLocalSrmSupported = trans.isSrmSupported();
        mTransport = trans;
    }

    /**
     * Create a ClientSession
     * @param trans The transport to use for OBEX transactions
     * @param supportsSrm True if Single Response Mode should be used e.g. if the
     *        supplied transport is a TCP or l2cap channel.
     * @throws IOException if it occurs while opening the transport streams.
     */
    public ClientSession(final ObexTransport trans, final boolean supportsSrm) throws IOException {
        mInput = trans.openInputStream();
        mOutput = trans.openOutputStream();
        mOpen = true;
        mRequestActive = false;
        mLocalSrmSupported = supportsSrm;
        mTransport = trans;
    }

    public HeaderSet connect(final HeaderSet header) throws IOException {
        ensureOpen();
        if (mObexConnected) {
            throw new IOException("Already connected to server");
        }
        setRequestActive();

        int totalLength = 4;
        byte[] head = null;

        // Determine the header byte array
        if (header != null) {
            if (header.nonce != null) {
                mChallengeDigest = new byte[16];
                System.arraycopy(header.nonce, 0, mChallengeDigest, 0, 16);
            }
            head = ObexHelper.createHeader(header, false);
            totalLength += head.length;
        }
        /*
        * Write the OBEX CONNECT packet to the server.
        * Byte 0: 0x80
        * Byte 1&2: Connect Packet Length
        * Byte 3: OBEX Version Number (Presently, 0x10)
        * Byte 4: Flags (For TCP 0x00)
        * Byte 5&6: Max OBEX Packet Length (Defined in MAX_PACKET_SIZE)
        * Byte 7 to n: headers
        */
        byte[] requestPacket = new byte[totalLength];
        int maxRxPacketSize = ObexHelper.getMaxRxPacketSize(mTransport);
        // We just need to start at  byte 3 since the sendRequest() method will
        // handle the length and 0x80.
        requestPacket[0] = (byte)0x10;
        requestPacket[1] = (byte)0x00;
        requestPacket[2] = (byte)(maxRxPacketSize >> 8);
        requestPacket[3] = (byte)(maxRxPacketSize & 0xFF);
        if (head != null) {
            System.arraycopy(head, 0, requestPacket, 4, head.length);
        }

        // Since we are not yet connected, the peer max packet size is unknown,
        // hence we are only guaranteed the server will use the first 7 bytes.
        if ((requestPacket.length + 3) > ObexHelper.MAX_PACKET_SIZE_INT) {
            throw new IOException("Packet size exceeds max packet size for connect");
        }

        HeaderSet returnHeaderSet = new HeaderSet();
        sendRequest(ObexHelper.OBEX_OPCODE_CONNECT, requestPacket, returnHeaderSet, null, false);

        /*
        * Read the response from the OBEX server.
        * Byte 0: Response Code (If successful then OBEX_HTTP_OK)
        * Byte 1&2: Packet Length
        * Byte 3: OBEX Version Number
        * Byte 4: Flags3
        * Byte 5&6: Max OBEX packet Length
        * Byte 7 to n: Optional HeaderSet
        */
        if (returnHeaderSet.responseCode == ResponseCodes.OBEX_HTTP_OK) {
            mObexConnected = true;
        }
        setRequestInactive();

        return returnHeaderSet;
    }

    public Operation get(HeaderSet header) throws IOException {

        if (!mObexConnected) {
            throw new IOException("Not connected to the server");
        }
        setRequestActive();

        ensureOpen();

        HeaderSet head;
        if (header == null) {
            head = new HeaderSet();
        } else {
            head = header;
            if (head.nonce != null) {
                mChallengeDigest = new byte[16];
                System.arraycopy(head.nonce, 0, mChallengeDigest, 0, 16);
            }
        }
        // Add the connection ID if one exists
        if (mConnectionId != null) {
            head.mConnectionID = new byte[4];
            System.arraycopy(mConnectionId, 0, head.mConnectionID, 0, 4);
        }

        if(mLocalSrmSupported) {
            head.setHeader(HeaderSet.SINGLE_RESPONSE_MODE, ObexHelper.OBEX_SRM_ENABLE);
            /* TODO: Consider creating an interface to get the wait state.
             * On an android system, I cannot see when this is to be used.
             * except perhaps if we are to wait for user accept on a push message.
            if(getLocalWaitState()) {
                head.setHeader(HeaderSet.SINGLE_RESPONSE_MODE_PARAMETER, ObexHelper.OBEX_SRMP_WAIT);
            }
            */
        }

