/*************************************************************************/
/*  video_player.cpp                                                     */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                      https://godotengine.org                          */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
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/* The above copyright notice and this permission notice shall be        */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
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/*************************************************************************/

#include "video_player.h"
#include "scene/scene_string_names.h"

#include "core/os/os.h"
#include "servers/audio_server.h"

int VideoPlayer::sp_get_channel_count() const {

	if (playback.is_null()) {
		return 0;
	}

	return playback->get_channels();
}

bool VideoPlayer::mix(AudioFrame *p_buffer, int p_frames) {

	// Check the amount resampler can really handle.
	// If it cannot, wait "wait_resampler_phase_limit" times.
	// This mechanism contributes to smoother pause/unpause operation.
	if (p_frames <= resampler.get_num_of_ready_frames() ||
			wait_resampler_limit <= wait_resampler) {
		wait_resampler = 0;
		return resampler.mix(p_buffer, p_frames);
	}
	wait_resampler++;
	return false;
}

// Called from main thread (eg VideoStreamPlaybackWebm::update)
int VideoPlayer::_audio_mix_callback(void *p_udata, const float *p_data, int p_frames) {

	ERR_FAIL_NULL_V(p_udata, 0);
	ERR_FAIL_NULL_V(p_data, 0);

	VideoPlayer *vp = (VideoPlayer *)p_udata;

	int todo = MIN(vp->resampler.get_writer_space(), p_frames);

	float *wb = vp->resampler.get_write_buffer();
	int c = vp->resampler.get_channel_count();

	for (int i = 0; i < todo * c; i++) {
		wb[i] = p_data[i];
	}
	vp->resampler.write(todo);

	return todo;
}

void VideoPlayer::_mix_audios(void *p_self) {

	ERR_FAIL_NULL(p_self);
	reinterpret_cast<VideoPlayer *>(p_self)->_mix_audio();
}

// Called from audio thread
void VideoPlayer::_mix_audio() {

	if (!stream.is_valid()) {
		return;
	}
	if (!playback.is_valid() || !playback->is_playing() || playback->is_paused()) {
		return;
	}

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

	// Resample
	if (!mix(buffer, buffer_size))
		return;

	AudioFrame vol = AudioFrame(volume, volume);

	int cc = AudioServer::get_singleton()->get_channel_count();

	if (cc == 1) {
		AudioFrame *target = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, 0);
		ERR_FAIL_COND(!target);

		for (int j = 0; j < buffer_size; j++) {

			target[j] += buffer[j] * vol;
		}

	} else {
		AudioFrame *targets[4];

		for (int k = 0; k < cc; k++) {
			targets[k] = AudioServer::get_singleton()->thread_get_channel_mix_buffer(bus_index, k);
			ERR_FAIL_COND(!targets[k]);
		}

		for (int j = 0; j < buffer_size; j++) {

			AudioFrame frame = buffer[j] * vol;
			for (int k = 0; k < cc; k++) {
				targets[k][j] += frame;
			}
		}
	}
}

void VideoPlayer::_notification(int p_notification) {

	switch (p_notification) {

		case NOTIFICATION_ENTER_TREE: {

			AudioServer::get_singleton()->add_callback(_mix_audios, this);

			if (stream.is_valid() && autoplay && !Engine::get_singleton()->is_editor_hint()) {
				play();
			}

		} break;

		case NOTIFICATION_EXIT_TREE: {

			AudioServer::get_singleton()->remove_callback(_mix_audios, this);

		} break;

		case NOTIFICATION_INTERNAL_PROCESS: {

			bus_index = AudioServer::get_singleton()->thread_find_bus_index(bus);

			if (stream.is_null() || paused || playback.is_null() || !playback->is_playing())
				return;

			double audio_time = USEC_TO_SEC(OS::get_singleton()->get_ticks_usec());

			double delta = last_audio_time == 0 ? 0 : audio_time - last_audio_time;
			last_audio_time = audio_time;

			if (delta == 0)
				return;

			playback->update(delta); // playback->is_playing() returns false in the last video frame

			if (!playback->is_playing()) {
				emit_signal(SceneStringNames::get_singleton()->finished);
			}

		} break;

		case NOTIFICATION_DRAW: {

			if (texture.is_null())
				return;
			if (texture->get_width() == 0)
				return;

			Size2 s = expand ? get_size() : texture->get_size();
			draw_texture_rect(texture, Rect2(Point2(), s), false);

		} break;
	};
};

