<?php
/**
 *
 *
 * Created on Sep 19, 2006
 *
 * Copyright © 2006 Yuri Astrakhan "<Firstname><Lastname>@gmail.com"
 *
 * 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.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 */

/**
 * API XML output formatter
 * @ingroup API
 */
class ApiFormatXml extends ApiFormatBase {

	private $mRootElemName = 'api';
	public static $namespace = 'http://www.mediawiki.org/xml/api/';
	private $mIncludeNamespace = false;
	private $mXslt = null;

	public function getMimeType() {
		return 'text/xml';
	}

	public function getNeedsRawData() {
		return true;
	}

	public function setRootElement( $rootElemName ) {
		$this->mRootElemName = $rootElemName;
	}

	public function execute() {
		$params = $this->extractRequestParams();
		$this->mIncludeNamespace = $params['includexmlnamespace'];
		$this->mXslt = $params['xslt'];

		$this->printText( '<?xml version="1.0"?>' );
		if ( !is_null( $this->mXslt ) ) {
			$this->addXslt();
		}
		if ( $this->mIncludeNamespace ) {
			// If the result data already contains an 'xmlns' namespace added
			// for custom XML output types, it will override the one for the
			// generic API results.
			// This allows API output of other XML types like Atom, RSS, RSD.
			$data = $this->getResultData() + array( 'xmlns' => self::$namespace );
		} else {
			$data = $this->getResultData();
		}

		$this->printText(
			self::recXmlPrint( $this->mRootElemName,
				$data,
				$this->getIsHtml() ? - 2 : null
			)
		);
	}

	/**
	 * This method takes an array and converts it to XML.
	 *
	 * There are several noteworthy cases:
	 *
	 * If array contains a key '_element', then the code assumes that ALL
	 * other keys are not important and replaces them with the
	 * value['_element'].
	 *
	 * @par Example:
	 * @verbatim
	 * name='root', value = array( '_element'=>'page', 'x', 'y', 'z')
	 * @endverbatim
	 * creates:
	 * @verbatim
	 * <root>  <page>x</page>  <page>y</page>  <page>z</page> </root>
	 * @endverbatim
	 *
	 * If any of the array's element key is '*', then the code treats all
	 * other key->value pairs as attributes, and the value['*'] as the
	 * element's content.
	 *
	 * @par Example:
	 * @verbatim
	 * name='root', value = array( '*'=>'text', 'lang'=>'en', 'id'=>10)
	 * @endverbatim
	 * creates:
	 * @verbatim
	 * <root lang='en' id='10'>text</root>
	 * @endverbatim
	 *
	 * Finally neither key is found, all keys become element names, and values
	 * become element content.
	 *
	 * @note The method is recursive, so the same rules apply to any
	 * sub-arrays.
	 *
	 * @param $elemName
	 * @param $elemValue
	 * @param $indent
	 *
	 * @return string
	 */
	public static function recXmlPrint( $elemName, $elemValue, $indent ) {
		$retval = '';
		if ( !is_null( $indent ) ) {
			$indent += 2;
			$indstr = "\n" . str_repeat( ' ', $indent );
		} else {
			$indstr = '';
		}
		$elemName = str_replace( ' ', '_', $elemName );

		if ( is_array( $elemValue ) ) {
			if ( isset( $elemValue['*'] ) ) {
				$subElemContent = $elemValue['*'];
				unset( $elemValue['*'] );

				// Add xml:space="preserve" to the
				// element so XML parsers will leave
				// whitespace in the content alone
				$elemValue['xml:space'] = 'preserve';
			} else {
				$subElemContent = null;
			}

			if ( isset( $elemValue['_element'] ) ) {
				$subElemIndName = $elemValue['_element'];
				unset( $elemValue['_element'] );
			} else {
				$subElemIndName = null;
			}

			$indElements = array();
			$subElements = array();
			foreach ( $elemValue as $subElemId => & $subElemValue ) {
				if ( is_int( $subElemId ) ) {
					$indElements[] = $subElemValue;
					unset( $elemValue[$subElemId] );
				} elseif ( is_array( $subElemValue ) ) {
					$subElements[$subElemId] = $subElemValue;
					unset( $elemValue[$subElemId] );
				}
			}

			if ( is_null( $subElemIndName ) && count( $indElements ) ) {
				ApiBase::dieDebug( __METHOD__, "($elemName, ...) has integer keys without _element value. Use ApiResult::setIndexedTagName()." );
			}

			if ( count( $subElements ) && count( $indElements ) && !is_null( $subElemContent ) ) {
				ApiBase::dieDebug( __METHOD__, "($elemName, ...) has content and subelements" );
			}

			if ( !is_null( $subElemContent ) ) {
				$retval .= $indstr . Xml::element( $elemName, $elemValue, $subElemContent );
			} elseif ( !count( $indElements ) && !count( $subElements ) ) {
				$retval .= $indstr . Xml::element( $elemName, $elemValue );
			} else {
				$retval .= $indstr . Xml::element( $elemName, $elemValue, null );

				foreach ( $subElements as $subElemId => & $subElemValue ) {
					$retval .= self::recXmlPrint( $subElemId, $subElemValue, $indent );
				}

				foreach ( $indElements as &$subElemValue ) {
					$retval .= self::recXmlPrint( $subElemIndName, $subElemValue, $indent );
				}

				$retval .= $indstr . Xml::closeElement( $elemName );
			}
		} elseif ( !is_object( $elemValue ) ) {
			// to make sure null value doesn't produce unclosed element,
			// which is what Xml::element( $elemName, null, null ) returns
			if ( $elemValue === null ) {
				$retval .= $indstr . Xml::element( $elemName );
			} else {
				$retval .= $indstr . Xml::element( $elemName, null, $elemValue );
			}
		}
		return $retval;
	}

	function addXslt() {
		$nt = Title::newFromText( $this->mXslt );
		if ( is_null( $nt ) || !$nt->exists() ) {
			$this->setWarning( 'Invalid or non-existent stylesheet specified' );
			return;
		}
		if ( $nt->getNamespace() != NS_MEDIAWIKI ) {
			$this->setWarning( 'Stylesheet should be in the MediaWiki namespace.' );
			return;
		}
		if ( substr( $nt->getText(), - 4 ) !== '.xsl' ) {
			$this->setWarning( 'Stylesheet should have .xsl extension.' );
			return;
		}
		$this->printText( '<?xml-stylesheet href="' . htmlspecialchars( $nt->getLocalURL( 'action=raw' ) ) . '" type="text/xsl" ?>' );
	}

	public function getAllowedParams() {
		return array(
			'xslt' => null,
			'includexmlnamespace' => false,
		);
	}

	public function getParamDescription() {
		return array(
			'xslt' => 'If specified, adds <xslt> as stylesheet. This should be a wiki page '
				. 'in the MediaWiki namespace whose page name ends with ".xsl"',
			'includexmlnamespace' => 'If specified, adds an XML namespace'
		);
	}

	public function getDescription() {
		return 'Output data in XML format' . parent::getDescription();
	}
}