/**
 * OpenAL cross platform audio library
 * Copyright (C) 2011-2013 by authors.
 * This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 *  Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the
 *  Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 * Or go to http://www.gnu.org/copyleft/lgpl.html
 */

#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <sched.h>
#include <errno.h>
#include <memory.h>
#include <sys/select.h>
#include <sys/asoundlib.h>
#include <sys/neutrino.h>

#include "alMain.h"
#include "alu.h"
#include "threads.h"


typedef struct {
    snd_pcm_t* pcmHandle;
    int audio_fd;

    snd_pcm_channel_setup_t  csetup;
    snd_pcm_channel_params_t cparams;

    ALvoid* buffer;
    ALsizei size;

    volatile int killNow;
    althrd_t thread;
} qsa_data;

typedef struct {
    ALCchar* name;
    int card;
    int dev;
} DevMap;

static const ALCchar qsaDevice[] = "QSA Default";
static DevMap* allDevNameMap;
static ALuint numDevNames;
static DevMap* allCaptureDevNameMap;
static ALuint numCaptureDevNames;

static const struct {
    int32_t format;
} formatlist[] = {
    {SND_PCM_SFMT_FLOAT_LE},
    {SND_PCM_SFMT_S32_LE},
    {SND_PCM_SFMT_U32_LE},
    {SND_PCM_SFMT_S16_LE},
    {SND_PCM_SFMT_U16_LE},
    {SND_PCM_SFMT_S8},
    {SND_PCM_SFMT_U8},
    {0},
};

static const struct {
    int32_t rate;
} ratelist[] = {
    {192000},
    {176400},
    {96000},
    {88200},
    {48000},
    {44100},
    {32000},
    {24000},
    {22050},
    {16000},
    {12000},
    {11025},
    {8000},
    {0},
};

static const struct {
    int32_t channels;
} channellist[] = {
    {8},
    {7},
    {6},
    {4},
    {2},
    {1},
    {0},
};

static DevMap *deviceList(int type, ALuint *count)
{
    snd_ctl_t* handle;
    snd_pcm_info_t pcminfo;
    int max_cards, card, err, dev, num_devices, idx;
    DevMap* dev_list;
    char name[1024];
    struct snd_ctl_hw_info info;
    void* temp;

    idx=0;
    num_devices=0;
    max_cards=snd_cards();

    if (max_cards<=0)
    {
        return 0;
    }

    dev_list=malloc(sizeof(DevMap)*1);
    dev_list[0].name=strdup(qsaDevice);
    num_devices=1;

    for (card=0; card<max_cards; card++)
    {
        if ((err=snd_ctl_open(&handle, card))<0)
        {
            continue;
        }
        if ((err=snd_ctl_hw_info(handle, &info))<0)
        {
            snd_ctl_close(handle);
            continue;
        }

        for (dev=0; dev<(int)info.pcmdevs; dev++)
        {
            if ((err=snd_ctl_pcm_info(handle, dev, &pcminfo)) < 0)
            {
                continue;
            }

            if ((type==SND_PCM_CHANNEL_PLAYBACK && (pcminfo.flags&SND_PCM_INFO_PLAYBACK)) ||
                (type==SND_PCM_CHANNEL_CAPTURE && (pcminfo.flags&SND_PCM_INFO_CAPTURE)))
            {
                temp=realloc(dev_list, sizeof(DevMap)*(num_devices+1));
                if (temp)
                {
                    dev_list=temp;
                    snprintf(name, sizeof(name), "%s [%s] (hw:%d,%d)", info.name, pcminfo.name, card, dev);
                    dev_list[num_devices].name=strdup(name);
                    dev_list[num_devices].card=card;
                    dev_list[num_devices].dev=dev;
                    num_devices++;
                }
            }
        }
        snd_ctl_close (handle);
    }

