/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Initial Developer of the Original Code is
 * CSIRO
 * Portions created by the Initial Developer are Copyright (C) 2007
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s): Michael Martin
 *                 Chris Double (chris.double@double.co.nz)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** *
 */
#include <stdlib.h>
#include <alsa/asoundlib.h>
#include "sydney_audio.h"

/* ALSA implementation based heavily on sydney_audio_mac.c */


struct sa_stream {
  snd_pcm_t*        output_unit;
  int64_t           bytes_written;

  /* audio format info */
  unsigned int      rate;
  unsigned int      n_channels;
};

/*
 * -----------------------------------------------------------------------------
 *  Error Handler to prevent output to stderr
 *  ----------------------------------------------------------------------------
 */
static void
quiet_error_handler(const char* file,
                    int         line,
                    const char* function,
                    int         err,
                    const char* format,
                    ...)
{
}

/*
 * -----------------------------------------------------------------------------
 * Startup and shutdown functions
 * -----------------------------------------------------------------------------
 */

int
sa_stream_create_pcm(
  sa_stream_t      ** _s,
  const char        * client_name,
  sa_mode_t           mode,
  sa_pcm_format_t     format,
  unsigned  int       rate,
  unsigned  int       n_channels
) {
  sa_stream_t   * s = 0;

  /*
   * Make sure we return a NULL stream pointer on failure.
   */
  if (_s == NULL) {
    return SA_ERROR_INVALID;
  }
  *_s = NULL;

  if (mode != SA_MODE_WRONLY) {
    return SA_ERROR_NOT_SUPPORTED;
  }
  if (format != SA_PCM_FORMAT_S16_NE) {
    return SA_ERROR_NOT_SUPPORTED;
  }

  /*
   * Allocate the instance and required resources.
   */
  if ((s = malloc(sizeof(sa_stream_t))) == NULL) {
    return SA_ERROR_OOM;
  }

  s->output_unit  = NULL;
  s->bytes_written = 0;
  s->rate         = rate;
  s->n_channels   = n_channels;

  *_s = s;
  return SA_SUCCESS;
}


int
sa_stream_open(sa_stream_t *s) {

  if (s == NULL) {
    return SA_ERROR_NO_INIT;
  }
  if (s->output_unit != NULL) {
    return SA_ERROR_INVALID;
  }

  /* Turn off debug output to stderr */
  snd_lib_error_set_handler(quiet_error_handler);

  if (snd_pcm_open(&s->output_unit, 
                   "default", 
                   SND_PCM_STREAM_PLAYBACK, 
                   0) < 0) {
    return SA_ERROR_NO_DEVICE;
  }
  
  if (snd_pcm_set_params(s->output_unit,
#ifdef SA_LITTLE_ENDIAN
                         SND_PCM_FORMAT_S16_LE,
#else
                         SND_PCM_FORMAT_S16_BE,
#endif
                         SND_PCM_ACCESS_RW_INTERLEAVED,
                         s->n_channels,
                         s->rate,
                         1,
                         500000) < 0) {
    snd_pcm_close(s->output_unit);
    s->output_unit = NULL;
    return SA_ERROR_NOT_SUPPORTED;
  }
  
  return SA_SUCCESS;
}


int
sa_stream_destroy(sa_stream_t *s) {
  int result = SA_SUCCESS;

  if (s == NULL) {
    return result;
  }
  /*
   * Shut down the audio output device.
   */
  if (s->output_unit != NULL) {
    if (snd_pcm_close(s->output_unit) < 0) {
      result = SA_ERROR_SYSTEM;
    }
  }
  free(s);
  return result;
}



/*
 * -----------------------------------------------------------------------------
 * Data read and write functions
 * -----------------------------------------------------------------------------
 */

int
sa_stream_write(sa_stream_t *s, const void *data, size_t nbytes) {
  snd_pcm_sframes_t frames, nframes;

