#include "string.h"

// Sources are points emitting sound, their number is limited, but a single source can play many buffers

// Buffers hold sound data and are unlimited

ALuint cache_size, cache_index, sources_number;

ALboolean instances_number;

al_sound_t *the_sounds;

ALint cache_pointer;

// Initialize an OpenAL contex and allocate memory space for data and buffers

// It can be called twice to increase the cache size

    int i;

    // reuse old context and resize the existing 

    if (openal_ready() == AL_TRUE) {

        cache_size += memorysize;

        fprintf(stderr,"(Bridge Info) - already initialized, resizing cache to %d\n", cache_size);

        the_sounds = (al_sound_t *)Realloc (the_sounds, sizeof(al_sound_t) * cache_size);

        for (i = cache_size - memorysize; i < cache_size; i++) {

            the_sounds[i].filename = NULL;

            the_sounds[i].buffer = -1;

            the_sounds[i].source_index = -1;

            the_sounds[i].stats = 0;

        }

        instances_number++;

        return AL_TRUE;

    }

    cache_pointer = 0;

    instances_number++;

        cache_size = 50;

        cache_size = memorysize;

    sources_number = 16;

        fprintf(stderr,"(Bridge Warning) - failed to open sound device, using software renderer\n");

        sources_number = 32;

            fprintf(stderr,"(Bridge ERROR) - failed to start software renderer, sound will be disabled\n");

    fprintf(stderr,"(Bridge Info) - output device: %s\n", alcGetString(device, ALC_DEVICE_SPECIFIER));

        fprintf(stderr,"(Bridge ERROR) - Failed to create a new contex\n");

    Sources = (ALuint *)Malloc (sizeof(ALuint) * sources_number);

    alGenSources(sources_number, Sources);

    ALfloat ListenerOri[] = {0.0, 0.0, -1.0, 0.0, 1.0, 0.0};

        fprintf(stderr,"(Bridge ERROR) - Failed to set Listener properties\n");

    the_sounds = (al_sound_t *)Malloc (sizeof(al_sound_t) * cache_size);

    for (i = 0; i < cache_size; i++) {

        the_sounds[i].filename = NULL;

        the_sounds[i].buffer = -1;

        the_sounds[i].source_index = -1;

        the_sounds[i].stats = 0;

    }

    alGetError();

// Stop all sounds, deallocate all memory and close OpenAL context

    int i;

    if (instances_number == 0) {

        fprintf(stderr,"(Bridge Warning) - OpenAL not initialized\n");

        return;

    }

    instances_number--;

    if (instances_number > 0) {

    //TODO: free other stuff also

    for (i = 0; i < cache_size; i++)

        alDeleteBuffers (1, &the_sounds[i].buffer);

    free(the_sounds);

    alSourceStopv	(sources_number, Sources);

    alDeleteSources (sources_number, Sources);

    fprintf(stderr,"(Bridge Info) - closed\n");

ALboolean openal_ready (void) {

    if (instances_number >= 1) 

        return AL_TRUE;

    else

        return AL_FALSE;

}

// Open a file, load into memory and allocate the Source buffer for playing

    ALenum format, error;

    uint32_t fileformat;

    al_sound_t soundData;

    int len, i;

    if (openal_ready() == AL_FALSE) {

        fprintf(stderr,"(Bridge Warning) - not initialized\n");

    // if this sound is already loaded return the index from the_sounds

    len = strlen(filename);

    for (i = 0; i < cache_size; i++) {

        if (the_sounds[i].filename != NULL && strncmp(the_sounds[i].filename, filename, len) == 0) {

#ifdef DEBUG

            fprintf(stderr,"(Bridge Debug) - sound %d is already loaded\n", i);

#endif

            return i;

        }

    }

    if (cache_pointer >= cache_size) {

        fprintf(stderr,"(Bridge ERROR) - Cache size limit reached; consider allocating more space\n", filename);

        return -2;

    }

    // detect the file format, as written in the first 4 bytes of the header

    fp = Fopen (filename, "rb");

    if (fp == NULL) {

        fprintf(stderr,"(Bridge ERROR) - File %s not loaded\n", filename);

    error = fread (&fileformat, sizeof(uint32_t), 1, fp);

    fclose (fp);

    if (error < 0) {

        fprintf(stderr,"(Bridge ERROR) - File %s is too short\n", filename);

            fprintf(stderr,"(Bridge ERROR) - File format (%08X) not supported\n", ENDIAN_BIG_32(fileformat));

            return -5;

    if (error != 0) {

        fprintf(stderr,"(Bridge ERROR) - error loading file %s\n", filename);

        free(data);

        return -6;

    }

    alGenBuffers(1, &soundData.buffer);

    soundData.filename = filename;

    soundData.source_index = -1;

    soundData.stats = 0;

    if (AL_NO_ERROR != alGetError()) {

        fprintf(stderr,"(Bridge ERROR) - Failed to allocate memory for buffers\n");

        return -5;

    }

    // copy pcm data in one buffer and free it

    alBufferData(soundData.buffer, format, data, bitsize, freq);

        fprintf(stderr,"(Bridge ERROR) - Failed to write data to buffers\n");

    // clear any AL errors beforehand

    alGetError();

    fprintf(stderr,"(Bridge Info) - successfully loaded %s\n", filename);

    // returns the index of the source you just loaded, increments it and exits

    the_sounds[cache_pointer] = soundData;

    return cache_pointer++;