<?php
/**
 * MediaWiki math extension
 *
 * @copyright 2002-2015 various MediaWiki contributors
 * @license GPL-2.0-or-later
 */

use MediaWiki\Logger\LoggerFactory;

class MathHooks {

	/**
	 * @var array[]
	 */
	private static $tags = [];

	const MATHCACHEKEY = 'math=';

	public static function mathConstantToString( $value, array $defs, $prefix, $default ) {
		foreach ( $defs as $defKey => $defValue ) {
			if ( !defined( $defKey ) ) {
				define( $defKey, $defValue );
			} elseif ( $defValue !== constant( $defKey ) ) {
				throw new Exception( 'Math constant "' . $defKey . '" has unexpected value "' .
					constant( $defKey ) . '" instead of "' . $defValue );
			}
		}
		$invDefs = array_flip( $defs );
		if ( is_int( $value ) ) {
			if ( array_key_exists( $value, $invDefs ) ) {
				$value = $invDefs[$value];
			} else {
				return $default;
			}
		}
		if ( is_string( $value ) ) {
			$newValues = [];
			foreach ( $defs as $k => $v ) {
				$newValues[$k] = preg_replace_callback( '/_(.)/', function ( $matches ) {
					return strtoupper( $matches[1] );
				}, strtolower( substr( $k, strlen( $prefix ) ) ) );
			}
			if ( array_key_exists( $value, $defs ) ) {
				return $newValues[$value];
			} elseif ( in_array( $value, $newValues ) ) {
				return $value;
			}
		}
		return $default;
	}

	public static function mathStyleToString( $style, $default = 'inlineDisplaystyle' ) {
		$defs = [
			'MW_MATHSTYLE_INLINE_DISPLAYSTYLE'  => 0, // default large operator inline
			'MW_MATHSTYLE_DISPLAY'              => 1, // large operators centered in a new line
			'MW_MATHSTYLE_INLINE'               => 2, // small operators inline
			'MW_MATHSTYLE_LINEBREAK'            => 3, // break long lines (experimental)
		];
		return self::mathConstantToString( $style, $defs, 'MW_MATHSTYLE_', $default );
	}

	public static function mathCheckToString( $style, $default = 'always' ) {
		$defs = [
			'MW_MATH_CHECK_ALWAYS' => 0,
			'MW_MATH_CHECK_NEVER'  => 1,
			'MW_MATH_CHECK_NEW'    => 2,
		];
		return self::mathConstantToString( $style, $defs, 'MW_MATH_CHECK_', $default );
	}

	public static function mathModeToString( $mode, $default = 'png' ) {
		// The following deprecated modes have been removed:
		// 'MW_MATH_SIMPLE'      => 1
		// 'MW_MATH_HTML'        => 2
		// 'MW_MATH_MODERN'      => 4
		// 'MW_MATH_MATHJAX'     => 6
		// 'MW_MATH_LATEXML_JAX' => 8

		$defs = [
			'MW_MATH_PNG'    => 0,
			'MW_MATH_SOURCE' => 3,
			'MW_MATH_MATHML' => 5,
			'MW_MATH_LATEXML' => 7 ];

		return self::mathConstantToString( $mode, $defs, 'MW_MATH_', $default );
	}

	public static function mathModeToHashKey( $mode, $default = 0 ) {
		$defs = [
			'png'    => 0,
			'source' => 3,
			'mathml' => 5,
			'latexml' => 7 ];

		if ( array_key_exists( $mode, $defs ) ) {
			return $defs[$mode];
		} else {
			return $default;
		}
	}

	/**
	 * Generate a user dependent hash cache key.
	 * The hash key depends on the rendering mode.
	 * @param string &$confstr The to-be-hashed key string that is being constructed
	 * @param User|bool $user reference to the current user
	 * @param array &$forOptions userOptions used on that page
	 * @return true
	 */
	public static function onPageRenderingHash( &$confstr, $user = false, &$forOptions = [] ) {
		global $wgUser;

		// To be independent of the MediaWiki core version,
		// we check if the core caching logic for math is still available.
		if ( !is_callable( 'ParserOptions::getMath' ) && in_array( 'math', $forOptions ) ) {
			if ( $user === false ) {
				$user = $wgUser;
			}

			$mathString = self::mathModeToString( $user->getOption( 'math' ) );
			$mathOption = self::mathModeToHashKey( $mathString, 0 );
			// Check if the key already contains the math option part
			if (
				!preg_match(
					'/(^|!)' . self::MATHCACHEKEY . $mathOption . '(!|$)/',
					$confstr
				)
			) {
				// The math part of cache key starts with "math="
				// followed by a star or a number for the math mode
				if ( preg_match( '/(^|!)' . self::MATHCACHEKEY . '[*\d]m?(!|$)/', $confstr ) ) {
					$confstr = preg_replace(
						'/(^|!)' . self::MATHCACHEKEY . '[*\d]m?(!|$)/',
						'\1' . self::MATHCACHEKEY . $mathOption . '\2',
						$confstr
					);
				} else {
					$confstr .= '!' . self::MATHCACHEKEY . $mathOption;
				}