  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }
  if (nbytes == 0) {
    return SA_SUCCESS;
  }

  nframes = snd_pcm_bytes_to_frames(s->output_unit, nbytes);

  while(nframes>0) {
    frames = snd_pcm_writei(s->output_unit, data, nframes);
    if (frames < 0) {
      int r = snd_pcm_recover(s->output_unit, frames, 1);
      if (r < 0) {
        return SA_ERROR_SYSTEM;
      }
    } else {
      nframes -= frames;
      data = ((unsigned char *)data) + snd_pcm_frames_to_bytes(s->output_unit, frames);
    }
  }

  s->bytes_written += nbytes;

  return SA_SUCCESS;
}

/*
 * -----------------------------------------------------------------------------
 * General query and support functions
 * -----------------------------------------------------------------------------
 */

int
sa_stream_get_write_size(sa_stream_t *s, size_t *size) {
  snd_pcm_sframes_t avail;

  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  do {
    avail = snd_pcm_avail_update(s->output_unit);
    if (avail < 0) {
      int r = snd_pcm_recover(s->output_unit, avail, 1);
      if (r < 0) {
        return SA_ERROR_SYSTEM;
      }
      continue;
    }
    break;
  } while (1);

  *size = snd_pcm_frames_to_bytes(s->output_unit, avail);

  return SA_SUCCESS;
}

int
sa_stream_get_position(sa_stream_t *s, sa_position_t position, int64_t *pos) {
  snd_pcm_state_t state;
  snd_pcm_sframes_t delay;
  
  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  if (position != SA_POSITION_WRITE_SOFTWARE) {
    return SA_ERROR_NOT_SUPPORTED;
  }

  state = snd_pcm_state(s->output_unit);
  if (state == SND_PCM_STATE_XRUN) {
    if (snd_pcm_recover(s->output_unit, -EPIPE, 1) < 0) {
      return SA_ERROR_SYSTEM;
    }
    state = snd_pcm_state(s->output_unit);
  }

  if (state == SND_PCM_STATE_RUNNING) {
    if (snd_pcm_delay(s->output_unit, &delay) != 0) {
      return SA_ERROR_SYSTEM;
    }
  } else {
    delay = 0;
  }

  /* delay means audio is 'x' frames behind what we've written. We need to
     subtract the delay from the data written to return the actual bytes played.

     due to buffering, the delay can be larger than the amount we've
     written--in this case, report position as zero. */
  *pos = s->bytes_written;
  if (*pos >= snd_pcm_frames_to_bytes(s->output_unit, delay)) {
    *pos -= snd_pcm_frames_to_bytes(s->output_unit, delay);
  } else {
    *pos = 0;
  }

  return SA_SUCCESS;
}


int
sa_stream_pause(sa_stream_t *s) {

  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  if (snd_pcm_pause(s->output_unit, 1) != 0)
    return SA_ERROR_NOT_SUPPORTED;

  return SA_SUCCESS;
}


int
sa_stream_resume(sa_stream_t *s) {

  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  if (snd_pcm_pause(s->output_unit, 0) != 0)
    return SA_ERROR_NOT_SUPPORTED;
  return SA_SUCCESS;
}


int
sa_stream_drain(sa_stream_t *s)
{
  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }
  snd_pcm_drain(s->output_unit);
  return SA_SUCCESS;
}



/*
 * -----------------------------------------------------------------------------
 * Extension functions
 * -----------------------------------------------------------------------------
 */

int
sa_stream_set_volume_abs(sa_stream_t *s, float vol) {
  snd_mixer_t* mixer = 0;
  snd_mixer_elem_t* elem = 0;
  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  if (snd_mixer_open(&mixer, 0) < 0) {
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_attach(mixer, "default") < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_selem_register(mixer, NULL, NULL) < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_load(mixer) < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

