/* GRH Audio Program
 *
 * Author: Paul Kavan, Project Engineer
 * Date: July 3, 2007
 */

#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>


/*************************************
 * Variable and Function Declarations 
 *************************************/
int             audio_type;                     //0 = sleep; 1 = capture; 2 = playback
int             nchannels = 1;
int             buffer_size = 512;
int             sample_rate = 8000;
int             bits = 8;
char           *snd_device_in  = "hw:0,0";
char           *snd_device_out = "hw:0,0";

void grh_capture(void);
void grh_playback(void);


/*************************************
 * Main Program Section
 *************************************/
int main(void)
{
  //Testing routine
  printf("Press enter to begin recording\n");
  getchar();
  grh_capture();
  printf("Audio Captured. Press enter to playback\n");
  getchar();

    
  /************************************
   * Decide between playback or capture
   ************************************/
  //TODO Determine best way to receive interrupts/mgs to parse
  //     between playback and capture


  /************************************
   * Call the appropriate function for
   * either playback or capture
   ************************************/
  /*if(audio_type==1)
    grh_capture();
  if(audio_type==2)
    grh_playback();*/

  return 0;
}



/*************************************************
 * Capture Function:
 * This fuction should capture audio from the PCM 
 * and store it in a buffer for transmission
 *************************************************/
void grh_capture(void)
{
  int i;
  int err;
  short buf[buffer_size];
  snd_pcm_t *capture_handle;
  snd_pcm_hw_params_t *hw_params;

  /************************************
   * Open the pcm interface
   ************************************/
  if ((err = snd_pcm_open(&capture_handle, snd_device_in, SND_PCM_STREAM_CAPTURE, 0)) < 0)
  {
    fprintf(stderr, "Failed to open input audio device %s: %s\n", snd_device_out, snd_strerror(err));
    exit(1);
  }

  /************************************
   * Configure the devices
   ************************************/
  if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) 
  {
    fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  if ((err = snd_pcm_hw_params_any (capture_handle, hw_params)) < 0) 
  {
    fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_access (capture_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) 
  {
    fprintf (stderr, "cannot set access type (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  if ((err = snd_pcm_hw_params_set_format (capture_handle, hw_params, SND_PCM_FORMAT_S8)) < 0) {
    fprintf (stderr, "cannot set sample format (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  if ((err = snd_pcm_hw_params_set_rate_near (capture_handle, hw_params, &sample_rate, 0)) < 0) 
  {
    fprintf (stderr, "cannot set sample rate (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_channels (capture_handle, hw_params, nchannels)) < 0) 
  {
    fprintf (stderr, "cannot set channel count (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  if ((err = snd_pcm_hw_params (capture_handle, hw_params)) < 0) {
    fprintf (stderr, "cannot set parameters (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  snd_pcm_hw_params_free (hw_params);

  if ((err = snd_pcm_prepare (capture_handle)) < 0) {
    fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  /******************************************
   * Perform capture and store to buffer
   ******************************************/
  for (i = 0; i < 10; ++i) {
    if ((err = snd_pcm_readi (capture_handle, buf, buffer_size)) != buffer_size) {
      fprintf (stderr, "read from audio interface failed (%s)\n",
          snd_strerror (err));
      exit (1);
    }
  }

  /*******************************************
   * Close PCM interface and exit
   *******************************************/
  snd_pcm_close (capture_handle);
  exit (0);
}

/************************************************
 * Playback Function:
 * This function should retrieve audio from a 
 * buffer and send it to the PCM for playback
 ************************************************/
void grh_playback(void)
{
  int i;
  int err;
  short buf[buffer_size];
  snd_pcm_t *playback_handle;
  snd_pcm_hw_params_t *hw_params;

  /************************************
   * Open the pcm interface
   ************************************/
  if ((err = snd_pcm_open(&playback_handle, snd_device_out, SND_PCM_STREAM_PLAYBACK, 0)) < 0) 
  {
    fprintf(stderr, "Failed to open output audio device %s: %s\n", snd_device_in, snd_strerror(err));
    exit(1);
  }

  /************************************
   * Configure the devices
   ************************************/
  if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0) {
    fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
        snd_strerror (err));
    exit (1);
  }
				 
  if ((err = snd_pcm_hw_params_any (playback_handle, hw_params)) < 0) {
    fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_access (playback_handle, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
    fprintf (stderr, "cannot set access type (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_format (playback_handle, hw_params, SND_PCM_FORMAT_S8)) < 0) {
    fprintf (stderr, "cannot set sample format (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_rate_near (playback_handle, hw_params, &sample_rate, 0)) < 0) {
    fprintf (stderr, "cannot set sample rate (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  if ((err = snd_pcm_hw_params_set_channels (playback_handle, hw_params, nchannels)) < 0) {
    fprintf (stderr, "cannot set channel count (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  if ((err = snd_pcm_hw_params (playback_handle, hw_params)) < 0) {
    fprintf (stderr, "cannot set parameters (%s)\n",
        snd_strerror (err));
    exit (1);
  }
	
  snd_pcm_hw_params_free (hw_params);

  if ((err = snd_pcm_prepare (playback_handle)) < 0) {
    fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
        snd_strerror (err));
    exit (1);
  }

  /******************************************
   * Playback from buffer
   ******************************************/
  for (i = 0; i < 10; ++i) {
    if ((err = snd_pcm_writei (playback_handle, buf, buffer_size)) != buffer_size) {
      fprintf (stderr, "write to audio interface failed (%s)\n",
          snd_strerror (err));
      exit (1);
    }
  }

  /*******************************************
   * Close PCM interface and exit
   *******************************************/
  snd_pcm_close (playback_handle);
  exit (0);
}