/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org

Telegram Desktop 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 3 of the License, or
(at your option) any later version.

It 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.

In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.

Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2016 John Preston, https://desktop.telegram.org
*/
#include "stdafx.h"
#include "media/media_audio_ffmpeg_loader.h"

constexpr AVSampleFormat AudioToFormat = AV_SAMPLE_FMT_S16;
constexpr int64_t AudioToChannelLayout = AV_CH_LAYOUT_STEREO;
constexpr int32 AudioToChannels = 2;

bool AbstractFFMpegLoader::open(qint64 position) {
	if (!AudioPlayerLoader::openFile()) {
		return false;
	}

	int res = 0;
	char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };

	ioBuffer = (uchar*)av_malloc(AVBlockSize);
	if (data.isEmpty()) {
		ioContext = avio_alloc_context(ioBuffer, AVBlockSize, 0, reinterpret_cast<void*>(this), &AbstractFFMpegLoader::_read_file, 0, &AbstractFFMpegLoader::_seek_file);
	} else {
		ioContext = avio_alloc_context(ioBuffer, AVBlockSize, 0, reinterpret_cast<void*>(this), &AbstractFFMpegLoader::_read_data, 0, &AbstractFFMpegLoader::_seek_data);
	}
	fmtContext = avformat_alloc_context();
	if (!fmtContext) {
		DEBUG_LOG(("Audio Read Error: Unable to avformat_alloc_context for file '%1', data size '%2'").arg(file.name()).arg(data.size()));
		return false;
	}
	fmtContext->pb = ioContext;

	if ((res = avformat_open_input(&fmtContext, 0, 0, 0)) < 0) {
		ioBuffer = 0;

		DEBUG_LOG(("Audio Read Error: Unable to avformat_open_input for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
		return false;
	}
	_opened = true;

	if ((res = avformat_find_stream_info(fmtContext, 0)) < 0) {
		DEBUG_LOG(("Audio Read Error: Unable to avformat_find_stream_info for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
		return false;
	}

	streamId = av_find_best_stream(fmtContext, AVMEDIA_TYPE_AUDIO, -1, -1, &codec, 0);
	if (streamId < 0) {
		LOG(("Audio Error: Unable to av_find_best_stream for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(streamId).arg(av_make_error_string(err, sizeof(err), streamId)));
		return false;
	}

	freq = fmtContext->streams[streamId]->codec->sample_rate;
	if (fmtContext->streams[streamId]->duration == AV_NOPTS_VALUE) {
		len = (fmtContext->duration * freq) / AV_TIME_BASE;
	} else {
		len = (fmtContext->streams[streamId]->duration * freq * fmtContext->streams[streamId]->time_base.num) / fmtContext->streams[streamId]->time_base.den;
	}

	return true;
}

AbstractFFMpegLoader::~AbstractFFMpegLoader() {
	if (ioContext) av_free(ioContext);
	if (_opened) {
		avformat_close_input(&fmtContext);
	} else if (ioBuffer) {
		av_free(ioBuffer);
	}
	if (fmtContext) avformat_free_context(fmtContext);
}

int AbstractFFMpegLoader::_read_data(void *opaque, uint8_t *buf, int buf_size) {
	AbstractFFMpegLoader *l = reinterpret_cast<AbstractFFMpegLoader*>(opaque);

	int32 nbytes = qMin(l->data.size() - l->dataPos, int32(buf_size));
	if (nbytes <= 0) {
		return 0;
	}

	memcpy(buf, l->data.constData() + l->dataPos, nbytes);
	l->dataPos += nbytes;
	return nbytes;
}

int64_t AbstractFFMpegLoader::_seek_data(void *opaque, int64_t offset, int whence) {
	AbstractFFMpegLoader *l = reinterpret_cast<AbstractFFMpegLoader*>(opaque);

	int32 newPos = -1;
	switch (whence) {
	case SEEK_SET: newPos = offset; break;
	case SEEK_CUR: newPos = l->dataPos + offset; break;
	case SEEK_END: newPos = l->data.size() + offset; break;
	}
	if (newPos < 0 || newPos > l->data.size()) {
		return -1;
	}
	l->dataPos = newPos;
	return l->dataPos;
}

