<?php

namespace MediaWiki\Extension\Notifications;

use LogicException;
use MediaWiki\Api\ApiModuleManager;
use MediaWiki\Api\Hook\ApiMain__moduleManagerHook;
use MediaWiki\Auth\AuthManager;
use MediaWiki\Config\Config;
use MediaWiki\DAO\WikiAwareEntity;
use MediaWiki\Deferred\DeferredUpdates;
use MediaWiki\Deferred\Hook\LinksUpdateCompleteHook;
use MediaWiki\Deferred\LinksUpdate\LinksTable;
use MediaWiki\Deferred\LinksUpdate\LinksUpdate;
use MediaWiki\Extension\Notifications\Controller\ModerationController;
use MediaWiki\Extension\Notifications\Controller\NotificationController;
use MediaWiki\Extension\Notifications\Formatters\EchoEventPresentationModel;
use MediaWiki\Extension\Notifications\Hooks\HookRunner;
use MediaWiki\Extension\Notifications\Mapper\EventMapper;
use MediaWiki\Extension\Notifications\Mapper\NotificationMapper;
use MediaWiki\Extension\Notifications\Model\Event;
use MediaWiki\Extension\Notifications\Notifications\UserRightsNotification;
use MediaWiki\Extension\Notifications\Push\Api\ApiEchoPushSubscriptions;
use MediaWiki\Hook\PreferencesGetIconHook;
use MediaWiki\HookContainer\HookContainer;
use MediaWiki\HTMLForm\Field\HTMLCheckMatrix;
use MediaWiki\Language\Language;
use MediaWiki\Linker\LinkRenderer;
use MediaWiki\Mail\MailAddress;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Notification\NotificationService;
use MediaWiki\Notification\RecipientSet;
use MediaWiki\Notification\Types\WikiNotification;
use MediaWiki\Output\Hook\BeforePageDisplayHook;
use MediaWiki\Output\Hook\OutputPageCheckLastModifiedHook;
use MediaWiki\Output\OutputPage;
use MediaWiki\Page\Hook\ArticleUndeleteHook;
use MediaWiki\Page\Hook\RollbackCompleteHook;
use MediaWiki\Page\WikiPage;
use MediaWiki\Permissions\PermissionManager;
use MediaWiki\Preferences\Hook\GetPreferencesHook;
use MediaWiki\Preferences\MultiTitleFilter;
use MediaWiki\Preferences\MultiUsernameFilter;
use MediaWiki\RecentChanges\Hook\RecentChange_saveHook;
use MediaWiki\RecentChanges\RecentChange;
use MediaWiki\Registration\ExtensionRegistry;
use MediaWiki\Request\WebRequest;
use MediaWiki\ResourceLoader as RL;
use MediaWiki\ResourceLoader\Hook\ResourceLoaderRegisterModulesHook;
use MediaWiki\ResourceLoader\ResourceLoader;
use MediaWiki\Revision\RevisionRecord;
use MediaWiki\Skin\Hook\GetNewMessagesAlertHook;
use MediaWiki\Skin\Hook\SkinTemplateNavigation__UniversalHook;
use MediaWiki\Skin\Skin;
use MediaWiki\Skin\SkinTemplate;
use MediaWiki\SpecialPage\SpecialPage;
use MediaWiki\Specials\Hook\EmailUserCompleteHook;
use MediaWiki\Specials\Hook\LoginFormValidErrorMessagesHook;
use MediaWiki\Specials\Hook\SpecialMuteModifyFormFieldsHook;
use MediaWiki\Title\NamespaceInfo;
use MediaWiki\Title\Title;
use MediaWiki\User\CentralId\CentralIdLookup;
use MediaWiki\User\Hook\UserClearNewTalkNotificationHook;
use MediaWiki\User\Hook\UserGetDefaultOptionsHook;
use MediaWiki\User\Hook\UserGroupsChangedHook;
use MediaWiki\User\Hook\UserSaveSettingsHook;
use MediaWiki\User\Options\Hook\LoadUserOptionsHook;
use MediaWiki\User\Options\Hook\SaveUserOptionsHook;
use MediaWiki\User\Options\UserOptionsManager;
use MediaWiki\User\TalkPageNotificationManager;
use MediaWiki\User\User;
use MediaWiki\User\UserEditTracker;
use MediaWiki\User\UserFactory;
use MediaWiki\User\UserIdentity;
use MediaWiki\WikiMap\WikiMap;
use MobileContext;
use Wikimedia\Message\MessageValue;
use Wikimedia\Stats\StatsFactory;

class Hooks implements
	ApiMain__moduleManagerHook,
	ArticleUndeleteHook,
	BeforePageDisplayHook,
	EmailUserCompleteHook,
	GetNewMessagesAlertHook,
	GetPreferencesHook,
	LinksUpdateCompleteHook,
	LoadUserOptionsHook,
	LoginFormValidErrorMessagesHook,
	OutputPageCheckLastModifiedHook,
	PreferencesGetIconHook,
	RecentChange_saveHook,
	ResourceLoaderRegisterModulesHook,
	RollbackCompleteHook,
	SaveUserOptionsHook,
	SkinTemplateNavigation__UniversalHook,
	UserClearNewTalkNotificationHook,
	UserGetDefaultOptionsHook,
	UserGroupsChangedHook,
	UserSaveSettingsHook,
	SpecialMuteModifyFormFieldsHook
{
	private readonly StatsFactory $statsFactory;

	private static array $revertedRevIds = [];

	public function __construct(
		private readonly AuthManager $authManager,
		private readonly CentralIdLookup $centralIdLookup,
		private readonly Config $config,
		private readonly AttributeManager $attributeManager,
		private readonly HookContainer $hookContainer,
		private readonly Language $contentLanguage,
		private readonly LinkRenderer $linkRenderer,
		private readonly NamespaceInfo $namespaceInfo,
		private readonly NotificationService $notificationService,
		private readonly PermissionManager $permissionManager,
		StatsFactory $statsFactory,
		private readonly TalkPageNotificationManager $talkPageNotificationManager,
		private readonly UserEditTracker $userEditTracker,
		private readonly UserFactory $userFactory,
		private readonly UserOptionsManager $userOptionsManager,
		private readonly ?MobileContext $mobileContext,
	) {
		$this->statsFactory = $statsFactory->withComponent( 'Echo' );
	}

	/**
	 * @param array &$defaults
	 */
	public function onUserGetDefaultOptions( &$defaults ) {
		if ( $this->config->get( MainConfigNames::AllowHTMLEmail ) ) {
			$defaults['echo-email-format'] = 'html';
		} else {
			$defaults['echo-email-format'] = 'plain-text';
		}