    *count=num_devices;

    return dev_list;
}


FORCE_ALIGN static int qsa_proc_playback(void* ptr)
{
    ALCdevice* device=(ALCdevice*)ptr;
    qsa_data* data=(qsa_data*)device->ExtraData;
    char* write_ptr;
    int avail;
    snd_pcm_channel_status_t status;
    struct sched_param param;
    fd_set wfds;
    int selectret;
    struct timeval timeout;

    SetRTPriority();
    althrd_setname(althrd_current(), MIXER_THREAD_NAME);

    /* Increase default 10 priority to 11 to avoid jerky sound */
    SchedGet(0, 0, &param);
    param.sched_priority=param.sched_curpriority+1;
    SchedSet(0, 0, SCHED_NOCHANGE, &param);

    ALint frame_size=FrameSizeFromDevFmt(device->FmtChans, device->FmtType);

    while (!data->killNow)
    {
        ALint len=data->size;
        write_ptr=data->buffer;

        avail=len/frame_size;
        aluMixData(device, write_ptr, avail);

        while (len>0 && !data->killNow)
        {
            FD_ZERO(&wfds);
            FD_SET(data->audio_fd, &wfds);
            timeout.tv_sec=2;
            timeout.tv_usec=0;

            /* Select also works like time slice to OS */
            selectret=select(data->audio_fd+1, NULL, &wfds, NULL, &timeout);
            switch (selectret)
            {
                case -1:
                     aluHandleDisconnect(device);
                     return 1;
                case 0:
                     break;
                default:
                     if (FD_ISSET(data->audio_fd, &wfds))
                     {
                         break;
                     }
                     break;
            }

            int wrote=snd_pcm_plugin_write(data->pcmHandle, write_ptr, len);

            if (wrote<=0)
            {
                if ((errno==EAGAIN) || (errno==EWOULDBLOCK))
                {
                    continue;
                }

                memset(&status, 0, sizeof (status));
                status.channel=SND_PCM_CHANNEL_PLAYBACK;

                snd_pcm_plugin_status(data->pcmHandle, &status);

                /* we need to reinitialize the sound channel if we've underrun the buffer */
                if ((status.status==SND_PCM_STATUS_UNDERRUN) ||
                    (status.status==SND_PCM_STATUS_READY))
                {
                    if ((snd_pcm_plugin_prepare(data->pcmHandle, SND_PCM_CHANNEL_PLAYBACK))<0)
                    {
                        aluHandleDisconnect(device);
                        break;
                    }
                }
            }
            else
            {
                write_ptr+=wrote;
                len-=wrote;
            }
        }
    }

    return 0;
}

/************/
/* Playback */
/************/

static ALCenum qsa_open_playback(ALCdevice* device, const ALCchar* deviceName)
{
    qsa_data* data;
    char driver[64];
    int status;
    int card, dev;

    strncpy(driver, GetConfigValue("qsa", "device", qsaDevice), sizeof(driver)-1);
    driver[sizeof(driver)-1]=0;

    data=(qsa_data*)calloc(1, sizeof(qsa_data));
    if (data==NULL)
    {
        return ALC_OUT_OF_MEMORY;
    }

    if (!deviceName)
    {
        deviceName=driver;
    }

    if (strcmp(deviceName, qsaDevice)==0)
    {
        if (!deviceName)
        {
            deviceName=qsaDevice;
        }

        status=snd_pcm_open_preferred(&data->pcmHandle, &card, &dev, SND_PCM_OPEN_PLAYBACK);
    }
    else
    {
        size_t idx;

        if (!allDevNameMap)
        {
            allDevNameMap=deviceList(SND_PCM_CHANNEL_PLAYBACK, &numDevNames);
        }

        for (idx=0; idx<numDevNames; idx++)
        {
            if (allDevNameMap[idx].name && strcmp(deviceName, allDevNameMap[idx].name)==0)
            {
                if (idx>0)
                {
                    break;
                }
            }
        }
        if (idx==numDevNames)
        {
            free(data);
            return ALC_INVALID_DEVICE;
        }

        status=snd_pcm_open(&data->pcmHandle, allDevNameMap[idx].card, allDevNameMap[idx].dev, SND_PCM_OPEN_PLAYBACK);
    }

