/*
 * Copyright (C) 2009,2010,2011,2012,2013 Samuel Audet
 *
 * This file is part of JavaCV.
 *
 * JavaCV 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 2 of the License, or
 * (at your option) any later version (subject to the "Classpath" exception
 * as provided in the LICENSE.txt file that accompanied this code).
 *
 * JavaCV 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 JavaCV.  If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * Based on the avcodec_sample.0.5.0.c file available at
 * http://web.me.com/dhoerl/Home/Tech_Blog/Entries/2009/1/22_Revised_avcodec_sample.c_files/avcodec_sample.0.5.0.c
 * by Martin Böhme, Stephen Dranger, and David Hoerl
 * as well as on the decoding_encoding.c file included in FFmpeg 0.11.1,
 * which is covered by the following copyright notice:
 *
 * Copyright (c) 2001 Fabrice Bellard
 *
 * 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 ntu.vashj;

import static com.googlecode.javacv.cpp.avcodec.*;
import static com.googlecode.javacv.cpp.avdevice.*;
import static com.googlecode.javacv.cpp.avformat.*;
import static com.googlecode.javacv.cpp.avutil.*;
import static com.googlecode.javacv.cpp.opencv_core.*;
import static com.googlecode.javacv.cpp.swscale.*;

import java.io.File;
import java.nio.Buffer;
import java.nio.ByteBuffer;

import com.googlecode.javacpp.BytePointer;
import com.googlecode.javacpp.DoublePointer;
import com.googlecode.javacpp.IntPointer;
import com.googlecode.javacpp.Loader;
import com.googlecode.javacpp.PointerPointer;
import com.googlecode.javacv.Frame;
import com.googlecode.javacv.FrameGrabber;
import com.googlecode.javacv.cpp.avcodec.AVCodec;
import com.googlecode.javacv.cpp.avcodec.AVCodecContext;
import com.googlecode.javacv.cpp.avcodec.AVPacket;
import com.googlecode.javacv.cpp.avcodec.AVPicture;
import com.googlecode.javacv.cpp.avformat.AVFormatContext;
import com.googlecode.javacv.cpp.avformat.AVInputFormat;
import com.googlecode.javacv.cpp.avformat.AVStream;
import com.googlecode.javacv.cpp.avutil.AVDictionary;
import com.googlecode.javacv.cpp.avutil.AVFrame;
import com.googlecode.javacv.cpp.avutil.AVRational;
import com.googlecode.javacv.cpp.opencv_core.IplImage;
import com.googlecode.javacv.cpp.swscale.SwsContext;

/**
 * 
 * @author Samuel Audet
 */
public class FFmpegKeyFrameGrabber extends FrameGrabber {
	public static String[] getDeviceDescriptions() throws Exception {
		tryLoad();
		throw new UnsupportedOperationException("Device enumeration not support by FFmpeg.");
	}

	public static FFmpegFrameGrabber createDefault(File deviceFile) throws Exception {
		return new FFmpegFrameGrabber(deviceFile);
	}

	public static FFmpegFrameGrabber createDefault(String devicePath) throws Exception {
		return new FFmpegFrameGrabber(devicePath);
	}

	public static FFmpegFrameGrabber createDefault(int deviceNumber) throws Exception {
		return null;
	}

	private static Exception loadingException = null;

	public static void tryLoad() throws Exception {
		if (loadingException != null) {
			throw loadingException;
		} else {
			try {
				Loader.load(com.googlecode.javacv.cpp.avutil.class);
				Loader.load(com.googlecode.javacv.cpp.avcodec.class);
				Loader.load(com.googlecode.javacv.cpp.avformat.class);
				Loader.load(com.googlecode.javacv.cpp.avdevice.class);
				Loader.load(com.googlecode.javacv.cpp.swscale.class);
			} catch (Throwable t) {
				if (t instanceof Exception) {
					throw loadingException = (Exception) t;
				} else {
					throw loadingException = new Exception("Failed to load " + FFmpegFrameGrabber.class, t);
				}
			}
		}
	}

	static {
		// Register all formats and codecs
		avcodec_register_all();
		avdevice_register_all();
		av_register_all();
		avformat_network_init();
	}

	public FFmpegKeyFrameGrabber(File file) {
		this(file.getAbsolutePath());
	}

	public FFmpegKeyFrameGrabber(String filename) {
		this.filename = filename;
	}

	public void release() throws Exception {
		synchronized (com.googlecode.javacv.cpp.avcodec.class) {
			releaseUnsafe();
		}
	}

	public void releaseUnsafe() throws Exception {
		if (pkt != null && pkt2 != null) {
			if (pkt2.size() > 0) {
				av_free_packet(pkt);
			}
			pkt = pkt2 = null;
		}

