<?php
/**
 * Methods to generate XML.
 *
 * 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
 */

/**
 * Module of static functions for generating XML
 */
class Xml {
	/**
	 * Format an XML element with given attributes and, optionally, text content.
	 * Element and attribute names are assumed to be ready for literal inclusion.
	 * Strings are assumed to not contain XML-illegal characters; special
	 * characters (<, >, &) are escaped but illegals are not touched.
	 *
	 * @param string $element element name
	 * @param array $attribs Name=>value pairs. Values will be escaped.
	 * @param string $contents NULL to make an open tag only; '' for a contentless closed tag (default)
	 * @param bool $allowShortTag whether '' in $contents will result in a contentless closed tag
	 * @return string
	 */
	public static function element( $element, $attribs = null, $contents = '', $allowShortTag = true ) {
		$out = '<' . $element;
		if ( !is_null( $attribs ) ) {
			$out .= self::expandAttributes( $attribs );
		}
		if ( is_null( $contents ) ) {
			$out .= '>';
		} else {
			if ( $allowShortTag && $contents === '' ) {
				$out .= ' />';
			} else {
				$out .= '>' . htmlspecialchars( $contents ) . "</$element>";
			}
		}
		return $out;
	}

	/**
	 * Given an array of ('attributename' => 'value'), it generates the code
	 * to set the XML attributes : attributename="value".
	 * The values are passed to Sanitizer::encodeAttribute.
	 * Return null if no attributes given.
	 * @param array $attribs of attributes for an XML element
	 * @throws MWException
	 * @return null|string
	 */
	public static function expandAttributes( $attribs ) {
		$out = '';
		if ( is_null( $attribs ) ) {
			return null;
		} elseif ( is_array( $attribs ) ) {
			foreach ( $attribs as $name => $val ) {
				$out .= " {$name}=\"" . Sanitizer::encodeAttribute( $val ) . '"';
			}
			return $out;
		} else {
			throw new MWException( 'Expected attribute array, got something else in ' . __METHOD__ );
		}
	}

	/**
	 * Format an XML element as with self::element(), but run text through the
	 * $wgContLang->normalize() validator first to ensure that no invalid UTF-8
	 * is passed.
	 *
	 * @param $element String:
	 * @param array $attribs Name=>value pairs. Values will be escaped.
	 * @param string $contents NULL to make an open tag only; '' for a contentless closed tag (default)
	 * @return string
	 */
	public static function elementClean( $element, $attribs = array(), $contents = '' ) {
		global $wgContLang;
		if ( $attribs ) {
			$attribs = array_map( array( 'UtfNormal', 'cleanUp' ), $attribs );
		}
		if ( $contents ) {
			wfProfileIn( __METHOD__ . '-norm' );
			$contents = $wgContLang->normalize( $contents );
			wfProfileOut( __METHOD__ . '-norm' );
		}
		return self::element( $element, $attribs, $contents );
	}

	/**
	 * This opens an XML element
	 *
	 * @param string $element name of the element
	 * @param array $attribs of attributes, see Xml::expandAttributes()
	 * @return string
	 */
	public static function openElement( $element, $attribs = null ) {
		return '<' . $element . self::expandAttributes( $attribs ) . '>';
	}

	/**
	 * Shortcut to close an XML element
	 * @param string $element element name
	 * @return string
	 */
	public static function closeElement( $element ) {
		return "</$element>";
	}

	/**
	 * Same as Xml::element(), but does not escape contents. Handy when the
	 * content you have is already valid xml.
	 *
	 * @param string $element element name
	 * @param array $attribs of attributes
	 * @param string $contents content of the element
	 * @return string
	 */
	public static function tags( $element, $attribs = null, $contents ) {
		return self::openElement( $element, $attribs ) . $contents . "</$element>";
	}

	/**
	 * Build a drop-down box for selecting a namespace
	 *
	 * @param $selected Mixed: Namespace which should be pre-selected
	 * @param $all Mixed: Value of an item denoting all namespaces, or null to omit
	 * @param $element_name String: value of the "name" attribute of the select tag
	 * @param string $label optional label to add to the field
	 * @return string
	 * @deprecated since 1.19
	 */
	public static function namespaceSelector( $selected = '', $all = null, $element_name = 'namespace', $label = null ) {
		wfDeprecated( __METHOD__, '1.19' );
		return Html::namespaceSelector( array(
			'selected' => $selected,
			'all' => $all,
			'label' => $label,
		), array(
			'name' => $element_name,
			'id' => 'namespace',
			'class' => 'namespaceselector',
		) );
	}