        return new ClientOperation(mMaxTxPacketSize, this, head, true);
    }

    /**
     * 0xCB Connection Id an identifier used for OBEX connection multiplexing
     */
    public void setConnectionID(long id) {
        if ((id < 0) || (id > 0xFFFFFFFFL)) {
            throw new IllegalArgumentException("Connection ID is not in a valid range");
        }
        mConnectionId = ObexHelper.convertToByteArray(id);
    }

    public HeaderSet delete(HeaderSet header) throws IOException {

        Operation op = put(header);
        op.getResponseCode();
        HeaderSet returnValue = op.getReceivedHeader();
        op.close();

        return returnValue;
    }

    public HeaderSet disconnect(HeaderSet header) throws IOException {
        if (!mObexConnected) {
            throw new IOException("Not connected to the server");
        }
        setRequestActive();

        ensureOpen();
        // Determine the header byte array
        byte[] head = null;
        if (header != null) {
            if (header.nonce != null) {
                mChallengeDigest = new byte[16];
                System.arraycopy(header.nonce, 0, mChallengeDigest, 0, 16);
            }
            // Add the connection ID if one exists
            if (mConnectionId != null) {
                header.mConnectionID = new byte[4];
                System.arraycopy(mConnectionId, 0, header.mConnectionID, 0, 4);
            }
            head = ObexHelper.createHeader(header, false);

            if ((head.length + 3) > mMaxTxPacketSize) {
                throw new IOException("Packet size exceeds max packet size");
            }
        } else {
            // Add the connection ID if one exists
            if (mConnectionId != null) {
                head = new byte[5];
                head[0] = (byte)HeaderSet.CONNECTION_ID;
                System.arraycopy(mConnectionId, 0, head, 1, 4);
            }
        }

        HeaderSet returnHeaderSet = new HeaderSet();
        sendRequest(ObexHelper.OBEX_OPCODE_DISCONNECT, head, returnHeaderSet, null, false);

        /*
         * An OBEX DISCONNECT reply from the server:
         * Byte 1: Response code
         * Bytes 2 & 3: packet size
         * Bytes 4 & up: headers
         */

        /* response code , and header are ignored
         * */

        synchronized (this) {
            mObexConnected = false;
            setRequestInactive();
        }

        return returnHeaderSet;
    }

    public long getConnectionID() {

        if (mConnectionId == null) {
            return -1;
        }
        return ObexHelper.convertToLong(mConnectionId);
    }

    public Operation put(HeaderSet header) throws IOException {
        if (!mObexConnected) {
            throw new IOException("Not connected to the server");
        }
        setRequestActive();

        ensureOpen();
        HeaderSet head;
        if (header == null) {
            head = new HeaderSet();
        } else {
            head = header;
            // when auth is initiated by client ,save the digest
            if (head.nonce != null) {
                mChallengeDigest = new byte[16];
                System.arraycopy(head.nonce, 0, mChallengeDigest, 0, 16);
            }
        }

        // Add the connection ID if one exists
        if (mConnectionId != null) {

            head.mConnectionID = new byte[4];
            System.arraycopy(mConnectionId, 0, head.mConnectionID, 0, 4);
        }

        if(mLocalSrmSupported) {
            head.setHeader(HeaderSet.SINGLE_RESPONSE_MODE, ObexHelper.OBEX_SRM_ENABLE);
            /* TODO: Consider creating an interface to get the wait state.
             * On an android system, I cannot see when this is to be used.
            if(getLocalWaitState()) {
                head.setHeader(HeaderSet.SINGLE_RESPONSE_MODE_PARAMETER, ObexHelper.OBEX_SRMP_WAIT);
            }
             */
        }
        return new ClientOperation(mMaxTxPacketSize, this, head, false);
    }

    public void setAuthenticator(Authenticator auth) throws IOException {
        if (auth == null) {
            throw new IOException("Authenticator may not be null");
        }
        mAuthenticator = auth;
    }

    public HeaderSet setPath(HeaderSet header, boolean backup, boolean create) throws IOException {
        if (!mObexConnected) {
            throw new IOException("Not connected to the server");
        }
        setRequestActive();
        ensureOpen();

        int totalLength = 2;
        byte[] head = null;
        HeaderSet headset;
        if (header == null) {
            headset = new HeaderSet();
        } else {
            headset = header;
            if (headset.nonce != null) {
                mChallengeDigest = new byte[16];
                System.arraycopy(headset.nonce, 0, mChallengeDigest, 0, 16);
            }
        }