		$presets = [
			// Set all of the events to notify by web but not email by default
			// (won't affect events that don't email)
			'default' => [
				'email' => false,
				'web' => true,
			],
			// most settings default to web on, email off, but override these
			'system' => [
				'email' => true,
			],
			'user-rights' => [
				'email' => true,
			],
			'article-linked' => [
				'web' => false,
			],
			'mention-failure' => [
				'web' => false,
			],
			'mention-success' => [
				'web' => false,
			],
			'watchlist' => [
				'web' => false,
			],
			'minor-watchlist' => [
				'web' => false,
			],
			'api-triggered' => [
				// emails are sent only if sender also sets the API option, which is disabled by default
				'email' => true,
			],
			'verify-email-reminder' => [
				'web' => true,
				// Echo emails are generally not sent if the user doesn't have a confirmed email
				// address, but we special case this notification type because of its
				// account security implications, see Notifier::notifyWithEmail
				'email' => true,
			],
		];

		$echoPushEnabled = $this->config->get( ConfigNames::EnablePush );
		if ( $echoPushEnabled ) {
			$presets['default']['push'] = true;
			$presets['article-linked']['push'] = false;
			$presets['mention-failure']['push'] = false;
			$presets['mention-success']['push'] = false;
			$presets['watchlist']['push'] = false;
			$presets['minor-watchlist']['push'] = false;
		}

		foreach ( $this->config->get( ConfigNames::NotificationCategories ) as $category => $categoryData ) {
			if ( !isset( $defaults["echo-subscriptions-email-{$category}"] ) ) {
				$defaults["echo-subscriptions-email-{$category}"] = $presets[$category]['email']
					?? $presets['default']['email'];
			}
			if ( !isset( $defaults["echo-subscriptions-web-{$category}"] ) ) {
				$defaults["echo-subscriptions-web-{$category}"] = $presets[$category]['web']
					?? $presets['default']['web'];
			}
			if ( $echoPushEnabled && !isset( $defaults["echo-subscriptions-push-{$category}"] ) ) {
				$defaults["echo-subscriptions-push-{$category}"] = $presets[$category]['push']
					// @phan-suppress-next-line PhanTypePossiblyInvalidDimOffset
					?? $presets['default']['push'];
			}
		}
	}

	/**
	 * Initialize Echo extension with necessary data, this function is invoked
	 * from $wgExtensionFunctions
	 */
	public static function initEchoExtension() {
		global $wgEchoNotifications, $wgEchoNotificationCategories, $wgEchoNotificationIcons,
			$wgEchoMentionStatusNotifications, $wgAllowArticleReminderNotification, $wgAPIModules,
			$wgEchoWatchlistNotifications, $wgEchoSeenTimeCacheType, $wgMainStash, $wgEnableEmail,
			$wgEnableUserEmail, $wgEchoEnableApiEvents;

		// add events defined in extension attributes (extension.json)
		$exReg = ExtensionRegistry::getInstance();
		$wgEchoNotifications += $exReg->getAttribute( 'EchoNotifications' );
		$wgEchoNotificationCategories += $exReg->getAttribute( 'EchoNotificationCategories' );
		$wgEchoNotificationIcons += $exReg->getAttribute( 'EchoNotificationIcons' );
		// allow extensions to define their events dynamically, or modify existing ones (deprecated)
		( new HookRunner( MediaWikiServices::getInstance()->getHookContainer() ) )->onBeforeCreateEchoEvent(
			$wgEchoNotifications, $wgEchoNotificationCategories, $wgEchoNotificationIcons );

		// Only allow mention status notifications when enabled
		if ( !$wgEchoMentionStatusNotifications ) {
			unset( $wgEchoNotificationCategories['mention-failure'] );
			unset( $wgEchoNotificationCategories['mention-success'] );
		}

		// Only allow article reminder notifications when enabled
		if ( !$wgAllowArticleReminderNotification ) {
			unset( $wgEchoNotificationCategories['article-reminder'] );
			unset( $wgAPIModules['echoarticlereminder'] );
		}

		// Only allow watchlist notifications when enabled
		if ( !$wgEchoWatchlistNotifications ) {
			unset( $wgEchoNotificationCategories['watchlist'] );
			unset( $wgEchoNotificationCategories['minor-watchlist'] );
		}

		// Only allow user email notifications when enabled
		if ( !$wgEnableEmail || !$wgEnableUserEmail ) {
			unset( $wgEchoNotificationCategories['emailuser'] );
		}

		// Only allow API-triggered notifications when enabled
		if ( !$wgEchoEnableApiEvents ) {
			unset( $wgEchoNotificationCategories['api-triggered'] );
		}

		// Default $wgEchoSeenTimeCacheType to $wgMainStash
		$wgEchoSeenTimeCacheType ??= $wgMainStash;
	}

	/**
	 * Handler for ResourceLoaderRegisterModules hook
	 */
	public function onResourceLoaderRegisterModules( ResourceLoader $resourceLoader ): void {
		$resourceLoader->register( 'ext.echo.emailicons', [
			'class' => ResourceLoaderEchoImageModule::class,
			'icons' => $this->config->get( ConfigNames::NotificationIcons ),
			'selector' => '.mw-echo-icon-{name}',
			'localBasePath' => $this->config->get( MainConfigNames::ExtensionDirectory ),
			'remoteExtPath' => 'Echo/modules',
		] );
		$resourceLoader->register( 'ext.echo.secondaryicons', [
			'class' => ResourceLoaderEchoImageModule::class,
			'icons' => $this->config->get( ConfigNames::SecondaryIcons ),
			'selector' => '.mw-echo-icon-{name}',
			'localBasePath' => $this->config->get( MainConfigNames::ExtensionDirectory ),
			'remoteExtPath' => 'Echo/modules',
		] );
	}

	/**
	 * Handler for GetPreferences hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/GetPreferences
	 *
	 * @param User $user User to get preferences for
	 * @param array &$preferences Preferences array
	 */
	public function onGetPreferences( $user, &$preferences ) {
		// The following messages are generated upstrem:
		// * prefs-echo
		// * prefs-description-echo

		// Show email frequency options
		$freqOptions = [
			'echo-pref-email-frequency-never' => EmailFrequency::NEVER,
			'echo-pref-email-frequency-immediately' => EmailFrequency::IMMEDIATELY,
		];
		// Only show digest options if email batch is enabled
		if ( $this->config->get( ConfigNames::EnableEmailBatch ) ) {
			$freqOptions += [
				'echo-pref-email-frequency-daily' => EmailFrequency::DAILY_DIGEST,
				'echo-pref-email-frequency-weekly' => EmailFrequency::WEEKLY_DIGEST,
			];
		}
		$preferences['echo-email-frequency'] = [
			'type' => 'select',
			'label-message' => 'echo-pref-send-me',
			// The following message is generated upstrem:
			// * prefs-emailsettings
			'section' => 'echo/emailsettings',
			'options-messages' => $freqOptions,
		];

