<?php

class EchoNotificationController {
	/**
	 * Retrieves number of unread notifications that a user has.
	 *
	 * @param $user User object to check notifications for
	 * @param $cached bool Set to false to bypass the cache.
	 * @return Integer: Number of unread notifications.
	 */
	public static function getNotificationCount( $user, $cached = true ) {
		global $wgMemc;

		$memcKey = wfMemcKey( 'echo-notification-count', $user->getId() );

		if ( $cached && $wgMemc->get( $memcKey ) !== false ) {
			return $wgMemc->get( $memcKey );
		}

		$dbr = wfGetDB( DB_SLAVE );
		$count = $dbr->selectField( 'echo_notification', 'count(*)',
			array(
				'notification_user' => $user->getId(),
				'notification_read_timestamp' => null,
			),
			__METHOD__
		);

		$wgMemc->set( $memcKey, $count, 86400 );

		return $count;
	}

	/**
	 * Mark one or more notifications read for a user.
	 *
	 * @param $user User object to mark items read for.
	 * @param $eventIDs Array of event IDs to mark read
	 */
	public static function markRead( $user, $eventIDs ) {
		$dbw = wfGetDB( DB_MASTER );

		$eventIDs = array_filter( (array)$eventIDs, 'is_numeric' );

		$dbw->update( 'echo_notification',
			array( 'notification_read_timestamp' => $dbw->timestamp( wfTimestampNow() ) ),
			array(
				'notification_user' => $user->getId(),
				'notification_event' => $eventIDs,
			),
			__METHOD__
		);

		self::resetNotificationCount( $user );
	}

	/**
	 * Recalculates the number of notifications that a user has.
	 *
	 * @param $user User object
	 */
	public static function resetNotificationCount( $user ) {
		self::getNotificationCount( $user, false );
		$user->invalidateCache();
	}

	/**
	 * Processes notifications for a newly-created EchoEvent
	 *
	 * @param $event EchoEvent to do notifications for
	 * @param $defer bool Defer to job queue
	 */
	public static function notify( $event, $defer = true ) {
		if ( $defer ) {
			$title = $event->getTitle() ? $event->getTitle() : Title::newMainPage();

			$job = new EchoNotificationJob( $title, array( 'event' => $event ) );
			$job->insert();
			return;
		}

		if ( $event->getType() == 'welcome' ) { // Welcome events should only be sent to the new user, no need for subscriptions.
			self::doNotification( $event, $event->getAgent(), 'notify' );
		} else {
			$subscriptions = self::getSubscriptionsForEvent( $event );

			foreach ( $subscriptions as $subscription ) {
				$user = $subscription->getUser();
				$notifyTypes = $subscription->getNotificationTypes();

				$notifyTypes = array_keys( array_filter( $notifyTypes ) );

				wfRunHooks( 'EchoGetNotificationTypes', array( $subscription, $event, &$notifyTypes ) );

				foreach ( $notifyTypes as $type ) {
					self::doNotification( $event, $user, $type );
				}
			}
		}
	}

	/**
	 * Processes a single notification for an EchoEvent
	 *
	 * @param $event EchoEvent to do a notification for.
	 * @param $user User object to notify.
	 * @param $type string The type of notification to process.
	 * @throws MWException
	 */
	public static function doNotification( $event, $user, $type ) {
		global $wgEchoNotifiers;

		if ( !isset( $wgEchoNotifiers[$type] ) ) {
			throw new MWException( "Invalid notification type $type" );
		}

		call_user_func_array( $wgEchoNotifiers[$type], array( $user, $event ) );
	}

	/**
	 * Retrieves an array of EchoSubscription objects applicable to an EchoEvent.
	 *
	 * @param $event EchoEvent to retrieve EchoSubscriptions for.
	 * @return Array of EchoSubscription objects.
	 */
	protected static function getSubscriptionsForEvent( $event ) {
		$dbr = wfGetDB( DB_SLAVE );

		$conds = array( 'sub_event_type' => $event->getType() );

		if ( $event->getTitle() ) {
			$conds['sub_page_namespace'] = $event->getTitle()->getNamespace();
			$conds['sub_page_title'] = $event->getTitle()->getDBkey();
		}

		$res = $dbr->select( 'echo_subscription', '*', $conds, __METHOD__,
			array( 'order by' => 'sub_user asc' ) );

		$subscriptions = array();
		$rowCollection = array();
		$lastUser = null;

		foreach ( $res as $row ) {
			if ( $lastUser && $row->sub_user != $lastUser ) {
				$subscriptions[$lastUser] = EchoSubscription::newFromRows( $rowCollection );
				$rowCollection = array();
			}

			$rowCollection[] = $row;
			$lastUser = $row->sub_user;
		}

		if ( count( $rowCollection ) ) {
			$subscriptions[$lastUser] = EchoSubscription::newFromRows( $rowCollection );
		}

		$users = array();
		wfRunHooks( 'EchoGetDefaultNotifiedUsers', array( $event, &$users ) );
		foreach ( $users as $u ) {
			if ( !isset( $subscriptions[$u->getId()] ) ) {
				$subscriptions[$u->getId()] = new EchoSubscription( $u, $event->getType(), $event->getTitle() );
			}
		}

		// Don't notify the person who made the edit, that's a bit silly.
		if ( $event->getAgent() ) {
			unset( $subscriptions[$event->getAgent()->getId()] );
		}

		return $subscriptions;
	}

	/**
	 * Formats a notification
	 *
	 * @param $event EchoEvent that the notification is for.
	 * @param $user User to format the notification for.
	 * @param $format string The format to show the notification in: text or html
	 * @param $type string The type of notification being distributed (e.g. email, notify)
	 * @return string type description
	 */
	public static function formatNotification( $event, $user, $format = 'text', $type = 'notify' ) {
		global $wgEchoNotificationFormatters;

		$eventType = $event->getType();

		static $runHook = true;
		// this hook should only be executed once to gather valid formatter
		if ( $runHook ) {
			// allow extensions to define their own notification formatter
			wfRunHooks( 'BeforeFormatEchoNotification', array( &$wgEchoNotificationFormatters ) );
			$runHook = false;
		}
		if ( isset( $wgEchoNotificationFormatters[$eventType] ) ) {
			$params = $wgEchoNotificationFormatters[$eventType];
			$notifier = EchoNotificationFormatter::factory( $params );
			$notifier->setOutputFormat( $format );

			return $notifier->format( $event, $user, $type );
		}

		return Xml::tags( 'span', array( 'class' => 'error' ),
			wfMessage( 'echo-error-no-formatter', $event->getType() )->escaped() );
	}
}