#!/usr/bin/perl
package IkiWiki::Plugin::conditional;

use warnings;
use strict;
use IkiWiki 3.00;

sub import {
	hook(type => "getsetup", id => "conditional", call => \&getsetup);
	hook(type => "preprocess", id => "if", call => \&preprocess_if);
}

sub getsetup {
	return
		plugin => {
			safe => 1,
			rebuild => undef,
			section => "widget",
		},
}

sub preprocess_if (@) {
	my %params=@_;

	foreach my $param (qw{test then}) {
		if (! exists $params{$param}) {
			error sprintf(gettext('%s parameter is required'), $param);
		}
	}

	my $result=0;
	if ((exists $params{all} && ! IkiWiki::yesno($params{all})) ||
	    # An optimisation to avoid needless looping over every page
	    # for simple uses of some of the tests.
	    $params{test} =~ /^([\s\!()]*((enabled|sourcepage|destpage|included)\([^)]*\)|(and|or))[\s\!()]*)+$/) {
		add_depends($params{page}, "($params{test}) and $params{page}");
		$result=pagespec_match($params{page}, $params{test},
				location => $params{page},
				sourcepage => $params{page},
				destpage => $params{destpage});
	}
	else {
		$result=pagespec_match_list($params{page}, $params{test},
			# stop after first match
			num => 1,
			sourcepage => $params{page},
			destpage => $params{destpage},
		);
	}

	my $ret;
	if ($result) {
		$ret=$params{then};
	}
	elsif (exists $params{else}) {
		$ret=$params{else};
	}
	else {
		$ret="";
	}
	return IkiWiki::preprocess($params{page}, $params{destpage}, $ret);
}

package IkiWiki::PageSpec;

sub match_enabled ($$;@) {
	shift;
	my $plugin=shift;
	
	# test if the plugin is enabled
	if (UNIVERSAL::can("IkiWiki::Plugin::".$plugin, "import")) {
		return IkiWiki::SuccessReason->new("$plugin is enabled");
	}
	else {
		return IkiWiki::FailReason->new("$plugin is not enabled");
	}
}

sub match_sourcepage ($$;@) {
	shift;
	my $glob=shift;
	my %params=@_;
	
	$glob=derel($glob, $params{location});

	return IkiWiki::FailReason->new("cannot match sourcepage") unless exists $params{sourcepage};
	if (match_glob($params{sourcepage}, $glob, @_)) {
		return IkiWiki::SuccessReason->new("sourcepage matches $glob");
	}
	else {
		return IkiWiki::FailReason->new("sourcepage does not match $glob");
	}
}

sub match_destpage ($$;@) {
	shift;
	my $glob=shift;
	my %params=@_;
	
	$glob=derel($glob, $params{location});

	return IkiWiki::FailReason->new("cannot match destpage") unless exists $params{destpage};
	if (match_glob($params{destpage}, $glob, @_)) {
		return IkiWiki::SuccessReason->new("destpage matches $glob");
	}
	else {
		return IkiWiki::FailReason->new("destpage does not match $glob");
	}
}

sub match_included ($$;@) {
	shift;
	shift;
	my %params=@_;

	return IkiWiki::FailReason->new("cannot match included") unless exists $params{sourcepage} && exists $params{destpage};
	if ($params{sourcepage} ne $params{destpage}) {
		return IkiWiki::SuccessReason->new("page $params{sourcepage} is included");
	}
	else {
		return IkiWiki::FailReason->new("page $params{sourcepage} is not included");
	}
}

1