int AbstractFFMpegLoader::_read_file(void *opaque, uint8_t *buf, int buf_size) {
	AbstractFFMpegLoader *l = reinterpret_cast<AbstractFFMpegLoader*>(opaque);
	return int(l->f.read((char*)(buf), buf_size));
}

int64_t AbstractFFMpegLoader::_seek_file(void *opaque, int64_t offset, int whence) {
	AbstractFFMpegLoader *l = reinterpret_cast<AbstractFFMpegLoader*>(opaque);

	switch (whence) {
	case SEEK_SET: return l->f.seek(offset) ? l->f.pos() : -1;
	case SEEK_CUR: return l->f.seek(l->f.pos() + offset) ? l->f.pos() : -1;
	case SEEK_END: return l->f.seek(l->f.size() + offset) ? l->f.pos() : -1;
	}
	return -1;
}

FFMpegLoader::FFMpegLoader(const FileLocation &file, const QByteArray &data) : AbstractFFMpegLoader(file, data) {
	frame = av_frame_alloc();
}

bool FFMpegLoader::open(qint64 position) {
	if (!AbstractFFMpegLoader::open(position)) {
		return false;
	}

	int res = 0;
	char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };

	// Get a pointer to the codec context for the audio stream
	av_opt_set_int(fmtContext->streams[streamId]->codec, "refcounted_frames", 1, 0);
	if ((res = avcodec_open2(fmtContext->streams[streamId]->codec, codec, 0)) < 0) {
		LOG(("Audio Error: Unable to avcodec_open2 for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
		return false;
	}
	codecContext = fmtContext->streams[streamId]->codec;

	uint64_t layout = codecContext->channel_layout;
	inputFormat = codecContext->sample_fmt;
	switch (layout) {
	case AV_CH_LAYOUT_MONO:
		switch (inputFormat) {
		case AV_SAMPLE_FMT_U8:
		case AV_SAMPLE_FMT_U8P: fmt = AL_FORMAT_MONO8; sampleSize = 1; break;
		case AV_SAMPLE_FMT_S16:
		case AV_SAMPLE_FMT_S16P: fmt = AL_FORMAT_MONO16; sampleSize = sizeof(uint16); break;
		default:
			sampleSize = -1; // convert needed
		break;
		}
	break;
	case AV_CH_LAYOUT_STEREO:
		switch (inputFormat) {
		case AV_SAMPLE_FMT_U8: fmt = AL_FORMAT_STEREO8; sampleSize = 2; break;
		case AV_SAMPLE_FMT_S16: fmt = AL_FORMAT_STEREO16; sampleSize = 2 * sizeof(uint16); break;
		default:
			sampleSize = -1; // convert needed
		break;
		}
	break;
	default:
		sampleSize = -1; // convert needed
	break;
	}
	if (freq != 44100 && freq != 48000) {
		sampleSize = -1; // convert needed
	}

	if (sampleSize < 0) {
		swrContext = swr_alloc();
		if (!swrContext) {
			LOG(("Audio Error: Unable to swr_alloc for file '%1', data size '%2'").arg(file.name()).arg(data.size()));
			return false;
		}
		int64_t src_ch_layout = layout, dst_ch_layout = AudioToChannelLayout;
		srcRate = freq;
		AVSampleFormat src_sample_fmt = inputFormat, dst_sample_fmt = AudioToFormat;
		dstRate = (freq != 44100 && freq != 48000) ? AudioVoiceMsgFrequency : freq;

		av_opt_set_int(swrContext, "in_channel_layout", src_ch_layout, 0);
		av_opt_set_int(swrContext, "in_sample_rate", srcRate, 0);
		av_opt_set_sample_fmt(swrContext, "in_sample_fmt", src_sample_fmt, 0);
		av_opt_set_int(swrContext, "out_channel_layout", dst_ch_layout, 0);
		av_opt_set_int(swrContext, "out_sample_rate", dstRate, 0);
		av_opt_set_sample_fmt(swrContext, "out_sample_fmt", dst_sample_fmt, 0);

		if ((res = swr_init(swrContext)) < 0) {
			LOG(("Audio Error: Unable to swr_init for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
			return false;
		}