        // when auth is initiated by client ,save the digest
        if (headset.nonce != null) {
            mChallengeDigest = new byte[16];
            System.arraycopy(headset.nonce, 0, mChallengeDigest, 0, 16);
        }

        // Add the connection ID if one exists
        if (mConnectionId != null) {
            headset.mConnectionID = new byte[4];
            System.arraycopy(mConnectionId, 0, headset.mConnectionID, 0, 4);
        }

        head = ObexHelper.createHeader(headset, false);
        totalLength += head.length;

        if (totalLength > mMaxTxPacketSize) {
            throw new IOException("Packet size exceeds max packet size");
        }

        int flags = 0;
        /*
         * The backup flag bit is bit 0 so if we add 1, this will set that bit
         */
        if (backup) {
            flags++;
        }
        /*
         * The create bit is bit 1 so if we or with 2 the bit will be set.
         */
        if (!create) {
            flags |= 2;
        }

        /*
         * An OBEX SETPATH packet to the server:
         * Byte 1: 0x85
         * Byte 2 & 3: packet size
         * Byte 4: flags
         * Byte 5: constants
         * Byte 6 & up: headers
         */
        byte[] packet = new byte[totalLength];
        packet[0] = (byte)flags;
        packet[1] = (byte)0x00;
        if (headset != null) {
            System.arraycopy(head, 0, packet, 2, head.length);
        }

        HeaderSet returnHeaderSet = new HeaderSet();
        sendRequest(ObexHelper.OBEX_OPCODE_SETPATH, packet, returnHeaderSet, null, false);

        /*
         * An OBEX SETPATH reply from the server:
         * Byte 1: Response code
         * Bytes 2 & 3: packet size
         * Bytes 4 & up: headers
         */

        setRequestInactive();

        return returnHeaderSet;
    }

    /**
     * Verifies that the connection is open.
     * @throws IOException if the connection is closed
     */
    public synchronized void ensureOpen() throws IOException {
        if (!mOpen) {
            throw new IOException("Connection closed");
        }
    }

    /**
     * Set request inactive. Allows Put and get operation objects to tell this
     * object when they are done.
     */
    /*package*/synchronized void setRequestInactive() {
        mRequestActive = false;
    }

    /**
     * Set request to active.
     * @throws IOException if already active
     */
    private synchronized void setRequestActive() throws IOException {
        if (mRequestActive) {
            throw new IOException("OBEX request is already being performed");
        }
        mRequestActive = true;
    }

    /**
     * Sends a standard request to the client. It will then wait for the reply
     * and update the header set object provided. If any authentication headers
     * (i.e. authentication challenge or authentication response) are received,
     * they will be processed.
     * @param opCode the type of request to send to the client
     * @param head the headers to send to the client
     * @param header the header object to update with the response
     * @param privateInput the input stream used by the Operation object; null
     *        if this is called on a CONNECT, SETPATH or DISCONNECT
     * @return
     *        <code>true</code> if the operation completed successfully;
     *        <code>false</code> if an authentication response failed to pass
     * @throws IOException if an IO error occurs
     */
    public boolean sendRequest(int opCode, byte[] head, HeaderSet header,
            PrivateInputStream privateInput, boolean srmActive) throws IOException {
        //check header length with local max size
        if (head != null) {
            if ((head.length + 3) > ObexHelper.MAX_PACKET_SIZE_INT) {
                // TODO: This is an implementation limit - not a specification requirement.
                throw new IOException("header too large ");
            }
        }

        boolean skipSend = false;
        boolean skipReceive = false;
        if (srmActive == true) {
            if (opCode == ObexHelper.OBEX_OPCODE_PUT) {
                // we are in the middle of a SRM PUT operation, don't expect a continue.
                skipReceive = true;
            } else if (opCode == ObexHelper.OBEX_OPCODE_GET) {
                // We are still sending the get request, send, but don't expect continue
                // until the request is transfered (the final bit is set)
                skipReceive = true;
            } else if (opCode == ObexHelper.OBEX_OPCODE_GET_FINAL) {
                // All done sending the request, expect data from the server, without
                // sending continue.
                skipSend = true;
            }