		$preferences['echo-dont-email-read-notifications'] = [
			'type' => 'toggle',
			'label-message' => 'echo-pref-dont-email-read-notifications',
			// The following message is generated upstrem:
			// * prefs-emailsettings
			'section' => 'echo/emailsettings',
			'hide-if' => [ 'OR', [ '===', 'echo-email-frequency', '-1' ], [ '===', 'echo-email-frequency', '0' ] ],
		];

		// Display information about the user's currently set email address
		$prefsTitle = SpecialPage::getTitleFor( 'Preferences', false, 'mw-prefsection-echo' );
		$link = $this->linkRenderer->makeLink(
			SpecialPage::getTitleFor( 'ChangeEmail' ),
			wfMessage( $user->getEmail() ? 'prefs-changeemail' : 'prefs-setemail' )->text(),
			[],
			[ 'returnto' => $prefsTitle->getFullText() ]
		);
		$emailAddress = $user->getEmail() && $this->permissionManager->userHasRight( $user, 'viewmyprivateinfo' )
			? htmlspecialchars( $user->getEmail() ) : '';
		if ( $this->permissionManager->userHasRight( $user, 'editmyprivateinfo' ) && $this->isEmailChangeAllowed() ) {
			if ( $emailAddress === '' ) {
				$emailAddress .= $link;
			} else {
				$emailAddress .= wfMessage( 'word-separator' )->escaped()
					. wfMessage( 'parentheses' )->rawParams( $link )->escaped();
			}
		}
		$preferences['echo-emailaddress'] = [
			'type' => 'info',
			'raw' => true,
			'default' => $emailAddress,
			'label-message' => 'echo-pref-send-to',
			// The following message is generated upstrem:
			// * prefs-emailsettings
			'section' => 'echo/emailsettings',
		];

		// Only show this option if html email is allowed, otherwise it is always plain text format
		if ( $this->config->get( MainConfigNames::AllowHTMLEmail ) ) {
			// Email format
			$preferences['echo-email-format'] = [
				'type' => 'select',
				'label-message' => 'echo-pref-email-format',
				// The following message is generated upstrem:
				// * prefs-emailsettings
				'section' => 'echo/emailsettings',
				'options-messages' => [
					'echo-pref-email-format-html' => EmailFormat::HTML,
					'echo-pref-email-format-plain-text' => EmailFormat::PLAIN_TEXT,
				],
			];
		}

		// Sort notification categories by priority
		$categoriesAndPriorities = [];
		foreach ( $this->attributeManager->getInternalCategoryNames() as $category ) {
			// See if the category should be hidden from preferences.
			if ( !$this->attributeManager->isCategoryDisplayedInPreferences( $category ) ) {
				continue;
			}

			// See if user is eligible to receive this notification (per user group restrictions)
			if ( $this->attributeManager->getCategoryEligibility( $user, $category ) ) {
				$categoriesAndPriorities[$category] = $this->attributeManager->getCategoryPriority( $category );
			}
		}
		asort( $categoriesAndPriorities );
		$validSortedCategories = array_keys( $categoriesAndPriorities );

		// Show subscription options.  IMPORTANT: 'echo-subscriptions-email-edit-user-talk',
		// 'echo-subscriptions-email-watchlist', and 'echo-subscriptions-email-minor-watchlist' are
		// virtual options, their values are saved to existing notification options 'enotifusertalkpages',
		// 'enotifwatchlistpages', and 'enotifminoredits', see onLoadUserOptions() and onSaveUserOptions()
		// for more information on how it is handled. Doing it in this way, we can avoid keeping running
		// massive data migration script to keep these two options synced when echo is enabled on
		// new wikis or Echo is disabled and re-enabled for some reason.  We can update the name
		// if Echo is ever merged to core

		// Build the columns (notify types)
		$columns = [];
		foreach ( $this->config->get( ConfigNames::Notifiers ) as $notifierType => $notifierData ) {
			// The following messages are generated here
			// * echo-pref-web
			// * echo-pref-email
			// * echo-pref-push
			$formatMessage = wfMessage( 'echo-pref-' . $notifierType )->escaped();
			$columns[$formatMessage] = $notifierType;
		}

		// Build the rows (notification categories)
		$rows = [];
		$tooltips = [];
		$notificationCategories = $this->config->get( ConfigNames::NotificationCategories );
		foreach ( $validSortedCategories as $category ) {
			$categoryTitle = $this->attributeManager->getCategoryTitle( $category );
			$categoryTooltip = $this->attributeManager->getCategoryTooltip( $category );

			$categoryMessage = wfMessage( $categoryTitle )->numParams( 1 )->escaped();
			$rows[$categoryMessage] = $category;
			if ( $categoryTooltip ) {
				$tooltips[$categoryMessage] = wfMessage( $categoryTooltip )->text();
			}
		}

		// Figure out the individual exceptions in the matrix and make them disabled
		$forceOptionsOff = $forceOptionsOn = [];
		foreach ( $this->config->get( ConfigNames::Notifiers ) as $notifierType => $notifierData ) {
			foreach ( $validSortedCategories as $category ) {
				// See if this notify type is non-dismissable
				if ( !$this->attributeManager->isNotifyTypeDismissableForCategory( $category, $notifierType ) ) {
					$forceOptionsOn[] = "$notifierType-$category";
				}

				if ( !$this->attributeManager->isNotifyTypeAvailableForCategory( $category, $notifierType ) ) {
					$forceOptionsOff[] = "$notifierType-$category";
				}
			}
		}

		$invalid = array_intersect( $forceOptionsOff, $forceOptionsOn );
		if ( $invalid ) {
			throw new LogicException( sprintf(
				'The following notifications are both forced and removed: %s',
				implode( ', ', $invalid )
			) );
		}
		$preferences['echo-subscriptions'] = [
			'class' => HTMLCheckMatrix::class,
			// The following message is generated upstrem:
			// * prefs-echosubscriptions
			'section' => 'echo/echosubscriptions',
			'rows' => $rows,
			'columns' => $columns,
			'prefix' => 'echo-subscriptions-',
			'force-options-off' => $forceOptionsOff,
			'force-options-on' => $forceOptionsOn,
			'tooltips' => $tooltips,
		];

		if ( $this->config->get( ConfigNames::CrossWikiNotifications ) ) {
			$preferences['echo-cross-wiki-notifications'] = [
				'type' => 'toggle',
				'label-message' => 'echo-pref-cross-wiki-notifications',
				// The following message is generated upstrem:
				// * prefs-echocrosswiki
				'section' => 'echo/echocrosswiki',
			];
		}

		if ( $this->config->get( ConfigNames::PollForUpdates ) ) {
			$preferences['echo-show-poll-updates'] = [
				'type' => 'toggle',
				'label-message' => 'echo-pref-show-poll-updates',
				'help-message' => 'echo-pref-show-poll-updates-help',
				// The following message is generated upstrem:
				// * prefs-echopollupdates
				'section' => 'echo/echopollupdates',
			];
		}