#if 0
  snd_mixer_elem_t* elem = 0;
  for (elem = snd_mixer_first_elem(mixer); elem != NULL; elem = snd_mixer_elem_next(elem)) {
    if (snd_mixer_selem_has_playback_volume(elem)) {
      printf("Playback %s\n", snd_mixer_selem_get_name(elem));
    }
    else {
      printf("No Playback: %s\n", snd_mixer_selem_get_name(elem));
    }
  }
#endif
  elem = snd_mixer_first_elem(mixer);
  if (elem && snd_mixer_selem_has_playback_volume(elem)) {
    long min = 0;
    long max = 0;
    if (snd_mixer_selem_get_playback_volume_range(elem, &min, &max) >= 0) {
      snd_mixer_selem_set_playback_volume_all(elem, (max-min)*vol + min);
    } 
  }
  snd_mixer_close(mixer);

  return SA_SUCCESS;
}


int
sa_stream_get_volume_abs(sa_stream_t *s, float *vol) {
  snd_mixer_t* mixer = 0;
  snd_mixer_elem_t* elem = 0;
  long value = 0;

  if (s == NULL || s->output_unit == NULL) {
    return SA_ERROR_NO_INIT;
  }

  if (snd_mixer_open(&mixer, 0) < 0) {
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_attach(mixer, "default") < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_selem_register(mixer, NULL, NULL) < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

  if (snd_mixer_load(mixer) < 0) {
    snd_mixer_close(mixer);
    return SA_ERROR_SYSTEM;
  }

  elem = snd_mixer_first_elem(mixer);
  if (elem && snd_mixer_selem_get_playback_volume(elem, 0, &value) >= 0) {
    long min = 0;
    long max = 0;
    if (snd_mixer_selem_get_playback_volume_range(elem, &min, &max) >= 0) {
      *vol = (float)(value-min)/(float)(max-min);
    } 
  }
  snd_mixer_close(mixer);

  return SA_SUCCESS;
}



/*
 * -----------------------------------------------------------------------------
 * Unsupported functions
 * -----------------------------------------------------------------------------
 */
#define UNSUPPORTED(func)   func { return SA_ERROR_NOT_SUPPORTED; }