    if (status<0)
    {
        free(data);
        return ALC_INVALID_DEVICE;
    }

    data->audio_fd=snd_pcm_file_descriptor(data->pcmHandle, SND_PCM_CHANNEL_PLAYBACK);
    if (data->audio_fd<0)
    {
        free(data);
        return ALC_INVALID_DEVICE;
    }

    al_string_copy_cstr(&device->DeviceName, deviceName);
    device->ExtraData = data;

    return ALC_NO_ERROR;
}

static void qsa_close_playback(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;

    if (data->buffer!=NULL)
    {
        free(data->buffer);
        data->buffer=NULL;
    }

    snd_pcm_close(data->pcmHandle);
    free(data);

    device->ExtraData=NULL;
}

static ALCboolean qsa_reset_playback(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;
    int32_t format=-1;

    switch(device->FmtType)
    {
        case DevFmtByte:
             format=SND_PCM_SFMT_S8;
             break;
        case DevFmtUByte:
             format=SND_PCM_SFMT_U8;
             break;
        case DevFmtShort:
             format=SND_PCM_SFMT_S16_LE;
             break;
        case DevFmtUShort:
             format=SND_PCM_SFMT_U16_LE;
             break;
        case DevFmtInt:
             format=SND_PCM_SFMT_S32_LE;
             break;
        case DevFmtUInt:
             format=SND_PCM_SFMT_U32_LE;
             break;
        case DevFmtFloat:
             format=SND_PCM_SFMT_FLOAT_LE;
             break;
    }

    /* we actually don't want to block on writes */
    snd_pcm_nonblock_mode(data->pcmHandle, 1);
    /* Disable mmap to control data transfer to the audio device */
    snd_pcm_plugin_set_disable(data->pcmHandle, PLUGIN_DISABLE_MMAP);
    snd_pcm_plugin_set_disable(data->pcmHandle, PLUGIN_DISABLE_BUFFER_PARTIAL_BLOCKS);

    // configure a sound channel
    memset(&data->cparams, 0, sizeof(data->cparams));
    data->cparams.channel=SND_PCM_CHANNEL_PLAYBACK;
    data->cparams.mode=SND_PCM_MODE_BLOCK;
    data->cparams.start_mode=SND_PCM_START_FULL;
    data->cparams.stop_mode=SND_PCM_STOP_STOP;

    data->cparams.buf.block.frag_size=device->UpdateSize*
        ChannelsFromDevFmt(device->FmtChans)*BytesFromDevFmt(device->FmtType);
    data->cparams.buf.block.frags_max=device->NumUpdates;
    data->cparams.buf.block.frags_min=device->NumUpdates;

    data->cparams.format.interleave=1;
    data->cparams.format.rate=device->Frequency;
    data->cparams.format.voices=ChannelsFromDevFmt(device->FmtChans);
    data->cparams.format.format=format;

    if ((snd_pcm_plugin_params(data->pcmHandle, &data->cparams))<0)
    {
        int original_rate=data->cparams.format.rate;
        int original_voices=data->cparams.format.voices;
        int original_format=data->cparams.format.format;
        int it;
        int jt;

        for (it=0; it<1; it++)
        {
            /* Check for second pass */
            if (it==1)
            {
                original_rate=ratelist[0].rate;
                original_voices=channellist[0].channels;
                original_format=formatlist[0].format;
            }

            do {
                /* At first downgrade sample format */
                jt=0;
                do {
                    if (formatlist[jt].format==data->cparams.format.format)
                    {
                        data->cparams.format.format=formatlist[jt+1].format;
                        break;
                    }
                    if (formatlist[jt].format==0)
                    {
                        data->cparams.format.format=0;
                        break;
                    }
                    jt++;
                } while(1);

                if (data->cparams.format.format==0)
                {
                    data->cparams.format.format=original_format;

