<?php

use Wikimedia\Timestamp\TimestampException;

/**
 * Class that returns structured data based
 * on the provided event.
 */
abstract class EchoEventPresentationModel implements JsonSerializable {

	/**
	 * Recommended length of usernames included in messages
	 */
	const USERNAME_RECOMMENDED_LENGTH = 20;

	/**
	 * Recommended length of usernames used as link label
	 */
	const USERNAME_AS_LABEL_RECOMMENDED_LENGTH = 15;

	/**
	 * Recommended length of page names included in messages
	 */
	const PAGE_NAME_RECOMMENDED_LENGTH = 50;

	/**
	 * Recommended length of page names used as link label
	 */
	const PAGE_NAME_AS_LABEL_RECOMMENDED_LENGTH = 15;

	/**
	 * Recommended length of section titles included in messages
	 */
	const SECTION_TITLE_RECOMMENDED_LENGTH = 50;

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

	/**
	 * @var Language
	 */
	protected $language;

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

	/**
	 * @var User for permissions checking
	 */
	private $user;

	/**
	 * @var string 'web' or 'email'
	 */
	private $distributionType;

	/**
	 * @param EchoEvent $event
	 * @param Language $language
	 * @param User $user Only used for permissions checking and GENDER
	 * @param string $distributionType
	 */
	protected function __construct( EchoEvent $event, Language $language, User $user, $distributionType ) {
		$this->event = $event;
		$this->type = $event->getType();
		$this->language = $language;
		$this->user = $user;
		$this->distributionType = $distributionType;
	}

	/**
	 * Convenience function to detect whether the event type
	 * has been updated to use the presentation model system
	 *
	 * @param string $type event type
	 * @return bool
	 */
	public static function supportsPresentationModel( $type ) {
		global $wgEchoNotifications;
		return isset( $wgEchoNotifications[$type]['presentation-model'] );
	}

	/**
	 * @param EchoEvent $event
	 * @param Language $language
	 * @param User $user
	 * @param string $distributionType 'web' or 'email'
	 * @return EchoEventPresentationModel
	 */
	public static function factory( EchoEvent $event, Language $language, User $user, $distributionType = 'web' ) {
		global $wgEchoNotifications;
		// @todo don't depend upon globals

		$class = $wgEchoNotifications[$event->getType()]['presentation-model'];
		return new $class( $event, $language, $user, $distributionType );
	}

	/**
	 * Get the type of event
	 *
	 * @return string
	 */
	final public function getType() {
		return $this->type;
	}

	/**
	 * Get the user receiving the notification
	 *
	 * @return User
	 */
	final public function getUser() {
		return $this->user;
	}

	/**
	 * Get the category of event
	 *
	 * @return string
	 */
	final public function getCategory() {
		return $this->event->getCategory();
	}

	/**
	 * Equivalent to IContextSource::msg for the current
	 * language
	 *
	 * @return Message
	 */
	protected function msg( /* ,,, */ ) {
		/**
		 * @var Message $msg
		 */
		$msg = call_user_func_array( 'wfMessage', func_get_args() );
		$msg->inLanguage( $this->language );

		// Notifications are considered UI (and should be in UI language, not
		// content), and this flag is set false by inLanguage.
		$msg->setInterfaceMessageFlag( true );

		return $msg;
	}

	/**
	 * @return EchoEvent[]
	 */
	final protected function getBundledEvents() {
		return $this->event->getBundledEvents() ?: [];
	}

	/**
	 * Get the ids of the bundled notifications or false if it's not bundled
	 *
	 * @return int[]|bool
	 */
	public function getBundledIds() {
		if ( $this->isBundled() ) {
			return array_map( function ( EchoEvent $event ) {
				return $event->getId();
			}, $this->getBundledEvents() );
		}
		return false;
	}

	/**
	 * This method returns true when there are bundled notifications, even if they are all
	 * in the same group according to getBundleGrouping(). For presentation purposes, you may
	 * want to check if getBundleCount( true, $yourCallback ) > 1 instead.
	 *
	 * @return bool Whether there are other notifications bundled with this one.
	 */
	final protected function isBundled() {
		return $this->getBundleCount() > 1;
	}

