/*************************************************************************/
/*  audio_stream_player.cpp                                              */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/*************************************************************************/

#include "audio_stream_player.h"

#include "core/config/engine.h"

void AudioStreamPlayer::_mix_to_bus(const AudioFrame *p_frames, int p_amount) {
	int bus_index = AudioServer::get_singleton()->thread_find_bus_index(bus);

	AudioFrame *targets[4] = { nullptr, nullptr, nullptr, nullptr };

	if (AudioServer::get_singleton()->get_speaker_mode() == AudioServer::SPEAKER_MODE_STEREO) {
		targets[0] = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, 0);
	} else {
		switch (mix_target) {
			case MIX_TARGET_STEREO: {
				targets[0] = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, 0);
			} break;
			case MIX_TARGET_SURROUND: {
				for (int i = 0; i < AudioServer::get_singleton()->get_channel_count(); i++) {
					targets[i] = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, i);
				}
			} break;
			case MIX_TARGET_CENTER: {
				targets[0] = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, 1);
			} break;
		}
	}

	for (int c = 0; c < 4; c++) {
		if (!targets[c]) {
			break;
		}
		for (int i = 0; i < p_amount; i++) {
			targets[c][i] += p_frames[i];
		}
	}
}

void AudioStreamPlayer::_mix_internal(bool p_fadeout) {
	//get data
	AudioFrame *buffer = mix_buffer.ptrw();
	int buffer_size = mix_buffer.size();

	if (p_fadeout) {
		// Short fadeout ramp
		buffer_size = MIN(buffer_size, 128);
	}

	stream_playback->mix(buffer, pitch_scale, buffer_size);

	//multiply volume interpolating to avoid clicks if this changes
	float target_volume = p_fadeout ? -80.0 : volume_db;
	float vol = Math::db2linear(mix_volume_db);
	float vol_inc = (Math::db2linear(target_volume) - vol) / float(buffer_size);

	for (int i = 0; i < buffer_size; i++) {
		buffer[i] *= vol;
		vol += vol_inc;
	}

	//set volume for next mix
	mix_volume_db = target_volume;

	_mix_to_bus(buffer, buffer_size);
}

void AudioStreamPlayer::_mix_audio() {
	if (use_fadeout) {
		_mix_to_bus(fadeout_buffer.ptr(), fadeout_buffer.size());
		use_fadeout = false;
	}

	if (!stream_playback.is_valid() || !active ||
			(stream_paused && !stream_paused_fade)) {
		return;
	}

	if (stream_paused) {
		if (stream_paused_fade) {
			_mix_internal(true);
			stream_paused_fade = false;
		}
		return;
	}

	if (setstop) {
		_mix_internal(true);
		stream_playback->stop();
		setstop = false;
	}

	if (setseek >= 0.0 && !stop_has_priority) {
		if (stream_playback->is_playing()) {
			//fade out to avoid pops
			_mix_internal(true);
		}

		stream_playback->start(setseek);
		setseek = -1.0; //reset seek
		mix_volume_db = volume_db; //reset ramp
	}

	stop_has_priority = false;

	_mix_internal(false);
}

void AudioStreamPlayer::_notification(int p_what) {
	if (p_what == NOTIFICATION_ENTER_TREE) {
		AudioServer::get_singleton()->add_callback(_mix_audios, this);
		if (autoplay && !Engine::get_singleton()->is_editor_hint()) {
			play();
		}
	}

	if (p_what == NOTIFICATION_INTERNAL_PROCESS) {
		if (!active || (setseek < 0 && !stream_playback->is_playing())) {
			active = false;
			set_process_internal(false);
			emit_signal("finished");
		}
	}

	if (p_what == NOTIFICATION_EXIT_TREE) {
		AudioServer::get_singleton()->remove_callback(_mix_audios, this);
	}

	if (p_what == NOTIFICATION_PAUSED) {
		if (!can_process()) {
			// Node can't process so we start fading out to silence
			set_stream_paused(true);
		}
	}

	if (p_what == NOTIFICATION_UNPAUSED) {
		set_stream_paused(false);
	}
}

void AudioStreamPlayer::set_stream(Ref<AudioStream> p_stream) {
	AudioServer::get_singleton()->lock();

	if (active && stream_playback.is_valid() && !stream_paused) {
		//changing streams out of the blue is not a great idea, but at least
		//lets try to somehow avoid a click

		AudioFrame *buffer = fadeout_buffer.ptrw();
		int buffer_size = fadeout_buffer.size();

		stream_playback->mix(buffer, pitch_scale, buffer_size);

