payphone.agi

#!/usr/bin/perl

use Asterisk::AGI;
use Cwd "realpath";
use File::Basename;
use Time::HiRes;
use strict;

use constant {
	# where we live
	SOUND_DIR => dirname(realpath($0)),

	# outbound context we'll send calls to (since our current context should
	# only allow dialing 0 from the ATA)
	OUTBOUND_CONTEXT => "payphone-outbound",

	# timeout in seconds to wait to get a number or a coin
	TIMEOUT => 30,

	# amount required to make a call
	CALL_CENTS => 25,

	# numbers allowed to be dialed without requiring coins
	FREE_CALLS => qr/^(1?(8[02345678]{2})[0-9]{7}|911)/,

	# valid numbers which will immediately dial instead of timing out
	VALID_NUMBER => qr/^(1?[2-8][0-9]{9}|911)/,
};

my $AGI = new Asterisk::AGI;

my $last_activity = time();
my @last_coins;
my $inserted = 0;
my $dialed = "";

# generate dialtone while we wait for coins
$AGI->exec("Playtones", "dial");
my $dialtone = 1;

while (1) {
	my $dig = $AGI->wait_for_digit(1000);

	if ($dig >= 1) {
		if ($dig == ord('$')) {
			$AGI->verbose("got coin tone at " . Time::HiRes::time, 4);

			# shift out old coins
			my @new_coins;
			for (my $x = 0; $x <= $#last_coins; $x++) {
				if (Time::HiRes::time - $last_coins[$x] < 0.5) {
					push(@new_coins, $last_coins[$x]);
				}
			}
			@last_coins = @new_coins;

			push(@last_coins, Time::HiRes::time);

			# if we've heard 3 coin tones in close proximity, always count it
			# as 5 since we might not hear the other 2
			if ($#last_coins == 2) {
				$inserted += 15;
				$AGI->verbose("got 5-cent tone, counting as 15 cents (now "
					. $inserted . " cents)", 4);
				# provide some audible feedback that it's ok to make a call
				$AGI->exec("Playtones", "stutter");
			}
			elsif ($#last_coins > 2) {
				$AGI->verbose("ignoring 4th or 5th 5-cent tone of 25-cents "
					. "(still " . $inserted . " cents)", 4);
			}
			else {
				$inserted += 5;
				$AGI->verbose("got 5-cent tone (now " . $inserted . " cents)",
					4);
			}
		}
		else {
			if ($dialtone) {
				$AGI->exec("StopPlaytones", "dial");
				$dialtone = 0;
			}

			$dialed .= chr($dig);
			$AGI->verbose("dialed " . chr($dig) . " (now " . $dialed . ")", 4);
		}

		$last_activity = time();
	}

	my $elapsed = time() - $last_activity;

	if ($dialed =~ FREE_CALLS) {
		$AGI->verbose("connecting to " . $dialed . " (free call)", 1);
		dial($dialed);
		exit;
	}
	elsif ($dialed =~ VALID_NUMBER) {
		if ($inserted < CALL_CENTS) {
			$AGI->verbose("need " . CALL_CENTS . " cents to dial " . $dialed
				. ", have " . $inserted, 4);

			$AGI->stream_file(SOUND_DIR . "/not_deposited", "0");
		}
		else {
			$AGI->verbose("connecting to " . $dialed . " (inserted "
				. $inserted . " cents)", 1);
			dial($dialed);
		}
		exit;
	}
	elsif ($elapsed >= TIMEOUT) {
		$AGI->verbose("timed out waiting for coins or digits", 1);

		if ($dialed ne "") {
			$AGI->stream_file(SOUND_DIR . "/invalid_number", "0");
		}

		exit;
	}
}

sub dial {
	my ($number) = @_;

	$AGI->set_context(OUTBOUND_CONTEXT);
	$AGI->set_extension($dialed);
	$AGI->exec("Goto", "1");
}