	/**
	 * Create a date selector
	 *
	 * @param $selected Mixed: the month which should be selected, default ''
	 * @param string $allmonths value of a special item denoting all month. Null to not include (default)
	 * @param string $id Element identifier
	 * @return String: Html string containing the month selector
	 */
	public static function monthSelector( $selected = '', $allmonths = null, $id = 'month' ) {
		global $wgLang;
		$options = array();
		if ( is_null( $selected ) ) {
			$selected = '';
		}
		if ( !is_null( $allmonths ) ) {
			$options[] = self::option( wfMessage( 'monthsall' )->text(), $allmonths, $selected === $allmonths );
		}
		for ( $i = 1; $i < 13; $i++ ) {
			$options[] = self::option( $wgLang->getMonthName( $i ), $i, $selected === $i );
		}
		return self::openElement( 'select', array( 'id' => $id, 'name' => 'month', 'class' => 'mw-month-selector' ) )
			. implode( "\n", $options )
			. self::closeElement( 'select' );
	}

	/**
	 * @param $year Integer
	 * @param $month Integer
	 * @return string Formatted HTML
	 */
	public static function dateMenu( $year, $month ) {
		# Offset overrides year/month selection
		if ( $month && $month !== -1 ) {
			$encMonth = intval( $month );
		} else {
			$encMonth = '';
		}
		if ( $year ) {
			$encYear = intval( $year );
		} elseif ( $encMonth ) {
			$timestamp = MWTimestamp::getInstance();
			$thisMonth = intval( $timestamp->format( 'n' ) );
			$thisYear = intval( $timestamp->format( 'Y' ) );
			if ( intval( $encMonth ) > $thisMonth ) {
				$thisYear--;
			}
			$encYear = $thisYear;
		} else {
			$encYear = '';
		}
		$inputAttribs = array( 'id' => 'year', 'maxlength' => 4, 'size' => 7 );
		return self::label( wfMessage( 'year' )->text(), 'year' ) . ' ' .
			Html::input( 'year', $encYear, 'number', $inputAttribs ) . ' ' .
			self::label( wfMessage( 'month' )->text(), 'month' ) . ' ' .
			self::monthSelector( $encMonth, -1 );
	}

	/**
	 * Construct a language selector appropriate for use in a form or preferences
	 *
	 * @param string $selected The language code of the selected language
	 * @param boolean $customisedOnly If true only languages which have some content are listed
	 * @param string $inLanguage The ISO code of the language to display the select list in (optional)
	 * @param array $overrideAttrs Override the attributes of the select tag (since 1.20)
	 * @param Message|null $msg Label message key (since 1.20)
	 * @return array containing 2 items: label HTML and select list HTML
	 */
	public static function languageSelector( $selected, $customisedOnly = true, $inLanguage = null, $overrideAttrs = array(), Message $msg = null ) {
		global $wgLanguageCode;

		$include = $customisedOnly ? 'mwfile' : 'mw';
		$languages = Language::fetchLanguageNames( $inLanguage, $include );

		// Make sure the site language is in the list;
		// a custom language code might not have a defined name...
		if ( !array_key_exists( $wgLanguageCode, $languages ) ) {
			$languages[$wgLanguageCode] = $wgLanguageCode;
		}

		ksort( $languages );

		/**
		 * If a bogus value is set, default to the content language.
		 * Otherwise, no default is selected and the user ends up
		 * with Afrikaans since it's first in the list.
		 */
		$selected = isset( $languages[$selected] ) ? $selected : $wgLanguageCode;
		$options = "\n";
		foreach ( $languages as $code => $name ) {
			$options .= Xml::option( "$code - $name", $code, $code == $selected ) . "\n";
		}

		$attrs = array( 'id' => 'wpUserLanguage', 'name' => 'wpUserLanguage' );
		$attrs = array_merge( $attrs, $overrideAttrs );

		if ( $msg === null ) {
			$msg = wfMessage( 'yourlanguage' );
		}
		return array(
			Xml::label( $msg->text(), $attrs['id'] ),
			Xml::tags( 'select', $attrs, $options )
		);