		// If we're using Echo to handle user talk page post or watchlist notifications,
		// hide the old (non-Echo) preferences for them. If Echo is moved to core
		// we'll want to remove the old user options entirely. For now, though,
		// we need to keep it defined in case Echo is ever uninstalled.
		// Otherwise, that preference could be lost entirely. This hiding logic
		// is not abstracted since there are only three preferences in core
		// that are potentially made obsolete by Echo.
		$notifications = $this->config->get( ConfigNames::Notifications );
		if ( isset( $notifications['edit-user-talk'] ) ) {
			$preferences['enotifusertalkpages']['type'] = 'hidden';
			unset( $preferences['enotifusertalkpages']['section'] );
		}
		if ( $this->config->get( ConfigNames::WatchlistNotifications ) &&
			isset( $notifications['watchlist-change'] )
		) {
			$preferences['enotifwatchlistpages']['type'] = 'hidden';
			unset( $preferences['enotifusertalkpages']['section'] );
			$preferences['enotifminoredits']['type'] = 'hidden';
			unset( $preferences['enotifminoredits']['section'] );
		}

		if ( $this->config->get( ConfigNames::PerUserBlacklist ) ) {
			$preferences['echo-notifications-blacklist'] = [
				'type' => 'usersmultiselect',
				'label-message' => 'echo-pref-notifications-blacklist',
				// The following message is generated upstrem:
				// * prefs-blocknotificationslist
				'section' => 'echo/blocknotificationslist',
				'filter' => MultiUsernameFilter::class,
			];
			$preferences['echo-notifications-page-linked-title-muted-list'] = [
				'type' => 'titlesmultiselect',
				'label-message' => 'echo-pref-notifications-page-linked-title-muted-list',
				// The following message is generated upstrem:
				// * prefs-mutedpageslist
				'section' => 'echo/mutedpageslist',
				'showMissing' => false,
				'creatable' => true,
				'filter' => new MultiTitleFilter(),
			];
		}
	}

	/**
	 * Add icon for Special:Preferences mobile layout
	 *
	 * @param array &$iconNames Array of icon names for their respective sections.
	 */
	public function onPreferencesGetIcon( &$iconNames ) {
		$iconNames[ 'echo' ] = 'bell';
	}

	/**
	 * Test whether email address change is supposed to be allowed
	 * @return bool
	 */
	private function isEmailChangeAllowed() {
		return $this->authManager->allowsPropertyChange( 'emailaddress' );
	}

	/**
	 * Handler for UserGroupsChanged hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/UserGroupsChanged
	 *
	 * @param UserIdentity $userId user that was changed
	 * @param string[] $add strings corresponding to groups added
	 * @param string[] $remove strings corresponding to groups removed
	 * @param User|bool $performer User who performed the change, or false for automatic changes
	 * @param string|bool $reason Reason given by the user changing the rights
	 * @param array $oldUGMs
	 * @param array $newUGMs
	 */
	public function onUserGroupsChanged( $userId, $add, $remove, $performer, $reason, $oldUGMs, $newUGMs ) {
		if ( $userId->getWikiId() !== WikiAwareEntity::LOCAL ) {
			// TODO: Support external users
			return;
		}

		$user = $this->userFactory->newFromUserIdentity( $userId );

		// Automatic changes (e.g. expiry) have no performer
		if ( !$performer ) {
			if ( $remove ) {
				$systemUser = self::getSystemUser();
				if ( !$systemUser ) {
					// loading the system user can fail in readOnly mode. skip the
					// Echo side-effect rather than breaking the rights expiry flow
					return;
				}

				$notification = new WikiNotification(
					'user-rights',
					$user->getUserPage(),
					$systemUser,
					[
						'user' => $user->getId(),
						'remove' => $remove,
						'automatic' => true,
					]
				);

				$this->notificationService->notify(
					$notification,
					new RecipientSet( [ $user ] )
				);
			}

			return;
		}

		// Don't notify for self changes
		if ( $user->equals( $performer ) ) {
			return;
		}

		// If any old groups are in $add, those groups are having their expiry
		// changed, not actually being added
		$expiryChanged = [];
		$reallyAdded = [];
		foreach ( $add as $group ) {
			if ( isset( $oldUGMs[$group] ) ) {
				$expiryChanged[] = $group;
			} else {
				$reallyAdded[] = $group;
			}
		}

		if ( $expiryChanged ) {
			// use a separate notification for these, so the notification text doesn't
			// get too long
			//
			$notification = UserRightsNotification::newForExpiryChanged(
				$user, $performer, $reason, $expiryChanged
			);

			$this->notificationService->notify(
				$notification, new RecipientSet( [ $user ] )
			);
		}

		if ( $reallyAdded || $remove ) {
			$notification = UserRightsNotification::newForRightsChange(
				$user, $performer, $reason, $reallyAdded, $remove
			);
			$this->notificationService->notify(
				$notification, new RecipientSet( [ $user ] )
			);
		}
	}

	/**
	 * Handler for LinksUpdateComplete hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/LinksUpdateComplete
	 * @param LinksUpdate $linksUpdate
	 * @param mixed $ticket
	 */
	public function onLinksUpdateComplete( $linksUpdate, $ticket ) {
		// Rollback or undo should not trigger link notification
		if ( $linksUpdate->getRevisionRecord() ) {
			$revId = $linksUpdate->getRevisionRecord()->getId();
			if ( isset( self::$revertedRevIds[$revId] ) ) {
				return;
			}
		}

		// Import should not trigger link notification (T381125)
		if ( $linksUpdate->getCauseAction() === 'page-import' ) {
			return;
		}

		// Handle only
		// 1. content namespace pages &&
		// 2. non-transcluding pages &&
		// 3. non-redirect pages
		if ( !$this->namespaceInfo->isContent( $linksUpdate->getTitle()->getNamespace() )
			|| !$linksUpdate->isRecursive() || $linksUpdate->getTitle()->isRedirect()
		) {
			return;
		}

		$revRecord = $linksUpdate->getRevisionRecord();
		$revid = $revRecord ? $revRecord->getId() : null;
		$user = $revRecord ? $revRecord->getUser() : null;
		if ( $user && $user->getName() === User::MAINTENANCE_SCRIPT_USER ) {
			$user = null;
		}

		// link notification is boundless as you can include infinite number of links in a page
		// db insert is expensive, limit it to a reasonable amount, we can increase this limit
		// once the storage is on Redis
		$max = 10;
		// Only create notifications for links to content namespace pages
		// @Todo - use one big insert instead of individual insert inside foreach loop
		foreach ( $linksUpdate->getPageReferenceIterator( 'pagelinks', LinksTable::INSERTED ) as $pageReference ) {
			if ( $this->namespaceInfo->isContent( $pageReference->getNamespace() ) ) {
				$title = Title::newFromPageReference( $pageReference );
				if ( $title->isRedirect() ) {
					continue;
				}

