/*
 * OpenAL Helpers
 *
 * Copyright (c) 2011 by Chris Robinson <chris.kcat@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

/* This file contains routines to help with some menial OpenAL-related tasks,
 * such as opening a device and setting up a context, closing the device and
 * destroying its context, converting between frame counts and byte lengths,
 * finding an appropriate buffer format, and getting readable strings for
 * channel configs and sample types. */

#include <time.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>

#include "AL/al.h"
#include "AL/alc.h"
#include "AL/alext.h"

#include "alhelpers.h"


/* InitAL opens a device and sets up a context using default attributes, making
 * the program ready to call OpenAL functions. */
int InitAL(char ***argv, int *argc)
{
    const ALCchar *name;
    ALCdevice *device;
    ALCcontext *ctx;

    /* Open and initialize a device */
    device = NULL;
    if(argc && argv && *argc > 1 && strcmp((*argv)[0], "-device") == 0)
    {
        device = alcOpenDevice((*argv)[1]);
        if(!device)
            fprintf(stderr, "Failed to open \"%s\", trying default\n", (*argv)[1]);
        (*argv) += 2;
        (*argc) -= 2;
    }
    if(!device)
        device = alcOpenDevice(NULL);
    if(!device)
    {
        fprintf(stderr, "Could not open a device!\n");
        return 1;
    }

    ctx = alcCreateContext(device, NULL);
    if(ctx == NULL || alcMakeContextCurrent(ctx) == ALC_FALSE)
    {
        if(ctx != NULL)
            alcDestroyContext(ctx);
        alcCloseDevice(device);
        fprintf(stderr, "Could not set a context!\n");
        return 1;
    }

    name = NULL;
    if(alcIsExtensionPresent(device, "ALC_ENUMERATE_ALL_EXT"))
        name = alcGetString(device, ALC_ALL_DEVICES_SPECIFIER);
    if(!name || alcGetError(device) != AL_NO_ERROR)
        name = alcGetString(device, ALC_DEVICE_SPECIFIER);
    printf("Opened \"%s\"\n", name);

    return 0;
}

/* CloseAL closes the device belonging to the current context, and destroys the
 * context. */
void CloseAL(void)
{
    ALCdevice *device;
    ALCcontext *ctx;

    ctx = alcGetCurrentContext();
    if(ctx == NULL)
        return;

    device = alcGetContextsDevice(ctx);

    alcMakeContextCurrent(NULL);
    alcDestroyContext(ctx);
    alcCloseDevice(device);
}


const char *FormatName(ALenum format)
{
    switch(format)
    {
        case AL_FORMAT_MONO8: return "Mono, U8";
        case AL_FORMAT_MONO16: return "Mono, S16";
        case AL_FORMAT_STEREO8: return "Stereo, U8";
        case AL_FORMAT_STEREO16: return "Stereo, S16";
    }
    return "Unknown Format";
}


#ifdef _WIN32

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <mmsystem.h>

int altime_get(void)
{
    static int start_time = 0;
    int cur_time;
    union {
        FILETIME ftime;
        ULARGE_INTEGER ulint;
    } systime;
    GetSystemTimeAsFileTime(&systime.ftime);
    /* FILETIME is in 100-nanosecond units, or 1/10th of a microsecond. */
    cur_time = (int)(systime.ulint.QuadPart/10000);

    if(!start_time)
        start_time = cur_time;
    return cur_time - start_time;
}

void al_nssleep(unsigned long nsec)
{
    Sleep(nsec / 1000000);
}

#else

#include <sys/time.h>
#include <unistd.h>
#include <time.h>

int altime_get(void)
{
    static int start_time = 0u;
    int cur_time;

#if _POSIX_TIMERS > 0
    struct timespec ts;
    int ret = clock_gettime(CLOCK_REALTIME, &ts);
    if(ret != 0) return 0;
    cur_time = ts.tv_sec*1000 + ts.tv_nsec/1000000;
#else /* _POSIX_TIMERS > 0 */
    struct timeval tv;
    int ret = gettimeofday(&tv, NULL);
    if(ret != 0) return 0;
    cur_time = tv.tv_sec*1000 + tv.tv_usec/1000;
#endif

    if(!start_time)
        start_time = cur_time;
    return cur_time - start_time;
}

void al_nssleep(unsigned long nsec)
{
    struct timespec ts, rem;
    ts.tv_sec = nsec / 1000000000ul;
    ts.tv_nsec = nsec % 1000000000ul;
    while(nanosleep(&ts, &rem) == -1 && errno == EINTR)
        ts = rem;
}

#endif