	}

	/**
	 * Shortcut to make a span element
	 * @param string $text content of the element, will be escaped
	 * @param string $class class name of the span element
	 * @param array $attribs other attributes
	 * @return string
	 */
	public static function span( $text, $class, $attribs = array() ) {
		return self::element( 'span', array( 'class' => $class ) + $attribs, $text );
	}

	/**
	 * Shortcut to make a specific element with a class attribute
	 * @param string $text content of the element, will be escaped
	 * @param string $class class name of the span element
	 * @param string $tag element name
	 * @param array $attribs other attributes
	 * @return string
	 */
	public static function wrapClass( $text, $class, $tag = 'span', $attribs = array() ) {
		return self::tags( $tag, array( 'class' => $class ) + $attribs, $text );
	}

	/**
	 * Convenience function to build an HTML text input field
	 * @param string $name value of the name attribute
	 * @param int $size value of the size attribute
	 * @param $value mixed value of the value attribute
	 * @param array $attribs other attributes
	 * @return string HTML
	 */
	public static function input( $name, $size = false, $value = false, $attribs = array() ) {
		$attributes = array( 'name' => $name );

		if ( $size ) {
			$attributes['size'] = $size;
		}

		if ( $value !== false ) { // maybe 0
			$attributes['value'] = $value;
		}

		return self::element( 'input', $attributes + $attribs );
	}

	/**
	 * Convenience function to build an HTML password input field
	 * @param string $name value of the name attribute
	 * @param int $size value of the size attribute
	 * @param $value mixed value of the value attribute
	 * @param array $attribs other attributes
	 * @return string HTML
	 */
	public static function password( $name, $size = false, $value = false, $attribs = array() ) {
		return self::input( $name, $size, $value, array_merge( $attribs, array( 'type' => 'password' ) ) );
	}

	/**
	 * Internal function for use in checkboxes and radio buttons and such.
	 *
	 * @param $name string
	 * @param $present bool
	 *
	 * @return array
	 */
	public static function attrib( $name, $present = true ) {
		return $present ? array( $name => $name ) : array();
	}

	/**
	 * Convenience function to build an HTML checkbox
	 * @param string $name value of the name attribute
	 * @param bool $checked Whether the checkbox is checked or not
	 * @param array $attribs other attributes
	 * @return string HTML
	 */
	public static function check( $name, $checked = false, $attribs = array() ) {
		return self::element( 'input', array_merge(
			array(
				'name' => $name,
				'type' => 'checkbox',
				'value' => 1 ),
			self::attrib( 'checked', $checked ),
			$attribs ) );
	}

	/**
	 * Convenience function to build an HTML radio button
	 * @param string $name value of the name attribute
	 * @param string $value value of the value attribute
	 * @param bool $checked Whether the checkbox is checked or not
	 * @param array $attribs other attributes
	 * @return string HTML
	 */
	public static function radio( $name, $value, $checked = false, $attribs = array() ) {
		return self::element( 'input', array(
			'name' => $name,
			'type' => 'radio',
			'value' => $value ) + self::attrib( 'checked', $checked ) + $attribs );
	}

	/**
	 * Convenience function to build an HTML form label
	 * @param string $label text of the label
	 * @param $id
	 * @param array $attribs an attribute array.  This will usually be
	 *     the same array as is passed to the corresponding input element,
	 *     so this function will cherry-pick appropriate attributes to
	 *     apply to the label as well; only class and title are applied.
	 * @return string HTML
	 */
	public static function label( $label, $id, $attribs = array() ) {
		$a = array( 'for' => $id );

		# FIXME avoid copy pasting below:
		if ( isset( $attribs['class'] ) ) {
				$a['class'] = $attribs['class'];
		}
		if ( isset( $attribs['title'] ) ) {
				$a['title'] = $attribs['title'];
		}

		return self::element( 'label', $a, $label );
	}

	/**
	 * Convenience function to build an HTML text input field with a label
	 * @param string $label text of the label
	 * @param string $name value of the name attribute
	 * @param string $id id of the input
	 * @param int|Bool $size value of the size attribute
	 * @param string|Bool $value value of the value attribute
	 * @param array $attribs other attributes
	 * @return string HTML
	 */
	public static function inputLabel( $label, $name, $id, $size = false, $value = false, $attribs = array() ) {
		list( $label, $input ) = self::inputLabelSep( $label, $name, $id, $size, $value, $attribs );
		return $label . '&#160;' . $input;
	}