	/**
	 * Count the number of event groups in this bundle.
	 *
	 * By default, each event is in its own group, and this method returns the number of events.
	 * To group events differently, pass $groupCallback. For example, to group events with the
	 * same title together, use $callback = function ( $event ) { return $event->getTitle()->getPrefixedText(); }
	 *
	 * If $includeCurrent is false, all events in the same group as the current one will be ignored.
	 *
	 * @param bool $includeCurrent Include the current event (and its group)
	 * @param callable|null $groupCallback Callback that takes an EchoEvent and returns a grouping value
	 * @return int Number of bundled events or groups
	 * @throws InvalidArgumentException
	 */
	final protected function getBundleCount( $includeCurrent = true, $groupCallback = null ) {
		$events = array_merge( $this->getBundledEvents(), [ $this->event ] );
		if ( $groupCallback ) {
			if ( !is_callable( $groupCallback ) ) {
				// If we pass an invalid callback to array_map(), it'll just throw a warning
				// and return NULL, so $count ends up being 0 or -1. Instead of doing that,
				// throw an exception.
				throw new InvalidArgumentException( 'Invalid callback passed to getBundleCount' );
			}
			$events = array_unique( array_map( $groupCallback, $events ) );
		}
		$count = count( $events );

		if ( !$includeCurrent ) {
			$count--;
		}
		return $count;
	}

	/**
	 * Return the count of notifications bundled together.
	 *
	 * For parameters, see getBundleCount().
	 *
	 * @param bool $includeCurrent
	 * @param callable|null $groupCallback
	 * @return int count
	 */
	final protected function getNotificationCountForOutput( $includeCurrent = true, $groupCallback = null ) {
		$count = $this->getBundleCount( $includeCurrent, $groupCallback );
		$cappedCount = EchoNotificationController::getCappedNotificationCount( $count );
		return $cappedCount;
	}

	/**
	 * @return string The symbolic icon name as defined in $wgEchoNotificationIcons
	 */
	abstract public function getIconType();

	/**
	 * @return string Timestamp the event occurred at
	 */
	final public function getTimestamp() {
		return $this->event->getTimestamp();
	}

	/**
	 * Helper for EchoEvent::userCan
	 *
	 * @param int $type Revision::DELETED_* constant
	 * @return bool
	 */
	final protected function userCan( $type ) {
		return $this->event->userCan( $type, $this->user );
	}

	/**
	 * @return array|bool ['wikitext to display', 'username for GENDER'], false if no agent
	 *
	 * We have to display wikitext so we can add CSS classes for revision deleted user.
	 * The goal of this function is for callers not to worry about whether
	 * the user is visible or not.
	 * @par Example:
	 * @code
	 * list( $formattedName, $genderName ) = $this->getAgentForOutput();
	 * $msg->params( $formattedName, $genderName );
	 * @endcode
	 */
	final protected function getAgentForOutput() {
		$agent = $this->event->getAgent();
		if ( !$agent ) {
			return false;
		}

		if ( $this->userCan( Revision::DELETED_USER ) ) {
			// Not deleted
			return [
				$this->getTruncatedUsername( $agent ),
				$agent->getName()
			];
		} else {
			// Deleted/hidden
			$msg = $this->msg( 'rev-deleted-user' )->plain();
			// HACK: Pass an invalid username to GENDER to force the default
			return [ '<span class="history-deleted">' . $msg . '</span>', '[]' ];
		}
	}

	/**
	 * Return a message with the given key and the agent's
	 * formatted name and name for GENDER as 1st and
	 * 2nd parameters.
	 * @param string $key
	 * @return Message
	 */
	final protected function getMessageWithAgent( $key ) {
		$msg = $this->msg( $key );
		list( $formattedName, $genderName ) = $this->getAgentForOutput();
		$msg->params( $formattedName, $genderName );
		return $msg;
	}

	/**
	 * Get the viewing user's name for usage in GENDER
	 *
	 * @return string
	 */
	final protected function getViewingUserForGender() {
		return $this->user->getName();
	}

	/**
	 * @return array|null Link object to the user's page or Special:Contributions for anon users.
	 *               Can be used for primary or secondary links.
	 *               Same format as secondary link.
	 *               Returns null if the current user cannot see the agent.
	 */
	final protected function getAgentLink() {
		return $this->getUserLink( $this->event->getAgent() );
	}

	/**
	 * To be overridden by subclasses if they are unable to render the
	 * notification, for example when a page is deleted.
	 * If this function returns false, no other methods will be called
	 * on the object.
	 *
	 * @return bool
	 */
	public function canRender() {
		return true;
	}

	/**
	 * @return string Message key that will be used in getHeaderMessage
	 */
	protected function getHeaderMessageKey() {
		return "notification-header-{$this->type}";
	}

