#!/usr/bin/perl

@ARGV >= 1 || die "Usage: $0 <po directory> [<file pattern>]\n";

my $source  = shift @ARGV;
my $pattern = shift @ARGV || '*.po';

sub read_header
{
	my $file = shift || return;
	local $/;

	open P, "< $file" || die "open(): $!";
	my $data = readline P;
	close P;

	$data =~ /
		^ (
		msgid \s "" \n
		msgstr \s "" \n
		(?: " [^\n]+ " \n )+
		\n )
	/mx;

	return $1;
}

sub write_header
{
	my $file = shift || return;
	my $head = shift || return;
	local $/;

	open P, "< $file" || die "open(): $!";
	my $data = readline P;
	close P;

	$data =~ s/
		^ (
		msgid \s "" \n
		msgstr \s "" \n
		(?: " [^\n]+ " \n )+
		\n )
	/$head/mx;

	open P, "> $file" || die "open(): $!";
	print P $data;
	close P;
}

if( open F, "find $source -type f -name '$pattern' |" )
{
	while( chomp( my $file = readline F ) )
	{
		my ( $basename ) = $file =~ m{.+/([^/]+)\.po$};
		
		if( -f "$source/templates/$basename.pot" )
		{
			my $head = read_header($file);

			printf "Updating %-40s", $file;
			system("msgmerge", "-U", "-N", $file, "$source/templates/$basename.pot");

			write_header($file, $head);
		}
	}

	close F;
}