<?php

class EchoNotification {

	/**
	 * @var User
	 */
	protected $user;

	/**
	 * @var EchoEvent
	 */
	protected $event;

	/**
	 * @var string
	 */
	protected $timestamp;

	/**
	 * @var string
	 */
	protected $readTimestamp;

	/**
	 * Do not use this constructor.
	 */
	protected function __construct() {}

	/**
	 * Creates an EchoNotification object based on event and user
	 * @param $info array The following keys are required:
	 * - 'event' The EchoEvent being notified about.
	 * - 'user' The User being notified.
	 * @throws MWException
	 * @return EchoNotification
	 */
	public static function create( array $info ) {
		$obj = new EchoNotification();
		static $validFields = array( 'event', 'user' );

		foreach ( $validFields as $field ) {
			if ( isset( $info[$field] ) ) {
				$obj->$field = $info[$field];
			} else {
				throw new MWException( "Field $field is required" );
			}
		}

		if ( !$obj->user instanceof User && !$obj->user instanceof StubObject ) {
			throw new MWException( 'Invalid user parameter, expected: User/StubObject object' );
		}

		if ( !$obj->event instanceof EchoEvent ) {
			throw new MWException( 'Invalid event parameter, expected: EchoEvent object' );
		}

		// Notification timestamp should be the same as event timestamp
		$obj->timestamp = $obj->event->getTimestamp();
		// Safe fallback
		if ( !$obj->timestamp ) {
			$obj->timestamp = wfTimestampNow();
		}

		$obj->insert();

		return $obj;
	}

	/**
	 * Adds this new notification object to the backend storage.
	 */
	protected function insert() {
		global $wgEchoBackend, $wgEchoNotifications;

		$row = array(
			'notification_event' => $this->event->getId(),
			'notification_user' => $this->user->getId(),
			'notification_timestamp' => $this->timestamp,
			'notification_read_timestamp' => $this->readTimestamp,
			'notification_bundle_hash' => '',
			'notification_bundle_display_hash' => ''
		);

		// Get the bundle key for this event if web bundling is enabled
		$bundleKey = '';
		if ( !empty( $wgEchoNotifications[$this->event->getType()]['bundle']['web'] ) ) {
			wfRunHooks( 'EchoGetBundleRules', array( $this->event, &$bundleKey ) );
		}
		if ( $bundleKey ) {
			$hash = md5( $bundleKey );
			$row['notification_bundle_hash'] = $hash;

			$lastStat = $wgEchoBackend->getLastBundleStat( $this->user, $hash );

			// Use a new display hash if:
			// 1. there was no last bundle notification
			// 2. last bundle notification with the same hash was read
			if ( $lastStat && !$lastStat->notification_read_timestamp ) {
				$row['notification_bundle_display_hash'] = $lastStat->notification_bundle_display_hash;
			} else {
				$row['notification_bundle_display_hash'] = md5( $bundleKey . '-display-hash-' . wfTimestampNow() );
			}
		}

		$wgEchoBackend->createNotification( $row );

		wfRunHooks( 'EchoCreateNotificationComplete', array( $this ) );
	}

	/**
	 * Getter method
	 * @return EchoEvent The event for this notification
	 */
	public function getEvent() {
		return $this->event;
	}

	/**
	 * Getter method
	 * @return User The recipient of this notification
	 */
	public function getUser() {
		return $this->user;
	}

	/**
	 * Getter method
	 * @return string Notification creation timestamp
	 */
	public function getTimestamp() {
		return $this->timestamp;
	}

	/**
	 * Getter method
	 * @return string|null Notification read timestamp
	 */
	public function getReadTimestamp() {
		return $this->readTimestamp;
	}
}