		sampleSize = AudioToChannels * sizeof(short);
		freq = dstRate;
		len = av_rescale_rnd(len, dstRate, srcRate, AV_ROUND_UP);
		fmt = AL_FORMAT_STEREO16;

		maxResampleSamples = av_rescale_rnd(AVBlockSize / sampleSize, dstRate, srcRate, AV_ROUND_UP);
		if ((res = av_samples_alloc_array_and_samples(&dstSamplesData, 0, AudioToChannels, maxResampleSamples, AudioToFormat, 0)) < 0) {
			LOG(("Audio Error: Unable to av_samples_alloc for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
			return false;
		}
	}
	if (position) {
		int64 ts = (position * fmtContext->streams[streamId]->time_base.den) / (freq * fmtContext->streams[streamId]->time_base.num);
		if (av_seek_frame(fmtContext, streamId, ts, AVSEEK_FLAG_ANY) < 0) {
			if (av_seek_frame(fmtContext, streamId, ts, 0) < 0) {
			}
		}
		//if (dstSamplesData) {
		//	position = qRound(srcRate * (position / float64(dstRate)));
		//}
	}

	return true;
}

AudioPlayerLoader::ReadResult FFMpegLoader::readMore(QByteArray &result, int64 &samplesAdded) {
	int res;
	if ((res = av_read_frame(fmtContext, &avpkt)) < 0) {
		if (res != AVERROR_EOF) {
			char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };
			LOG(("Audio Error: Unable to av_read_frame() file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));
			return ReadResult::Error;
		}
		return ReadResult::EndOfFile;
	}
	if (avpkt.stream_index == streamId) {
		av_frame_unref(frame);
		int got_frame = 0;
		if ((res = avcodec_decode_audio4(codecContext, frame, &got_frame, &avpkt)) < 0) {
			char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };
			LOG(("Audio Error: Unable to avcodec_decode_audio4() file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));

			av_packet_unref(&avpkt);
			if (res == AVERROR_INVALIDDATA) {
				return ReadResult::NotYet; // try to skip bad packet
			}
			return ReadResult::Error;
		}

		if (got_frame) {
			if (dstSamplesData) { // convert needed
				int64_t dstSamples = av_rescale_rnd(swr_get_delay(swrContext, srcRate) + frame->nb_samples, dstRate, srcRate, AV_ROUND_UP);
				if (dstSamples > maxResampleSamples) {
					maxResampleSamples = dstSamples;
					av_free(dstSamplesData[0]);

					if ((res = av_samples_alloc(dstSamplesData, 0, AudioToChannels, maxResampleSamples, AudioToFormat, 1)) < 0) {
						dstSamplesData[0] = 0;
						char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };
						LOG(("Audio Error: Unable to av_samples_alloc for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));

						av_packet_unref(&avpkt);
						return ReadResult::Error;
					}
				}
				if ((res = swr_convert(swrContext, dstSamplesData, dstSamples, (const uint8_t**)frame->extended_data, frame->nb_samples)) < 0) {
					char err[AV_ERROR_MAX_STRING_SIZE] = { 0 };
					LOG(("Audio Error: Unable to swr_convert for file '%1', data size '%2', error %3, %4").arg(file.name()).arg(data.size()).arg(res).arg(av_make_error_string(err, sizeof(err), res)));

					av_packet_unref(&avpkt);
					return ReadResult::Error;
				}
				int32 resultLen = av_samples_get_buffer_size(0, AudioToChannels, res, AudioToFormat, 1);
				result.append((const char*)dstSamplesData[0], resultLen);
				samplesAdded += resultLen / sampleSize;
			} else {
				result.append((const char*)frame->extended_data[0], frame->nb_samples * sampleSize);
				samplesAdded += frame->nb_samples;
			}
		}
	}
	av_packet_unref(&avpkt);
	return ReadResult::Ok;
}

FFMpegLoader::~FFMpegLoader() {
	if (codecContext) avcodec_close(codecContext);
	if (swrContext) swr_free(&swrContext);
	if (dstSamplesData) {
		if (dstSamplesData[0]) {
			av_freep(&dstSamplesData[0]);
		}
		av_freep(&dstSamplesData);
	}
	av_frame_free(&frame);
}