/*
 * Copyright (C) 2013 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.media;

import android.media.MediaCodec.BufferInfo;
import dalvik.system.CloseGuard;

import java.io.FileDescriptor;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.util.Map;

/**
 * MediaMuxer facilitates muxing elementary streams. Currently only supports an
 * mp4 file as the output and at most one audio and/or one video elementary
 * stream.
 * <p>
 * It is generally used like this:
 *
 * <pre>
 * MediaMuxer muxer = new MediaMuxer("temp.mp4", OutputFormat.MUXER_OUTPUT_MPEG_4);
 * // More often, the MediaFormat will be retrieved from MediaCodec.getOutputFormat()
 * // or MediaExtractor.getTrackFormat().
 * MediaFormat audioFormat = new MediaFormat(...);
 * MediaFormat videoFormat = new MediaFormat(...);
 * int audioTrackIndex = muxer.addTrack(audioFormat);
 * int videoTrackIndex = muxer.addTrack(videoFormat);
 * ByteBuffer inputBuffer = ByteBuffer.allocate(bufferSize);
 * boolean finished = false;
 * BufferInfo bufferInfo = new BufferInfo();
 *
 * muxer.start();
 * while(!finished) {
 *   // getInputBuffer() will fill the inputBuffer with one frame of encoded
 *   // sample from either MediaCodec or MediaExtractor, set isAudioSample to
 *   // true when the sample is audio data, set up all the fields of bufferInfo,
 *   // and return true if there are no more samples.
 *   finished = getInputBuffer(inputBuffer, isAudioSample, bufferInfo);
 *   if (!finished) {
 *     int currentTrackIndex = isAudioSample ? audioTrackIndex : videoTrackIndex;
 *     muxer.writeSampleData(currentTrackIndex, inputBuffer, bufferInfo);
 *   }
 * };
 * muxer.stop();
 * muxer.release();
 * </pre>
 */

final public class MediaMuxer {

    static {
        System.loadLibrary("media_jni");
    }

    /**
     * Defines the output format. These constants are used with constructor.
     */
    public static final class OutputFormat {
        /* Do not change these values without updating their counterparts
         * in include/media/stagefright/MediaMuxer.h!
         */
        private OutputFormat() {}
        /** MPEG4 media file format*/
        public static final int MUXER_OUTPUT_MPEG_4 = 0;
        public static final int MUXER_OUTPUT_WEBM   = 1;
    };

    // All the native functions are listed here.
    private static native long nativeSetup(FileDescriptor fd, int format);
    private static native void nativeRelease(long nativeObject);
    private static native void nativeStart(long nativeObject);
    private static native void nativeStop(long nativeObject);
    private static native int nativeAddTrack(long nativeObject, String[] keys,
            Object[] values);
    private static native void nativeSetOrientationHint(long nativeObject,
            int degrees);
    private static native void nativeSetLocation(long nativeObject, int latitude, int longitude);
    private static native void nativeWriteSampleData(long nativeObject,
            int trackIndex, ByteBuffer byteBuf,
            int offset, int size, long presentationTimeUs, int flags);

    // Muxer internal states.
    private static final int MUXER_STATE_UNINITIALIZED  = -1;
    private static final int MUXER_STATE_INITIALIZED    = 0;
    private static final int MUXER_STATE_STARTED        = 1;
    private static final int MUXER_STATE_STOPPED        = 2;

    private int mState = MUXER_STATE_UNINITIALIZED;

    private final CloseGuard mCloseGuard = CloseGuard.get();
    private int mLastTrackIndex = -1;

    private long mNativeObject;

