#!/usr/bin/perl -i
use warnings;
use strict;

my $regex = qr{
	(\\?)		# 1: escape?
	\[\[(!?)	# directive open; 2: optional prefix
	([-\w]+)	# 3: command
	(		# 4: the parameters (including initial whitespace)
	\s+
		(?:
			(?:[-\w]+=)?		# named parameter key?
			(?:
				""".*?"""	# triple-quoted value
				|
				"[^"]+"		# single-quoted value
				|
				[^\s\]]+	# unquoted value
			)
			\s*			# whitespace or end
						# of directive
		)
	*)		# 0 or more parameters
	\]\]		# directive closed
}sx;

sub handle_directive {
	my $escape = shift;
	my $prefix = shift;
	my $directive = shift;
	my $args = shift;

	if (length $escape) {
		return "${escape}[[${prefix}${directive}${args}]]"
	}
	if ($directive =~ m/^(if|more|table|template|toggleable)$/) {
		$args =~ s{$regex}{handle_directive($1, $2, $3, $4)}eg;
	}
	return "[[!${directive}${args}]]"
}

sub prefix_directives {
	$/=undef; # process whole files at once
	
	while (<>) {
		s{$regex}{handle_directive($1, $2, $3, $4)}eg;
		print;
	}
}

sub usage {
	print STDERR "Usage: ikiwiki-transition type file ...\n";
	print STDERR "Currently supported transition types:\n";
	print STDERR "	prefix_directives\n";
	exit 1;
}

usage() unless @ARGV;

my $mode=shift;
if ($mode eq 'prefix_directives') {
	prefix_directives(@ARGV);
}
else {
	usage();
}