/*************************************************************************/
/*  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) {
		if (stream_playback.is_valid() && active.is_set() && !AudioServer::get_singleton()->is_playback_active(stream_playback)) {
			active.clear();
			set_process_internal(false);
			emit_signal(SNAME("finished"));
		}
	}

	if (p_what == NOTIFICATION_EXIT_TREE) {
		if (stream_playback.is_valid()) {
			AudioServer::get_singleton()->stop_playback_stream(stream_playback);
		}
	}

	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) {
	if (stream_playback.is_valid()) {
		stop();
		stream_playback.unref();
		stream.unref();
	}

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

	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;

	AudioServer::get_singleton()->set_playback_all_bus_volumes_linear(stream_playback, _get_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;

	AudioServer::get_singleton()->set_playback_pitch_scale(stream_playback, pitch_scale);
}

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

void AudioStreamPlayer::play(float p_from_pos) {
	stop();
	if (stream.is_valid()) {
		stream_playback = stream->instance_playback();
	}
	if (stream_playback.is_valid()) {
		AudioServer::get_singleton()->start_playback_stream(stream_playback, bus, _get_volume_vector(), p_from_pos);
		active.set();
	}
}

void AudioStreamPlayer::seek(float p_seconds) {
	if (stream_playback.is_valid() && active.is_set()) {
		play(p_seconds);
	}
}

void AudioStreamPlayer::stop() {
	if (stream_playback.is_valid()) {
		active.clear();
		AudioServer::get_singleton()->stop_playback_stream(stream_playback);
	}
}

bool AudioStreamPlayer::is_playing() const {
	if (stream_playback.is_valid()) {
		return AudioServer::get_singleton()->is_playback_active(stream_playback);
	}

	return false;
}

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

	return 0;
}

void AudioStreamPlayer::set_bus(const StringName &p_bus) {
	bus = p_bus;
	if (stream_playback.is_valid()) {
		AudioServer::get_singleton()->set_playback_bus_exclusive(stream_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 "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 {
	if (stream_playback.is_valid()) {
		return AudioServer::get_singleton()->is_playback_active(stream_playback);
	}
	return false;
}

void AudioStreamPlayer::set_stream_paused(bool p_pause) {
	// TODO this does not have perfect recall, fix that maybe? If the stream isn't set, we can't persist this bool.
	if (stream_playback.is_valid()) {
		AudioServer::get_singleton()->set_playback_paused(stream_playback, p_pause);
	}
}

bool AudioStreamPlayer::get_stream_paused() const {
	if (stream_playback.is_valid()) {
		return AudioServer::get_singleton()->is_playback_paused(stream_playback);
	}
	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;
	}
}

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

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

AudioStreamPlayer::~AudioStreamPlayer() {
}