    /**
     * Constructor.
     * Creates a media muxer that writes to the specified path.
     * @param path The path of the output media file.
     * @param format The format of the output media file.
     * @see android.media.MediaMuxer.OutputFormat
     * @throws IOException if failed to open the file for write
     */
    public MediaMuxer(String path, int format) throws IOException {
        if (path == null) {
            throw new IllegalArgumentException("path must not be null");
        }
        if (format != OutputFormat.MUXER_OUTPUT_MPEG_4 &&
                format != OutputFormat.MUXER_OUTPUT_WEBM) {
            throw new IllegalArgumentException("format is invalid");
        }
        // Use RandomAccessFile so we can open the file with RW access;
        // RW access allows the native writer to memory map the output file.
        RandomAccessFile file = null;
        try {
            file = new RandomAccessFile(path, "rws");
            FileDescriptor fd = file.getFD();
            mNativeObject = nativeSetup(fd, format);
            mState = MUXER_STATE_INITIALIZED;
            mCloseGuard.open("release");
        } finally {
            if (file != null) {
                file.close();
            }
        }
    }

    /**
     * Sets the orientation hint for output video playback.
     * <p>This method should be called before {@link #start}. Calling this
     * method will not rotate the video frame when muxer is generating the file,
     * but add a composition matrix containing the rotation angle in the output
     * video if the output format is
     * {@link OutputFormat#MUXER_OUTPUT_MPEG_4} so that a video player can
     * choose the proper orientation for playback. Note that some video players
     * may choose to ignore the composition matrix in a video during playback.
     * By default, the rotation degree is 0.</p>
     * @param degrees the angle to be rotated clockwise in degrees.
     * The supported angles are 0, 90, 180, and 270 degrees.
     */
    public void setOrientationHint(int degrees) {
        if (degrees != 0 && degrees != 90  && degrees != 180 && degrees != 270) {
            throw new IllegalArgumentException("Unsupported angle: " + degrees);
        }
        if (mState == MUXER_STATE_INITIALIZED) {
            nativeSetOrientationHint(mNativeObject, degrees);
        } else {
            throw new IllegalStateException("Can't set rotation degrees due" +
                    " to wrong state.");
        }
    }

    /**
     * Set and store the geodata (latitude and longitude) in the output file.
     * This method should be called before {@link #start}. The geodata is stored
     * in udta box if the output format is
     * {@link OutputFormat#MUXER_OUTPUT_MPEG_4}, and is ignored for other output
     * formats. The geodata is stored according to ISO-6709 standard.
     *
     * @param latitude Latitude in degrees. Its value must be in the range [-90,
     * 90].
     * @param longitude Longitude in degrees. Its value must be in the range
     * [-180, 180].
     * @throws IllegalArgumentException If the given latitude or longitude is out
     * of range.
     * @throws IllegalStateException If this method is called after {@link #start}.
     */
    public void setLocation(float latitude, float longitude) {
        int latitudex10000  = (int) (latitude * 10000 + 0.5);
        int longitudex10000 = (int) (longitude * 10000 + 0.5);

        if (latitudex10000 > 900000 || latitudex10000 < -900000) {
            String msg = "Latitude: " + latitude + " out of range.";
            throw new IllegalArgumentException(msg);
        }
        if (longitudex10000 > 1800000 || longitudex10000 < -1800000) {
            String msg = "Longitude: " + longitude + " out of range";
            throw new IllegalArgumentException(msg);
        }

        if (mState == MUXER_STATE_INITIALIZED && mNativeObject != 0) {
            nativeSetLocation(mNativeObject, latitudex10000, longitudex10000);
        } else {
            throw new IllegalStateException("Can't set location due to wrong state.");
        }
    }

    /**
     * Starts the muxer.
     * <p>Make sure this is called after {@link #addTrack} and before
     * {@link #writeSampleData}.</p>
     */
    public void start() {
        if (mNativeObject == 0) {
            throw new IllegalStateException("Muxer has been released!");
        }
        if (mState == MUXER_STATE_INITIALIZED) {
            nativeStart(mNativeObject);
            mState = MUXER_STATE_STARTED;
        } else {
            throw new IllegalStateException("Can't start due to wrong state.");
        }
    }

    /**
     * Stops the muxer.
     * <p>Once the muxer stops, it can not be restarted.</p>
     */
    public void stop() {
        if (mState == MUXER_STATE_STARTED) {
            nativeStop(mNativeObject);
            mState = MUXER_STATE_STOPPED;
        } else {
            throw new IllegalStateException("Can't stop due to wrong state.");
        }
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            if (mCloseGuard != null) {
                mCloseGuard.warnIfOpen();
            }
            if (mNativeObject != 0) {
                nativeRelease(mNativeObject);
                mNativeObject = 0;
            }
        } finally {
            super.finalize();
        }
    }

