/*****************************************************************************
 * kai.c : KAI audio output plugin for vlc
 *****************************************************************************
 * Copyright (C) 2010-2013 VLC authors and VideoLAN
 *
 * Authors: KO Myung-Hun <komh@chollian.net>
 *
 * 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.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_aout.h>

#include <float.h>

#include <kai.h>

#define FRAME_SIZE 2048

#define AUDIO_BUFFER_SIZE_IN_SECONDS ( AOUT_MAX_ADVANCE_TIME / CLOCK_FREQ )

struct audio_buffer_t
{
    uint8_t    *data;
    int         read_pos;
    int         write_pos;
    int         length;
    int         size;
    vlc_mutex_t mutex;
    vlc_cond_t  cond;
};

typedef struct audio_buffer_t audio_buffer_t;

/*****************************************************************************
 * aout_sys_t: KAI audio output method descriptor
 *****************************************************************************
 * This structure is part of the audio output thread descriptor.
 * It describes the specific properties of an audio device.
 *****************************************************************************/
struct aout_sys_t
{
    audio_buffer_t *buffer;
    HKAI            hkai;
    float           soft_gain;
    bool            soft_mute;
    audio_sample_format_t format;
};

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
static int  Open    ( vlc_object_t * );
static void Close   ( vlc_object_t * );
static void Play    ( audio_output_t *_p_aout, block_t *block );
static void Pause   ( audio_output_t *, bool, mtime_t );
static void Flush   ( audio_output_t *, bool );
static int  TimeGet ( audio_output_t *, mtime_t *restrict );

static ULONG APIENTRY KaiCallback ( PVOID, PVOID, ULONG );

static int  CreateBuffer ( audio_output_t *, int );
static void DestroyBuffer( audio_output_t * );
static int  ReadBuffer   ( audio_output_t *, uint8_t *, int );
static int  WriteBuffer  ( audio_output_t *, uint8_t *, int );

#include "audio_output/volume.h"

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
#define KAI_AUDIO_DEVICE_TEXT N_( \
    "Device" )
#define KAI_AUDIO_DEVICE_LONGTEXT N_( \
    "Select a proper audio device to be used by KAI." )

#define KAI_AUDIO_EXCLUSIVE_MODE_TEXT N_( \
    "Open audio in exclusive mode." )
#define KAI_AUDIO_EXCLUSIVE_MODE_LONGTEXT N_( \
    "Enable this option if you want your audio not to be interrupted by the " \
    "other audio." )

static const char *const ppsz_kai_audio_device[] = {
    "auto", "dart", "uniaud" };
static const char *const ppsz_kai_audio_device_text[] = {
    N_("Auto"), "DART", "UNIAUD" };

vlc_module_begin ()
    set_shortname( "KAI" )
    set_description( N_("K Audio Interface audio output") )
    set_capability( "audio output", 100 )
    set_category( CAT_AUDIO )
    set_subcategory( SUBCAT_AUDIO_AOUT )
    add_string( "kai-audio-device", ppsz_kai_audio_device[0],
                KAI_AUDIO_DEVICE_TEXT, KAI_AUDIO_DEVICE_LONGTEXT, false )
        change_string_list( ppsz_kai_audio_device, ppsz_kai_audio_device_text )
    add_sw_gain( )
    add_bool( "kai-audio-exclusive-mode", false,
              KAI_AUDIO_EXCLUSIVE_MODE_TEXT, KAI_AUDIO_EXCLUSIVE_MODE_LONGTEXT,
              true )
    set_callbacks( Open, Close )
vlc_module_end ()

/*****************************************************************************
 * Open: open the audio device
 *****************************************************************************/
static int Start ( audio_output_t *p_aout, audio_sample_format_t *fmt )
{
    aout_sys_t *p_sys = p_aout->sys;
    char *psz_mode;
    ULONG i_kai_mode;
    KAISPEC ks_wanted, ks_obtained;
    int i_nb_channels;
    int i_bytes_per_frame;
    vlc_value_t val, text;
    audio_sample_format_t format = *fmt;

    psz_mode = var_InheritString( p_aout, "kai-audio-device" );
    if( !psz_mode )
        psz_mode = ( char * )ppsz_kai_audio_device[ 0 ];  // "auto"

    i_kai_mode = KAIM_AUTO;
    if( strcmp( psz_mode, "dart" ) == 0 )
        i_kai_mode = KAIM_DART;
    else if( strcmp( psz_mode, "uniaud" ) == 0 )
        i_kai_mode = KAIM_UNIAUD;
    msg_Dbg( p_aout, "selected mode = %s", psz_mode );

    if( psz_mode != ppsz_kai_audio_device[ 0 ])
        free( psz_mode );

    i_nb_channels = aout_FormatNbChannels( &format );
    if ( i_nb_channels >= 2 )
    {
        /* KAI doesn't support more than two channels. */
        i_nb_channels = 2;
        format.i_physical_channels = AOUT_CHANS_STEREO;
    }
    else
        format.i_physical_channels = AOUT_CHAN_CENTER;