				LoggerFactory::getInstance( 'Math' )->debug( "New cache key: $confstr" );
			} else {
				LoggerFactory::getInstance( 'Math' )->debug( "Cache key found: $confstr" );
			}
		}

		return true;
	}

	/**
	 * Set up $wgMathPath and $wgMathDirectory globals if they're not already set.
	 */
	public static function setup() {
		global $wgMathPath, $wgMathDirectory,
			$wgUploadPath, $wgUploadDirectory;

		if ( $wgMathPath === false ) {
			$wgMathPath = "{$wgUploadPath}/math";
		}

		if ( $wgMathDirectory === false ) {
			$wgMathDirectory = "{$wgUploadDirectory}/math";
		}
	}

	/**
	 * Register the <math> tag with the Parser.
	 *
	 * @param Parser $parser instance of Parser
	 * @return bool true
	 */
	public static function onParserFirstCallInit( $parser ) {
		$parser->setHook( 'math', [ self::class, 'mathTagHook' ] );
		// @deprecated the ce tag is deprecated in favour of chem cf. T153606
		$parser->setHook( 'ce', [ self::class, 'chemTagHook' ] );
		$parser->setHook( 'chem', [ self::class, 'chemTagHook' ] );

		return true;
	}

	/**
	 * Callback function for the <math> parser hook.
	 *
	 * @param string $content (the LaTeX input)
	 * @param array $attributes
	 * @param Parser $parser
	 * @return array|string
	 */
	public static function mathTagHook( $content, $attributes, $parser ) {
		static $n = 1;
		if ( trim( $content ) === '' ) { // bug 8372 https://phabricator.wikimedia.org/rSVN18870
			return '';
		}

		$mode = self::mathModeToString( $parser->getUser()->getOption( 'math' ) );
		// Indicate that this page uses math.
		// This affects the page caching behavior.
		$parser->getOptions()->optionUsed( 'math' );
		$renderer = MathRenderer::getRenderer( $content, $attributes, $mode );

		$parser->getOutput()->addModuleStyles( [ 'ext.math.styles' ] );
		if ( $mode == 'mathml' ) {
			$parser->getOutput()->addModules( [ 'ext.math.scripts' ] );
			$marker = Parser::MARKER_PREFIX .
				'-postMath-' . sprintf( '%08X', $n++ ) .
				Parser::MARKER_SUFFIX;
			self::$tags[$marker] = [ $renderer, $parser ];
			return $marker;
		}
		return [ self::mathPostTagHook( $renderer, $parser ), 'markerType' => 'nowiki' ];
	}

	/**
	 * Callback function for the <math> parser hook.
	 *
	 * @param MathRenderer $renderer
	 * @param Parser $parser
	 * @return string
	 * @throws FatalError
	 * @throws MWException
	 */
	private static function mathPostTagHook( $renderer, $parser ) {
		$checkResult = $renderer->checkTeX();

		if ( $checkResult !== true ) {
			$renderer->addTrackingCategories( $parser );
			return $renderer->getLastError();
		}

		if ( $renderer->render() ) {
			LoggerFactory::getInstance( 'Math' )->debug( "Rendering successful. Writing output" );
			$renderedMath = $renderer->getHtmlOutput();
			$renderer->addTrackingCategories( $parser );
		} else {
			LoggerFactory::getInstance( 'Math' )->warning(
				"Rendering failed. Printing error message." );
			// Set a short parser cache time (10 minutes) after encountering
			// render issues, but not syntax issues.
			$parser->getOutput()->updateCacheExpiry( 600 );
			$renderer->addTrackingCategories( $parser );
			return $renderer->getLastError();
		}
		Hooks::run( 'MathFormulaPostRender',
			[ $parser, $renderer, &$renderedMath ] );// Enables indexing of math formula

		// Writes cache if rendering was successful
		$renderer->writeCache();

		return $renderedMath;
	}

	/**
	 * Add the new math rendering options to Special:Preferences.
	 *
	 * @param User $user current User object
	 * @param array &$defaultPreferences Preferences array
	 * @return bool true
	 */
	public static function onGetPreferences( $user, &$defaultPreferences ) {
		global $wgDefaultUserOptions;
		$defaultPreferences['math'] = [
			'type' => 'radio',
			'options' => array_flip( self::getMathNames() ),
			'label' => '&#160;',
			'section' => 'rendering/math',
		];
		// If the default option is not in the valid options the
		// user interface throws an exception (BUG 64844)
		$mode = self::mathModeToString( $wgDefaultUserOptions['math'] );
		$validModes = MathRenderer::getValidModes();
		if ( !in_array( $mode, $validModes ) ) {
			LoggerFactory::getInstance( 'Math' )->error( 'Misconfiguration: ' .
				"\$wgDefaultUserOptions['math'] is not in [ " . implode( ', ', $validModes ) . " ].\n" .
				"Please check your LocalSetting.php file." );
			// Display the checkbox in the first option.
			$wgDefaultUserOptions['math'] = $validModes[0];
		}
		return true;
	}