                    /* At secod downgrade sample rate */
                    jt=0;
                    do {
                        if (ratelist[jt].rate==data->cparams.format.rate)
                        {
                            data->cparams.format.rate=ratelist[jt+1].rate;
                            break;
                        }
                        if (ratelist[jt].rate==0)
                        {
                            data->cparams.format.rate=0;
                            break;
                        }
                        jt++;
                    } while(1);

                    if (data->cparams.format.rate==0)
                    {
                        data->cparams.format.rate=original_rate;
                        data->cparams.format.format=original_format;

                        /* At third downgrade channels number */
                        jt=0;
                        do {
                            if(channellist[jt].channels==data->cparams.format.voices)
                            {
                                data->cparams.format.voices=channellist[jt+1].channels;
                                break;
                            }
                            if (channellist[jt].channels==0)
                            {
                                data->cparams.format.voices=0;
                                break;
                            }
                           jt++;
                        } while(1);
                    }

                    if (data->cparams.format.voices==0)
                    {
                        break;
                    }
                }

                data->cparams.buf.block.frag_size=device->UpdateSize*
                    data->cparams.format.voices*
                    snd_pcm_format_width(data->cparams.format.format)/8;
                data->cparams.buf.block.frags_max=device->NumUpdates;
                data->cparams.buf.block.frags_min=device->NumUpdates;
                if ((snd_pcm_plugin_params(data->pcmHandle, &data->cparams))<0)
                {
                    continue;
                }
                else
                {
                    break;
                }
            } while(1);

            if (data->cparams.format.voices!=0)
            {
                break;
            }
        }

        if (data->cparams.format.voices==0)
        {
            return ALC_FALSE;
        }
    }

    if ((snd_pcm_plugin_prepare(data->pcmHandle, SND_PCM_CHANNEL_PLAYBACK))<0)
    {
        return ALC_FALSE;
    }

    memset(&data->csetup, 0, sizeof(data->csetup));
    data->csetup.channel=SND_PCM_CHANNEL_PLAYBACK;
    if (snd_pcm_plugin_setup(data->pcmHandle, &data->csetup)<0)
    {
        return ALC_FALSE;
    }

    /* now fill back to the our AL device */
    device->Frequency=data->cparams.format.rate;

    switch (data->cparams.format.voices)
    {
        case 1:
             device->FmtChans=DevFmtMono;
             break;
        case 2:
             device->FmtChans=DevFmtStereo;
             break;
        case 4:
             device->FmtChans=DevFmtQuad;
             break;
        case 6:
             device->FmtChans=DevFmtX51;
             break;
        case 7:
             device->FmtChans=DevFmtX61;
             break;
        case 8:
             device->FmtChans=DevFmtX71;
             break;
        default:
             device->FmtChans=DevFmtMono;
             break;
    }

    switch (data->cparams.format.format)
    {
        case SND_PCM_SFMT_S8:
             device->FmtType=DevFmtByte;
             break;
        case SND_PCM_SFMT_U8:
             device->FmtType=DevFmtUByte;
             break;
        case SND_PCM_SFMT_S16_LE:
             device->FmtType=DevFmtShort;
             break;
        case SND_PCM_SFMT_U16_LE:
             device->FmtType=DevFmtUShort;
             break;
        case SND_PCM_SFMT_S32_LE:
             device->FmtType=DevFmtInt;
             break;
        case SND_PCM_SFMT_U32_LE:
             device->FmtType=DevFmtUInt;
             break;
        case SND_PCM_SFMT_FLOAT_LE:
             device->FmtType=DevFmtFloat;
             break;
        default:
             device->FmtType=DevFmtShort;
             break;
    }