UNSUPPORTED(int sa_stream_create_opaque(sa_stream_t **s, const char *client_name, sa_mode_t mode, const char *codec))
UNSUPPORTED(int sa_stream_set_write_lower_watermark(sa_stream_t *s, size_t size))
UNSUPPORTED(int sa_stream_set_read_lower_watermark(sa_stream_t *s, size_t size))
UNSUPPORTED(int sa_stream_set_write_upper_watermark(sa_stream_t *s, size_t size))
UNSUPPORTED(int sa_stream_set_read_upper_watermark(sa_stream_t *s, size_t size))
UNSUPPORTED(int sa_stream_set_channel_map(sa_stream_t *s, const sa_channel_t map[], unsigned int n))
UNSUPPORTED(int sa_stream_set_xrun_mode(sa_stream_t *s, sa_xrun_mode_t mode))
UNSUPPORTED(int sa_stream_set_non_interleaved(sa_stream_t *s, int enable))
UNSUPPORTED(int sa_stream_set_dynamic_rate(sa_stream_t *s, int enable))
UNSUPPORTED(int sa_stream_set_driver(sa_stream_t *s, const char *driver))
UNSUPPORTED(int sa_stream_start_thread(sa_stream_t *s, sa_event_callback_t callback))
UNSUPPORTED(int sa_stream_stop_thread(sa_stream_t *s))
UNSUPPORTED(int sa_stream_change_device(sa_stream_t *s, const char *device_name))
UNSUPPORTED(int sa_stream_change_read_volume(sa_stream_t *s, const int32_t vol[], unsigned int n))
UNSUPPORTED(int sa_stream_change_write_volume(sa_stream_t *s, const int32_t vol[], unsigned int n))
UNSUPPORTED(int sa_stream_change_rate(sa_stream_t *s, unsigned int rate))
UNSUPPORTED(int sa_stream_change_meta_data(sa_stream_t *s, const char *name, const void *data, size_t size))
UNSUPPORTED(int sa_stream_change_user_data(sa_stream_t *s, const void *value))
UNSUPPORTED(int sa_stream_set_adjust_rate(sa_stream_t *s, sa_adjust_t direction))
UNSUPPORTED(int sa_stream_set_adjust_nchannels(sa_stream_t *s, sa_adjust_t direction))
UNSUPPORTED(int sa_stream_set_adjust_pcm_format(sa_stream_t *s, sa_adjust_t direction))
UNSUPPORTED(int sa_stream_set_adjust_watermarks(sa_stream_t *s, sa_adjust_t direction))
UNSUPPORTED(int sa_stream_get_mode(sa_stream_t *s, sa_mode_t *access_mode))
UNSUPPORTED(int sa_stream_get_codec(sa_stream_t *s, char *codec, size_t *size))
UNSUPPORTED(int sa_stream_get_pcm_format(sa_stream_t *s, sa_pcm_format_t *format))
UNSUPPORTED(int sa_stream_get_rate(sa_stream_t *s, unsigned int *rate))
UNSUPPORTED(int sa_stream_get_nchannels(sa_stream_t *s, int *nchannels))
UNSUPPORTED(int sa_stream_get_user_data(sa_stream_t *s, void **value))
UNSUPPORTED(int sa_stream_get_write_lower_watermark(sa_stream_t *s, size_t *size))
UNSUPPORTED(int sa_stream_get_read_lower_watermark(sa_stream_t *s, size_t *size))
UNSUPPORTED(int sa_stream_get_write_upper_watermark(sa_stream_t *s, size_t *size))
UNSUPPORTED(int sa_stream_get_read_upper_watermark(sa_stream_t *s, size_t *size))
UNSUPPORTED(int sa_stream_get_channel_map(sa_stream_t *s, sa_channel_t map[], unsigned int *n))
UNSUPPORTED(int sa_stream_get_xrun_mode(sa_stream_t *s, sa_xrun_mode_t *mode))
UNSUPPORTED(int sa_stream_get_non_interleaved(sa_stream_t *s, int *enabled))
UNSUPPORTED(int sa_stream_get_dynamic_rate(sa_stream_t *s, int *enabled))
UNSUPPORTED(int sa_stream_get_driver(sa_stream_t *s, char *driver_name, size_t *size))
UNSUPPORTED(int sa_stream_get_device(sa_stream_t *s, char *device_name, size_t *size))
UNSUPPORTED(int sa_stream_get_read_volume(sa_stream_t *s, int32_t vol[], unsigned int *n))
UNSUPPORTED(int sa_stream_get_write_volume(sa_stream_t *s, int32_t vol[], unsigned int *n))
UNSUPPORTED(int sa_stream_get_meta_data(sa_stream_t *s, const char *name, void*data, size_t *size))
UNSUPPORTED(int sa_stream_get_adjust_rate(sa_stream_t *s, sa_adjust_t *direction))
UNSUPPORTED(int sa_stream_get_adjust_nchannels(sa_stream_t *s, sa_adjust_t *direction))
UNSUPPORTED(int sa_stream_get_adjust_pcm_format(sa_stream_t *s, sa_adjust_t *direction))
UNSUPPORTED(int sa_stream_get_adjust_watermarks(sa_stream_t *s, sa_adjust_t *direction))
UNSUPPORTED(int sa_stream_get_state(sa_stream_t *s, sa_state_t *state))
UNSUPPORTED(int sa_stream_get_event_error(sa_stream_t *s, sa_error_t *error))
UNSUPPORTED(int sa_stream_get_event_notify(sa_stream_t *s, sa_notify_t *notify))
UNSUPPORTED(int sa_stream_read(sa_stream_t *s, void *data, size_t nbytes))
UNSUPPORTED(int sa_stream_read_ni(sa_stream_t *s, unsigned int channel, void *data, size_t nbytes))
UNSUPPORTED(int sa_stream_write_ni(sa_stream_t *s, unsigned int channel, const void *data, size_t nbytes))
UNSUPPORTED(int sa_stream_pwrite(sa_stream_t *s, const void *data, size_t nbytes, int64_t offset, sa_seek_t whence))
UNSUPPORTED(int sa_stream_pwrite_ni(sa_stream_t *s, unsigned int channel, const void *data, size_t nbytes, int64_t offset, sa_seek_t whence))
UNSUPPORTED(int sa_stream_get_read_size(sa_stream_t *s, size_t *size))

const char *sa_strerror(int code) { return NULL; }

