<?php

/**
 * API module to send thanks notifications for revisions and log entries.
 *
 * @ingroup API
 * @ingroup Extensions
 */
class ApiCoreThank extends ApiThank {

	/**
	 * Perform the API request.
	 */
	public function execute() {
		// Initial setup.
		$this->dieIfEchoNotInstalled();
		$user = $this->getUser();
		$this->dieOnBadUser( $user );
		$params = $this->extractRequestParams();

		// Extract type and ID from the parameters.
		if ( isset( $params['rev'] ) && !isset( $params['log'] ) ) {
			$type = 'rev';
			$id = $params['rev'];
		} elseif ( !isset( $params['rev'] ) && isset( $params['log'] ) ) {
			$type = 'log';
			$id = $params['log'];
		} else {
			$this->dieWithError( 'thanks-error-api-params', 'thanks-error-api-params' );
		}

		// Determine thanks parameters.
		if ( $type === 'log' ) {
			$logEntry = $this->getLogEntryFromId( $id );
			// If there's an associated revision, thank for that instead.
			if ( $logEntry->getAssociatedRevId() ) {
				$type = 'rev';
				$id = $logEntry->getAssociatedRevId();
			} else {
				$formatter = LogFormatter::newFromEntry( $logEntry );
				$excerpt = $formatter->getPlainActionText();
				$title = $logEntry->getTarget();
				$recipient = $this->getUserFromLog( $logEntry );
				$recipientUsername = $recipient->getName();
			}
		}
		if ( $type === 'rev' ) {
			$revision = $this->getRevisionFromParams( $params );
			$excerpt = EchoDiscussionParser::getEditExcerpt( $revision, $this->getLanguage() );
			$title = $this->getTitleFromRevision( $revision );
			$recipient = $this->getUserFromRevision( $revision );
			$recipientUsername = $revision->getUserText();
		}

		// Send thanks.
		if ( $this->userAlreadySentThanks( $user, $type, $id ) ) {
			$this->markResultSuccess( $recipientUsername );
		} else {
			$this->dieOnBadRecipient( $user, $recipient );
			$this->sendThanks(
				$user,
				$type,
				$id,
				$excerpt,
				$recipient,
				$this->getSourceFromParams( $params ),
				$title
			);
		}
	}

	/**
	 * Check the session data for an indication of whether this user has already sent this thanks.
	 * @param User $user The user being thanked.
	 * @param string $type Either 'rev' or 'log'.
	 * @param int $id The revision or log ID.
	 * @return bool
	 */
	protected function userAlreadySentThanks( User $user, $type, $id ) {
		return (bool)$user->getRequest()->getSessionData( "thanks-thanked-$type$id" );
	}

	private function getRevisionFromParams( $params ) {
		$revision = Revision::newFromId( $params['rev'] );
		// Revision ID 1 means an invalid argument was passed in.
		if ( !$revision || $revision->getId() === 1 ) {
			$this->dieWithError( 'thanks-error-invalidrevision', 'invalidrevision' );
		} elseif ( $revision->isDeleted( Revision::DELETED_TEXT ) ) {
			$this->dieWithError( 'thanks-error-revdeleted', 'revdeleted' );
		}
		return $revision;
	}

	/**
	 * Get the log entry from the ID.
	 * @param int $logId The log entry ID.
	 * @return DatabaseLogEntry
	 */
	protected function getLogEntryFromId( $logId ) {
		$queryInfo = DatabaseLogEntry::getSelectQueryData();
		$queryInfo['conds'] += [ 'log_id' => $logId ];
		$db = wfGetDB( DB_REPLICA );
		$logEntryData = $db->select(
			$queryInfo['tables'],
			$queryInfo['fields'],
			$queryInfo['conds'],
			__METHOD__,
			$queryInfo['options'],
			$queryInfo['join_conds']
		);
		$logEntry = DatabaseLogEntry::newFromRow( $logEntryData->current() );

		// Make sure this log type is whitelisted.
		$logTypeWhitelist = $this->getConfig()->get( 'ThanksLogTypeWhitelist' );
		if ( !in_array( $logEntry->getType(), $logTypeWhitelist ) ) {
			$err = $this->msg( 'thanks-error-invalid-log-type', $logEntry->getType() );
			$this->dieWithError( $err, 'thanks-error-invalid-log-type' );
		}