		// Free the RGB image
		if (buffer_rgb != null) {
			av_free(buffer_rgb);
			buffer_rgb = null;
		}
		if (picture_rgb != null) {
			avcodec_free_frame(picture_rgb);
			picture_rgb = null;
		}

		// Free the native format picture frame
		if (picture != null) {
			avcodec_free_frame(picture);
			picture = null;
		}

		// Close the video codec
		if (video_c != null) {
			avcodec_close(video_c);
			video_c = null;
		}

		// Free the audio samples frame
		if (samples_frame != null) {
			avcodec_free_frame(samples_frame);
			samples_frame = null;
		}

		// Close the audio codec
		if (audio_c != null) {
			avcodec_close(audio_c);
			audio_c = null;
		}

		// Close the video file
		if (oc != null && !oc.isNull()) {
			avformat_close_input(oc);
			oc = null;
		}

		if (img_convert_ctx != null) {
			sws_freeContext(img_convert_ctx);
			img_convert_ctx = null;
		}

		got_frame = null;
		return_image = null;
		frameGrabbed = false;
		frame = null;
		timestamp = 0;
		frameNumber = 0;
	}

	@Override
	protected void finalize() throws Throwable {
		super.finalize();
		release();
	}

	private String filename;
	private AVFormatContext oc;
	private AVStream video_st, audio_st;
	private AVCodecContext video_c, audio_c;
	public AVFrame picture, picture_rgb;
	private BytePointer buffer_rgb;
	private AVFrame samples_frame;
	private BytePointer[] samples_ptr;
	private Buffer[] samples_buf;
	private AVPacket pkt, pkt2;
	private int sizeof_pkt;
	private int[] got_frame;
	private SwsContext img_convert_ctx;
	private IplImage return_image;
	private boolean frameGrabbed;
	private Frame frame;

	@Override
	public double getGamma() {
		// default to a gamma of 2.2 for cheap Webcams, DV cameras, etc.
		if (gamma == 0.0) {
			return 2.2;
		} else {
			return gamma;
		}
	}

	@Override
	public String getFormat() {
		if (oc == null) {
			return super.getFormat();
		} else {
			return oc.iformat().name().getString();
		}
	}

	@Override
	public int getImageWidth() {
		return return_image == null ? super.getImageWidth() : return_image.width();
	}

	@Override
	public int getImageHeight() {
		return return_image == null ? super.getImageHeight() : return_image.height();
	}

	@Override
	public int getAudioChannels() {
		return audio_c == null ? super.getAudioChannels() : audio_c.channels();
	}

	@Override
	public int getPixelFormat() {
		if (imageMode == ImageMode.COLOR || imageMode == ImageMode.GRAY) {
			if (pixelFormat == AV_PIX_FMT_NONE) {
				return imageMode == ImageMode.COLOR ? AV_PIX_FMT_BGR24 : AV_PIX_FMT_GRAY8;
			} else {
				return pixelFormat;
			}
		} else if (video_c != null) { // RAW
			return video_c.pix_fmt();
		} else {
			return super.getPixelFormat();
		}
	}

	@Override
	public double getFrameRate() {
		if (video_st == null) {
			return super.getFrameRate();
		} else {
			AVRational r = video_st.r_frame_rate();
			return (double) r.num() / r.den();
		}
	}

	@Override
	public int getSampleFormat() {
		return audio_c == null ? super.getSampleFormat() : audio_c.sample_fmt();
	}

	@Override
	public int getSampleRate() {
		return audio_c == null ? super.getSampleRate() : audio_c.sample_rate();
	}

	@Override
	public void setFrameNumber(int frameNumber) throws Exception {
		// best guess, AVSEEK_FLAG_FRAME has not been implemented in FFmpeg...
		setTimestamp(Math.round(1000000L * frameNumber / getFrameRate()));
	}

	@Override
	public void setTimestamp(long timestamp) throws Exception {
		int ret;
		if (oc == null || video_c == null) {
			super.setTimestamp(timestamp);
		} else {
			timestamp = timestamp * AV_TIME_BASE / 1000000L;
			/* add the stream start time */
			if (oc.start_time() != AV_NOPTS_VALUE) {
				timestamp += oc.start_time();
			}
			if ((ret = avformat_seek_file(oc, -1, Long.MIN_VALUE, timestamp, Long.MAX_VALUE, AVSEEK_FLAG_BACKWARD)) < 0) {
				throw new Exception("avformat_seek_file() error " + ret + ": Could not seek file to timestamp " + timestamp + ".");
			}
			avcodec_flush_buffers(video_c);
			if (audio_c != null) {
				avcodec_flush_buffers(audio_c);
			}
			while (this.timestamp > timestamp && grab(false) != null) {
				// flush frames if seeking backwards
			}
			while (this.timestamp < timestamp && grab(false) != null) {
				// decode up to the desired frame
			}
			frameGrabbed = true;
		}
	}

