/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
OpenAL support based on work by:
Copyright (C) 2011 Sebastian 'Bahamada' Rühl
Copyright (C) 2011 Cyriaque 'Cisoun' Skrapits <cysoun@gmail.com>
Copyright (C) 2011 Giuseppe Bilotta <giuseppe.bilotta@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; ifnot, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "sound_openal.h"

#if defined(_WIN32)
	#include <al.h>
	#include <alc.h>
	//#include <alext.h>
#elif defined(__APPLE__)
	#include <OpenAL/al.h>
	#include <OpenAL/alc.h>
	//#include <OpenAL/alext.h>
#else
	#include <AL/al.h>
	#include <AL/alc.h>
	#include <AL/alext.h>
#endif
#include <cmath>
#include <vorbis/vorbisfile.h>
#include <cassert>
#include "log.h"
#include "util/numeric.h" // myrand()
#include "porting.h"
#include <vector>
#include <fstream>
#include <unordered_map>

#define BUFFER_SIZE 30000

static const char *alcErrorString(ALCenum err)
{
	switch (err) {
	case ALC_NO_ERROR:
		return "no error";
	case ALC_INVALID_DEVICE:
		return "invalid device";
	case ALC_INVALID_CONTEXT:
		return "invalid context";
	case ALC_INVALID_ENUM:
		return "invalid enum";
	case ALC_INVALID_VALUE:
		return "invalid value";
	case ALC_OUT_OF_MEMORY:
		return "out of memory";
	default:
		return "<unknown OpenAL error>";
	}
}

static const char *alErrorString(ALenum err)
{
	switch (err) {
	case AL_NO_ERROR:
		return "no error";
	case AL_INVALID_NAME:
		return "invalid name";
	case AL_INVALID_ENUM:
		return "invalid enum";
	case AL_INVALID_VALUE:
		return "invalid value";
	case AL_INVALID_OPERATION:
		return "invalid operation";
	case AL_OUT_OF_MEMORY:
		return "out of memory";
	default:
		return "<unknown OpenAL error>";
	}
}

static ALenum warn_if_error(ALenum err, const char *desc)
{
	if(err == AL_NO_ERROR)
		return err;
	warningstream<<desc<<": "<<alErrorString(err)<<std::endl;
	return err;
}

void f3_set(ALfloat *f3, v3f v)
{
	f3[0] = v.X;
	f3[1] = v.Y;
	f3[2] = v.Z;
}

struct SoundBuffer
{
	ALenum format;
	ALsizei freq;
	ALuint buffer_id;
	std::vector<char> buffer;
};

SoundBuffer *load_opened_ogg_file(OggVorbis_File *oggFile,
		const std::string &filename_for_logging)
{
	int endian = 0; // 0 for Little-Endian, 1 for Big-Endian
	int bitStream;
	long bytes;
	char array[BUFFER_SIZE]; // Local fixed size array
	vorbis_info *pInfo;

	SoundBuffer *snd = new SoundBuffer;

	// Get some information about the OGG file
	pInfo = ov_info(oggFile, -1);

	// Check the number of channels... always use 16-bit samples
	if(pInfo->channels == 1)
		snd->format = AL_FORMAT_MONO16;
	else
		snd->format = AL_FORMAT_STEREO16;

	// The frequency of the sampling rate
	snd->freq = pInfo->rate;

	// Keep reading until all is read
	do
	{
		// Read up to a buffer's worth of decoded sound data
		bytes = ov_read(oggFile, array, BUFFER_SIZE, endian, 2, 1, &bitStream);

		if(bytes < 0)
		{
			ov_clear(oggFile);
			infostream << "Audio: Error decoding "
				<< filename_for_logging << std::endl;
			delete snd;
			return NULL;
		}

		// Append to end of buffer
		snd->buffer.insert(snd->buffer.end(), array, array + bytes);
	} while (bytes > 0);

	alGenBuffers(1, &snd->buffer_id);
	alBufferData(snd->buffer_id, snd->format,
			&(snd->buffer[0]), snd->buffer.size(),
			snd->freq);

	ALenum error = alGetError();

	if(error != AL_NO_ERROR){
		infostream<<"Audio: OpenAL error: "<<alErrorString(error)
				<<"preparing sound buffer"<<std::endl;
	}

	infostream << "Audio file "
		<< filename_for_logging << " loaded" << std::endl;

	// Clean up!
	ov_clear(oggFile);

	return snd;
}

SoundBuffer *load_ogg_from_file(const std::string &path)
{
	OggVorbis_File oggFile;

