#!/usr/bin/perl

use strict;
use warnings;
use Log::Log4perl qw(:easy);
use Getopt::Long qw(GetOptions);

my $log_file = "gsgd.log";
sub get_log_name { return $log_file; };
my $log_conf = q(
        log4perl.rootLogger              = INFO, LOG1, screen
        log4perl.appender.LOG1           = Log::Log4perl::Appender::File
        log4perl.appender.LOG1.filename  = sub { get_log_name(); }
        log4perl.appender.LOG1.mode      = append
        log4perl.appender.LOG1.layout    = Log::Log4perl::Layout::PatternLayout
        log4perl.appender.LOG1.layout.ConversionPattern = %d %p >> %m %n

        log4perl.appender.screen = Log::Log4perl::Appender::Screen
        log4perl.appender.screen.stderr = 0
        log4perl.appender.screen.layout = PatternLayout
        log4perl.appender.screen.layout.ConversionPattern = %d %p >> %m %n
);

Log::Log4perl::init(\$log_conf);
my $logger = get_logger();

my %args;
GetOptions(
	\%args,
	'gsg-cmd=s',
	'comms-file=s'
);

my $comm_file = "talk.gsgd";
my $LOCK_FILE = "lock.gsgd";
my $regen_cmd;

sub process_args() {
	
	if ( ! defined $args{'gsg-cmd'} || $args{'gsg-cmd'} eq "" ) {
		$logger->error("Must pass --gsg-cmd");
		exit 1;
	}

	$regen_cmd = $args{'gsg-cmd'};

	if ( defined $args{'comms-file'} ) {
		if ( ! -f $args{'comms-file'} ) {
			$logger->error("$args{'comms-file'} doesn't look like a regular file");
			exit 1;
		}

		if ( ! -w $args{'comms-file'} ) {
			$logger->error("$0 doesn't appear to have permission to write to $args{'comms-file'}");
			exit 1;
		}

		$comm_file = $args{'comms-file'};
	}

}

process_args();

sub create_lock() {

	$logger->debug("Creating lock file while operating");
	open(my $fh, ">", $LOCK_FILE) or die $logger->error("Couldn't create $LOCK_FILE");
	print $fh "";
	close $fh;

}

sub remove_lock() {

	$logger->debug("Removing lock file, not operating");
	unlink($LOCK_FILE) or die $logger->error("Couldn't unlink $LOCK_FILE");

}

sub check_lock() {

	if ( -f $LOCK_FILE ) {
		$logger->info("Found lock file");
		sleeper(5);
		if ( -f $LOCK_FILE ) {
			die $logger->error("$LOCK_FILE still exists even after waiting, why?");
		}
	}

}
	

sub remove_instruction($) {

	my $instruction_to_remove = shift;

	$logger->debug("Removing $instruction_to_remove instruction");
	$logger->debug("Opening $comm_file for writing");
	open(my $fh, ">", $comm_file);
	my @lines = $fh;
	foreach my $line ( @lines ) {
		# This is bad TODO
		print $fh "$line\n" unless ( $line =~ m/$instruction_to_remove/ || $line =~ m/GLOB/);
	}
	$logger->debug("Closing $comm_file");
	close $fh;

}

sub regen() {

	$logger->info("Regening site");
	system("$regen_cmd") == 0
		or die $logger->error("Failed to exec $regen_cmd !");
	check_lock();
	create_lock();
	remove_instruction("Regen");
	remove_lock();

}

sub gsgd_exit() {

	check_lock();
	create_lock();
	remove_instruction("Exit");
	remove_lock();
	exit 0;

}

sub sleeper($) {

	my $sleep_time = shift;
	$logger->debug("Sleeping $sleep_time seconds");
	sleep $sleep_time;

}

sub open_comms() {

	$logger->debug("Opening $comm_file for reading");
	open(my $fh, "<", $comm_file) or die $logger->error("Could not open $comm_file for reading");
	my @instructions = <$fh>;
	$logger->debug("Closing $comm_file");
	close $fh;

	foreach my $line ( @instructions ) {
		chomp $line;
		if ( $line =~ m/^Regen$/ ) {
			$logger->info("Got $line instruction");
			regen();
		} elsif ( $line =~ m/^Exit$/ ) {
			$logger->info("Got $line instruction");
			gsgd_exit();
		} else {
			$logger->error("Unrecognized instruction $line");
		}
	}

}

$logger->info("Starting");
while() {

	sleeper(1);
	open_comms();

}