/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

// Disable symbol overrides for FILE and fseek as those are used in the
// Vorbis headers.
#define FORBIDDEN_SYMBOL_EXCEPTION_FILE
#define FORBIDDEN_SYMBOL_EXCEPTION_fseek

#include "audio/decoders/vorbis.h"

#ifdef USE_VORBIS

#include "common/ptr.h"
#include "common/stream.h"
#include "common/textconsole.h"
#include "common/util.h"

#include "audio/audiostream.h"

#ifdef USE_TREMOR
#ifdef USE_TREMOLO
#include <tremolo/ivorbisfile.h>
#else
#include <tremor/ivorbisfile.h>
#endif
#else
#define OV_EXCLUDE_STATIC_CALLBACKS
#include <vorbis/vorbisfile.h>
#endif


namespace Audio {

// These are wrapper functions to allow using a SeekableReadStream object to
// provide data to the OggVorbis_File object.

static size_t read_stream_wrap(void *ptr, size_t size, size_t nmemb, void *datasource) {
	Common::SeekableReadStream *stream = (Common::SeekableReadStream *)datasource;

	uint32 result = stream->read(ptr, size * nmemb);

	return result / size;
}

static int seek_stream_wrap(void *datasource, ogg_int64_t offset, int whence) {
	Common::SeekableReadStream *stream = (Common::SeekableReadStream *)datasource;
	stream->seek((int32)offset, whence);
	return stream->pos();
}

static int close_stream_wrap(void *datasource) {
	// Do nothing -- we leave it up to the VorbisStream to free memory as appropriate.
	return 0;
}

static long tell_stream_wrap(void *datasource) {
	Common::SeekableReadStream *stream = (Common::SeekableReadStream *)datasource;
	return stream->pos();
}

static ov_callbacks g_stream_wrap = {
	read_stream_wrap, seek_stream_wrap, close_stream_wrap, tell_stream_wrap
};



#pragma mark -
#pragma mark --- Ogg Vorbis stream ---
#pragma mark -


class VorbisStream : public SeekableAudioStream {
protected:
	Common::DisposablePtr<Common::SeekableReadStream> _inStream;

	bool _isStereo;
	int _rate;

	Timestamp _length;

	OggVorbis_File _ovFile;

	int16 _buffer[4096];
	const int16 *_bufferEnd;
	const int16 *_pos;

public:
	// startTime / duration are in milliseconds
	VorbisStream(Common::SeekableReadStream *inStream, DisposeAfterUse::Flag dispose);
	~VorbisStream();

	int readBuffer(int16 *buffer, const int numSamples) override;

	bool endOfData() const override		{ return _pos >= _bufferEnd; }
	bool isStereo() const override		{ return _isStereo; }
	int getRate() const override			{ return _rate; }

	bool seek(const Timestamp &where) override;
	Timestamp getLength() const override { return _length; }
protected:
	bool refill();
};

VorbisStream::VorbisStream(Common::SeekableReadStream *inStream, DisposeAfterUse::Flag dispose) :
	_inStream(inStream, dispose),
	_length(0, 1000),
	_bufferEnd(ARRAYEND(_buffer)) {

	int res = ov_open_callbacks(inStream, &_ovFile, nullptr, 0, g_stream_wrap);
	if (res < 0) {
		warning("Could not create Vorbis stream (%d)", res);
		_pos = _bufferEnd;
		return;
	}

	// Read in initial data
	if (!refill())
		return;

	// Setup some header information
	_isStereo = ov_info(&_ovFile, -1)->channels >= 2;
	_rate = ov_info(&_ovFile, -1)->rate;

#ifdef USE_TREMOR
	_length = Timestamp(ov_time_total(&_ovFile, -1), getRate());
#else
	_length = Timestamp(uint32(ov_time_total(&_ovFile, -1) * 1000.0), getRate());
#endif
}

VorbisStream::~VorbisStream() {
	ov_clear(&_ovFile);
}

int VorbisStream::readBuffer(int16 *buffer, const int numSamples) {
	int samples = 0;
	while (samples < numSamples && _pos < _bufferEnd) {
		const int len = MIN(numSamples - samples, (int)(_bufferEnd - _pos));
		memcpy(buffer, _pos, len * 2);
		buffer += len;
		_pos += len;
		samples += len;
		if (_pos >= _bufferEnd) {
			if (!refill())
				break;
		}
	}
	return samples;
}

bool VorbisStream::seek(const Timestamp &where) {
	// Vorbisfile uses the sample pair number, thus we always use "false" for the isStereo parameter
	// of the convertTimeToStreamPos helper.
	int res = ov_pcm_seek(&_ovFile, convertTimeToStreamPos(where, getRate(), false).totalNumberOfFrames());
	if (res) {
		warning("Error seeking in Vorbis stream (%d)", res);
		_pos = _bufferEnd;
		return false;
	}

	return refill();
}

bool VorbisStream::refill() {
	// Read the samples
	uint len_left = sizeof(_buffer);
	char *read_pos = (char *)_buffer;

	while (len_left > 0) {
		long result;

#ifdef USE_TREMOR
		// Tremor ov_read() always returns data as signed 16 bit interleaved PCM
		// in host byte order. As such, it does not take arguments to request
		// specific signedness, byte order or bit depth as in Vorbisfile.
		result = ov_read(&_ovFile, read_pos, len_left,
						NULL);
#else
#ifdef SCUMM_BIG_ENDIAN
		result = ov_read(&_ovFile, read_pos, len_left,
						1,
						2,	// 16 bit
						1,	// signed
						NULL);
#else
		result = ov_read(&_ovFile, read_pos, len_left,
						0,
						2,	// 16 bit
						1,	// signed
						nullptr);
#endif
#endif
		if (result == OV_HOLE) {
			// Possibly recoverable, just warn about it
			warning("Corrupted data in Vorbis file");
		} else if (result == 0) {
			//warning("End of file while reading from Vorbis file");
			//_pos = _bufferEnd;
			//return false;
			break;
		} else if (result < 0) {
			warning("Error reading from Vorbis stream (%d)", int(result));
			_pos = _bufferEnd;
			// Don't delete it yet, that causes problems in
			// the CD player emulation code.
			return false;
		} else {
			len_left -= result;
			read_pos += result;
		}
	}

	_pos = _buffer;
	_bufferEnd = (int16 *)read_pos;

	return true;
}


#pragma mark -
#pragma mark --- Ogg Vorbis factory functions ---
#pragma mark -

SeekableAudioStream *makeVorbisStream(
	Common::SeekableReadStream *stream,
	DisposeAfterUse::Flag disposeAfterUse) {
	SeekableAudioStream *s = new VorbisStream(stream, disposeAfterUse);
	if (s && s->endOfData()) {
		delete s;
		return nullptr;
	} else {
		return s;
	}
}

} // End of namespace Audio

#endif // #ifdef USE_VORBIS
