#!/usr/bin/perl

# Minimal PerlDaemon (c) 2011 Paul Buetow

use strict;
use warnings;

use Shell qw(mv);
use POSIX qw(setsid strftime);

use PerlDaemon::Logger;
use PerlDaemon::RunModules;

$| = 1;

sub trimstr (@) {
	my @str = 
		@_;

	for (@str) {
		chomp;
		s/^[\t\s]+//;
		s/[\t\s]+$//;
	}

	return @str;
}

sub trunc ($) {
	my $file = shift;
	open my $fh, ">$file" or die "Can't write $file: $!\n";
	print $fh '';
	close $fh;
}

sub checkpid ($) {
	my $conf = shift;
	my $pidfile = $conf->{'daemon.pidfile'};
	my $logger = $conf->{logger};

	trunc $pidfile unless -f $pidfile;

	open my $fh, $pidfile or $logger->err("Can't read pidfile $pidfile: $!");
	my ($pid) = <$fh>;
	close $fh;

	if (defined $pid) {
		chomp $pid;
		$logger->err("Process with pid $pid already running") if 0 < int $pid && kill 0, $pid;
	}
}

sub writepid ($) {
	my $conf = shift;
	my $logger = $conf->{logger};

	my $pidfile = $conf->{'daemon.pidfile'};

	open my $fh, ">$pidfile" or $logger->err("Can't write pidfile: $!");
	print $fh "$$\n";
	close $fh;
}


sub readconf ($) {
	my $conffile = shift;

	open my $fh, $conffile or die "Can't read $conffile\n";
	my %conf;
	
	while (<$fh>) {
		next if /^[\t\w]+#/;
		s/#.*//;

		my ($key, $val) = trimstr split '=', $_, 2;
		next unless defined $val;

		$conf{$key} = $val;	
	}

	close $fh;

	# Check
	my $msg = 'Missing property:';

	foreach (qw(wd loopinterval alivefile pidfile logfile)) {
		my $key = "daemon.$_";
		die "$msg $key\n" unless exists $conf{$key};
	}

	return \%conf;
}

sub daemonize ($) {
	my $conf = shift;
	my $logger = $conf->{logger};
	$logger->logmsg('Daemonizing...');

	chdir $conf->{'daemon.wd'} or $logger->err("Can't chdir to wd: $!");

	my $msg = 'Can\'t read /dev/null:';

	open STDIN, '>/dev/null' or $logger->err("$msg $!");
	open STDOUT, '>/dev/null' or $logger->err("$msg $!");
	open STDERR, '>/dev/null' or $logger->err("$msg $!");

	defined (my $pid = fork) or $logger->err("Can't fork: $!");	
	exit if $pid;
	
	setsid or $logger->err("Can't start a new session: $!");

	writepid $conf;
	$logger->logmsg('Daemonizing completed');
}

sub sighandlers ($) {
	my $conf = shift;
	my $logger = $conf->{logger};

	$SIG{TERM} = sub {
		# On shutdown
		$logger->logmsg('Received SIGTERM. Shutting down....');
		unlink $conf->{'daemon.pidfile'} if -f $conf->{'daemon.pidfile'};
		exit 0;
	};

	$SIG{HUP} = sub {
		# On logrotate
		$logger->logmsg('Received SIGHUP.');
		$logger->rotatelog();
	};
}

sub prestartup ($) {
	my $conf = shift;
	checkpid $conf;
}

sub alive ($) {
	my $conf = shift;
}

sub daemonloop ($) {
	my $conf = shift;
	my $rmodule = PerlDaemon::RunModules->new($conf);
	my $loopinterval = $conf->{'daemon.loopinterval'};

	my $loop = shift;
	for (my $i = 1;;++$i) {
		$rmodule->do();
		sleep $loopinterval;
		alive $conf;
	}
}

my $conf = readconf shift;
$conf->{logger} = PerlDaemon::Logger->new($conf);

prestartup $conf;
daemonize $conf;
sighandlers $conf;
daemonloop $conf;