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/* Copyright (c) 2014, Aaron Herting 'qwertos' <aaron@herting.cc>        */
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/**
 * @defgroup dtmfio dtmfio
 *
 * DTMF input/output module
 *
 *
 * # DTMFIO Module
 *
 * ## Description
 *
 * Writes received dtmf button presses to a FIFO located at /tmp/dtmf.out.
 *
 * Also, will write an 'E' when a call is established and an 'F' when the
 * call is finished.
 *
 * ## To Do
 *
 * +   Proper error handling
 * +   Using a dtmf.in file, be able to send DTMF signals
 * +   Use a filename specified by the user in the config file
 * +   Clean up build output so there aren't errors regarding unused vars
 */

#include <unistd.h>
#include <stdio.h>
#include <re.h>
#include <baresip.h>
#include <sys/types.h>
#include <sys/stat.h>


static FILE *fd;
static const char *DTMF_OUT = "/tmp/dtmf.out";


static void dtmf_handler(struct call *call, char key, void *arg)
{
	(void)call;
	(void)arg;

	if ( key != 0 ) {
		fprintf(fd, "%c", key);
		fflush(fd);
	}
}


static void ua_event_handler(struct ua *ua,
			     enum ua_event ev,
			     struct call *call,
			     const char *prm,
			     void *arg )
{
	(void)ua;
	(void)prm;
	(void)arg;

	if ( ev == UA_EVENT_CALL_ESTABLISHED ) {
		fprintf(fd, "E");
		fflush(fd);
		call_set_handlers( call, NULL, dtmf_handler, NULL);
	}

	if (ev == UA_EVENT_CALL_CLOSED ) {
		fprintf(fd, "F");
		fflush(fd);
	}
}


static int module_init(void)
{
	if ( mkfifo( DTMF_OUT, S_IWUSR | S_IRUSR ) ) {
		int err = errno;
		error("Creation of the FIFO errored."
		      " This might cause issues. (%m)\n", err);
		return err;
	}

	fd = fopen( DTMF_OUT , "w+" );

	if ( fd == 0 ){
		error("Opening of the FIFO errored."
		      " This might cause issues.\n");
	}

	uag_event_register( ua_event_handler, NULL );

	return 0;
}


static int module_close(void)
{
	uag_event_unregister(ua_event_handler);

	fclose(fd);

	unlink(DTMF_OUT);

	return 0;
}


const struct mod_export DECL_EXPORTS(dtmfio) = {
	"dtmfio",
	"application",
	module_init,
	module_close
};