	/**
	 * Same as Xml::inputLabel() but return input and label in an array
	 *
	 * @param $label String
	 * @param $name String
	 * @param $id String
	 * @param $size Int|Bool
	 * @param $value String|Bool
	 * @param $attribs array
	 *
	 * @return array
	 */
	public static function inputLabelSep( $label, $name, $id, $size = false, $value = false, $attribs = array() ) {
		return array(
			Xml::label( $label, $id, $attribs ),
			self::input( $name, $size, $value, array( 'id' => $id ) + $attribs )
		);
	}

	/**
	 * Convenience function to build an HTML checkbox with a label
	 *
	 * @param $label
	 * @param $name
	 * @param $id
	 * @param $checked bool
	 * @param $attribs array
	 *
	 * @return string HTML
	 */
	public static function checkLabel( $label, $name, $id, $checked = false, $attribs = array() ) {
		return self::check( $name, $checked, array( 'id' => $id ) + $attribs ) .
			'&#160;' .
			self::label( $label, $id, $attribs );
	}

	/**
	 * Convenience function to build an HTML radio button with a label
	 *
	 * @param $label
	 * @param $name
	 * @param $value
	 * @param $id
	 * @param $checked bool
	 * @param $attribs array
	 *
	 * @return string HTML
	 */
	public static function radioLabel( $label, $name, $value, $id, $checked = false, $attribs = array() ) {
		return self::radio( $name, $value, $checked, array( 'id' => $id ) + $attribs ) .
			'&#160;' .
			self::label( $label, $id, $attribs );
	}

	/**
	 * Convenience function to build an HTML submit button
	 * @param string $value label text for the button
	 * @param array $attribs optional custom attributes
	 * @return string HTML
	 */
	public static function submitButton( $value, $attribs = array() ) {
		return Html::element( 'input', array( 'type' => 'submit', 'value' => $value ) + $attribs );
	}

	/**
	 * Convenience function to build an HTML drop-down list item.
	 * @param string $text text for this item. Will be HTML escaped
	 * @param string $value form submission value; if empty, use text
	 * @param $selected boolean: if true, will be the default selected item
	 * @param array $attribs optional additional HTML attributes
	 * @return string HTML
	 */
	public static function option( $text, $value = null, $selected = false,
			$attribs = array() ) {
		if ( !is_null( $value ) ) {
			$attribs['value'] = $value;
		}
		if ( $selected ) {
			$attribs['selected'] = 'selected';
		}
		return Html::element( 'option', $attribs, $text );
	}

	/**
	 * Build a drop-down box from a textual list.
	 *
	 * @param $name Mixed: Name and id for the drop-down
	 * @param $list Mixed: Correctly formatted text (newline delimited) to be used to generate the options
	 * @param $other Mixed: Text for the "Other reasons" option
	 * @param $selected Mixed: Option which should be pre-selected
	 * @param $class Mixed: CSS classes for the drop-down
	 * @param $tabindex Mixed: Value of the tabindex attribute
	 * @return string
	 */
	public static function listDropDown( $name = '', $list = '', $other = '', $selected = '', $class = '', $tabindex = null ) {
		$optgroup = false;

		$options = self::option( $other, 'other', $selected === 'other' );

		foreach ( explode( "\n", $list ) as $option ) {
				$value = trim( $option );
				if ( $value == '' ) {
					continue;
				} elseif ( substr( $value, 0, 1 ) == '*' && substr( $value, 1, 1 ) != '*' ) {
					// A new group is starting ...
					$value = trim( substr( $value, 1 ) );
					if ( $optgroup ) {
						$options .= self::closeElement( 'optgroup' );
					}
					$options .= self::openElement( 'optgroup', array( 'label' => $value ) );
					$optgroup = true;
				} elseif ( substr( $value, 0, 2 ) == '**' ) {
					// groupmember
					$value = trim( substr( $value, 2 ) );
					$options .= self::option( $value, $value, $selected === $value );
				} else {
					// groupless reason list
					if ( $optgroup ) {
						$options .= self::closeElement( 'optgroup' );
					}
					$options .= self::option( $value, $value, $selected === $value );
					$optgroup = false;
				}
			}

			if ( $optgroup ) {
				$options .= self::closeElement( 'optgroup' );
			}

		$attribs = array();

		if ( $name ) {
			$attribs['id'] = $name;
			$attribs['name'] = $name;
		}

		if ( $class ) {
			$attribs['class'] = $class;
		}

		if ( $tabindex ) {
			$attribs['tabindex'] = $tabindex;
		}

		return Xml::openElement( 'select', $attribs )
			. "\n"
			. $options
			. "\n"
			. Xml::closeElement( 'select' );
	}

