<?php
/**
 * Handler for SVG images.
 *
 * 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
 * @ingroup Media
 */

/**
 * Handler for SVG images.
 *
 * @ingroup Media
 */
class SvgHandler extends ImageHandler {
	const SVG_METADATA_VERSION = 2;

	function isEnabled() {
		global $wgSVGConverters, $wgSVGConverter;
		if ( !isset( $wgSVGConverters[$wgSVGConverter] ) ) {
			wfDebug( "\$wgSVGConverter is invalid, disabling SVG rendering.\n" );
			return false;
		} else {
			return true;
		}
	}

	function mustRender( $file ) {
		return true;
	}

	function isVectorized( $file ) {
		return true;
	}

	/**
	 * @param $file File
	 * @return bool
	 */
	function isAnimatedImage( $file ) {
		# TODO: detect animated SVGs
		$metadata = $file->getMetadata();
		if ( $metadata ) {
			$metadata = $this->unpackMetadata( $metadata );
			if ( isset( $metadata['animated'] ) ) {
				return $metadata['animated'];
			}
		}
		return false;
	}

	/**
	 * We do not support making animated svg thumbnails
	 */
	function canAnimateThumb( $file ) {
		return false;
	}

	/**
	 * @param $image File
	 * @param  $params
	 * @return bool
	 */
	function normaliseParams( $image, &$params ) {
		global $wgSVGMaxSize;
		if ( !parent::normaliseParams( $image, $params ) ) {
			return false;
		}
		# Don't make an image bigger than wgMaxSVGSize on the smaller side
		if ( $params['physicalWidth'] <= $params['physicalHeight'] ) {
			if ( $params['physicalWidth'] > $wgSVGMaxSize ) {
				$srcWidth = $image->getWidth( $params['page'] );
				$srcHeight = $image->getHeight( $params['page'] );
				$params['physicalWidth'] = $wgSVGMaxSize;
				$params['physicalHeight'] = File::scaleHeight( $srcWidth, $srcHeight, $wgSVGMaxSize );
			}
		} else {
			if ( $params['physicalHeight'] > $wgSVGMaxSize ) {
				$srcWidth = $image->getWidth( $params['page'] );
				$srcHeight = $image->getHeight( $params['page'] );
				$params['physicalWidth'] = File::scaleHeight( $srcHeight, $srcWidth, $wgSVGMaxSize );
				$params['physicalHeight'] = $wgSVGMaxSize;
			}
		}
		return true;
	}

	/**
	 * @param $image File
	 * @param  $dstPath
	 * @param  $dstUrl
	 * @param  $params
	 * @param int $flags
	 * @return bool|MediaTransformError|ThumbnailImage|TransformParameterError
	 */
	function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
		if ( !$this->normaliseParams( $image, $params ) ) {
			return new TransformParameterError( $params );
		}
		$clientWidth = $params['width'];
		$clientHeight = $params['height'];
		$physicalWidth = $params['physicalWidth'];
		$physicalHeight = $params['physicalHeight'];
		$lang = isset( $params['lang'] ) ? $params['lang'] : 'en';

		if ( $flags & self::TRANSFORM_LATER ) {
			return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
		}

		$metadata = $this->unpackMetadata( $image->getMetadata() );
		if ( isset( $metadata['error'] ) ) { // sanity check
			$err = wfMessage( 'svg-long-error', $metadata['error']['message'] )->text();
			return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight, $err );
		}

		if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
			return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight,
				wfMessage( 'thumbnail_dest_directory' )->text() );
		}

		$srcPath = $image->getLocalRefPath();
		$status = $this->rasterize( $srcPath, $dstPath, $physicalWidth, $physicalHeight, $lang );
		if ( $status === true ) {
			return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
		} else {
			return $status; // MediaTransformError
		}
	}