	@Override
	public int getLengthInFrames() {
		// best guess...
		return (int) (getLengthInTime() * getFrameRate() / 1000000L);
	}

	@Override
	public long getLengthInTime() {
		return oc.duration() * 1000000L / AV_TIME_BASE;
	}

	public void start() throws Exception {
		synchronized (com.googlecode.javacv.cpp.avcodec.class) {
			startUnsafe();
		}
	}

	public void startUnsafe() throws Exception {
		int ret;
		img_convert_ctx = null;
		oc = new AVFormatContext(null);
		video_c = null;
		audio_c = null;
		pkt = new AVPacket();
		pkt2 = new AVPacket();
		sizeof_pkt = pkt.sizeof();
		got_frame = new int[1];
		return_image = null;
		frameGrabbed = false;
		frame = new Frame();
		timestamp = 0;
		frameNumber = 0;

		pkt2.size(0);

		// Open video file
		AVInputFormat f = null;
		if (format != null && format.length() > 0) {
			if ((f = av_find_input_format(format)) == null) {
				throw new Exception("av_find_input_format() error: Could not find input format \"" + format + "\".");
			}
		}
		AVDictionary options = new AVDictionary(null);
		if (frameRate > 0) {
			AVRational r = av_d2q(frameRate, 1001000);
			av_dict_set(options, "framerate", r.num() + "/" + r.den(), 0);
		}
		if (imageMode != ImageMode.RAW) {
			av_dict_set(options, "pixel_format", imageMode == ImageMode.COLOR ? "bgr24" : "gray8", 0);
		}
		if (imageWidth > 0 && imageHeight > 0) {
			av_dict_set(options, "video_size", imageWidth + "x" + imageHeight, 0);
		}
		if (sampleRate > 0) {
			av_dict_set(options, "sample_rate", "" + sampleRate, 0);
		}
		if (audioChannels > 0) {
			av_dict_set(options, "channels", "" + audioChannels, 0);
		}
		if ((ret = avformat_open_input(oc, filename, f, options)) < 0) {
			throw new Exception("avformat_open_input() error " + ret + ": Could not open input \"" + filename + "\". (Has setFormat() been called?)");
		}
		av_dict_free(options);

		// Retrieve stream information
		if ((ret = avformat_find_stream_info(oc, (PointerPointer) null)) < 0) {
			throw new Exception("avformat_find_stream_info() error " + ret + ": Could not find stream information.");
		}

		// Dump information about file onto standard error
		av_dump_format(oc, 0, filename, 0);

		// Find the first video and audio stream
		video_st = audio_st = null;
		int nb_streams = oc.nb_streams();
		for (int i = 0; i < nb_streams; i++) {
			AVStream st = oc.streams(i);
			// Get a pointer to the codec context for the video or audio stream
			AVCodecContext c = st.codec();
			if (video_st == null && c.codec_type() == AVMEDIA_TYPE_VIDEO) {
				video_st = st;
				video_c = c;
			} else if (audio_st == null && c.codec_type() == AVMEDIA_TYPE_AUDIO) {
				audio_st = st;
				audio_c = c;
			}
		}
		if (video_st == null && audio_st == null) {
			throw new Exception("Did not find a video or audio stream inside \"" + filename + "\".");
		}

		if (video_st != null) {
			// Find the decoder for the video stream
			AVCodec codec = avcodec_find_decoder(video_c.codec_id());
			if (codec == null) {
				throw new Exception("avcodec_find_decoder() error: Unsupported video format or codec not found: " + video_c.codec_id() + ".");
			}

			// Open video codec
			if ((ret = avcodec_open2(video_c, codec, (PointerPointer) null)) < 0) {
				throw new Exception("avcodec_open2() error " + ret + ": Could not open video codec.");
			}

			// Hack to correct wrong frame rates that seem to be generated by some codecs
			if (video_c.time_base().num() > 1000 && video_c.time_base().den() == 1) {
				video_c.time_base().den(1000);
			}