	/**
	 * Shortcut for creating fieldsets.
	 *
	 * @param string|bool $legend Legend of the fieldset. If evaluates to false, legend is not added.
	 * @param string $content Pre-escaped content for the fieldset. If false, only open fieldset is returned.
	 * @param array $attribs Any attributes to fieldset-element.
	 *
	 * @return string
	 */
	public static function fieldset( $legend = false, $content = false, $attribs = array() ) {
		$s = Xml::openElement( 'fieldset', $attribs ) . "\n";

		if ( $legend ) {
			$s .= Xml::element( 'legend', null, $legend ) . "\n";
		}

		if ( $content !== false ) {
			$s .= $content . "\n";
			$s .= Xml::closeElement( 'fieldset' ) . "\n";
		}

		return $s;
	}

	/**
	 * Shortcut for creating textareas.
	 *
	 * @param string $name The 'name' for the textarea
	 * @param string $content Content for the textarea
	 * @param int $cols The number of columns for the textarea
	 * @param int $rows The number of rows for the textarea
	 * @param array $attribs Any other attributes for the textarea
	 *
	 * @return string
	 */
	public static function textarea( $name, $content, $cols = 40, $rows = 5, $attribs = array() ) {
		return self::element( 'textarea',
					array(
						'name' => $name,
						'id' => $name,
						'cols' => $cols,
						'rows' => $rows
					) + $attribs,
					$content, false );
	}

	/**
	 * Returns an escaped string suitable for inclusion in a string literal
	 * for JavaScript source code.
	 * Illegal control characters are assumed not to be present.
	 *
	 * @deprecated since 1.21; use Xml::encodeJsVar() or Xml::encodeJsCall() instead
	 * @param string $string to escape
	 * @return String
	 */
	public static function escapeJsString( $string ) {
		// See ECMA 262 section 7.8.4 for string literal format
		$pairs = array(
			"\\" => "\\\\",
			"\"" => "\\\"",
			'\'' => '\\\'',
			"\n" => "\\n",
			"\r" => "\\r",

			# To avoid closing the element or CDATA section
			"<" => "\\x3c",
			">" => "\\x3e",

			# To avoid any complaints about bad entity refs
			"&" => "\\x26",

			# Work around https://bugzilla.mozilla.org/show_bug.cgi?id=274152
			# Encode certain Unicode formatting chars so affected
			# versions of Gecko don't misinterpret our strings;
			# this is a common problem with Farsi text.
			"\xe2\x80\x8c" => "\\u200c", // ZERO WIDTH NON-JOINER
			"\xe2\x80\x8d" => "\\u200d", // ZERO WIDTH JOINER
		);

		return strtr( $string, $pairs );
	}

	/**
	 * Encode a variable of arbitrary type to JavaScript.
	 * If the value is an XmlJsCode object, pass through the object's value verbatim.
	 *
	 * @note Only use this function for generating JavaScript code. If generating output
	 *       for a proper JSON parser, just call FormatJson::encode() directly.
	 *
	 * @param mixed $value The value being encoded. Can be any type except a resource.
	 * @param bool $pretty If true, add non-significant whitespace to improve readability.
	 * @return string|bool: String if successful; false upon failure
	 */
	public static function encodeJsVar( $value, $pretty = false ) {
		if ( $value instanceof XmlJsCode ) {
			return $value->value;
		}
		return FormatJson::encode( $value, $pretty, FormatJson::UTF8_OK );
	}

