/*************************************************************************/
/*  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"
#include "core/math/audio_frame.h"
#include "servers/audio_server.h"

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

	if (p_what == NOTIFICATION_INTERNAL_PROCESS) {
		Vector<Ref<AudioStreamPlayback>> playbacks_to_remove;
		for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
			if (playback.is_valid() && !AudioServer::get_singleton()->is_playback_active(playback) && !AudioServer::get_singleton()->is_playback_paused(playback)) {
				playbacks_to_remove.push_back(playback);
			}
		}
		// Now go through and remove playbacks that have finished. Removing elements from a Vector in a range based for is asking for trouble.
		for (Ref<AudioStreamPlayback> &playback : playbacks_to_remove) {
			stream_playbacks.erase(playback);
		}
		if (!playbacks_to_remove.is_empty() && stream_playbacks.is_empty()) {
			// This node is no longer actively playing audio.
			active.clear();
			set_process_internal(false);
		}
		if (!playbacks_to_remove.is_empty()) {
			emit_signal(SNAME("finished"));
		}
	}

	if (p_what == NOTIFICATION_EXIT_TREE) {
		for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
			AudioServer::get_singleton()->stop_playback_stream(playback);
		}
		stream_playbacks.clear();
	}

	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) {
	stop();
	stream = p_stream;
}

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

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

	Vector<AudioFrame> volume_vector = _get_volume_vector();
	for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		AudioServer::get_singleton()->set_playback_all_bus_volumes_linear(playback, volume_vector);
	}
}

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;

	for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		AudioServer::get_singleton()->set_playback_pitch_scale(playback, pitch_scale);
	}
}

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

void AudioStreamPlayer::set_max_polyphony(int p_max_polyphony) {
	if (p_max_polyphony > 0) {
		max_polyphony = p_max_polyphony;
	}
}

int AudioStreamPlayer::get_max_polyphony() const {
	return max_polyphony;
}

void AudioStreamPlayer::play(float p_from_pos) {
	if (stream.is_null()) {
		return;
	}
	ERR_FAIL_COND_MSG(!is_inside_tree(), "Playback can only happen when a node is inside the scene tree");
	if (stream->is_monophonic() && is_playing()) {
		stop();
	}
	Ref<AudioStreamPlayback> stream_playback = stream->instance_playback();
	ERR_FAIL_COND_MSG(stream_playback.is_null(), "Failed to instantiate playback.");

	AudioServer::get_singleton()->start_playback_stream(stream_playback, bus, _get_volume_vector(), p_from_pos, pitch_scale);
	stream_playbacks.push_back(stream_playback);
	active.set();
	set_process_internal(true);
	while (stream_playbacks.size() > max_polyphony) {
		AudioServer::get_singleton()->stop_playback_stream(stream_playbacks[0]);
		stream_playbacks.remove(0);
	}
}

void AudioStreamPlayer::seek(float p_seconds) {
	if (is_playing()) {
		stop();
		play(p_seconds);
	}
}

void AudioStreamPlayer::stop() {
	for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		AudioServer::get_singleton()->stop_playback_stream(playback);
	}
	stream_playbacks.clear();
	active.clear();
	set_process_internal(false);
}

bool AudioStreamPlayer::is_playing() const {
	for (const Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		if (AudioServer::get_singleton()->is_playback_active(playback)) {
			return true;
		}
	}
	return false;
}

float AudioStreamPlayer::get_playback_position() {
	// Return the playback position of the most recently started playback stream.
	if (!stream_playbacks.is_empty()) {
		return AudioServer::get_singleton()->get_playback_position(stream_playbacks[stream_playbacks.size() - 1]);
	}
	return 0;
}

void AudioStreamPlayer::set_bus(const StringName &p_bus) {
	bus = p_bus;
	for (const Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		AudioServer::get_singleton()->set_playback_bus_exclusive(playback, p_bus, _get_volume_vector());
	}
}

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) == String(bus)) {
			return bus;
		}
	}
	return SNAME("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 {
	for (const Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		if (AudioServer::get_singleton()->is_playback_active(playback)) {
			return true;
		}
	}
	return false;
}

void AudioStreamPlayer::set_stream_paused(bool p_pause) {
	// TODO this does not have perfect recall, fix that maybe? If there are zero playbacks registered with the AudioServer, this bool isn't persisted.
	for (Ref<AudioStreamPlayback> &playback : stream_playbacks) {
		AudioServer::get_singleton()->set_playback_paused(playback, p_pause);
	}
}

bool AudioStreamPlayer::get_stream_paused() const {
	// There's currently no way to pause some playback streams but not others. Check the first and don't bother looking at the rest.
	if (!stream_playbacks.is_empty()) {
		return AudioServer::get_singleton()->is_playback_paused(stream_playbacks[0]);
	}
	return false;
}

Vector<AudioFrame> AudioStreamPlayer::_get_volume_vector() {
	Vector<AudioFrame> volume_vector;
	// We need at most four stereo pairs (for 7.1 systems).
	volume_vector.resize(4);

	// Initialize the volume vector to zero.
	for (AudioFrame &channel_volume_db : volume_vector) {
		channel_volume_db = AudioFrame(0, 0);
	}

	float volume_linear = Math::db2linear(volume_db);

	// Set the volume vector up according to the speaker mode and mix target.
	// TODO do we need to scale the volume down when we output to more channels?
	if (AudioServer::get_singleton()->get_speaker_mode() == AudioServer::SPEAKER_MODE_STEREO) {
		volume_vector.write[0] = AudioFrame(volume_linear, volume_linear);
	} else {
		switch (mix_target) {
			case MIX_TARGET_STEREO: {
				volume_vector.write[0] = AudioFrame(volume_linear, volume_linear);
			} break;
			case MIX_TARGET_SURROUND: {
				// TODO Make sure this is right.
				volume_vector.write[0] = AudioFrame(volume_linear, volume_linear);
				volume_vector.write[1] = AudioFrame(volume_linear, /* LFE= */ 1.0f);
				volume_vector.write[2] = AudioFrame(volume_linear, volume_linear);
				volume_vector.write[3] = AudioFrame(volume_linear, volume_linear);
			} break;
			case MIX_TARGET_CENTER: {
				// TODO Make sure this is right.
				volume_vector.write[1] = AudioFrame(volume_linear, /* LFE= */ 1.0f);
			} break;
		}
	}
	return volume_vector;
}

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;
	}

	Node::_validate_property(property);
}

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

Ref<AudioStreamPlayback> AudioStreamPlayer::get_stream_playback() {
	if (!stream_playbacks.is_empty()) {
		return stream_playbacks[stream_playbacks.size() - 1];
	}
	return nullptr;
}

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("set_max_polyphony", "max_polyphony"), &AudioStreamPlayer::set_max_polyphony);
	ClassDB::bind_method(D_METHOD("get_max_polyphony"), &AudioStreamPlayer::get_max_polyphony);

	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::INT, "max_polyphony", PROPERTY_HINT_NONE, ""), "set_max_polyphony", "get_max_polyphony");
	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() {
	AudioServer::get_singleton()->connect("bus_layout_changed", callable_mp(this, &AudioStreamPlayer::_bus_layout_changed));
}

AudioStreamPlayer::~AudioStreamPlayer() {
}