			// Allocate video frame and an AVFrame structure for the RGB image
			if ((picture = avcodec_alloc_frame()) == null) {
				throw new Exception("avcodec_alloc_frame() error: Could not allocate raw picture frame.");
			}
			if ((picture_rgb = avcodec_alloc_frame()) == null) {
				throw new Exception("avcodec_alloc_frame() error: Could not allocate RGB picture frame.");
			}

			int width = getImageWidth() > 0 ? getImageWidth() : video_c.width();
			int height = getImageHeight() > 0 ? getImageHeight() : video_c.height();

			switch (imageMode) {
			case COLOR:
			case GRAY:
				int fmt = getPixelFormat();

				// Determine required buffer size and allocate buffer
				int size = avpicture_get_size(fmt, width, height);
				buffer_rgb = new BytePointer(av_malloc(size));

				// Assign appropriate parts of buffer to image planes in picture_rgb
				// Note that picture_rgb is an AVFrame, but AVFrame is a superset of AVPicture
				avpicture_fill(new AVPicture(picture_rgb), buffer_rgb, fmt, width, height);

				return_image = IplImage.createHeader(width, height, IPL_DEPTH_8U, 1);
				break;

			case RAW:
				buffer_rgb = null;
				return_image = IplImage.createHeader(video_c.width(), video_c.height(), IPL_DEPTH_8U, 1);
				break;

			default:
				assert false;
			}
		}

		if (audio_st != null) {
			// Find the decoder for the audio stream
			AVCodec codec = avcodec_find_decoder(audio_c.codec_id());
			if (codec == null) {
				throw new Exception("avcodec_find_decoder() error: Unsupported audio format or codec not found: " + audio_c.codec_id() + ".");
			}

			// Open audio codec
			if ((ret = avcodec_open2(audio_c, codec, (PointerPointer) null)) < 0) {
				throw new Exception("avcodec_open2() error " + ret + ": Could not open audio codec.");
			}

			// Allocate audio samples frame
			if ((samples_frame = avcodec_alloc_frame()) == null) {
				throw new Exception("avcodec_alloc_frame() error: Could not allocate audio frame.");
			}
		}
	}

	public void stop() throws Exception {
		release();
	}

	public void trigger() throws Exception {
		if (oc == null || oc.isNull()) {
			throw new Exception("Could not trigger: No AVFormatContext. (Has start() been called?)");
		}
		if (pkt2.size() > 0) {
			pkt2.size(0);
			av_free_packet(pkt);
		}
		for (int i = 0; i < numBuffers + 1; i++) {
			if (av_read_frame(oc, pkt) < 0) {
				return;
			}
			av_free_packet(pkt);
		}
	}

	private void processImage() throws Exception {
		switch (imageMode) {
		case COLOR:
		case GRAY:
			// Deinterlace Picture
			if (deinterlace) {
				AVPicture p = new AVPicture(picture);
				avpicture_deinterlace(p, p, video_c.pix_fmt(), video_c.width(), video_c.height());
			}

			// Convert the image into BGR or GRAY format that OpenCV uses
			img_convert_ctx = sws_getCachedContext(img_convert_ctx, video_c.width(), video_c.height(), video_c.pix_fmt(), getImageWidth(), getImageHeight(), getPixelFormat(), SWS_BILINEAR, null, null, (DoublePointer) null);
			if (img_convert_ctx == null) {
				throw new Exception("sws_getCachedContext() error: Cannot initialize the conversion context.");
			}

			// Convert the image from its native format to RGB or GRAY
			sws_scale(img_convert_ctx, new PointerPointer(picture), picture.linesize(), 0, video_c.height(), new PointerPointer(picture_rgb), picture_rgb.linesize());
			return_image.imageData(buffer_rgb);
			return_image.widthStep(picture_rgb.linesize(0));
			break;

		case RAW:
			assert video_c.width() == return_image.width() && video_c.height() == return_image.height();
			return_image.imageData(picture.data(0));
			return_image.widthStep(picture.linesize(0));
			break;

		default:
			assert false;
		}
		return_image.imageSize(return_image.height() * return_image.widthStep());
		return_image.nChannels(return_image.widthStep() / return_image.width());
	}

	public IplImage grab() throws Exception {
		Frame frame = grabFrame(true, false, false);
		return frame != null ? frame.image : null;
	}

	private IplImage grab(boolean processImage) throws Exception {
		Frame frame = grabFrame(processImage, false, false);
		return frame != null ? frame.image : null;
	}

