#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pulse/pulseaudio.h>
#include <libnotify/notify.h>
 
/**
 * Global variable to keep track of the main pulse audio loop, that
 * will be terminated on the success or failure of the switch. */
pa_mainloop* mainloop;
 
/**
 * @brief Callback called by toggle_mute when the switch operation
 * is completed (with success or failure). It terminates the mainloop
 * and exit the program.
 *
 * @param c the Pulseaudio context.
 * @param success 0 if the switch has gone well, not zero othewise.
 * @param new_output The description of the new active output.
 */
void
success_callback(pa_context *c, int success, char* new_output)
{
  /* Notify to the user that the switch was successful */
  GError* error = NULL;
  char *title, *body;
 
  body = (char*) malloc(sizeof(char) * 255);
 
  /* Set messages of the notification based on the success
   * of the switching operation */
  if (!success)
    {
      title = "Audio switch failure";
      body = "Audio switching operation failed.";
    }
  else
    {
      title = "Audio switched";
      if (strlen(new_output) < 235)
	sprintf(body, "New active output: %s", new_output);
      else
	strncpy(body, new_output, 255);
    }
 
  /* Display the notification */
  NotifyNotification *notification = notify_notification_new (title,
							      body,
							      "gnome-mixer");
  notify_notification_show (notification,
			    &error);
 
  /* Free vars */
  free (body);
 
  /* Exit the pulseaudio mainloop */
  pa_mainloop_quit(mainloop, success);
}
 
/**
 * @brief Called for every sink output of pulse audio.
 * It toggles mute cycling through the available output
 * ports.
 */
void
toggle_mute(pa_context *c, pa_sink_info *i, void* user_data)
{
  int j;
  if (i) {
    /* Cycle through available active ports. This should
     * rotate between headphones and/or analog output. */
    for(j = 0; j < i->n_ports; j++) {
      if (i->active_port == i->ports[j]) {
	pa_context_set_sink_port_by_index(c,
					  i->index,
					  i->ports[(j + 1) % i->n_ports]->name,
					  (pa_context_success_cb_t) success_callback,
					  (char*) i->ports[(j+1) % i->n_ports]->description);
      }
    }
  }
}
 
 
/**
 * @brief Callback called on the phasis of the connection
 * to the default Pulseaudio server.
 */
void
context_connected_cb(pa_context *c, void* user_data)
{
  if (pa_context_get_state(c) == PA_CONTEXT_READY) {
    pa_context_get_sink_info_list(c,
				  (pa_sink_info_cb_t) toggle_mute,
				  NULL);
  }
}
 
/**
 * @brief main routine
 */
int
main()
{
  pa_mainloop_api *api;
  pa_context *c;
  int retval;
  pa_proplist *proplist;
 
  /* Create a new pulseaudio mainloop */
  mainloop = pa_mainloop_new();
  api = pa_mainloop_get_api(mainloop);
 
  /* Init notification system */
  notify_init ("AudioSwitch");
 
  /* Create a new Pualseaudio context with the propery
   * dictionary */
  proplist = pa_proplist_new();
  pa_proplist_sets(proplist, PA_PROP_DEVICE_API, "alsa");
  c = pa_context_new_with_proplist(api, "Audio Switcher",
				   proplist);
 
  /* Connect to the default Pulseaudio server, ask for
  * information about Front so we can check if it is
  * already muted or not. */
  pa_context_connect(c, NULL, PA_CONTEXT_NOFLAGS, NULL);
  pa_context_set_state_callback(c, (pa_context_notify_cb_t) context_connected_cb, mainloop);
 
  /* Loop until quit is explictly require by the success_callback */
  pa_mainloop_run(mainloop, &retval);
 
  return retval;
}