		//multiply volume interpolating to avoid clicks if this changes
		float target_volume = -80.0;
		float vol = Math::db2linear(mix_volume_db);
		float vol_inc = (Math::db2linear(target_volume) - vol) / float(buffer_size);

		for (int i = 0; i < buffer_size; i++) {
			buffer[i] *= vol;
			vol += vol_inc;
		}

		use_fadeout = true;
	}

	mix_buffer.resize(AudioServer::get_singleton()->thread_get_mix_buffer_size());

	if (stream_playback.is_valid()) {
		stream_playback.unref();
		stream.unref();
		active = false;
		setseek = -1;
		setstop = false;
	}

	if (p_stream.is_valid()) {
		stream = p_stream;
		stream_playback = p_stream->instance_playback();
	}

	AudioServer::get_singleton()->unlock();

	if (p_stream.is_valid() && stream_playback.is_null()) {
		stream.unref();
	}
}

Ref<AudioStream> AudioStreamPlayer::get_stream() const {
	return stream;
}

void AudioStreamPlayer::set_volume_db(float p_volume) {
	volume_db = p_volume;
}

float AudioStreamPlayer::get_volume_db() const {
	return volume_db;
}

void AudioStreamPlayer::set_pitch_scale(float p_pitch_scale) {
	ERR_FAIL_COND(p_pitch_scale <= 0.0);
	pitch_scale = p_pitch_scale;
}

float AudioStreamPlayer::get_pitch_scale() const {
	return pitch_scale;
}

void AudioStreamPlayer::play(float p_from_pos) {
	if (stream_playback.is_valid()) {
		//mix_volume_db = volume_db; do not reset volume ramp here, can cause clicks
		setseek = p_from_pos;
		stop_has_priority = false;
		active = true;
		set_process_internal(true);
	}
}

void AudioStreamPlayer::seek(float p_seconds) {
	if (stream_playback.is_valid()) {
		setseek = p_seconds;
	}
}

void AudioStreamPlayer::stop() {
	if (stream_playback.is_valid() && active) {
		setstop = true;
		stop_has_priority = true;
	}
}

bool AudioStreamPlayer::is_playing() const {
	if (stream_playback.is_valid()) {
		return active && !setstop; //&& stream_playback->is_playing();
	}

	return false;
}

float AudioStreamPlayer::get_playback_position() {
	if (stream_playback.is_valid()) {
		return stream_playback->get_playback_position();
	}

	return 0;
}

void AudioStreamPlayer::set_bus(const StringName &p_bus) {
	//if audio is active, must lock this
	AudioServer::get_singleton()->lock();
	bus = p_bus;
	AudioServer::get_singleton()->unlock();
}

StringName AudioStreamPlayer::get_bus() const {
	for (int i = 0; i < AudioServer::get_singleton()->get_bus_count(); i++) {
		if (AudioServer::get_singleton()->get_bus_name(i) == bus) {
			return bus;
		}
	}
	return "Master";
}

void AudioStreamPlayer::set_autoplay(bool p_enable) {
	autoplay = p_enable;
}

bool AudioStreamPlayer::is_autoplay_enabled() {
	return autoplay;
}

void AudioStreamPlayer::set_mix_target(MixTarget p_target) {
	mix_target = p_target;
}

AudioStreamPlayer::MixTarget AudioStreamPlayer::get_mix_target() const {
	return mix_target;
}

void AudioStreamPlayer::_set_playing(bool p_enable) {
	if (p_enable) {
		play();
	} else {
		stop();
	}
}

bool AudioStreamPlayer::_is_active() const {
	return active;
}

void AudioStreamPlayer::set_stream_paused(bool p_pause) {
	if (p_pause != stream_paused) {
		stream_paused = p_pause;
		stream_paused_fade = p_pause;
	}
}

bool AudioStreamPlayer::get_stream_paused() const {
	return stream_paused;
}

void AudioStreamPlayer::_validate_property(PropertyInfo &property) const {
	if (property.name == "bus") {
		String options;
		for (int i = 0; i < AudioServer::get_singleton()->get_bus_count(); i++) {
			if (i > 0) {
				options += ",";
			}
			String name = AudioServer::get_singleton()->get_bus_name(i);
			options += name;
		}

		property.hint_string = options;
	}
}

void AudioStreamPlayer::_bus_layout_changed() {
	_change_notify();
}

Ref<AudioStreamPlayback> AudioStreamPlayer::get_stream_playback() {
	return stream_playback;
}

void AudioStreamPlayer::_bind_methods() {
	ClassDB::bind_method(D_METHOD("set_stream", "stream"), &AudioStreamPlayer::set_stream);
	ClassDB::bind_method(D_METHOD("get_stream"), &AudioStreamPlayer::get_stream);