	@Override
	public Frame grabFrame() throws Exception {
		return grabFrame(true, true, false);
	}

	public Frame grabKeyFrame() throws Exception {
		return grabFrame(true, false, true);
	}

	private Frame grabFrame(boolean processImage, boolean doAudio, boolean iframes) throws Exception {
		if (oc == null || oc.isNull()) {
			throw new Exception("Could not grab: No AVFormatContext. (Has start() been called?)");
		}
		frame.keyFrame = false;
		frame.image = null;
		frame.samples = null;
		if (frameGrabbed) {
			frameGrabbed = false;
			if (processImage) {
				processImage();
			}
			frame.image = return_image;
			return frame;
		}
		boolean done = false;
		while (!done) {
			if (pkt2.size() <= 0) {
				if (av_read_frame(oc, pkt) < 0) {
					if (video_st != null) {
						// The video codec may have buffered some frames
						pkt.stream_index(video_st.index());
						pkt.data(null);
						pkt.size(0);
					} else {
						return null;
					}
				}
			}

			// Is this a packet from the video stream?
			if (video_st != null && pkt.stream_index() == video_st.index() && pkt.flags() == AV_PKT_FLAG_KEY) {
				// Decode video frame
				int len = avcodec_decode_video2(video_c, picture, got_frame, pkt);

				// Did we get a video frame?
				if (len >= 0 && got_frame[0] != 0) {
					long pts = av_frame_get_best_effort_timestamp(picture);
					AVRational time_base = video_st.time_base();
					timestamp = 1000000L * pts * time_base.num() / time_base.den();
					// best guess, AVCodecContext.frame_number = number of decoded frames...
					frameNumber = (int) (timestamp * getFrameRate() / 1000000L);
					if (processImage && picture.pict_type() == AV_PICTURE_TYPE_I) {
						processImage();
					}
					done = true;
					frame.keyFrame = picture.key_frame() != 0;
					frame.image = return_image;
				} else if (pkt.data() == null && pkt.size() == 0) {
					return null;
				}
			} else if (doAudio && audio_st != null && pkt.stream_index() == audio_st.index()) {
				if (pkt2.size() <= 0) {
					// HashMap is unacceptably slow on Android
					// pkt2.put(pkt);
					BytePointer.memcpy(pkt2, pkt, sizeof_pkt);
				}
				avcodec_get_frame_defaults(samples_frame);
				// Decode audio frame
				int len = avcodec_decode_audio4(audio_c, samples_frame, got_frame, pkt2);
				if (len <= 0) {
					// On error, trash the whole packet
					pkt2.size(0);
				} else {
					pkt2.data(pkt2.data().position(len));
					pkt2.size(pkt2.size() - len);
					if (got_frame[0] != 0) {
						long pts = av_frame_get_best_effort_timestamp(samples_frame);
						AVRational time_base = audio_st.time_base();
						timestamp = 1000000L * pts * time_base.num() / time_base.den();
						/* if a frame has been decoded, output it */
						done = true;
						int sample_format = samples_frame.format();
						int planes = av_sample_fmt_is_planar(sample_format) != 0 ? (int) samples_frame.channels() : 1;
						int data_size = av_samples_get_buffer_size((IntPointer) null, audio_c.channels(), samples_frame.nb_samples(), audio_c.sample_fmt(), 1) / planes;
						if (samples_buf == null || samples_buf.length != planes) {
							samples_ptr = new BytePointer[planes];
							samples_buf = new Buffer[planes];
						}
						frame.keyFrame = samples_frame.key_frame() != 0;
						frame.samples = samples_buf;
						int sample_size = data_size / av_get_bytes_per_sample(sample_format);
						for (int i = 0; i < planes; i++) {
							BytePointer p = samples_frame.data(i);
							if (!p.equals(samples_ptr[i]) || samples_ptr[i].capacity() < data_size) {
								samples_ptr[i] = p.capacity(data_size);
								ByteBuffer b = p.asBuffer();
								switch (sample_format) {
								case AV_SAMPLE_FMT_U8:
								case AV_SAMPLE_FMT_U8P:
									samples_buf[i] = b;
									break;
								case AV_SAMPLE_FMT_S16:
								case AV_SAMPLE_FMT_S16P:
									samples_buf[i] = b.asShortBuffer();
									break;
								case AV_SAMPLE_FMT_S32:
								case AV_SAMPLE_FMT_S32P:
									samples_buf[i] = b.asIntBuffer();
									break;
								case AV_SAMPLE_FMT_FLT:
								case AV_SAMPLE_FMT_FLTP:
									samples_buf[i] = b.asFloatBuffer();
									break;
								case AV_SAMPLE_FMT_DBL:
								case AV_SAMPLE_FMT_DBLP:
									samples_buf[i] = b.asDoubleBuffer();
									break;
								default:
									assert false;
								}
							}
							samples_buf[i].position(0).limit(sample_size);
						}
					}
				}
			}

			if (pkt2.size() <= 0) {
				// Free the packet that was allocated by av_read_frame
				av_free_packet(pkt);
			}
		}
		return frame;
	}
}