	/**
	 * Create a call to a JavaScript function. The supplied arguments will be
	 * encoded using Xml::encodeJsVar().
	 *
	 * @since 1.17
	 * @param string $name The name of the function to call, or a JavaScript expression
	 *    which evaluates to a function object which is called.
	 * @param array $args The arguments to pass to the function.
	 * @param bool $pretty If true, add non-significant whitespace to improve readability.
	 * @return string|bool: String if successful; false upon failure
	 */
	public static function encodeJsCall( $name, $args, $pretty = false ) {
		foreach ( $args as &$arg ) {
			$arg = Xml::encodeJsVar( $arg, $pretty );
			if ( $arg === false ) {
				return false;
			}
		}

		return "$name(" . ( $pretty
			? ( ' ' . implode( ', ', $args ) . ' ' )
			: implode( ',', $args )
		) . ");";
	}

	/**
	 * Check if a string is well-formed XML.
	 * Must include the surrounding tag.
	 *
	 * @param string $text string to test.
	 * @return bool
	 *
	 * @todo Error position reporting return
	 */
	public static function isWellFormed( $text ) {
		$parser = xml_parser_create( "UTF-8" );

		# case folding violates XML standard, turn it off
		xml_parser_set_option( $parser, XML_OPTION_CASE_FOLDING, false );

		if ( !xml_parse( $parser, $text, true ) ) {
			//$err = xml_error_string( xml_get_error_code( $parser ) );
			//$position = xml_get_current_byte_index( $parser );
			//$fragment = $this->extractFragment( $html, $position );
			//$this->mXmlError = "$err at byte $position:\n$fragment";
			xml_parser_free( $parser );
			return false;
		}

		xml_parser_free( $parser );

		return true;
	}

	/**
	 * Check if a string is a well-formed XML fragment.
	 * Wraps fragment in an \<html\> bit and doctype, so it can be a fragment
	 * and can use HTML named entities.
	 *
	 * @param $text String:
	 * @return bool
	 */
	public static function isWellFormedXmlFragment( $text ) {
		$html =
			Sanitizer::hackDocType() .
			'<html>' .
			$text .
			'</html>';

		return Xml::isWellFormed( $html );
	}

	/**
	 * Replace " > and < with their respective HTML entities ( &quot;,
	 * &gt;, &lt;)
	 *
	 * @param string $in text that might contain HTML tags.
	 * @return string Escaped string
	 */
	public static function escapeTagsOnly( $in ) {
		return str_replace(
			array( '"', '>', '<' ),
			array( '&quot;', '&gt;', '&lt;' ),
			$in );
	}

	/**
	 * Generate a form (without the opening form element).
	 * Output optionally includes a submit button.
	 * @param array $fields Associative array, key is the name of a message that contains a description for the field, value is an HTML string containing the appropriate input.
	 * @param string $submitLabel The name of a message containing a label for the submit button.
	 * @param array $submitAttribs The attributes to add to the submit button
	 * @return string HTML form.
	 */
	public static function buildForm( $fields, $submitLabel = null, $submitAttribs = array() ) {
		$form = '';
		$form .= "<table><tbody>";

		foreach ( $fields as $labelmsg => $input ) {
			$id = "mw-$labelmsg";
			$form .= Xml::openElement( 'tr', array( 'id' => $id ) );

			// TODO use a <label> here for accessibility purposes - will need
			// to either not use a table to build the form, or find the ID of
			// the input somehow.

			$form .= Xml::tags( 'td', array( 'class' => 'mw-label' ), wfMessage( $labelmsg )->parse() );
			$form .= Xml::openElement( 'td', array( 'class' => 'mw-input' ) ) . $input . Xml::closeElement( 'td' );
			$form .= Xml::closeElement( 'tr' );
		}

		if ( $submitLabel ) {
			$form .= Xml::openElement( 'tr' );
			$form .= Xml::tags( 'td', array(), '' );
			$form .= Xml::openElement( 'td', array( 'class' => 'mw-submit' ) ) . Xml::submitButton( wfMessage( $submitLabel )->text(), $submitAttribs ) . Xml::closeElement( 'td' );
			$form .= Xml::closeElement( 'tr' );
		}

