/*
Minetest
Copyright (C) 2022 DS
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; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#pragma once

#include "sound_data.h"
namespace sound { struct ALExtensions; }

namespace sound {

/**
 * A sound that is currently played.
 * Can be streaming.
 * Can be fading.
 */
class PlayingSound final
{
	struct FadeState {
		f32 step;
		f32 target_gain;
	};

	ALuint m_source_id;
	std::shared_ptr<ISoundDataOpen> m_data;
	ALuint m_next_sample_pos = 0;
	bool m_looping;
	bool m_is_positional;
	bool m_stopped_means_dead = true;
	std::optional<FadeState> m_fade_state = std::nullopt;

public:
	PlayingSound(ALuint source_id, std::shared_ptr<ISoundDataOpen> data, bool loop,
			f32 volume, f32 pitch, f32 start_time,
			const std::optional<std::pair<v3f, v3f>> &pos_vel_opt,
			const ALExtensions &exts [[maybe_unused]]);

	~PlayingSound() noexcept
	{
		alDeleteSources(1, &m_source_id);
	}

	DISABLE_CLASS_COPY(PlayingSound)

	// return false means streaming finished
	bool stepStream();

	// retruns true if it wasn't fading already
	bool fade(f32 step, f32 target_gain) noexcept;

	// returns true if more fade is needed later
	bool doFade(f32 dtime) noexcept;

	void updatePosVel(const v3f &pos, const v3f &vel) noexcept;

	void setGain(f32 gain) noexcept;

	f32 getGain() noexcept;

	void setPitch(f32 pitch) noexcept { alSourcef(m_source_id, AL_PITCH, pitch); }

	bool isStreaming() const noexcept { return m_data->isStreaming(); }

	void play() noexcept { alSourcePlay(m_source_id); }

	// returns one of AL_INITIAL, AL_PLAYING, AL_PAUSED, AL_STOPPED
	ALint getState() noexcept
	{
		ALint state;
		alGetSourcei(m_source_id, AL_SOURCE_STATE, &state);
		return state;
	}

	bool isDead() noexcept
	{
		// streaming sounds can (but should not) stop because the queue runs empty
		return m_stopped_means_dead && getState() == AL_STOPPED;
	}

	void pause() noexcept
	{
		// this is a NOP if state != AL_PLAYING
		alSourcePause(m_source_id);
	}

	void resume() noexcept
	{
		if (getState() == AL_PAUSED)
			play();
	}
};

} // namespace sound