    SetDefaultChannelOrder(device);

    device->UpdateSize=data->csetup.buf.block.frag_size/
        (ChannelsFromDevFmt(device->FmtChans)*BytesFromDevFmt(device->FmtType));
    device->NumUpdates=data->csetup.buf.block.frags;

    data->size=data->csetup.buf.block.frag_size;
    data->buffer=malloc(data->size);
    if (!data->buffer)
    {
        return ALC_FALSE;
    }

    return ALC_TRUE;
}

static ALCboolean qsa_start_playback(ALCdevice* device)
{
    qsa_data *data = (qsa_data*)device->ExtraData;

    data->killNow = 0;
    if(althrd_create(&data->thread, qsa_proc_playback, device) != althrd_success)
        return ALC_FALSE;

    return ALC_TRUE;
}

static void qsa_stop_playback(ALCdevice* device)
{
    qsa_data *data = (qsa_data*)device->ExtraData;
    int res;

    if(data->killNow)
        return;

    data->killNow = 1;
    althrd_join(data->thread, &res);
}

/***********/
/* Capture */
/***********/

static ALCenum qsa_open_capture(ALCdevice* device, const ALCchar* deviceName)
{
    qsa_data* data;
    int format=-1;
    char driver[64];
    int card, dev;
    int status;

    strncpy(driver, GetConfigValue("qsa", "capture", qsaDevice), sizeof(driver)-1);
    driver[sizeof(driver)-1]=0;

    data=(qsa_data*)calloc(1, sizeof(qsa_data));
    if (data==NULL)
    {
        return ALC_OUT_OF_MEMORY;
    }

    if (!deviceName)
    {
        deviceName=driver;
    }

    if (strcmp(deviceName, qsaDevice)==0)
    {
        if (!deviceName)
        {
            deviceName=qsaDevice;
        }

        status=snd_pcm_open_preferred(&data->pcmHandle, &card, &dev, SND_PCM_OPEN_CAPTURE);
    }
    else
    {
        size_t idx;

        if (!allCaptureDevNameMap)
        {
            allCaptureDevNameMap=deviceList(SND_PCM_CHANNEL_CAPTURE, &numDevNames);
        }

        for (idx=0; idx<numDevNames; idx++)
        {
            if (allCaptureDevNameMap[idx].name && strcmp(deviceName, allCaptureDevNameMap[idx].name)==0)
            {
                if (idx>0)
                {
                    break;
                }
            }
        }
        if (idx==numDevNames)
        {
            free(data);
            return ALC_INVALID_DEVICE;
        }

        status=snd_pcm_open(&data->pcmHandle, allCaptureDevNameMap[idx].card, allCaptureDevNameMap[idx].dev, SND_PCM_OPEN_CAPTURE);
    }

    if (status<0)
    {
        free(data);
        return ALC_INVALID_DEVICE;
    }

    data->audio_fd=snd_pcm_file_descriptor(data->pcmHandle, SND_PCM_CHANNEL_CAPTURE);
    if (data->audio_fd<0)
    {
        free(data);
        return ALC_INVALID_DEVICE;
    }

    al_string_copy_cstr(&device->DeviceName, deviceName);
    device->ExtraData = data;

    switch (device->FmtType)
    {
        case DevFmtByte:
             format=SND_PCM_SFMT_S8;
             break;
        case DevFmtUByte:
             format=SND_PCM_SFMT_U8;
             break;
        case DevFmtShort:
             format=SND_PCM_SFMT_S16_LE;
             break;
        case DevFmtUShort:
             format=SND_PCM_SFMT_U16_LE;
             break;
        case DevFmtInt:
             format=SND_PCM_SFMT_S32_LE;
             break;
        case DevFmtUInt:
             format=SND_PCM_SFMT_U32_LE;
             break;
        case DevFmtFloat:
             format=SND_PCM_SFMT_FLOAT_LE;
             break;
    }

    /* we actually don't want to block on reads */
    snd_pcm_nonblock_mode(data->pcmHandle, 1);
    /* Disable mmap to control data transfer to the audio device */
    snd_pcm_plugin_set_disable(data->pcmHandle, PLUGIN_DISABLE_MMAP);