				$linkFromPageId = $linksUpdate->getTitle()->getArticleID();
				// T318523: Don't send page-linked notifications for pages created by bot users.
				$articleAuthor = UserLocator::getArticleAuthorByArticleId( $title->getArticleID() );
				if ( $articleAuthor && $articleAuthor->isBot() ) {
					continue;
				}
				Event::create( [
					'type' => 'page-linked',
					'title' => $title,
					'agent' => $user,
					'extra' => [
						'target-page' => $linkFromPageId,
						'link-from-page-id' => $linkFromPageId,
						'revid' => $revid,
					],
				] );
				$max--;
			}
			if ( $max < 0 ) {
				break;
			}
		}
	}

	/**
	 * Handler for BeforePageDisplay hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/BeforePageDisplay
	 * @param OutputPage $out
	 * @param Skin $skin Skin being used.
	 */
	public function onBeforePageDisplay( $out, $skin ): void {
		$user = $out->getUser();

		if ( !$user->isRegistered() ) {
			if ( ExtensionRegistry::getInstance()->isLoaded( 'CentralAuth' ) ) {
				$out->addModules( [ 'ext.echo.centralauth' ] );
			}
			return;
		}

		if ( $this->shouldDisplayTalkAlert( $user, $out->getTitle() ) ) {
			// Load the module for the Orange alert
			$out->addModuleStyles( 'ext.echo.styles.alert' );
		}

		// Load the module for the Notifications flyout
		$out->addModules( [ 'ext.echo.init' ] );
		// Load the styles for the Notifications badge
		$out->addModuleStyles( [
			'ext.echo.styles.badge',
			'oojs-ui.styles.icons-alerts',
		] );
	}

	private function processMarkAsRead( User $user, WebRequest $request, Title $title ): array {
		$subtractions = [
			AttributeManager::ALERT => 0,
			AttributeManager::MESSAGE => 0,
		];

		// Attempt to mark a notification as read when visiting a page
		$eventIds = [];
		if ( $title->getArticleID() ) {
			$eventMapper = new EventMapper();
			$events = $eventMapper->fetchUnreadByUserAndPage( $user, $title->getArticleID() );

			foreach ( $events as $event ) {
				$subtractions[$event->getSection()]++;
				$eventIds[] = $event->getId();
			}
		}

		// Attempt to mark as read the event IDs in the ?markasread= parameter, if present
		$markAsReadIds = array_filter( explode( '|', $request->getText( 'markasread' ) ) );
		$markAsReadWiki = $request->getText( 'markasreadwiki', WikiMap::getCurrentWikiId() );
		$markAsReadLocal = !$this->config->get( ConfigNames::CrossWikiNotifications ) ||
			$markAsReadWiki === WikiMap::getCurrentWikiId();
		if ( $markAsReadIds ) {
			if ( $markAsReadLocal ) {
				// gather the IDs that we didn't already find with target_pages
				$eventsToMarkAsRead = [];
				foreach ( $markAsReadIds as $markAsReadId ) {
					$markAsReadId = intval( $markAsReadId );
					if ( $markAsReadId !== 0 && !in_array( $markAsReadId, $eventIds ) ) {
						$eventsToMarkAsRead[] = $markAsReadId;
					}
				}

				if ( $eventsToMarkAsRead ) {
					// fetch the notifications to adjust the counters
					$notifMapper = new NotificationMapper();
					$notifs = $notifMapper->fetchByUserEvents( $user, $eventsToMarkAsRead );

					foreach ( $notifs as $notif ) {
						if ( !$notif->getReadTimestamp() ) {
							$subtractions[$notif->getEvent()->getSection()]++;
							$eventIds[] = intval( $notif->getEvent()->getId() );
						}
					}
				}
			} else {
				$markAsReadIds = array_map( 'intval', $markAsReadIds );
				// Look up the notifications on the foreign wiki
				$notifUser = NotifUser::newFromUser( $user );
				$notifInfo = $notifUser->getForeignNotificationInfo( $markAsReadIds, $markAsReadWiki, $request );
				foreach ( $notifInfo as $id => $info ) {
					$subtractions[$info['section']]++;
				}

				// Schedule a deferred update to mark these notifications as read on the foreign wiki
				DeferredUpdates::addCallableUpdate(
					static function () use ( $user, $markAsReadIds, $markAsReadWiki, $request ) {
						$notifUser = NotifUser::newFromUser( $user );
						$notifUser->markReadForeign( $markAsReadIds, $markAsReadWiki, $request );
					}
				);
			}
		}

		// Schedule a deferred update to mark local target_page and ?markasread= notifications as read
		if ( $eventIds ) {
			DeferredUpdates::addCallableUpdate( static function () use ( $user, $eventIds ) {
				$notifUser = NotifUser::newFromUser( $user );
				$notifUser->markRead( $eventIds );
			} );
		}

		$subtractions[AttributeManager::ALL] = array_sum( $subtractions );

		return $subtractions;
	}

	/**
	 * Determine if a talk page alert should be displayed.
	 * We need to check:
	 * - User actually has new messages
	 * - User is not viewing their user talk page, as user_newtalk will not have been cleared yet.
	 *   (bug T107655).
	 *
	 * @param User $user
	 * @param Title $title
	 * @return bool
	 */
	private function shouldDisplayTalkAlert( $user, $title ) {
		$userHasNewMessages = $this->talkPageNotificationManager->userHasNewMessages( $user );

		return $userHasNewMessages && !$user->getTalkPage()->equals( $title );
	}

	/**
	 * Handler for SkinTemplateNavigation::Universal hook.
	 * Adds "Notifications" items to the notifications content navigation.
	 * SkinTemplate automatically merges these into the personal tools for older skins.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/SkinTemplateNavigation::Universal
	 * @param SkinTemplate $skinTemplate
	 * @param array &$links Array of URLs to append to.
	 */
	public function onSkinTemplateNavigation__Universal( $skinTemplate, &$links ): void {
		if ( !$skinTemplate->getAuthority()->isRegistered() ) {
			return;
		}
		if ( !$skinTemplate->getAuthority()->isAllowed( 'echo-read-notifications' ) ) {
			return;
		}

		$title = $skinTemplate->getTitle();
		$out = $skinTemplate->getOutput();
		$user = $skinTemplate->getUser();

		$subtractions = $this->processMarkAsRead( $user, $out->getRequest(), $title );

		$skinName = strtolower( $skinTemplate->getSkinName() );
		// HACK: inverted icons only work in the "MediaWiki" OOUI theme
		// Avoid flashes in skins that don't use it (T111821)
		$out::setupOOUI( $skinName, $out->getLanguage()->getDir() );

