# Selima Website Content Management System
# RelURI.pm: The converter to turn all URIs to relative URIs.

#  Copyright (c) 2003-2018 imacat.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

# Author: imacat <imacat@mail.imacat.idv.tw>
# First written: 2003-04-03

package Selima::RelURI;
use 5.008;
use strict;
use warnings;
use base qw(Exporter);
use vars qw(@EXPORT @EXPORT_OK);
BEGIN {
@EXPORT = qw(reluri);
@EXPORT_OK = @EXPORT;
# Prototype declaration
sub reluri($;$);
}

use Encode qw(encode decode is_utf8);
use URI qw();

use Selima::DataVars qw(:requri);

# reluri: Turn an absolute URI to a relative URI
sub reluri($;$) {
    local ($_, %_);
    my ($uri, $base, $encoded);
    ($uri, $base) = @_;
    
    # URI has bug with encode().  We get around it here.
    $encoded = 0;
    if (is_utf8($uri)) {
        $uri = encode("UTF-8", $uri);
        $encoded = 1;
    }
    # Default base to $REQUEST_FULLURI
    $base = defined $base?
                ($base =~ /^\//? new URI($REQUEST_HOSTPORT . $base):
                    new URI($base)):
                new URI($REQUEST_FULLURI);
    # Absolute path -- add the root difference and absolute it
    if ($uri =~ /^\//) {
        $uri = "$ROOT_DIFF$uri" ;
        $uri = new URI($uri);
        $uri = $uri->abs($REQUEST_FULLURI);
    } else {
        $uri = new URI($uri);
    }
    # Obtain the relative URI
    $uri = $uri->rel($base);
    
    $uri = $uri->canonical->as_string;
    # Fix it for my own style
    $uri =~ s/\/$// if $uri =~ /(?<![^\/])\.\.\/$/ || $uri =~ /(?<![^\/])\.\/$/;
    # URI has bug with encode().  We get around it here.
    $uri = decode("UTF-8", $uri) if $encoded;
    return $uri;
}

return 1;