	// Try opening the given file.
	// This requires libvorbis >= 1.3.2, as
	// previous versions expect a non-const char *
	if (ov_fopen(path.c_str(), &oggFile) != 0) {
		infostream << "Audio: Error opening " << path
			<< " for decoding" << std::endl;
		return NULL;
	}

	return load_opened_ogg_file(&oggFile, path);
}

struct BufferSource {
	const char *buf;
	size_t cur_offset;
	size_t len;
};

size_t buffer_sound_read_func(void *ptr, size_t size, size_t nmemb, void *datasource)
{
	BufferSource *s = (BufferSource *)datasource;
	size_t copied_size = MYMIN(s->len - s->cur_offset, size);
	memcpy(ptr, s->buf + s->cur_offset, copied_size);
	s->cur_offset += copied_size;
	return copied_size;
}

int buffer_sound_seek_func(void *datasource, ogg_int64_t offset, int whence)
{
	BufferSource *s = (BufferSource *)datasource;
	if (whence == SEEK_SET) {
		if (offset < 0 || (size_t)MYMAX(offset, 0) >= s->len) {
			// offset out of bounds
			return -1;
		}
		s->cur_offset = offset;
		return 0;
	} else if (whence == SEEK_CUR) {
		if ((size_t)MYMIN(-offset, 0) > s->cur_offset
				|| s->cur_offset + offset > s->len) {
			// offset out of bounds
			return -1;
		}
		s->cur_offset += offset;
		return 0;
	}
	// invalid whence param (SEEK_END doesn't have to be supported)
	return -1;
}

long BufferSourceell_func(void *datasource)
{
	BufferSource *s = (BufferSource *)datasource;
	return s->cur_offset;
}

static ov_callbacks g_buffer_ov_callbacks = {
	&buffer_sound_read_func,
	&buffer_sound_seek_func,
	NULL,
	&BufferSourceell_func
};

SoundBuffer *load_ogg_from_buffer(const std::string &buf, const std::string &id_for_log)
{
	OggVorbis_File oggFile;

	BufferSource s;
	s.buf = buf.c_str();
	s.cur_offset = 0;
	s.len = buf.size();

	if (ov_open_callbacks(&s, &oggFile, NULL, 0, g_buffer_ov_callbacks) != 0) {
		infostream << "Audio: Error opening " << id_for_log
			<< " for decoding" << std::endl;
		return NULL;
	}

	return load_opened_ogg_file(&oggFile, id_for_log);
}

struct PlayingSound
{
	ALuint source_id;
	bool loop;
};

class OpenALSoundManager: public ISoundManager
{
private:
	OnDemandSoundFetcher *m_fetcher;
	ALCdevice *m_device;
	ALCcontext *m_context;
	int m_next_id;
	std::unordered_map<std::string, std::vector<SoundBuffer*>> m_buffers;
	std::unordered_map<int, PlayingSound*> m_sounds_playing;
	v3f m_listener_pos;
	struct FadeState {
		FadeState() = default;

		FadeState(float step, float current_gain, float target_gain):
			step(step),
			current_gain(current_gain),
			target_gain(target_gain) {}
		float step;
		float current_gain;
		float target_gain;
	};

	std::unordered_map<int, FadeState> m_sounds_fading;
	float m_fade_delay;
public:
	bool m_is_initialized;
	OpenALSoundManager(OnDemandSoundFetcher *fetcher):
		m_fetcher(fetcher),
		m_device(NULL),
		m_context(NULL),
		m_next_id(1),
		m_fade_delay(0),
		m_is_initialized(false)
	{
		ALCenum error = ALC_NO_ERROR;

		infostream<<"Audio: Initializing..."<<std::endl;

		m_device = alcOpenDevice(NULL);
		if(!m_device){
			infostream<<"Audio: No audio device available, audio system "
				<<"not initialized"<<std::endl;
			return;
		}

		m_context = alcCreateContext(m_device, NULL);
		if(!m_context){
			error = alcGetError(m_device);
			infostream<<"Audio: Unable to initialize audio context, "
					<<"aborting audio initialization ("<<alcErrorString(error)
					<<")"<<std::endl;
			alcCloseDevice(m_device);
			m_device = NULL;
			return;
		}

		if(!alcMakeContextCurrent(m_context) ||
				(error = alcGetError(m_device) != ALC_NO_ERROR))
		{
			infostream<<"Audio: Error setting audio context, aborting audio "
					<<"initialization ("<<alcErrorString(error)<<")"<<std::endl;
			alcDestroyContext(m_context);
			m_context = NULL;
			alcCloseDevice(m_device);
			m_device = NULL;
			return;
		}

		alDistanceModel(AL_INVERSE_DISTANCE_CLAMPED);

		infostream<<"Audio: Initialized: OpenAL "<<alGetString(AL_VERSION)
				<<", using "<<alcGetString(m_device, ALC_DEVICE_SPECIFIER)
				<<std::endl;

		m_is_initialized = true;
	}

	~OpenALSoundManager()
	{
		infostream<<"Audio: Deinitializing..."<<std::endl;
		// KABOOM!
		// TODO: Clear SoundBuffers
		alcMakeContextCurrent(NULL);
		alcDestroyContext(m_context);
		m_context = NULL;
		alcCloseDevice(m_device);
		m_device = NULL;

		for (auto &buffer : m_buffers) {
			for (SoundBuffer *sb : buffer.second) {
				delete sb;
			}
			buffer.second.clear();
		}
		m_buffers.clear();