    /* configure a sound channel */
    memset(&data->cparams, 0, sizeof(data->cparams));
    data->cparams.mode=SND_PCM_MODE_BLOCK;
    data->cparams.channel=SND_PCM_CHANNEL_CAPTURE;
    data->cparams.start_mode=SND_PCM_START_GO;
    data->cparams.stop_mode=SND_PCM_STOP_STOP;

    data->cparams.buf.block.frag_size=device->UpdateSize*
        ChannelsFromDevFmt(device->FmtChans)*BytesFromDevFmt(device->FmtType);
    data->cparams.buf.block.frags_max=device->NumUpdates;
    data->cparams.buf.block.frags_min=device->NumUpdates;

    data->cparams.format.interleave=1;
    data->cparams.format.rate=device->Frequency;
    data->cparams.format.voices=ChannelsFromDevFmt(device->FmtChans);
    data->cparams.format.format=format;

    if ((snd_pcm_plugin_params(data->pcmHandle, &data->cparams))<0)
    {
        int original_rate=data->cparams.format.rate;
        int original_voices=data->cparams.format.voices;
        int original_format=data->cparams.format.format;
        int it;
        int jt;

        for (it=0; it<1; it++)
        {
            /* Check for second pass */
            if (it==1)
            {
                original_rate=ratelist[0].rate;
                original_voices=channellist[0].channels;
                original_format=formatlist[0].format;
            }

            do {
                /* At first downgrade sample format */
                jt=0;
                do {
                    if (formatlist[jt].format==data->cparams.format.format)
                    {
                        data->cparams.format.format=formatlist[jt+1].format;
                        break;
                    }
                    if (formatlist[jt].format==0)
                    {
                        data->cparams.format.format=0;
                        break;
                    }
                    jt++;
                } while(1);

                if (data->cparams.format.format==0)
                {
                    data->cparams.format.format=original_format;

                    /* At secod downgrade sample rate */
                    jt=0;
                    do {
                        if (ratelist[jt].rate==data->cparams.format.rate)
                        {
                            data->cparams.format.rate=ratelist[jt+1].rate;
                            break;
                        }
                        if (ratelist[jt].rate==0)
                        {
                            data->cparams.format.rate=0;
                            break;
                        }
                        jt++;
                    } while(1);

                    if (data->cparams.format.rate==0)
                    {
                        data->cparams.format.rate=original_rate;
                        data->cparams.format.format=original_format;

                        /* At third downgrade channels number */
                        jt=0;
                        do {
                            if(channellist[jt].channels==data->cparams.format.voices)
                            {
                                data->cparams.format.voices=channellist[jt+1].channels;
                                break;
                            }
                            if (channellist[jt].channels==0)
                            {
                                data->cparams.format.voices=0;
                                break;
                            }
                           jt++;
                        } while(1);
                    }

                    if (data->cparams.format.voices==0)
                    {
                        break;
                    }
                }

                data->cparams.buf.block.frag_size=device->UpdateSize*
                    data->cparams.format.voices*
                    snd_pcm_format_width(data->cparams.format.format)/8;
                data->cparams.buf.block.frags_max=device->NumUpdates;
                data->cparams.buf.block.frags_min=device->NumUpdates;
                if ((snd_pcm_plugin_params(data->pcmHandle, &data->cparams))<0)
                {
                    continue;
                }
                else
                {
                    break;
                }
            } while(1);

            if (data->cparams.format.voices!=0)
            {
                break;
            }
        }

        if (data->cparams.format.voices==0)
        {
            return ALC_INVALID_VALUE;
        }
    }

    /* now fill back to the our AL device */
    device->Frequency=data->cparams.format.rate;

    switch (data->cparams.format.voices)
    {
        case 1:
             device->FmtChans=DevFmtMono;
             break;
        case 2:
             device->FmtChans=DevFmtStereo;
             break;
        case 4:
             device->FmtChans=DevFmtQuad;
             break;
        case 6:
             device->FmtChans=DevFmtX51;
             break;
        case 7:
             device->FmtChans=DevFmtX61;
             break;
        case 8:
             device->FmtChans=DevFmtX71;
             break;
        default:
             device->FmtChans=DevFmtMono;
             break;
    }