		$form .= "</tbody></table>";

		return $form;
	}

	/**
	 * Build a table of data
	 * @param array $rows An array of arrays of strings, each to be a row in a table
	 * @param array $attribs An array of attributes to apply to the table tag [optional]
	 * @param array $headers An array of strings to use as table headers [optional]
	 * @return string
	 */
	public static function buildTable( $rows, $attribs = array(), $headers = null ) {
		$s = Xml::openElement( 'table', $attribs );

		if ( is_array( $headers ) ) {
			$s .= Xml::openElement( 'thead', $attribs );

			foreach ( $headers as $id => $header ) {
				$attribs = array();

				if ( is_string( $id ) ) {
					$attribs['id'] = $id;
				}

				$s .= Xml::element( 'th', $attribs, $header );
			}
			$s .= Xml::closeElement( 'thead' );
		}

		foreach ( $rows as $id => $row ) {
			$attribs = array();

			if ( is_string( $id ) ) {
				$attribs['id'] = $id;
			}

			$s .= Xml::buildTableRow( $attribs, $row );
		}

		$s .= Xml::closeElement( 'table' );

		return $s;
	}

	/**
	 * Build a row for a table
	 * @param array $attribs An array of attributes to apply to the tr tag
	 * @param array $cells An array of strings to put in <td>
	 * @return string
	 */
	public static function buildTableRow( $attribs, $cells ) {
		$s = Xml::openElement( 'tr', $attribs );

		foreach ( $cells as $id => $cell ) {
			$attribs = array();

			if ( is_string( $id ) ) {
				$attribs['id'] = $id;
			}

			$s .= Xml::element( 'td', $attribs, $cell );
		}

		$s .= Xml::closeElement( 'tr' );

		return $s;
	}
}

class XmlSelect {
	protected $options = array();
	protected $default = false;
	protected $attributes = array();

	public function __construct( $name = false, $id = false, $default = false ) {
		if ( $name ) {
			$this->setAttribute( 'name', $name );
		}

		if ( $id ) {
			$this->setAttribute( 'id', $id );
		}

		if ( $default !== false ) {
			$this->default = $default;
		}
	}

	/**
	 * @param $default
	 */
	public function setDefault( $default ) {
		$this->default = $default;
	}

	/**
	 * @param $name string
	 * @param $value
	 */
	public function setAttribute( $name, $value ) {
		$this->attributes[$name] = $value;
	}

	/**
	 * @param $name
	 * @return array|null
	 */
	public function getAttribute( $name ) {
		if ( isset( $this->attributes[$name] ) ) {
			return $this->attributes[$name];
		} else {
			return null;
		}
	}

	/**
	 * @param $name
	 * @param $value bool
	 */
	public function addOption( $name, $value = false ) {
		// Stab stab stab
		$value = $value !== false ? $value : $name;

		$this->options[] = array( $name => $value );
	}

	/**
	 * This accepts an array of form
	 * label => value
	 * label => ( label => value, label => value )
	 *
	 * @param  $options
	 */
	public function addOptions( $options ) {
		$this->options[] = $options;
	}

	/**
	 * This accepts an array of form
	 * label => value
	 * label => ( label => value, label => value )
	 *
	 * @param  $options
	 * @param bool $default
	 * @return string
	 */
	static function formatOptions( $options, $default = false ) {
		$data = '';

		foreach ( $options as $label => $value ) {
			if ( is_array( $value ) ) {
				$contents = self::formatOptions( $value, $default );
				$data .= Html::rawElement( 'optgroup', array( 'label' => $label ), $contents ) . "\n";
			} else {
				$data .= Xml::option( $label, $value, $value === $default ) . "\n";
			}
		}

		return $data;
	}

	/**
	 * @return string
	 */
	public function getHTML() {
		$contents = '';

		foreach ( $this->options as $options ) {
			$contents .= self::formatOptions( $options, $this->default );
		}

		return Html::rawElement( 'select', $this->attributes, rtrim( $contents ) );
	}
}

/**
 * A wrapper class which causes Xml::encodeJsVar() and Xml::encodeJsCall() to
 * interpret a given string as being a JavaScript expression, instead of string
 * data.
 *
 * Example:
 *
 *    Xml::encodeJsVar( new XmlJsCode( 'a + b' ) );
 *
 * Returns "a + b".
 *
 * @note As of 1.21, XmlJsCode objects cannot be nested inside objects or arrays. The sole
 *       exception is the $args argument to Xml::encodeJsCall() because Xml::encodeJsVar() is
 *       called for each individual element in that array.
 *
 * @since 1.17
 */
class XmlJsCode {
	public $value;

	function __construct( $value ) {
		$this->value = $value;
	}
}