<?php

class EchoNotificationController {
	/**
	 * Retrieves number of unread notifications that a user has.
	 *
	 * @param $user User object to check notifications for
	 * @param $cached Whether or not to return cached results.
	 * @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 );
	}

	/**
	 * Processes notifications for a newly-created EchoEvent
	 * 
	 * @param $event EchoEvent to do notifications for
	 * @param $defer 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;
		}

		$subscriptions = self::getSubscriptionsForEvent( $event );

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

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

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

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

		$eventType = $event->getType();

		if ( isset($wgEchoNotificationFormatters[$eventType]) ) {
			$params = $wgEchoNotificationFormatters[$eventType];
			$notifier = EchoNotificationFormatter::factory($params);
			$notifier->setOutputFormat( $format );

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

		// throw new MWException( "Unable to find notification formatter for event " . $event->getType() );
	}
}