	/**
	 * Transform an SVG file to PNG
	 * This function can be called outside of thumbnail contexts
	 * @param string $srcPath
	 * @param string $dstPath
	 * @param string $width
	 * @param string $height
	 * @param string $lang Language code of the language to render the SVG in
	 * @throws MWException
	 * @return bool|MediaTransformError
	 */
	public function rasterize( $srcPath, $dstPath, $width, $height, $lang = false ) {
		global $wgSVGConverters, $wgSVGConverter, $wgSVGConverterPath;
		$err = false;
		$retval = '';
		if ( isset( $wgSVGConverters[$wgSVGConverter] ) ) {
			if ( is_array( $wgSVGConverters[$wgSVGConverter] ) ) {
				// This is a PHP callable
				$func = $wgSVGConverters[$wgSVGConverter][0];
				$args = array_merge( array( $srcPath, $dstPath, $width, $height, $lang ),
					array_slice( $wgSVGConverters[$wgSVGConverter], 1 ) );
				if ( !is_callable( $func ) ) {
					throw new MWException( "$func is not callable" );
				}
				$err = call_user_func_array( $func, $args );
				$retval = (bool)$err;
			} else {
				// External command
				$cmd = str_replace(
					array( '$path/', '$width', '$height', '$input', '$output' ),
					array( $wgSVGConverterPath ? wfEscapeShellArg( "$wgSVGConverterPath/" ) : "",
						intval( $width ),
						intval( $height ),
						wfEscapeShellArg( $srcPath ),
						wfEscapeShellArg( $dstPath ) ),
					$wgSVGConverters[$wgSVGConverter]
				);

				$env = array();
				if ( $lang !== false ) {
					$env['LANG'] = $lang;
				}

				wfProfileIn( 'rsvg' );
				wfDebug( __METHOD__ . ": $cmd\n" );
				$err = wfShellExecWithStderr( $cmd, $retval, $env );
				wfProfileOut( 'rsvg' );
			}
		}
		$removed = $this->removeBadFile( $dstPath, $retval );
		if ( $retval != 0 || $removed ) {
			wfDebugLog( 'thumbnail', sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
					wfHostname(), $retval, trim( $err ), $cmd ) );
			return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
		}
		return true;
	}

	public static function rasterizeImagickExt( $srcPath, $dstPath, $width, $height ) {
		$im = new Imagick( $srcPath );
		$im->setImageFormat( 'png' );
		$im->setBackgroundColor( 'transparent' );
		$im->setImageDepth( 8 );

		if ( !$im->thumbnailImage( intval( $width ), intval( $height ), /* fit */ false ) ) {
			return 'Could not resize image';
		}
		if ( !$im->writeImage( $dstPath ) ) {
			return "Could not write to $dstPath";
		}
	}

	/**
	 * @param $file File
	 * @param  $path
	 * @param bool $metadata
	 * @return array
	 */
	function getImageSize( $file, $path, $metadata = false ) {
		if ( $metadata === false ) {
			$metadata = $file->getMetaData();
		}
		$metadata = $this->unpackMetaData( $metadata );

		if ( isset( $metadata['width'] ) && isset( $metadata['height'] ) ) {
			return array( $metadata['width'], $metadata['height'], 'SVG',
					"width=\"{$metadata['width']}\" height=\"{$metadata['height']}\"" );
		} else { // error
			return array( 0, 0, 'SVG', "width=\"0\" height=\"0\"" );
		}
	}

	function getThumbType( $ext, $mime, $params = null ) {
		return array( 'png', 'image/png' );
	}

	/**
	 * Subtitle for the image. Different from the base
	 * class so it can be denoted that SVG's have
	 * a "nominal" resolution, and not a fixed one,
	 * as well as so animation can be denoted.
	 *
	 * @param $file File
	 * @return string
	 */
	function getLongDesc( $file ) {
		global $wgLang;

		$metadata = $this->unpackMetadata( $file->getMetadata() );
		if ( isset( $metadata['error'] ) ) {
			return wfMessage( 'svg-long-error', $metadata['error']['message'] )->text();
		}

		$size = $wgLang->formatSize( $file->getSize() );

		if ( $this->isAnimatedImage( $file ) ) {
			$msg = wfMessage( 'svg-long-desc-animated' );
		} else {
			$msg = wfMessage( 'svg-long-desc' );
		}

