<?php
/**
 * Implement the 'templatedata' query module in the API.
 * Format JSON only.
 *
 * @file
 */

use MediaWiki\MediaWikiServices;

/**
 * @ingroup API
 * @emits error.code templatedata-corrupt
 * @todo Support continuation (see I1a6e51cd)
 */
class ApiTemplateData extends ApiBase {

	/**
	 * @var ApiPageSet|null
	 */
	private $mPageSet = null;

	/**
	 * For backwards compatibility, this module needs to output format=json when
	 * no format is specified.
	 * @return ApiFormatBase|null
	 */
	public function getCustomPrinter() {
		if ( $this->getMain()->getVal( 'format' ) === null ) {
			$this->addDeprecation(
				'apiwarn-templatedata-deprecation-format', 'action=templatedata&!format'
			);
			return $this->getMain()->createPrinterByName( 'json' );
		}
		return null;
	}

	/**
	 * @return ApiPageSet
	 */
	private function getPageSet() {
		if ( $this->mPageSet === null ) {
			$this->mPageSet = new ApiPageSet( $this );
		}
		return $this->mPageSet;
	}

	/**
	 * @inheritDoc
	 */
	public function execute() {
		$services = MediaWikiServices::getInstance();
		$params = $this->extractRequestParams();
		$result = $this->getResult();

		$continuationManager = new ApiContinuationManager( $this, [], [] );
		$this->setContinuationManager( $continuationManager );

		if ( $params['lang'] === null ) {
			$langCode = false;
		} elseif ( !$services->getLanguageNameUtils()->isValidCode( $params['lang'] ) ) {
			$this->dieWithError( [ 'apierror-invalidlang', 'lang' ] );
			throw new LogicException();
		} else {
			$langCode = $params['lang'];
		}

		$pageSet = $this->getPageSet();
		$pageSet->execute();
		$titles = $pageSet->getGoodTitles(); // page_id => Title object
		$missingTitles = $pageSet->getMissingTitles(); // page_id => Title object

		$includeMissingTitles = $this->getParameter( 'includeMissingTitles' );
		$doNotIgnoreMissingTitles = $this->getParameter( 'doNotIgnoreMissingTitles' );
		if ( $doNotIgnoreMissingTitles ) {
			$includeMissingTitles = $doNotIgnoreMissingTitles;
		}

		if ( !$titles && ( !$includeMissingTitles || !$missingTitles ) ) {
			$result->addValue( null, 'pages', (object)[] );
			$this->setContinuationManager();
			$continuationManager->setContinuationIntoResult( $this->getResult() );
			return;
		}

		$resp = [];

		if ( $includeMissingTitles ) {
			foreach ( $missingTitles as $missingTitleId => $missingTitle ) {
				$resp[ $missingTitleId ] = [ 'title' => $missingTitle, 'missing' => true ];
			}

			foreach ( $titles as $titleId => $title ) {
				$resp[ $titleId ] = [ 'title' => $title, 'notemplatedata' => true ];
			}
		}

		if ( $titles ) {
			$db = $this->getDB();
			$res = $db->select( 'page_props',
				[ 'pp_page', 'pp_value' ], [
					'pp_page' => array_keys( $titles ),
					'pp_propname' => 'templatedata'
				],
				__METHOD__,
				[ 'ORDER BY', 'pp_page' ]
			);

			foreach ( $res as $row ) {
				$rawData = $row->pp_value;
				$tdb = TemplateDataBlob::newFromDatabase( $db, $rawData );
				$status = $tdb->getStatus();

				if ( !$status->isOK() ) {
					$this->dieWithError(
						[ 'apierror-templatedata-corrupt', intval( $row->pp_page ), $status->getMessage() ]
					);
				}

				if ( $langCode !== false ) {
					$data = $tdb->getDataInLanguage( $langCode );
				} else {
					$data = $tdb->getData();
				}

