<?php
/**
 *
 * Copyright 2004, Evan Prodromou <evan@wikitravel.org>.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 *
 * @author Evan Prodromou <evan@wikitravel.org>
 * @file
 */

abstract class RdfMetaData {
	const RDF_TYPE_PREFS = 'application/rdf+xml,text/xml;q=0.7,application/xml;q=0.5,text/rdf;q=0.1';

	/**
	 * Constructor
	 * @param $article Article object
	 */
	public function __construct( Page $article ) {
		$this->mArticle = $article;
	}

	public abstract function show();

	protected function setup() {
		global $wgOut, $wgRequest;

		$httpaccept = isset( $_SERVER['HTTP_ACCEPT'] ) ? $_SERVER['HTTP_ACCEPT'] : null;
		$rdftype = wfNegotiateType( wfAcceptToPrefs( $httpaccept ), wfAcceptToPrefs( self::RDF_TYPE_PREFS ) );

		if( !$rdftype ){
			throw new HttpError( 406, wfMessage( 'notacceptable' ) );
		}

		$wgOut->disable();
		$wgRequest->response()->header( "Content-type: {$rdftype}; charset=utf-8" );
		$wgOut->sendCacheControl();
		return true;
	}

	protected function reallyFullUrl() {
		return $this->mArticle->getTitle()->getFullURL();
	}

	protected function basics() {
		global $wgLanguageCode, $wgSitename;

		$this->element( 'title', $this->mArticle->getTitle()->getText() );
		$this->pageOrString( 'publisher', wfMsg( 'aboutpage' ), $wgSitename );
		$this->element( 'language', $wgLanguageCode );
		$this->element( 'type', 'Text' );
		$this->element( 'format', 'text/html' );
		$this->element( 'identifier', $this->reallyFullUrl() );
		$this->element( 'date', $this->date( $this->mArticle->getTimestamp() ) );

		$lastEditor = User::newFromId( $this->mArticle->getUser() );
		$this->person( 'creator', $lastEditor );

		foreach( $this->mArticle->getContributors() as $user ){
			$this->person( 'contributor', $user );
		}

		$this->rights();
	}

	protected function element( $name, $value ) {
		$value = htmlspecialchars( $value );
		print "\t\t<dc:{$name}>{$value}</dc:{$name}>\n";
	}

	protected function date($timestamp) {
		return substr($timestamp, 0, 4) . '-'
		  . substr($timestamp, 4, 2) . '-'
		  . substr($timestamp, 6, 2);
	}

	protected function pageOrString( $name, $page, $str ) {
		if( $page instanceof Title ) {
			$nt = $page;
		} else {
			$nt = Title::newFromText( $page );
		}

		if( !$nt || $nt->getArticleID() == 0 ){
			$this->element( $name, $str );
		} else {
			$this->page( $name, $nt );
		}
	}

	/**
	 * @param $name string
	 * @param $title Title
	 */
	protected function page( $name, $title ) {
		$this->url( $name, $title->getFullUrl() );
	}

	protected function url($name, $url) {
		$url = htmlspecialchars( $url );
		print "\t\t<dc:{$name} rdf:resource=\"{$url}\" />\n";
	}

	protected function person( $name, User $user ) {
		if( $user->isAnon() ){
			$this->element( $name, wfMsgExt( 'anonymous', array( 'parsemag' ), 1 ) );
		} else {
			$real = $user->getRealName();
			if( $real ) {
				$this->element( $name, $real );
			} else {
				$userName = $user->getName();
				$this->pageOrString( $name, $user->getUserPage(), wfMsgExt( 'siteuser', 'parsemag', $userName, $userName ) );
			}
		}
	}

	/**
	 * Takes an arg, for future enhancement with different rights for
	 * different pages.
	 */
	protected function rights() {
		global $wgRightsPage, $wgRightsUrl, $wgRightsText;

		if( $wgRightsPage && ( $nt = Title::newFromText( $wgRightsPage ) )
			&& ($nt->getArticleID() != 0)) {
			$this->page('rights', $nt);
		} elseif( $wgRightsUrl ){
			$this->url('rights', $wgRightsUrl);
		} elseif( $wgRightsText ){
			$this->element( 'rights', $wgRightsText );
		}
	}

	protected function getTerms( $url ){
		global $wgLicenseTerms;

		if( $wgLicenseTerms ){
			return $wgLicenseTerms;
		} else {
			$known = $this->getKnownLicenses();
			if( isset( $known[$url] ) ) {
				return $known[$url];
			} else {
				return array();
			}
		}
	}

	protected function getKnownLicenses() {
		$ccLicenses = array('by', 'by-nd', 'by-nd-nc', 'by-nc',
							'by-nc-sa', 'by-sa');
		$ccVersions = array('1.0', '2.0');
		$knownLicenses = array();

		foreach ($ccVersions as $version) {
			foreach ($ccLicenses as $license) {
				if( $version == '2.0' && substr( $license, 0, 2) != 'by' ) {
					# 2.0 dropped the non-attribs licenses
					continue;
				}
				$lurl = "http://creativecommons.org/licenses/{$license}/{$version}/";
				$knownLicenses[$lurl] = explode('-', $license);
				$knownLicenses[$lurl][] = 're';
				$knownLicenses[$lurl][] = 'di';
				$knownLicenses[$lurl][] = 'no';
				if (!in_array('nd', $knownLicenses[$lurl])) {
					$knownLicenses[$lurl][] = 'de';
				}
			}
		}

		/* Handle the GPL and LGPL, too. */

		$knownLicenses['http://creativecommons.org/licenses/GPL/2.0/'] =
		  array('de', 're', 'di', 'no', 'sa', 'sc');
		$knownLicenses['http://creativecommons.org/licenses/LGPL/2.1/'] =
		  array('de', 're', 'di', 'no', 'sa', 'sc');
		$knownLicenses['http://www.gnu.org/copyleft/fdl.html'] =
		  array('de', 're', 'di', 'no', 'sa', 'sc');

		return $knownLicenses;
	}
}