    /* Support S16 only */
    format.i_format = VLC_CODEC_S16N;

    aout_FormatPrepare( &format );

    i_bytes_per_frame = format.i_bytes_per_frame;

    /* Initialize library */
    if( kaiInit( i_kai_mode ))
    {
        msg_Err( p_aout, "cannot initialize KAI");

        return VLC_EGENERIC;
    }

    ks_wanted.usDeviceIndex   = 0;
    ks_wanted.ulType          = KAIT_PLAY;
    ks_wanted.ulBitsPerSample = BPS_16;
    ks_wanted.ulSamplingRate  = format.i_rate;
    ks_wanted.ulDataFormat    = MCI_WAVE_FORMAT_PCM;
    ks_wanted.ulChannels      = i_nb_channels;
    ks_wanted.ulNumBuffers    = 2;
    ks_wanted.ulBufferSize    = FRAME_SIZE * i_bytes_per_frame;
    ks_wanted.fShareable      = !var_InheritBool( p_aout,
                                                  "kai-audio-exclusive-mode");
    ks_wanted.pfnCallBack     = KaiCallback;
    ks_wanted.pCallBackData   = p_aout;
    msg_Dbg( p_aout, "requested ulBufferSize = %ld", ks_wanted.ulBufferSize );

    /* Open the sound device. */
    if( kaiOpen( &ks_wanted, &ks_obtained, &p_sys->hkai ))
    {
        msg_Err( p_aout, "cannot open KAI device");

        goto exit_kai_done;
    }

    msg_Dbg( p_aout, "open in %s mode",
             ks_obtained.fShareable ? "shareable" : "exclusive" );
    msg_Dbg( p_aout, "obtained i_nb_samples = %lu",
             ks_obtained.ulBufferSize / i_bytes_per_frame );
    msg_Dbg( p_aout, "obtained i_bytes_per_frame = %d",
             format.i_bytes_per_frame );

    p_sys->format = *fmt = format;

    p_aout->time_get = TimeGet;
    p_aout->play     = Play;
    p_aout->pause    = Pause;
    p_aout->flush    = Flush;

    aout_SoftVolumeStart( p_aout );

    CreateBuffer( p_aout, AUDIO_BUFFER_SIZE_IN_SECONDS *
                          format.i_rate * format.i_bytes_per_frame );

    /* Prevent SIG_FPE */
    _control87(MCW_EM, MCW_EM);

    return VLC_SUCCESS;

exit_kai_done :
    kaiDone();

    return VLC_EGENERIC;
}

/*****************************************************************************
 * Play: play a sound samples buffer
 *****************************************************************************/
static void Play (audio_output_t *p_aout, block_t *block)
{
    aout_sys_t *p_sys = p_aout->sys;

    kaiPlay( p_sys->hkai );

    WriteBuffer( p_aout, block->p_buffer, block->i_buffer );

    block_Release( block );
}

/*****************************************************************************
 * Close: close the audio device
 *****************************************************************************/
static void Stop ( audio_output_t *p_aout )
{
    aout_sys_t *p_sys = p_aout->sys;

    kaiClose( p_sys->hkai );
    kaiDone();

    DestroyBuffer( p_aout );
}

/*****************************************************************************
 * KaiCallback: what to do once KAI has played sound samples
 *****************************************************************************/
static ULONG APIENTRY KaiCallback( PVOID p_cb_data,
                                   PVOID p_buffer,
                                   ULONG i_buf_size )
{
    audio_output_t *p_aout = (audio_output_t *)p_cb_data;
    int i_len;

    i_len = ReadBuffer( p_aout, p_buffer, i_buf_size );
    if(( ULONG )i_len < i_buf_size )
        memset(( uint8_t * )p_buffer + i_len, 0, i_buf_size - i_len );