        }

        int bytesReceived;
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        out.write((byte)opCode);

        // Determine if there are any headers to send
        if (head == null) {
            out.write(0x00);
            out.write(0x03);
        } else {
            out.write((byte)((head.length + 3) >> 8));
            out.write((byte)(head.length + 3));
            out.write(head);
        }

        if (!skipSend) {
            // Write the request to the output stream and flush the stream
            mOutput.write(out.toByteArray());
            // TODO: is this really needed? if this flush is implemented
            //       correctly, we will get a gap between each obex packet.
            //       which is kind of the idea behind SRM to avoid.
            //  Consider offloading to another thread (async action)
            mOutput.flush();
        }

        if (!skipReceive) {
            header.responseCode = mInput.read();

            int length = ((mInput.read() << 8) | (mInput.read()));

            if (length > ObexHelper.getMaxRxPacketSize(mTransport)) {
                throw new IOException("Packet received exceeds packet size limit");
            }
            if (length > ObexHelper.BASE_PACKET_LENGTH) {
                byte[] data = null;
                if (opCode == ObexHelper.OBEX_OPCODE_CONNECT) {
                    @SuppressWarnings("unused")
                    int version = mInput.read();
                    @SuppressWarnings("unused")
                    int flags = mInput.read();
                    mMaxTxPacketSize = (mInput.read() << 8) + mInput.read();

                    //check with local max size
                    if (mMaxTxPacketSize > ObexHelper.MAX_CLIENT_PACKET_SIZE) {
                        mMaxTxPacketSize = ObexHelper.MAX_CLIENT_PACKET_SIZE;
                    }

                    // check with transport maximum size
                    if(mMaxTxPacketSize > ObexHelper.getMaxTxPacketSize(mTransport)) {
                        // To increase this size, increase the buffer size in L2CAP layer
                        // in Bluedroid.
                        Log.w(TAG, "An OBEX packet size of " + mMaxTxPacketSize + "was"
                                + " requested. Transport only allows: "
                                + ObexHelper.getMaxTxPacketSize(mTransport)
                                + " Lowering limit to this value.");
                        mMaxTxPacketSize = ObexHelper.getMaxTxPacketSize(mTransport);
                    }

                    if (length > 7) {
                        data = new byte[length - 7];

                        bytesReceived = mInput.read(data);
                        while (bytesReceived != (length - 7)) {
                            bytesReceived += mInput.read(data, bytesReceived, data.length
                                    - bytesReceived);
                        }
                    } else {
                        return true;
                    }
                } else {
                    data = new byte[length - 3];
                    bytesReceived = mInput.read(data);

                    while (bytesReceived != (length - 3)) {
                        bytesReceived += mInput.read(data, bytesReceived, data.length - bytesReceived);
                    }
                    if (opCode == ObexHelper.OBEX_OPCODE_ABORT) {
                        return true;
                    }
                }

                byte[] body = ObexHelper.updateHeaderSet(header, data);
                if ((privateInput != null) && (body != null)) {
                    privateInput.writeBytes(body, 1);
                }

                if (header.mConnectionID != null) {
                    mConnectionId = new byte[4];
                    System.arraycopy(header.mConnectionID, 0, mConnectionId, 0, 4);
                }

                if (header.mAuthResp != null) {
                    if (!handleAuthResp(header.mAuthResp)) {
                        setRequestInactive();
                        throw new IOException("Authentication Failed");
                    }
                }

                if ((header.responseCode == ResponseCodes.OBEX_HTTP_UNAUTHORIZED)
                        && (header.mAuthChall != null)) {

                    if (handleAuthChall(header)) {
                        out.write((byte)HeaderSet.AUTH_RESPONSE);
                        out.write((byte)((header.mAuthResp.length + 3) >> 8));
                        out.write((byte)(header.mAuthResp.length + 3));
                        out.write(header.mAuthResp);
                        header.mAuthChall = null;
                        header.mAuthResp = null;

                        byte[] sendHeaders = new byte[out.size() - 3];
                        System.arraycopy(out.toByteArray(), 3, sendHeaders, 0, sendHeaders.length);

                        return sendRequest(opCode, sendHeaders, header, privateInput, false);
                    }
                }
            }
        }

        return true;
    }

    public void close() throws IOException {
        mOpen = false;
        mInput.close();
        mOutput.close();
    }

    public boolean isSrmSupported() {
        return mLocalSrmSupported;
    }
}