/*
This Source Code Form is subject to the
terms of the Mozilla Public License, v.
2.0. If a copy of the MPL was not
distributed with this file, You can
obtain one at
http://mozilla.org/MPL/2.0/.
*/

#pragma once

#if defined(__APPLE__) && !__has_include(<AL/al.h>)
#include <OpenAL/al.h>
#include <OpenAL/alc.h>
#else
#include <AL/al.h>
#include <AL/alc.h>
#include <AL/alext.h>
#endif

namespace audio {

ALuint const null_resource{ ~ALuint{0} };

// wrapper for audio sample
struct openal_buffer {
// members
    ALuint id { null_resource }; // associated AL resource
    unsigned int rate {}; // sample rate of the data
    std::string name;
    std::string caption;
// constructors
    openal_buffer() = default;
    explicit openal_buffer( std::string const &Filename );
	// methods
	// retrieves sound caption in currently set language
	void
		fetch_caption();

};

using buffer_handle = std::size_t;


// 
class buffer_manager {

public:
// constructors
    buffer_manager(); // makes empty bindings for null buffer
// destructor
    ~buffer_manager();
// methods
    // creates buffer object out of data stored in specified file. returns: handle to the buffer or null_handle if creation failed
    buffer_handle
        create( std::string const &Filename );
    // provides direct access to a specified buffer. a buffer still decoded in the background is completed first
    audio::openal_buffer const &
        buffer( audio::buffer_handle const Buffer ) const;
    // creates AL buffers for files decoded in the background so far, or for all of them if requested
    void
        update( bool const Wait = false );

private:
// types
    using buffer_sequence = std::vector<openal_buffer>;
    using index_map = std::unordered_map<std::string, std::size_t>;
    struct decoder; // background decoding of sound files, used with sound.asyncload
// methods
    // places in the bank a buffer containing data stored in specified file. returns: handle to the buffer
    buffer_handle
        emplace( std::string Filename );
    // checks whether specified buffer is in the buffer bank. returns: buffer handle, or null_handle.
    buffer_handle
        find_buffer( std::string const &Buffername ) const;
    // checks whether specified file exists. returns: name of the located file, or empty string.
    std::string
        find_file( std::string const &Filename ) const;
    // creates AL buffer for a file decoded in the background, waiting for the decoder if needed
    void
        complete( audio::buffer_handle const Buffer ) const;
// members
    mutable buffer_sequence m_buffers; // buffers decoded in the background are completed on first access
    index_map m_buffermappings;
    mutable std::unique_ptr<decoder> m_decoder;
};

} // audio

//---------------------------------------------------------------------------