		// Add notifications items to personal URLs
		// (On mobile, they're combined into one for reasons lost to mists of time)
		// TODO: Make this a skin option (T299229), and remove other Minerva special-cases below.
		$isMobile = $this->mobileContext && $this->mobileContext->shouldDisplayMobileView();
		$sections = $skinName === 'minerva' && $isMobile
			? [ AttributeManager::ALL ]
			: [ AttributeManager::ALERT, AttributeManager::MESSAGE ];

		$notifUser = NotifUser::newFromUser( $user );
		$seenTime = SeenTime::newFromUser( $user );
		if ( $title->isSpecial( 'Notifications' ) ) {
			// If this is the Special:Notifications page, seenTime to now
			$seenTime->setTime( wfTimestamp( TS_MW ), AttributeManager::ALL );
		}

		$iconsClasses = [
			AttributeManager::ALERT => 'oo-ui-icon-bell',
			AttributeManager::MESSAGE => 'oo-ui-icon-tray',
			AttributeManager::ALL => 'oo-ui-icon-bellOutline',
		];
		$hasUnseen = false;
		$counts = $notifTimes = $seenTimes = $formattedCounts = $linksClasses = [];
		foreach ( $sections as $section ) {
			$counts[$section] = $notifUser->getNotificationCount( $section ) - $subtractions[$section];
			// But make sure we never show a negative number (T130853)
			$counts[$section] = max( 0, $counts[$section] );

			$notifTimes[$section] = $notifUser->getLastUnreadNotificationTime( $section );
			$seenTimes[$section] = $seenTime->getTime( $section, TS_ISO_8601 );

			$formattedCounts[$section] = NotificationController::formatNotificationCount( $counts[$section] );

			$linksClasses[$section] = [ "mw-echo-notifications-badge", "mw-echo-notification-badge-nojs" ];
			if ( $skinName !== 'minerva' ) {
				$linksClasses[$section][] = $iconsClasses[$section];
			}

			if (
				// no unread notifications
				$counts[$section] !== 0 &&
				// should already always be false if count === 0
				$notifTimes[$section] !== false &&
				// all notifications have already been seen
				( $seenTimes[$section] === null ||
					$seenTimes[$section] < $notifTimes[$section]->getTimestamp( TS_ISO_8601 ) )
			) {
				$linksClasses[$section][] = 'mw-echo-unseen-notifications';
				$hasUnseen = true;
			} elseif ( $counts[$section] === 0 ) {
				$linksClasses[$section][] = 'mw-echo-notifications-badge-all-read';
			}

			if ( $counts[$section] > NotifUser::MAX_BADGE_COUNT ) {
				$linksClasses[$section][] = 'mw-echo-notifications-badge-long-label';
			}
		}

		$out->addJsConfigVars( 'wgEchoSeenTime', $seenTimes );

		$mytalk = $links['user-menu']['mytalk'] ?? false;
		if (
			$mytalk &&
			$this->shouldDisplayTalkAlert( $user, $title ) &&
			( new HookRunner( $this->hookContainer ) )->onBeforeDisplayOrangeAlert( $user, $title )
		) {
			// Create new talk alert inheriting from the talk link data.
			$links['notifications']['talk-alert'] = array_merge(
				$links['user-menu']['mytalk'],
				[
					// Hardcode id, which is needed to dismiss the talk alert notification
					'id' => 'pt-talk-alert',
					// If Vector hook ran anicon will have  been copied to the link class.
					// We must reset it.
					'link-class' => [],
					'text' => $skinTemplate->msg( 'echo-new-messages' )->text(),
					'class' => [ 'mw-echo-alert' ],
					// unset icon
					'icon' => null,
				]
			);

			// If there's exactly one new user talk message, then link directly to it from the alert.
			$notificationMapper = new NotificationMapper();
			$notifications = $notificationMapper->fetchUnreadByUser( $user, 2, null, [ 'edit-user-talk' ] );
			if ( count( $notifications ) === 1 ) {
				$presModel = EchoEventPresentationModel::factory(
					current( $notifications )->getEvent(),
					$out->getLanguage(),
					$user
				);
				$links['notifications']['talk-alert']['href'] = $presModel->getPrimaryLink()['url'];
			}
		}

		$keys = [
			AttributeManager::ALERT => 'notifications-alert',
			AttributeManager::MESSAGE => 'notifications-notice',
			AttributeManager::ALL => 'notifications',
		];
		$messages = [
			AttributeManager::ALERT => MessageValue::new( 'echo-notification-alert' ),
			AttributeManager::MESSAGE => MessageValue::new( 'echo-notification-notice' ),
			AttributeManager::ALL => MessageValue::new( 'echo-notification-all' ),
		];
		$icons = [
			AttributeManager::ALERT => 'bell',
			AttributeManager::MESSAGE => 'tray',
			AttributeManager::ALL => 'bellOutline',
		];
		// This item used to be part of personal tools, and much CSS relies on it using this id.
		$ids = [
			AttributeManager::ALERT => 'pt-notifications-alert',
			AttributeManager::MESSAGE => 'pt-notifications-notice',
			AttributeManager::ALL => 'pt-notifications',
		];
		$url = SpecialPage::getTitleFor( 'Notifications' )->getLocalURL();
		foreach ( $sections as $section ) {
			$links['notifications'][$keys[$section]] = [
				'href' => $url,
				'text' => $skinTemplate->msg( $messages[$section] )->params( $counts[$section] )->text(),
				'active' => ( $url == $title->getLocalURL() ),
				'link-class' => $linksClasses[$section],
				'icon' => $icons[$section],
				'data' => [
					'mw-notifications-section' => $section,
					'badge-icon' => $icons[$section],
					// FIXME: What is this for and why is it like this?
					'event-name' => $section === AttributeManager::MESSAGE ? null : 'ui.notifications',
					'counter-num' => $counts[$section],
					'counter-text' => $formattedCounts[$section],
				],
				'id' => $ids[$section],
			];
		}

		if ( $hasUnseen ) {
			// Record that the user is going to see an indicator that they have unseen notifications
			// This is part of tracking how likely users are to click a badge with unseen notifications.
			// The other part is the 'echo.unseen.click' counter, see ext.echo.init.js.
			// TODO: remove the dedicated Graphite metric counter.MediaWiki.echo.unseen.click once
			// dashboard consuming Prometheus is setup, T381607
			$this->statsFactory->getCounter( 'unseen_total' )
				->copyToStatsdAt( 'echo.unseen' )
				->increment();