		// Don't permit thanks if any part of the log entry is deleted.
		if ( $logEntry->getDeleted() ) {
			$this->dieWithError( 'thanks-error-log-deleted', 'thanks-error-log-deleted' );
		}

		return $logEntry;
	}

	private function getTitleFromRevision( Revision $revision ) {
		$title = Title::newFromID( $revision->getPage() );
		if ( !$title instanceof Title ) {
			$this->dieWithError( 'thanks-error-notitle', 'notitle' );
		}
		return $title;
	}

	/**
	 * Set the source of the thanks, e.g. 'diff' or 'history'
	 * @param string[] $params Incoming API parameters, with a 'source' key.
	 * @return string The source, or 'undefined' if not provided.
	 */
	private function getSourceFromParams( $params ) {
		if ( $params['source'] ) {
			return trim( $params['source'] );
		} else {
			return 'undefined';
		}
	}

	private function getUserFromRevision( Revision $revision ) {
		$recipient = $revision->getUser();
		if ( !$recipient ) {
			$this->dieWithError( 'thanks-error-invalidrecipient', 'invalidrecipient' );
		}
		return User::newFromId( $recipient );
	}

	private function getUserFromLog( LogEntry $logEntry ) {
		$recipient = $logEntry->getPerformer();
		if ( !$recipient ) {
			$this->dieWithError( 'thanks-error-invalidrecipient', 'invalidrecipient' );
		}
		return $recipient;
	}

	/**
	 * Create the thanks notification event, and log the thanks.
	 * @param User $user The thanks-sending user.
	 * @param string $type The thanks type ('rev' or 'log').
	 * @param int $id The log or revision ID.
	 * @param string $excerpt The excerpt to display as the thanks notification. This will only
	 * be used if it is not possible to retrieve the relevant excerpt at the time the
	 * notification is displayed (in order to account for changing visibility in the meantime).
	 * @param User $recipient The recipient of the thanks.
	 * @param string $source Where the thanks was given.
	 * @param Title $title The title of the page for which thanks is given.
	 */
	protected function sendThanks(
		User $user, $type, $id, $excerpt, User $recipient, $source, Title $title
	) {
		$uniqueId = $type . '-' . $id;
		// Do one last check to make sure we haven't sent Thanks before
		if ( $this->haveAlreadyThanked( $user, $uniqueId ) ) {
			// Pretend the thanks were sent
			$this->markResultSuccess( $recipient->getName() );
			return;
		}

		// Create the notification via Echo extension
		EchoEvent::create( [
			'type' => 'edit-thank',
			'title' => $title,
			'extra' => [
				$type . 'id' => $id,
				'thanked-user-id' => $recipient->getId(),
				'source' => $source,
				'excerpt' => $excerpt,
			],
			'agent' => $user,
		] );

		// And mark the thank in session for a cheaper check to prevent duplicates (Phab:T48690).
		$user->getRequest()->setSessionData( "thanks-thanked-$type$id", true );
		// Set success message
		$this->markResultSuccess( $recipient->getName() );
		$this->logThanks( $user, $recipient, $uniqueId );
	}

	public function getAllowedParams() {
		return [
			'rev' => [
				ApiBase::PARAM_TYPE => 'integer',
				ApiBase::PARAM_MIN => 1,
				ApiBase::PARAM_REQUIRED => false,
			],
			'log' => [
				ApiBase::PARAM_TYPE => 'integer',
				ApiBase::PARAM_MIN => 1,
				ApiBase::PARAM_REQUIRED => false,
			],
			'token' => [
				ApiBase::PARAM_TYPE => 'string',
				ApiBase::PARAM_REQUIRED => true,
			],
			'source' => [
				ApiBase::PARAM_TYPE => 'string',
				ApiBase::PARAM_REQUIRED => false,
			]
		];
	}

	public function getHelpUrls() {
		return [
			'https://www.mediawiki.org/wiki/Extension:Thanks#API_Documentation',
		];
	}

	/**
	 * @see ApiBase::getExamplesMessages()
	 * @return array
	 */
	protected function getExamplesMessages() {
		return [
			'action=thank&revid=456&source=diff&token=123ABC'
				=> 'apihelp-thank-example-1',
		];
	}
}