    switch (data->cparams.format.format)
    {
        case SND_PCM_SFMT_S8:
             device->FmtType=DevFmtByte;
             break;
        case SND_PCM_SFMT_U8:
             device->FmtType=DevFmtUByte;
             break;
        case SND_PCM_SFMT_S16_LE:
             device->FmtType=DevFmtShort;
             break;
        case SND_PCM_SFMT_U16_LE:
             device->FmtType=DevFmtUShort;
             break;
        case SND_PCM_SFMT_S32_LE:
             device->FmtType=DevFmtInt;
             break;
        case SND_PCM_SFMT_U32_LE:
             device->FmtType=DevFmtUInt;
             break;
        case SND_PCM_SFMT_FLOAT_LE:
             device->FmtType=DevFmtFloat;
             break;
        default:
             device->FmtType=DevFmtShort;
             break;
    }

    return ALC_NO_ERROR;
}

static void qsa_close_capture(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;

    if (data->pcmHandle!=NULL)
    {
        snd_pcm_close(data->pcmHandle);
    }
    free(data);
    device->ExtraData=NULL;
}

static void qsa_start_capture(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;
    int rstatus;

    if ((rstatus=snd_pcm_plugin_prepare(data->pcmHandle, SND_PCM_CHANNEL_CAPTURE))<0)
    {
        ERR("capture prepare failed: %s\n", snd_strerror(rstatus));
        return;
    }

    memset(&data->csetup, 0, sizeof(data->csetup));
    data->csetup.channel=SND_PCM_CHANNEL_CAPTURE;
    if ((rstatus=snd_pcm_plugin_setup(data->pcmHandle, &data->csetup))<0)
    {
        ERR("capture setup failed: %s\n", snd_strerror(rstatus));
        return;
    }

    snd_pcm_capture_go(data->pcmHandle);

    device->UpdateSize=data->csetup.buf.block.frag_size/
        (ChannelsFromDevFmt(device->FmtChans)*BytesFromDevFmt(device->FmtType));
    device->NumUpdates=data->csetup.buf.block.frags;
}

static void qsa_stop_capture(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;

    snd_pcm_capture_flush(data->pcmHandle);
}

static ALCuint qsa_available_samples(ALCdevice* device)
{
    qsa_data* data=(qsa_data*)device->ExtraData;
    snd_pcm_channel_status_t status;
    ALint frame_size=FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
    ALint free_size;
    int rstatus;

    memset(&status, 0, sizeof (status));
    status.channel=SND_PCM_CHANNEL_CAPTURE;
    snd_pcm_plugin_status(data->pcmHandle, &status);
    if ((status.status==SND_PCM_STATUS_OVERRUN) ||
        (status.status==SND_PCM_STATUS_READY))
    {
        if ((rstatus=snd_pcm_plugin_prepare(data->pcmHandle, SND_PCM_CHANNEL_CAPTURE))<0)
        {
            ERR("capture prepare failed: %s\n", snd_strerror(rstatus));
            aluHandleDisconnect(device);
            return 0;
        }

        snd_pcm_capture_go(data->pcmHandle);
        return 0;
    }

    free_size=data->csetup.buf.block.frag_size*data->csetup.buf.block.frags;
    free_size-=status.free;

    return free_size/frame_size;
}

static ALCenum qsa_capture_samples(ALCdevice *device, ALCvoid *buffer, ALCuint samples)
{
    qsa_data* data=(qsa_data*)device->ExtraData;
    char* read_ptr;
    snd_pcm_channel_status_t status;
    fd_set rfds;
    int selectret;
    struct timeval timeout;
    int bytes_read;
    ALint frame_size=FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
    ALint len=samples*frame_size;
    int rstatus;

    read_ptr=buffer;

    while (len>0)
    {
        FD_ZERO(&rfds);
        FD_SET(data->audio_fd, &rfds);
        timeout.tv_sec=2;
        timeout.tv_usec=0;