Size2 VideoPlayer::get_minimum_size() const {

	if (!expand && !texture.is_null())
		return texture->get_size();
	else
		return Size2();
}

void VideoPlayer::set_expand(bool p_expand) {

	expand = p_expand;
	update();
	minimum_size_changed();
}

bool VideoPlayer::has_expand() const {

	return expand;
}

void VideoPlayer::set_stream(const Ref<VideoStream> &p_stream) {

	stop();

	AudioServer::get_singleton()->lock();
	mix_buffer.resize(AudioServer::get_singleton()->thread_get_mix_buffer_size());
	stream = p_stream;
	if (stream.is_valid()) {
		stream->set_audio_track(audio_track);
		playback = stream->instance_playback();
	} else {
		playback = Ref<VideoStreamPlayback>();
	}
	AudioServer::get_singleton()->unlock();

	if (!playback.is_null()) {
		playback->set_loop(loops);
		playback->set_paused(paused);
		texture = playback->get_texture();

		const int channels = playback->get_channels();

		AudioServer::get_singleton()->lock();
		if (channels > 0)
			resampler.setup(channels, playback->get_mix_rate(), AudioServer::get_singleton()->get_mix_rate(), buffering_ms, 0);
		else
			resampler.clear();
		AudioServer::get_singleton()->unlock();

		if (channels > 0)
			playback->set_mix_callback(_audio_mix_callback, this);

	} else {
		texture.unref();
		AudioServer::get_singleton()->lock();
		resampler.clear();
		AudioServer::get_singleton()->unlock();
	}

	update();

	if (!expand) {
		minimum_size_changed();
	}
};

Ref<VideoStream> VideoPlayer::get_stream() const {

	return stream;
};

void VideoPlayer::play() {

	ERR_FAIL_COND(!is_inside_tree());
	if (playback.is_null())
		return;
	playback->stop();
	playback->play();
	set_process_internal(true);
	//	AudioServer::get_singleton()->stream_set_active(stream_rid,true);
	//	AudioServer::get_singleton()->stream_set_volume_scale(stream_rid,volume);
	last_audio_time = 0;
};

void VideoPlayer::stop() {

	if (!is_inside_tree())
		return;
	if (playback.is_null())
		return;

	playback->stop();
	//	AudioServer::get_singleton()->stream_set_active(stream_rid,false);
	resampler.flush();
	set_process_internal(false);
	last_audio_time = 0;
};

bool VideoPlayer::is_playing() const {

	if (playback.is_null())
		return false;

	return playback->is_playing();
};

void VideoPlayer::set_paused(bool p_paused) {

	paused = p_paused;
	if (playback.is_valid()) {
		playback->set_paused(p_paused);
		set_process_internal(!p_paused);
	};
	last_audio_time = 0;
};

bool VideoPlayer::is_paused() const {

	return paused;
}

void VideoPlayer::set_buffering_msec(int p_msec) {

	buffering_ms = p_msec;
}

int VideoPlayer::get_buffering_msec() const {

	return buffering_ms;
}

void VideoPlayer::set_audio_track(int p_track) {
	audio_track = p_track;
}

int VideoPlayer::get_audio_track() const {

	return audio_track;
}

void VideoPlayer::set_volume(float p_vol) {

	volume = p_vol;
};

float VideoPlayer::get_volume() const {

	return volume;
};

void VideoPlayer::set_volume_db(float p_db) {

	if (p_db < -79)
		set_volume(0);
	else
		set_volume(Math::db2linear(p_db));
};

float VideoPlayer::get_volume_db() const {

	if (volume == 0)
		return -80;
	else
		return Math::linear2db(volume);
};

String VideoPlayer::get_stream_name() const {

	if (stream.is_null())
		return "<No Stream>";
	return stream->get_name();
};

float VideoPlayer::get_stream_position() const {

	if (playback.is_null())
		return 0;
	return playback->get_playback_position();
};

void VideoPlayer::set_stream_position(float p_position) {

	if (playback.is_valid())
		playback->seek(p_position);
}

Ref<Texture> VideoPlayer::get_video_texture() const {

	if (playback.is_valid())
		return playback->get_texture();

	return Ref<Texture>();
}

void VideoPlayer::set_autoplay(bool p_enable) {

	autoplay = p_enable;
};

bool VideoPlayer::has_autoplay() const {

	return autoplay;
};

void VideoPlayer::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 VideoPlayer::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 VideoPlayer::_validate_property(PropertyInfo &p_property) const {

	if (p_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;
		}

		p_property.hint_string = options;
	}
}

void VideoPlayer::_bind_methods() {

	ClassDB::bind_method(D_METHOD("set_stream", "stream"), &VideoPlayer::set_stream);
	ClassDB::bind_method(D_METHOD("get_stream"), &VideoPlayer::get_stream);