			$wiki = WikiMap::getCurrentWikiId();
			$this->statsFactory->getCounter( 'unseen_impression_total' )
				->setLabel( 'wiki', $wiki )
				->setLabel( 'user_type', $this->getUserTypeForStats( $user ) )
				->increment();
		}
	}

	private function getUserTypeForStats( User $user ): string {
		if ( $user->isAnon() ) {
			return 'ip';
		} elseif ( $user->isTemp() ) {
			return 'temp';
		} elseif ( $user->isNamed() ) {
			return 'registered';
		}
		return 'unknown';
	}

	/**
	 * @param array &$modifiedTimes
	 * @param OutputPage $out
	 */
	public function onOutputPageCheckLastModified( &$modifiedTimes, $out ) {
		$req = $out->getRequest();
		if ( $req->getRawVal( 'action' ) === 'raw' || $req->getRawVal( 'action' ) === 'render' ) {
			// Optimisation: Avoid expensive SeenTime compute on non-skin responses (T279213)
			return;
		}

		$user = $out->getUser();
		if ( $user->isRegistered() ) {
			$notifUser = NotifUser::newFromUser( $user );
			$lastUpdate = $notifUser->getGlobalUpdateTime();
			if ( $lastUpdate !== false ) {
				$modifiedTimes['notifications-global'] = $lastUpdate;
			}

			$modifiedTimes['notifications-seen-alert'] = SeenTime::newFromUser( $user )->getTime( 'alert' );
			$modifiedTimes['notifications-seen-message'] = SeenTime::newFromUser( $user )->getTime( 'message' );
		}
	}

	/**
	 * Handler for GetNewMessagesAlert hook.
	 * We're using the GetNewMessagesAlert hook instead of the
	 * ArticleEditUpdateNewTalk hook since we still want the user_newtalk data
	 * to be updated and available to client-side tools and the API.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/GetNewMessagesAlert
	 * @param string &$newMessagesAlert An alert that the user has new messages
	 *     or an empty string if the user does not (empty by default)
	 * @param array $newtalks This will be empty if the user has no new messages
	 *     or an Array containing links and revisions if there are new messages
	 * @param User $user The user who is loading the page
	 * @param OutputPage $out
	 * @return bool Should return false to prevent the new messages alert (OBOD)
	 *     or true to allow the new messages alert
	 */
	public function onGetNewMessagesAlert( &$newMessagesAlert, $newtalks, $user, $out ) {
		// If the user has the notifications flyout turned on and is receiving
		// notifications for talk page messages, disable the new messages alert.
		if ( $user->isRegistered()
			&& isset( $this->config->get( ConfigNames::Notifications )['edit-user-talk'] )
			&& ( new HookRunner( $this->hookContainer ) )->onEchoCanAbortNewMessagesAlert()
		) {
			// hide new messages alert
			return false;
		} else {
			// show new messages alert
			return true;
		}
	}

	/**
	 * Handler for RollbackComplete hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/RollbackComplete
	 *
	 * @param WikiPage $wikiPage The article that was edited
	 * @param UserIdentity $agent The user who did the rollback
	 * @param RevisionRecord $newRevision The revision the page was reverted back to
	 * @param RevisionRecord $oldRevision The revision of the top edit that was reverted
	 */
	public function onRollbackComplete(
		$wikiPage,
		$agent,
		$newRevision,
		$oldRevision
	) {
		$revertedUser = $oldRevision->getUser();
		$latestRevision = $wikiPage->getRevisionRecord();

		if (
			$revertedUser &&
			// No notifications for anonymous users
			$revertedUser->isRegistered() &&
			// No notifications for null rollbacks
			!$oldRevision->hasSameContent( $newRevision )
		) {
			Event::create( [
				'type' => 'reverted',
				'title' => $wikiPage->getTitle(),
				'extra' => [
					'revid' => $latestRevision->getId(),
					'reverted-user-id' => $revertedUser->getId(),
					'reverted-revision-id' => $oldRevision->getId(),
					'method' => 'rollback',
				],
				'agent' => $agent,
			] );
		}
	}

	/**
	 * Handler for UserSaveSettings hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/UserSaveSettings
	 * @param User $user whose settings were saved
	 */
	public function onUserSaveSettings( $user ) {
		// Extensions like AbuseFilter might create an account, but
		// the tables we need might not exist. Bug 57335
		if ( !defined( 'MW_UPDATER' ) ) {
			// Reset the notification count since it may have changed due to user
			// option changes. This covers both explicit changes in the preferences
			// and changes made through the options API (since both call this hook).
			DeferredUpdates::addCallableUpdate( static function () use ( $user ) {
				if ( !$user->isRegistered() ) {
					// It's possible the user account was deleted before the deferred
					// update runs (T318081)
					return;
				}
				NotifUser::newFromUser( $user )->resetNotificationCount();
			} );
		}
	}

	/**
	 * Some of Echo's subscription user preferences are mapped to existing user preferences defined in
	 * core MediaWiki. This returns the map of Echo preference names to core preference names.
	 *
	 * @param Config $config
	 * @return array
	 */
	public static function getVirtualUserOptions( Config $config ) {
		$options = [];
		$options['echo-subscriptions-email-edit-user-talk'] = 'enotifusertalkpages';
		if ( $config->get( ConfigNames::WatchlistNotifications ) ) {
			$options['echo-subscriptions-email-watchlist'] = 'enotifwatchlistpages';
			$options['echo-subscriptions-email-minor-watchlist'] = 'enotifminoredits';
		}
		return $options;
	}

	/**
	 * Handler for LoadUserOptions hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/LoadUserOptions
	 * @param UserIdentity $user User whose options were loaded
	 * @param array &$options Options can be modified
	 */
	public function onLoadUserOptions( UserIdentity $user, &$options ): void {
		foreach ( self::getVirtualUserOptions( $this->config ) as $echoPref => $mwPref ) {
			// Use the existing core option's value for the Echo option
			if ( isset( $options[ $mwPref ] ) ) {
				$options[ $echoPref ] = $options[ $mwPref ];
			}
		}
	}

	/**
	 * Handler for SaveUserOptions hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/SaveUserOptions
	 * @param UserIdentity $user User whose options are being saved
	 * @param array &$modifiedOptions Options can be modified
	 * @param array $originalOptions
	 */
	public function onSaveUserOptions( UserIdentity $user, array &$modifiedOptions, array $originalOptions ) {
		foreach ( self::getVirtualUserOptions( $this->config ) as $echoPref => $mwPref ) {
			// Save virtual option values in corresponding real option values
			if ( isset( $modifiedOptions[ $echoPref ] ) ) {
				$modifiedOptions[ $mwPref ] = $modifiedOptions[ $echoPref ];
				unset( $modifiedOptions[ $echoPref ] );
			}
		}
	}