				// HACK: don't let ApiResult's formatversion=1 compatibility layer mangle our booleans
				// to empty strings / absent properties
				foreach ( $data->params as $param ) {
					$param->{ApiResult::META_BC_BOOLS} = [ 'required', 'suggested', 'deprecated' ];
				}

				$data->params->{ApiResult::META_TYPE} = 'kvp';
				$data->params->{ApiResult::META_KVP_KEY_NAME} = 'key';
				$data->params->{ApiResult::META_INDEXED_TAG_NAME} = 'param';
				if ( isset( $data->paramOrder ) ) {
					ApiResult::setIndexedTagName( $data->paramOrder, 'p' );
				}

				if ( $includeMissingTitles ) {
					unset( $resp[$row->pp_page]['notemplatedata'] );
				} else {
					$resp[ $row->pp_page ] = [ 'title' => $titles[ $row->pp_page ] ];
				}
				$resp[$row->pp_page] += (array)$data;
			}
		}

		$wikiPageFactory = $services->getWikiPageFactory();

		// Now go through all the titles again, and attempt to extract parameter names from the
		// wikitext for templates with no templatedata.
		if ( $includeMissingTitles ) {
			foreach ( $resp as $pageId => $pageInfo ) {
				if ( !isset( $pageInfo['notemplatedata'] ) ) {
					// Ignore pages that already have templatedata or that don't exist.
					continue;
				}

				$content = $wikiPageFactory->newFromTitle( $pageInfo['title'] )->getContent();
				$text = $content instanceof TextContent
					? $content->getText()
					: $content->getTextForSearchIndex();
				$resp[ $pageId ][ 'params' ] = TemplateDataBlob::getRawParams( $text );
			}
		}

		// TODO tracking will only be implemented temporarily to answer questions on
		// template usage for the Technical Wishes topic area see T258917
		if ( ExtensionRegistry::getInstance()->isLoaded( 'EventLogging' ) ) {
			foreach ( $resp as $pageInfo ) {
				EventLogging::logEvent(
					'TemplateDataApi',
					-1,
					[
						'template_name' => $wikiPageFactory->newFromTitle( $pageInfo['title'] )
							->getTitle()->getDBkey(),
						'has_template_data' => !isset( $pageInfo['notemplatedata'] ),
					]
				);
			}
		}

		ApiResult::setArrayType( $resp, 'kvp', 'id' );
		ApiResult::setIndexedTagName( $resp, 'page' );

		// Set top level element
		$result->addValue( null, 'pages', (object)$resp );

		$values = $pageSet->getNormalizedTitlesAsResult();
		if ( $values ) {
			$result->addValue( null, 'normalized', $values );
		}
		$redirects = $pageSet->getRedirectTitlesAsResult();
		if ( $redirects ) {
			$result->addValue( null, 'redirects', $redirects );
		}

		$this->setContinuationManager();
		$continuationManager->setContinuationIntoResult( $this->getResult() );
	}

	/**
	 * @inheritDoc
	 */
	public function getAllowedParams( $flags = 0 ) {
		$result = [
			'includeMissingTitles' => [
				ApiBase::PARAM_TYPE => 'boolean',
			],
			'doNotIgnoreMissingTitles' => [
				ApiBase::PARAM_TYPE => 'boolean',
				ApiBase::PARAM_DEPRECATED => true,
			],
			'lang' => [
				ApiBase::PARAM_TYPE => 'string',
			],
		];
		if ( $flags ) {
			$result += $this->getPageSet()->getFinalParams( $flags );
		}
		return $result;
	}

	/**
	 * @inheritDoc
	 */
	protected function getExamplesMessages() {
		return [
			'action=templatedata&titles=Template:Stub|Template:Example&includeMissingTitles=1'
				=> 'apihelp-templatedata-example-1',
			'action=templatedata&titles=Template:Stub|Template:Example'
				=> 'apihelp-templatedata-example-2',
		];
	}

	/**
	 * @inheritDoc
	 */
	public function getHelpUrls() {
		return 'https://www.mediawiki.org/wiki/Special:MyLanguage/Extension:TemplateData';
	}
}