Asterisk Hunting Groups for incoming calls

;get the next available extension from hunting group 100 (command g)
exten => 100,n,agi,hunting.php|100|g
exten => 100,n,dial,SIP/${HUNTEXTEN}
exten => 100,n,hangup

;add current extension from hunting group (command a)
exten => 108,1,answer
exten => 108,n,set,HUNTGROUP=100
exten => 108,n,agi,hunting.php|${HUNTGROUP}|a|${CALLERID(num)}
exten => 108,n,playback,hunting-add
exten => 108,n,playback,hunting-yourextension
exten => 108,n,playback,hunting-togroup
exten => 108,n,saydigits,${HUNTGROUP}
exten => 108,n,hangup

;remove current extension from hunting group (command r)
exten => 109,1,answer
exten => 109,n,set,HUNTGROUP=100
exten => 109,n,agi,hunting.php|${HUNTGROUP}|r|${CALLERID(num)}
exten => 109,n,playback,hunting-remove
exten => 109,n,playback,hunting-yourextension
exten => 109,n,playback,hunting-fromgroup
exten => 109,n,saydigits,${HUNTGROUP}
exten => 109,n,hangup

;add given extension from hunting group (command a)
exten => 208,1,answer
exten => 208,n,set,HUNTGROUP=100
exten => 208,n,set,HUNTEXTEN=120
exten => 208,n,agi,hunting.php|${HUNTGROUP}|a|${HUNTEXTEN}
exten => 208,n,playback,hunting-add
exten => 208,n,saydigits,${HUNTEXTEN}
exten => 208,n,playback,hunting-togroup
exten => 208,n,saydigits,${HUNTGROUP}
exten => 208,n,hangup

;remove given extension from hunting group (command r)
exten => 209,1,answer
exten => 209,n,set,HUNTGROUP=100
exten => 209,n,set,HUNTEXTEN=120
exten => 209,n,agi,hunting.php|${HUNTGROUP}|r|${HUNTEXTEN}
exten => 209,n,playback,hunting-remove
exten => 209,n,saydigits,${HUNTEXTEN}
exten => 209,n,playback,hunting-fromgroup
exten => 209,n,saydigits,${HUNTGROUP}
exten => 209,n,hangup

#!/usr/bin/php -q
<?php
//hunting groups for asterisk
//copyright (c) 2007 felix simmet

function loadgroup($group) {
	$filename="$huntingfilename$group";		//build filename
	if(file_exists($filename)) {		//make sure file exists
		$filehandler=fopen($filename,"r");		//open file for read
		while(!feof($filehandler)) {			//read while not end of file
			$line=fgets($filehandler);			//read line
			$line=trim($line);			//remove trailing spaces & CR & LF
			if($line!="") {			//if line is not empty
			$extensions[]=$line;			//add extension
			}
		}
	fclose($filehandler);			//close file
	}
}

function savegroup($group) {
	$filename="$huntingfilename$group";			//build filename
	$filehandler=fopen($filename,"w");			//open file for write
	foreach($extensions as $key => $value) {			//work with every item

		if($value!="") {			//if value is not empty
    	fwrite($filehandler,$value . "\n");			//write extension + CR
    }

	}
	fclose($filehandler);			//close file
}

function addextension($extension) {
	if(!in_array($extension,$extensions)) {			//extension is not in extensions-list
		$extensions[]=$extension;			//add to extensions list
		return true;			//quit function and return true
	} else {			//not in list ->
		return false;			//quit function and return false
	}
}

function removeextension($extension) {
	$key=array_search($extension,$extensions);
	if($key!==false) {			//extension was found
		$extensions[$key]="";			//remove extensions (set empty)
	} else {			//extension not found
		return false;
	}
}

function getnextextension() {
	$nextextension=$extensions[0];			//get first extension
	array_shift($extensions);			//remove first extension
	$extensions[]=$nextextension;			//add extension at the end
	return $nextextension;			//returns next extension
}

# --- settings
#the filename where the extensions are stored (group number will be added at the end of the filename)
$huntingfilename="/tmp/huntinggroup-";

# --- internal variables
$extensions=array();

# --- set some php parameters for agi interface
ob_implicit_flush(false);
set_time_limit(30);
error_reporting(0);

# --- open stdin & stdout for agi communications
$stdin=fopen("php://stdin", "r");
$stdout=fopen("php://stdout", "w");
    
# --- get agi variables
while(!feof($stdin)) {
	$temp=fgets($stdin);
	$temp=str_replace("\n","",$temp);
	$s=explode(":",$temp);
	$agivar[$s[0]]=trim($s[1]);
	if(($temp=="") || ($temp=="\n"))
	{
		break;
	}
} 

# --- get variables from asterisk
$group=$argv[1];
$command=$argv[2];
$extension=$argv[3];

if(($group!="") && ($command!="")) {	//enough arguments???
	loadgroup($group);			//load current group settings
	
		if($command=="g") {			//get next extension -> put to variable HUNTEXT
			$huntext=getnextextension();
			fwrite($stdout,"SET VARIABLE HUNTEXTEN $huntext\n");	//write agi command
		}

	if(($extension!="")) {			//enough arguments???
		if($command=="a") {			//add given extension
			addextension($extension);
		}
		
		if($command=="r") {		//remove given extension
			removeextension($extension);
		}
	}
	
	savegroup($group);		//save group settings
}

# --- close all files
fclose($stdin);
fclose($stdout);
    
exit;
?>

#!/bin/sh
echo "Adding" | text2wave -F 8000 > /var/lib/asterisk/sounds/hunting-add.wav
echo "Removing" | text2wave -F 8000 > /var/lib/asterisk/sounds/hunting-remove.wav
echo "your extension" | text2wave -F 8000 > /var/lib/asterisk/sounds/hunting-yourextension.wav
echo "to hunting group" | text2wave -F 8000 > /var/lib/asterisk/sounds/hunting-togroup.wav
echo "from hunting group" | text2wave -F 8000 > /var/lib/asterisk/sounds/hunting-fromgroup.wav
exit 0