	/**
	 * Convert all values in an array to integers and filter out zeroes.
	 *
	 * @param array $numbers
	 *
	 * @return int[]
	 */
	protected static function mapToInt( array $numbers ) {
		$data = [];

		foreach ( $numbers as $value ) {
			$int = intval( $value );
			if ( $int === 0 ) {
				continue;
			}
			$data[] = $int;
		}

		return $data;
	}

	/**
	 * Handler for UserClearNewTalkNotification hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/UserClearNewTalkNotification
	 * @param UserIdentity $user User whose talk page notification should be marked as read
	 * @param int $oldid
	 */
	public function onUserClearNewTalkNotification( $user, $oldid ) {
		if ( $user->isRegistered() ) {
			DeferredUpdates::addCallableUpdate( static function () use ( $user ) {
				NotifUser::newFromUser( $user )->clearUserTalkNotifications();
			} );
		}
	}

	/**
	 * Handler for EmailUserComplete hook.
	 * @see https://www.mediawiki.org/wiki/Manual:Hooks/EmailUserComplete
	 * @param MailAddress $address Adress of receiving user
	 * @param MailAddress $from Adress of sending user
	 * @param string $subject Subject of the mail
	 * @param string $text Text of the mail
	 */
	public function onEmailUserComplete( $address, $from, $subject, $text ) {
		if ( $from->name === $address->name ) {
			// nothing to notify
			return;
		}
		$userTo = User::newFromName( $address->name );
		$userFrom = User::newFromName( $from->name );

		$autoSubject = wfMessage( 'defemailsubject', $from->name )->inContentLanguage()->text();
		if ( $subject === $autoSubject ) {
			$autoFooter = "\n\n-- \n" . wfMessage( 'emailuserfooter', $from->name, $address->name )
				->inContentLanguage()->text();
			$textWithoutFooter = preg_replace( '/' . preg_quote( $autoFooter, '/' ) . '$/', '', $text );
			$preview = $this->contentLanguage->truncateForVisual( $textWithoutFooter, 125 );
		} else {
			$preview = $subject;
		}

		Event::create( [
			'type' => 'emailuser',
			'extra' => [
				'preview' => $preview,
			],
			'agent' => $userFrom,
		], new RecipientSet( $userTo ) );
	}

	/**
	 * Sets custom login message for redirect from notification page
	 */
	public function onLoginFormValidErrorMessages( array &$messages ) {
		$messages[] = 'echo-notification-loginrequired';
	}

	public static function getConfigVars( RL\Context $context, Config $config ): array {
		return [
			'EchoMaxNotificationCount' => NotifUser::MAX_BADGE_COUNT,
			'EchoPollForUpdates' => $config->get( ConfigNames::PollForUpdates ),
		];
	}

	/**
	 * @param Title $title
	 * @param bool $create
	 * @param string $comment
	 * @param int $oldPageId
	 * @param array $restoredPages
	 */
	public function onArticleUndelete( $title, $create, $comment, $oldPageId, $restoredPages ) {
		if ( $create ) {
			DeferredUpdates::addCallableUpdate( static function () use ( $oldPageId ) {
				$eventMapper = new EventMapper();
				$eventIds = $eventMapper->fetchIdsByPage( $oldPageId );
				ModerationController::moderate( $eventIds, false );
			} );
		}
	}

	/**
	 * Handler for SpecialMuteModifyFormFields hook
	 *
	 * @param UserIdentity|null $target
	 * @param User $user
	 * @param array &$fields
	 */
	public function onSpecialMuteModifyFormFields( $target, $user, &$fields ) {
		$echoPerUserBlacklist = $this->config->get( ConfigNames::PerUserBlacklist );
		if ( $echoPerUserBlacklist ) {
			$id = $target ? $this->centralIdLookup->centralIdFromLocalUser( $target ) : 0;
			$notificationList = $this->userOptionsManager->getOption( $user, 'echo-notifications-blacklist' );
			$list = $notificationList ? MultiUsernameFilter::splitIds(
				$notificationList
			) : [];
			$fields[ 'echo-notifications-blacklist'] = [
				'type' => 'check',
				'label-message' => [
					'echo-specialmute-label-mute-notifications',
					$target ? $target->getName() : '',
				],
				'default' => in_array( $id, $list, true ),
			];
		}
	}

	/**
	 * @param RecentChange $change
	 * @return bool|void
	 */
	public function onRecentChange_save( $change ) {
		if ( !$this->config->get( 'EchoWatchlistNotifications' ) ) {
			return;
		}
		if ( !$change->isInternal() ) {
			// Ignore external changes (e.g. Wikidata), as Echo events can't have agents that correspond
			// to actors but are not local users (T387050, see also T286153).
			// Also ignore Flow edits, as Flow generates Echo events on its own.
			return;
		}
		if ( $change->getAttribute( 'rc_minor' ) ) {
			$type = 'minor-watchlist-change';
		} else {
			$type = 'watchlist-change';
		}
		Event::create( [
			'type' => $type,
			'title' => $change->getTitle(),
			'extra' => [
				'page_title' => $change->getPage()->getDBkey(),
				'page_namespace' => $change->getPage()->getNamespace(),
				'revid' => $change->getAttribute( "rc_this_oldid" ),
				'logid' => $change->getAttribute( "rc_logid" ),
				'status' => $change->mExtra["pageStatus"],
				'timestamp' => $change->getAttribute( "rc_timestamp" ),
				'emailonce' => $this->config->get( ConfigNames::WatchlistEmailOncePerPage ),
			],
			'agent' => $change->getPerformerIdentity(),
		] );
	}

	/**
	 * Hook handler for ApiMain::moduleManager.
	 * Used here to put the echopushsubscriptions API module behind our push feature flag.
	 * TODO: Register this the usual way in extension.json when we don't need the feature flag
	 *  anymore.
	 * @param ApiModuleManager $moduleManager
	 */
	public function onApiMain__moduleManager( $moduleManager ) {
		$pushEnabled = $this->config->get( 'EchoEnablePush' );
		if ( $pushEnabled ) {
			$moduleManager->addModule(
				'echopushsubscriptions',
				'action',
				ApiEchoPushSubscriptions::class
			);
		}
	}

	/**
	 * Get the system user for automated notifications.
	 * @return User|null Null if the system user could not be loaded (e.g. in read-only mode)
	 */
	private static function getSystemUser(): ?User {
		static $systemUser = null;
		if ( $systemUser === null ) {
			$systemUser = User::newSystemUser(
				User::MAINTENANCE_SCRIPT_USER,
				[ 'steal' => true ]
			) ?: null;
		}
		return $systemUser;
	}

	/**
	 *  Save the revert status for the LinksUpdateComplete hook
	 * TODO: Deprecate this when LinksUpdateComplete is migrated to it's corresponding
	 * Domain event
	 * @param bool $isRevert
	 * @param RevisionRecord $revisionRecord
	 */
	public static function setRevertStatus( bool $isRevert, $revisionRecord ) {
		if ( $isRevert ) {
			self::$revertedRevIds[$revisionRecord->getId()] = true;
		}
	}

}