    return i_buf_size;
}

static int Open (vlc_object_t *obj)
{
    audio_output_t *aout = (audio_output_t *)obj;
    aout_sys_t *sys = calloc( 1, sizeof( aout_sys_t ) );

    if( unlikely( sys == NULL ))
        return VLC_ENOMEM;

    aout->sys = sys;
    aout->start = Start;
    aout->stop = Stop;
    aout_SoftVolumeInit( aout );
    return VLC_SUCCESS;
}

static void Close( vlc_object_t *obj )
{
    audio_output_t *aout = (audio_output_t *)obj;
    aout_sys_t *sys = aout->sys;

    free(sys);
}

static void Pause( audio_output_t *aout, bool pause, mtime_t date )
{
    VLC_UNUSED( date );

    aout_sys_t *sys = aout->sys;

    if( pause )
        kaiPause( sys->hkai );
    else
        kaiResume( sys->hkai );
}

static void Flush( audio_output_t *aout, bool drain )
{
    audio_buffer_t *buffer = aout->sys->buffer;

    vlc_mutex_lock( &buffer->mutex );

    if( drain )
    {
        while( buffer->length > 0 )
            vlc_cond_wait( &buffer->cond, &buffer->mutex );
    }
    else
    {
        buffer->read_pos = buffer->write_pos;
        buffer->length   = 0;
    }

    vlc_mutex_unlock( &buffer->mutex );
}

static int TimeGet( audio_output_t *aout, mtime_t *restrict delay )
{
    aout_sys_t            *sys = aout->sys;
    audio_sample_format_t *format = &sys->format;
    audio_buffer_t        *buffer = sys->buffer;

    vlc_mutex_lock( &buffer->mutex );

    *delay = ( buffer->length / format->i_bytes_per_frame ) * CLOCK_FREQ /
             format->i_rate;

    vlc_mutex_unlock( &buffer->mutex );

    return 0;
}

static int CreateBuffer( audio_output_t *aout, int size )
{
    audio_buffer_t *buffer;

    buffer = calloc( 1, sizeof( *buffer ));
    if( !buffer )
        return -1;

    buffer->data = malloc( size );
    if( !buffer->data )
    {
        free( buffer );

        return -1;
    }

    buffer->size = size;

    vlc_mutex_init( &buffer->mutex );
    vlc_cond_init( &buffer->cond );

    aout->sys->buffer = buffer;

    return 0;
}

static void DestroyBuffer( audio_output_t *aout )
{
    audio_buffer_t *buffer = aout->sys->buffer;

    vlc_mutex_destroy( &buffer->mutex );
    vlc_cond_destroy( &buffer->cond );

    free( buffer->data );
    free( buffer );
}

static int ReadBuffer( audio_output_t *aout, uint8_t *data, int size )
{
    audio_buffer_t *buffer = aout->sys->buffer;
    int             len;
    int             remain_len = 0;

    vlc_mutex_lock( &buffer->mutex );

    len = MIN( buffer->length, size );
    if( buffer->read_pos + len > buffer->size )
    {
        remain_len  = len;
        len         = buffer->size - buffer->read_pos;
        remain_len -= len;
    }

    memcpy( data, buffer->data + buffer->read_pos, len );
    if( remain_len )
        memcpy( data + len, buffer->data, remain_len );

    len += remain_len;

    buffer->read_pos += len;
    buffer->read_pos %= buffer->size;

    buffer->length -= len;

    vlc_cond_signal( &buffer->cond );

    vlc_mutex_unlock( &buffer->mutex );

    return len;
}

static int WriteBuffer( audio_output_t *aout, uint8_t *data, int size )
{
    audio_buffer_t *buffer = aout->sys->buffer;
    int             len;
    int             remain_len = 0;

    vlc_mutex_lock( &buffer->mutex );

    /* FIXME :
     * If size is larger than buffer->size, this is locked indefinitely.
     */
    while( buffer->length + size > buffer->size )
        vlc_cond_wait( &buffer->cond, &buffer->mutex );

    len = size;
    if( buffer->write_pos + len > buffer->size )
    {
        remain_len  = len;
        len         = buffer->size - buffer->write_pos;
        remain_len -= len;
    }

    memcpy( buffer->data + buffer->write_pos, data, len );
    if( remain_len )
        memcpy( buffer->data, data + len, remain_len );

    buffer->write_pos += size;
    buffer->write_pos %= buffer->size;

    buffer->length += size;

    vlc_mutex_unlock( &buffer->mutex );

    return size;
}