	ClassDB::bind_method(D_METHOD("play"), &VideoPlayer::play);
	ClassDB::bind_method(D_METHOD("stop"), &VideoPlayer::stop);

	ClassDB::bind_method(D_METHOD("is_playing"), &VideoPlayer::is_playing);

	ClassDB::bind_method(D_METHOD("set_paused", "paused"), &VideoPlayer::set_paused);
	ClassDB::bind_method(D_METHOD("is_paused"), &VideoPlayer::is_paused);

	ClassDB::bind_method(D_METHOD("set_volume", "volume"), &VideoPlayer::set_volume);
	ClassDB::bind_method(D_METHOD("get_volume"), &VideoPlayer::get_volume);

	ClassDB::bind_method(D_METHOD("set_volume_db", "db"), &VideoPlayer::set_volume_db);
	ClassDB::bind_method(D_METHOD("get_volume_db"), &VideoPlayer::get_volume_db);

	ClassDB::bind_method(D_METHOD("set_audio_track", "track"), &VideoPlayer::set_audio_track);
	ClassDB::bind_method(D_METHOD("get_audio_track"), &VideoPlayer::get_audio_track);

	ClassDB::bind_method(D_METHOD("get_stream_name"), &VideoPlayer::get_stream_name);

	ClassDB::bind_method(D_METHOD("set_stream_position", "position"), &VideoPlayer::set_stream_position);
	ClassDB::bind_method(D_METHOD("get_stream_position"), &VideoPlayer::get_stream_position);

	ClassDB::bind_method(D_METHOD("set_autoplay", "enabled"), &VideoPlayer::set_autoplay);
	ClassDB::bind_method(D_METHOD("has_autoplay"), &VideoPlayer::has_autoplay);

	ClassDB::bind_method(D_METHOD("set_expand", "enable"), &VideoPlayer::set_expand);
	ClassDB::bind_method(D_METHOD("has_expand"), &VideoPlayer::has_expand);

	ClassDB::bind_method(D_METHOD("set_buffering_msec", "msec"), &VideoPlayer::set_buffering_msec);
	ClassDB::bind_method(D_METHOD("get_buffering_msec"), &VideoPlayer::get_buffering_msec);

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

	ClassDB::bind_method(D_METHOD("get_video_texture"), &VideoPlayer::get_video_texture);

	ADD_SIGNAL(MethodInfo("finished"));

	ADD_PROPERTY(PropertyInfo(Variant::INT, "audio_track", PROPERTY_HINT_RANGE, "0,128,1"), "set_audio_track", "get_audio_track");
	ADD_PROPERTY(PropertyInfo(Variant::OBJECT, "stream", PROPERTY_HINT_RESOURCE_TYPE, "VideoStream"), "set_stream", "get_stream");
	//ADD_PROPERTY( PropertyInfo(Variant::BOOL, "stream/loop"), "set_loop", "has_loop") ;
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "volume_db", PROPERTY_HINT_RANGE, "-80,24,0.01"), "set_volume_db", "get_volume_db");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "volume", PROPERTY_HINT_EXP_RANGE, "0,15,0.01", 0), "set_volume", "get_volume");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "autoplay"), "set_autoplay", "has_autoplay");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "paused"), "set_paused", "is_paused");
	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "expand"), "set_expand", "has_expand");
	ADD_PROPERTY(PropertyInfo(Variant::INT, "buffering_msec", PROPERTY_HINT_RANGE, "10,1000"), "set_buffering_msec", "get_buffering_msec");
	ADD_PROPERTY(PropertyInfo(Variant::REAL, "stream_position", PROPERTY_HINT_RANGE, "0,1280000,0.1", 0), "set_stream_position", "get_stream_position");

	ADD_PROPERTY(PropertyInfo(Variant::STRING, "bus", PROPERTY_HINT_ENUM, ""), "set_bus", "get_bus");
}

VideoPlayer::VideoPlayer() {

	volume = 1;
	loops = false;
	paused = false;
	autoplay = false;
	expand = true;

	audio_track = 0;
	bus_index = 0;

	buffering_ms = 500;

	//	internal_stream.player=this;
	//	stream_rid=AudioServer::get_singleton()->audio_stream_create(&internal_stream);
	last_audio_time = 0;

	wait_resampler = 0;
	wait_resampler_limit = 2;
};

VideoPlayer::~VideoPlayer() {

	//	if (stream_rid.is_valid())
	//		AudioServer::get_singleton()->free(stream_rid);
	resampler.clear(); //Not necessary here, but make in consistent with other "stream_player" classes
};