	ClassDB::bind_method(D_METHOD("set_volume_db", "volume_db"), &AudioStreamPlayer::set_volume_db);
	ClassDB::bind_method(D_METHOD("get_volume_db"), &AudioStreamPlayer::get_volume_db);

	ClassDB::bind_method(D_METHOD("set_pitch_scale", "pitch_scale"), &AudioStreamPlayer::set_pitch_scale);
	ClassDB::bind_method(D_METHOD("get_pitch_scale"), &AudioStreamPlayer::get_pitch_scale);

	ClassDB::bind_method(D_METHOD("play", "from_position"), &AudioStreamPlayer::play, DEFVAL(0.0));
	ClassDB::bind_method(D_METHOD("seek", "to_position"), &AudioStreamPlayer::seek);
	ClassDB::bind_method(D_METHOD("stop"), &AudioStreamPlayer::stop);

	ClassDB::bind_method(D_METHOD("is_playing"), &AudioStreamPlayer::is_playing);
	ClassDB::bind_method(D_METHOD("get_playback_position"), &AudioStreamPlayer::get_playback_position);

	ClassDB::bind_method(D_METHOD("set_bus", "bus"), &AudioStreamPlayer::set_bus);
	ClassDB::bind_method(D_METHOD("get_bus"), &AudioStreamPlayer::get_bus);

	ClassDB::bind_method(D_METHOD("set_autoplay", "enable"), &AudioStreamPlayer::set_autoplay);
	ClassDB::bind_method(D_METHOD("is_autoplay_enabled"), &AudioStreamPlayer::is_autoplay_enabled);

	ClassDB::bind_method(D_METHOD("set_mix_target", "mix_target"), &AudioStreamPlayer::set_mix_target);
	ClassDB::bind_method(D_METHOD("get_mix_target"), &AudioStreamPlayer::get_mix_target);

	ClassDB::bind_method(D_METHOD("_set_playing", "enable"), &AudioStreamPlayer::_set_playing);
	ClassDB::bind_method(D_METHOD("_is_active"), &AudioStreamPlayer::_is_active);

	ClassDB::bind_method(D_METHOD("set_stream_paused", "pause"), &AudioStreamPlayer::set_stream_paused);
	ClassDB::bind_method(D_METHOD("get_stream_paused"), &AudioStreamPlayer::get_stream_paused);

	ClassDB::bind_method(D_METHOD("get_stream_playback"), &AudioStreamPlayer::get_stream_playback);

	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "stream", PROPERTY_HINT_RESOURCE_TYPE, "AudioStream"), "set_stream", "get_stream");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "volume_db", PROPERTY_HINT_RANGE, "-80,24"), "set_volume_db", "get_volume_db");
	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "pitch_scale", PROPERTY_HINT_RANGE, "0.01,4,0.01,or_greater"), "set_pitch_scale", "get_pitch_scale");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "playing", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_EDITOR), "_set_playing", "is_playing");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "autoplay"), "set_autoplay", "is_autoplay_enabled");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "stream_paused", PROPERTY_HINT_NONE, ""), "set_stream_paused", "get_stream_paused");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "mix_target", PROPERTY_HINT_ENUM, "Stereo,Surround,Center"), "set_mix_target", "get_mix_target");
	ADD_PROPERTY(PropertyInfo(Variant::STRING_NAME, "bus", PROPERTY_HINT_ENUM, ""), "set_bus", "get_bus");

	ADD_SIGNAL(MethodInfo("finished"));

	BIND_ENUM_CONSTANT(MIX_TARGET_STEREO);
	BIND_ENUM_CONSTANT(MIX_TARGET_SURROUND);
	BIND_ENUM_CONSTANT(MIX_TARGET_CENTER);
}

AudioStreamPlayer::AudioStreamPlayer() {
	mix_volume_db = 0;
	pitch_scale = 1.0;
	volume_db = 0;
	autoplay = false;
	setseek = -1;
	active = false;
	stream_paused = false;
	stream_paused_fade = false;
	mix_target = MIX_TARGET_STEREO;
	fadeout_buffer.resize(512);
	setstop = false;
	use_fadeout = false;

	AudioServer::get_singleton()->connect("bus_layout_changed", callable_mp(this, &AudioStreamPlayer::_bus_layout_changed));
}

AudioStreamPlayer::~AudioStreamPlayer() {
}