		$msg->numParams( $file->getWidth(), $file->getHeight() )->params( $size );

		return $msg->parse();
	}

	function getMetadata( $file, $filename ) {
		$metadata = array( 'version' => self::SVG_METADATA_VERSION );
		try {
			$metadata += SVGMetadataExtractor::getMetadata( $filename );
		} catch ( MWException $e ) { // @todo SVG specific exceptions
			// File not found, broken, etc.
			$metadata['error'] = array(
				'message' => $e->getMessage(),
				'code' => $e->getCode()
			);
			wfDebug( __METHOD__ . ': ' . $e->getMessage() . "\n" );
		}
		return serialize( $metadata );
	}

	function unpackMetadata( $metadata ) {
		wfSuppressWarnings();
		$unser = unserialize( $metadata );
		wfRestoreWarnings();
		if ( isset( $unser['version'] ) && $unser['version'] == self::SVG_METADATA_VERSION ) {
			return $unser;
		} else {
			return false;
		}
	}

	function getMetadataType( $image ) {
		return 'parsed-svg';
	}

	function isMetadataValid( $image, $metadata ) {
		$meta = $this->unpackMetadata( $metadata );
		if ( $meta === false ) {
			return self::METADATA_BAD;
		}
		if ( !isset( $meta['originalWidth'] ) ) {
			// Old but compatible
			return self::METADATA_COMPATIBLE;
		}
		return self::METADATA_GOOD;
	}

	function visibleMetadataFields() {
		$fields = array( 'objectname', 'imagedescription' );
		return $fields;
	}

	/**
	 * @param $file File
	 * @return array|bool
	 */
	function formatMetadata( $file ) {
		$result = array(
			'visible' => array(),
			'collapsed' => array()
		);
		$metadata = $file->getMetadata();
		if ( !$metadata ) {
			return false;
		}
		$metadata = $this->unpackMetadata( $metadata );
		if ( !$metadata || isset( $metadata['error'] ) ) {
			return false;
		}

		/* TODO: add a formatter
		$format = new FormatSVG( $metadata );
		$formatted = $format->getFormattedData();
		*/

		// Sort fields into visible and collapsed
		$visibleFields = $this->visibleMetadataFields();

		// Rename fields to be compatible with exif, so that
		// the labels for these fields work and reuse existing messages.
		$conversion = array(
			'originalwidth' => 'imagewidth',
			'originalheight' => 'imagelength',
			'description' => 'imagedescription',
			'title' => 'objectname',
		);
		$showMeta = false;
		foreach ( $metadata as $name => $value ) {
			$tag = strtolower( $name );
			if ( isset( $conversion[$tag] ) ) {
				$tag = $conversion[$tag];
			} else {
				// Do not output other metadata not in list
				continue;
			}
			$showMeta = true;
			self::addMeta( $result,
				in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
				'exif',
				$tag,
				$value
			);
		}
		return $showMeta ? $result : false;
	}


	/**
	 * @param string $name Parameter name
	 * @param $string $value Parameter value
	 * @return bool Validity
	 */
	function validateParam( $name, $value ) {
		if ( in_array( $name, array( 'width', 'height' ) ) ) {
			// Reject negative heights, widths
			return ( $value > 0 );
		} elseif ( $name == 'lang' ) {
			// Validate $code
			if ( !Language::isValidBuiltinCode( $value ) ) {
				wfDebug( "Invalid user language code\n" );
				return false;
			}
			return true;
		}
		// Only lang, width and height are acceptable keys
		return false;
	}

	/**
	 * @param array $params name=>value pairs of parameters
	 * @return string Filename to use
	 */
	function makeParamString( $params ) {
		$lang = '';
		if ( isset( $params['lang'] ) && $params['lang'] !== 'en' ) {
			$params['lang'] = mb_strtolower( $params['lang'] );
			$lang = "lang{$params['lang']}-";
		}
		if ( !isset( $params['width'] ) ) {
			return false;
		}
		return "$lang{$params['width']}px";
	}

	function parseParamString( $str ) {
		$m = false;
		if ( preg_match( '/^lang([a-z]+(?:-[a-z]+)*)-(\d+)px$/', $str, $m ) ) {
			return array( 'width' => array_pop( $m ), 'lang' => $m[1] );
		} elseif ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
			return array( 'width' => $m[1], 'lang' => 'en' );
		} else {
			return false;
		}
	}

	function getParamMap() {
		return array( 'img_lang' => 'lang', 'img_width' => 'width' );
	}

	/**
	 * @param $params
	 * @return array
	 */
	function getScriptParams( $params ) {
		return array(
			'width' => $params['width'],
			'lang' => $params['lang'],
		);
	}
}
