<?php
/**
 * Return a rounded pixel equivalent for a labeled CSS/SVG length.
 * http://www.w3.org/TR/SVG11/coords.html#UnitIdentifiers
 *
 * @param $length String: CSS/SVG length.
 * @return Integer: length in pixels
 */
function wfScaleSVGUnit( $length ) {
	static $unitLength = array(
		'px' => 1.0,
		'pt' => 1.25,
		'pc' => 15.0,
		'mm' => 3.543307,
		'cm' => 35.43307,
		'in' => 90.0,
		''   => 1.0, // "User units" pixels by default
		'%'  => 2.0, // Fake it!
		);
	$matches = array();
	if( preg_match( '/^(\d+(?:\.\d+)?)(em|ex|px|pt|pc|cm|mm|in|%|)$/', $length, $matches ) ) {
		$length = floatval( $matches[1] );
		$unit = $matches[2];
		return round( $length * $unitLength[$unit] );
	} else {
		// Assume pixels
		return round( floatval( $length ) );
	}
}

/**
 * Compatible with PHP getimagesize()
 * @todo support gzipped SVGZ
 * @todo check XML more carefully
 * @todo sensible defaults
 *
 * @param $filename String: full name of the file (passed to php fopen()).
 * @return array
 */
function wfGetSVGsize( $filename ) {
	$width = 256;
	$height = 256;

	// Read a chunk of the file
	$f = fopen( $filename, "rt" );
	if( !$f ) return false;
	$chunk = fread( $f, 4096 );
	fclose( $f );

	// Uber-crappy hack! Run through a real XML parser.
	$matches = array();
	if( !preg_match( '/<svg\s*([^>]*)\s*>/s', $chunk, $matches ) ) {
		return false;
	}
	$tag = $matches[1];
	if( preg_match( '/\bwidth\s*=\s*("[^"]+"|\'[^\']+\')/s', $tag, $matches ) ) {
		$width = wfScaleSVGUnit( trim( substr( $matches[1], 1, -1 ) ) );
	}
	if( preg_match( '/\bheight\s*=\s*("[^"]+"|\'[^\']+\')/s', $tag, $matches ) ) {
		$height = wfScaleSVGUnit( trim( substr( $matches[1], 1, -1 ) ) );
	}

	return array( $width, $height, 'SVG',
		"width=\"$width\" height=\"$height\"" );
}

/**
 * Determine if an image exists on the 'bad image list'.
 *
 * The format of MediaWiki:Bad_image_list is as follows:
 *    * Only list items (lines starting with "*") are considered
 *    * The first link on a line must be a link to a bad image
 *    * Any subsequent links on the same line are considered to be exceptions,
 *      i.e. articles where the image may occur inline.
 *
 * @param string $name the image name to check
 * @param Title $contextTitle The page on which the image occurs, if known
 * @return bool
 */
function wfIsBadImage( $name, $contextTitle = false ) {
	static $badImages = false;
	wfProfileIn( __METHOD__ );

	# Run the extension hook
	$bad = false;
	if( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
		wfProfileOut( __METHOD__ );
		return $bad;
	}

	if( !$badImages ) {
		# Build the list now
		$badImages = array();
		$lines = explode( "\n", wfMsgForContentNoTrans( 'bad_image_list' ) );
		foreach( $lines as $line ) {
			# List items only
			if ( substr( $line, 0, 1 ) !== '*' ) {
				continue;
			}

			# Find all links
			$m = array();
			if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
				continue;
			}

			$exceptions = array();
			$imageDBkey = false;
			foreach ( $m[1] as $i => $titleText ) {
				$title = Title::newFromText( $titleText );
				if ( !is_null( $title ) ) {
					if ( $i == 0 ) {
						$imageDBkey = $title->getDBkey();
					} else {
						$exceptions[$title->getPrefixedDBkey()] = true;
					}
				}
			}

			if ( $imageDBkey !== false ) {
				$badImages[$imageDBkey] = $exceptions;
			}
		}
	}
	
	$contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
	$bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
	wfProfileOut( __METHOD__ );
	return $bad;
}

/**
 * Calculate the largest thumbnail width for a given original file size
 * such that the thumbnail's height is at most $maxHeight.
 * @param $boxWidth Integer Width of the thumbnail box.
 * @param $boxHeight Integer Height of the thumbnail box.
 * @param $maxHeight Integer Maximum height expected for the thumbnail.
 * @return Integer.
 */
function wfFitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
	$idealWidth = $boxWidth * $maxHeight / $boxHeight;
	$roundedUp = ceil( $idealWidth );
	if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight )
		return floor( $idealWidth );
	else
		return $roundedUp;
}