    /**
     * Adds a track with the specified format.
     * @param format The media format for the track.
     * @return The track index for this newly added track, and it should be used
     * in the {@link #writeSampleData}.
     */
    public int addTrack(MediaFormat format) {
        if (format == null) {
            throw new IllegalArgumentException("format must not be null.");
        }
        if (mState != MUXER_STATE_INITIALIZED) {
            throw new IllegalStateException("Muxer is not initialized.");
        }
        if (mNativeObject == 0) {
            throw new IllegalStateException("Muxer has been released!");
        }
        int trackIndex = -1;
        // Convert the MediaFormat into key-value pairs and send to the native.
        Map<String, Object> formatMap = format.getMap();

        String[] keys = null;
        Object[] values = null;
        int mapSize = formatMap.size();
        if (mapSize > 0) {
            keys = new String[mapSize];
            values = new Object[mapSize];
            int i = 0;
            for (Map.Entry<String, Object> entry : formatMap.entrySet()) {
                keys[i] = entry.getKey();
                values[i] = entry.getValue();
                ++i;
            }
            trackIndex = nativeAddTrack(mNativeObject, keys, values);
        } else {
            throw new IllegalArgumentException("format must not be empty.");
        }

        // Track index number is expected to incremented as addTrack succeed.
        // However, if format is invalid, it will get a negative trackIndex.
        if (mLastTrackIndex >= trackIndex) {
            throw new IllegalArgumentException("Invalid format.");
        }
        mLastTrackIndex = trackIndex;
        return trackIndex;
    }

    /**
     * Writes an encoded sample into the muxer.
     * <p>The application needs to make sure that the samples are written into
     * the right tracks. Also, it needs to make sure the samples for each track
     * are written in chronological order (e.g. in the order they are provided
     * by the encoder.)</p>
     * @param byteBuf The encoded sample.
     * @param trackIndex The track index for this sample.
     * @param bufferInfo The buffer information related to this sample.
     * MediaMuxer uses the flags provided in {@link MediaCodec.BufferInfo},
     * to signal sync frames.
     */
    public void writeSampleData(int trackIndex, ByteBuffer byteBuf,
            BufferInfo bufferInfo) {
        if (trackIndex < 0 || trackIndex > mLastTrackIndex) {
            throw new IllegalArgumentException("trackIndex is invalid");
        }

        if (byteBuf == null) {
            throw new IllegalArgumentException("byteBuffer must not be null");
        }

        if (bufferInfo == null) {
            throw new IllegalArgumentException("bufferInfo must not be null");
        }
        if (bufferInfo.size < 0 || bufferInfo.offset < 0
                || (bufferInfo.offset + bufferInfo.size) > byteBuf.capacity()
                || bufferInfo.presentationTimeUs < 0) {
            throw new IllegalArgumentException("bufferInfo must specify a" +
                    " valid buffer offset, size and presentation time");
        }

        if (mNativeObject == 0) {
            throw new IllegalStateException("Muxer has been released!");
        }

        if (mState != MUXER_STATE_STARTED) {
            throw new IllegalStateException("Can't write, muxer is not started");
        }

        nativeWriteSampleData(mNativeObject, trackIndex, byteBuf,
                bufferInfo.offset, bufferInfo.size,
                bufferInfo.presentationTimeUs, bufferInfo.flags);
    }

    /**
     * Make sure you call this when you're done to free up any resources
     * instead of relying on the garbage collector to do this for you at
     * some point in the future.
     */
    public void release() {
        if (mState == MUXER_STATE_STARTED) {
            stop();
        }
        if (mNativeObject != 0) {
            nativeRelease(mNativeObject);
            mNativeObject = 0;
            mCloseGuard.close();
        }
        mState = MUXER_STATE_UNINITIALIZED;
    }
}