	/**
	 * List of message keys for the various math output settings.
	 *
	 * @return array of strings
	 */
	public static function getMathNames() {
		$names = [];
		foreach ( MathRenderer::getValidModes() as $mode ) {
			$names[$mode] = wfMessage( 'mw_math_' . $mode )->escaped();
		}

		return $names;
	}

	/**
	 * MaintenanceRefreshLinksInit handler; optimize settings for refreshLinks batch job.
	 *
	 * @param Maintenance $maint
	 * @return bool hook return code
	 */
	public static function onMaintenanceRefreshLinksInit( $maint ) {
		global $wgUser;

		# Don't generate TeX PNGs (the lack of a sensible current directory causes errors anyway)
		$wgUser->setOption( 'math', 'source' );

		return true;
	}

	/**
	 * LoadExtensionSchemaUpdates handler; set up math table on install/upgrade.
	 *
	 * @param DatabaseUpdater|null $updater
	 * @throws Exception
	 * @return bool
	 */
	public static function onLoadExtensionSchemaUpdates( $updater = null ) {
		$type = $updater->getDB()->getType();

		if ( in_array( 'latexml', MathRenderer::getValidModes() ) ) {
			if ( in_array( $type, [ 'mysql', 'sqlite', 'postgres' ] ) ) {
				$sql = __DIR__ . '/../db/mathlatexml.' . $type . '.sql';
				$updater->addExtensionTable( 'mathlatexml', $sql );
				if ( $type == 'mysql' ) {
					$sql = __DIR__ . '/../db/patches/mathlatexml.mathml-length-adjustment.mysql.sql';
					$updater->modifyExtensionField( 'mathlatexml', 'math_mathml', $sql );
				}
			} else {
				throw new Exception( "Math extension does not currently support $type database for LaTeXML." );
			}
		}
		if ( in_array( 'mathml', MathRenderer::getValidModes() ) ) {
			if ( in_array( $type, [ 'mysql', 'sqlite', 'postgres' ] ) ) {
				$sql = __DIR__ . '/../db/mathoid.' . $type . '.sql';
				$updater->addExtensionTable( 'mathoid', $sql );
				if ( $type == 'mysql' ) {
					$sql = __DIR__ . '/../db/patches/mathoid.add_png.mysql.sql';
					$updater->addExtensionField( 'mathoid', 'math_png', $sql );
				}
			} else {
				throw new Exception( "Math extension does not currently support $type database for Mathoid." );
			}
		}

		return true;
	}

	/**
	 * Add 'math' and 'mathlatexml' tables to the list of tables that need to be copied to
	 * temporary tables for parser tests to run.
	 *
	 * @param array &$tables
	 * @return bool
	 */
	public static function onParserTestTables( &$tables ) {
		$tables[] = 'math';
		$tables[] = 'mathlatexml';
		return true;
	}

	/**
	 * @param Parser $parser
	 * @param string &$text
	 * @return bool
	 */
	public static function onParserAfterTidy( $parser, &$text ) {
		global $wgMathoidCli;
		if ( $wgMathoidCli ) {
			MathMathMLCli::batchEvaluate( self::$tags );
		} else {
			MathMathML::batchEvaluate( self::$tags );
		}
		foreach ( self::$tags as $key => $tag ) {
			$value = call_user_func_array( [ self::class, 'mathPostTagHook' ], $tag );
			// Workaround for https://phabricator.wikimedia.org/T103269
			$text = preg_replace( '/(<mw:editsection[^>]*>.*?)' . preg_quote( $key ) .
				'(.*?)<\/mw:editsection>/',
				'\1 $' . htmlspecialchars( $tag[0]->getTex() ) . '\2</mw:editsection>', $text );
			$text = str_replace( $key, $value, $text );
		}
		// This hook might be called multiple times. However one the tags are rendered the job is done.
		self::$tags = [];
		return true;
	}

	public static function registerExtension() {
		global $wgDefaultUserOptions, $wgMathValidModes, $wgMathDisableTexFilter;
		$wgMathValidModes = MathRenderer::getValidModes();
		if ( $wgMathDisableTexFilter === true ) { // ensure backwards compatibility
			$wgMathDisableTexFilter = 'never';
		}
		$wgMathDisableTexFilter = MathRenderer::getDisableTexFilter();
		$wgDefaultUserOptions['math'] = self::mathModeToString( $wgDefaultUserOptions['math'] );
	}

	/**
	 * Callback function for the <ce> parser hook.
	 *
	 * @param string $content (the LaTeX input)
	 * @param array $attributes
	 * @param Parser $parser
	 * @return array
	 */
	public static function chemTagHook( $content, $attributes, $parser ) {
		$attributes['chem'] = true;
		return self::mathTagHook( '\ce{' . $content . '}', $attributes, $parser );
	}

}