        /* Select also works like time slice to OS */
        bytes_read=0;
        selectret=select(data->audio_fd+1, &rfds, NULL, NULL, &timeout);
        switch (selectret)
        {
            case -1:
                 aluHandleDisconnect(device);
                 return ALC_INVALID_DEVICE;
            case 0:
                 break;
            default:
                 if (FD_ISSET(data->audio_fd, &rfds))
                 {
                     bytes_read=snd_pcm_plugin_read(data->pcmHandle, read_ptr, len);
                     break;
                 }
                 break;
        }

        if (bytes_read<=0)
        {
            if ((errno==EAGAIN) || (errno==EWOULDBLOCK))
            {
                continue;
            }

            memset(&status, 0, sizeof (status));
            status.channel=SND_PCM_CHANNEL_CAPTURE;
            snd_pcm_plugin_status(data->pcmHandle, &status);

            /* we need to reinitialize the sound channel if we've overrun the buffer */
            if ((status.status==SND_PCM_STATUS_OVERRUN) ||
                (status.status==SND_PCM_STATUS_READY))
            {
                if ((rstatus=snd_pcm_plugin_prepare(data->pcmHandle, SND_PCM_CHANNEL_CAPTURE))<0)
                {
                    ERR("capture prepare failed: %s\n", snd_strerror(rstatus));
                    aluHandleDisconnect(device);
                    return ALC_INVALID_DEVICE;
                }
                snd_pcm_capture_go(data->pcmHandle);
            }
        }
        else
        {
            read_ptr+=bytes_read;
            len-=bytes_read;
        }
    }

    return ALC_NO_ERROR;
}

static ALint64 qsa_get_latency(ALCdevice* device)
{
    ALint frame_size=FrameSizeFromDevFmt(device->FmtChans, device->FmtType);

    return (ALint64)(device->UpdateSize*device->NumUpdates/frame_size)*
        1000000000/device->Frequency;
}

BackendFuncs qsa_funcs=
{
    qsa_open_playback,
    qsa_close_playback,
    qsa_reset_playback,
    qsa_start_playback,
    qsa_stop_playback,
    qsa_open_capture,
    qsa_close_capture,
    qsa_start_capture,
    qsa_stop_capture,
    qsa_capture_samples,
    qsa_available_samples,
    qsa_get_latency,
};

ALCboolean alc_qsa_init(BackendFuncs* func_list)
{
    *func_list=qsa_funcs;

    return ALC_TRUE;
}

void alc_qsa_deinit(void)
{
    ALuint i;

    for (i=0; i<numDevNames; ++i)
    {
        free(allDevNameMap[i].name);
    }
    free(allDevNameMap);
    allDevNameMap=NULL;
    numDevNames=0;

    for (i=0; i<numCaptureDevNames; ++i)
    {
        free(allCaptureDevNameMap[i].name);
    }
    free(allCaptureDevNameMap);
    allCaptureDevNameMap=NULL;
    numCaptureDevNames=0;
}

void alc_qsa_probe(enum DevProbe type)
{
    ALuint i;

    switch (type)
    {
        case ALL_DEVICE_PROBE:
             for (i=0; i<numDevNames; ++i)
             {
                 free(allDevNameMap[i].name);
             }
             free(allDevNameMap);

             allDevNameMap=deviceList(SND_PCM_CHANNEL_PLAYBACK, &numDevNames);
             for (i=0; i<numDevNames; ++i)
             {
                 AppendAllDevicesList(allDevNameMap[i].name);
             }
             break;
        case CAPTURE_DEVICE_PROBE:
             for (i=0; i<numCaptureDevNames; ++i)
             {
                 free(allCaptureDevNameMap[i].name);
             }
             free(allCaptureDevNameMap);

             allCaptureDevNameMap=deviceList(SND_PCM_CHANNEL_CAPTURE, &numCaptureDevNames);
             for (i=0; i<numCaptureDevNames; ++i)
             {
                 AppendCaptureDeviceList(allCaptureDevNameMap[i].name);
             }
             break;
    }
}