	/**
	 * Get a message object and add the performer's name as
	 * a parameter. It is expected that subclasses will override
	 * this.
	 *
	 * @return Message
	 */
	public function getHeaderMessage() {
		return $this->getMessageWithAgent( $this->getHeaderMessageKey() );
	}

	/**
	 * @return string Message key that will be used in getCompactHeaderMessage
	 */
	public function getCompactHeaderMessageKey() {
		return "notification-compact-header-{$this->type}";
	}

	/**
	 * Get a message object and add the performer's name as
	 * a parameter. It is expected that subclasses will override
	 * this.
	 *
	 * This message should be more compact than the header message
	 * ( getHeaderMessage() ). It is displayed when a
	 * notification is part of an expanded bundle.
	 *
	 * @return Message
	 */
	public function getCompactHeaderMessage() {
		$msg = $this->getMessageWithAgent( $this->getCompactHeaderMessageKey() );
		if ( $msg->isDisabled() ) {
			// Back-compat for models that haven't been updated yet
			$msg = $this->getHeaderMessage();
		}

		return $msg;
	}

	/**
	 * @return string Message key that will be used in getSubjectMessage
	 */
	protected function getSubjectMessageKey() {
		return "notification-subject-{$this->type}";
	}

	/**
	 * Get a message object and add the performer's name as
	 * a parameter. It is expected that subclasses will override
	 * this. The output of the message should be plaintext.
	 *
	 * This message is used as the subject line in
	 * single-notification emails.
	 *
	 * For backward compatibility, if this is not defined,
	 * the header message ( getHeaderMessage() ) is used instead.
	 *
	 * @return Message
	 */
	public function getSubjectMessage() {
		$msg = $this->getMessageWithAgent( $this->getSubjectMessageKey() );
		if ( $msg->isDisabled() ) {
			// Back-compat for models that haven't been updated yet
			$msg = $this->getHeaderMessage();
		}

		return $msg;
	}

	/**
	 * Get a message for the notification's body, false if it has no body
	 *
	 * @return bool|Message
	 */
	public function getBodyMessage() {
		return false;
	}

	/**
	 * Array of primary link details, with possibly-relative URL & label.
	 *
	 * @return array|bool Array of link data, or false for no link:
	 *                    ['url' => (string) url, 'label' => (string) link text (non-escaped)]
	 */
	abstract public function getPrimaryLink();

	/**
	 * Like getPrimaryLink(), but with the URL altered to add ?markasread=XYZ. When this link is followed,
	 * the notification is marked as read.
	 *
	 * When the notification is a bundle, the notification IDs are added to the parameter value
	 * separated by a "|".
	 *
	 * @return array|bool
	 */
	final public function getPrimaryLinkWithMarkAsRead() {
		$primaryLink = $this->getPrimaryLink();
		if ( $primaryLink ) {
			$eventIds = [ $this->event->getId() ];
			if ( $this->getBundledIds() ) {
				$eventIds = array_merge( $eventIds, $this->getBundledIds() );
			}
			$primaryLink['url'] = wfAppendQuery( $primaryLink['url'], [ 'markasread' => implode( '|', $eventIds ) ] );
		}
		return $primaryLink;
	}

	/**
	 * Array of secondary link details, including possibly-relative URLs, label,
	 * description & icon name.
	 *
	 * @return array Array of links in the format of:
	 *               [['url' => (string) url,
	 *                 'label' => (string) link text (non-escaped),
	 *                 'description' => (string) descriptive text (optional, non-escaped),
	 *                 'icon' => (bool|string) symbolic ooui icon name (or false if there is none),
	 *                 'type' => (string) optional action type. Used to note a dynamic action, by setting it to 'dynamic-action'
	 *                 'data' => (array) optional array containing information about the dynamic action. It must include 'tokenType' (string), 'messages' (array) with messages supplied for the item and the confirmation dialog and 'params' (array) for the API operation needed to complete the action. For example:
	 *                 'data' => [
	 *                     'tokenType' => 'watch',
	 *                     'params' => [
	 *                         'action' => 'watch',
	 *                         'titles' => 'Namespace:SomeTitle'
	 *                     ],
	 *                     'messages' => [
	 *                         'confirmation' => [
	 *                         	'title' => 'message (parsed as HTML)',
	 *                         	'description' => 'optional message (parsed as HTML)'
	 *                         ]
	 *                     ]
	 *                 	]
	 *                 'prioritized' => (bool) true if the link should be outside the
	 *                                  action menu, false for inside)],
	 *                ...]
	 *
	 *               Note that you should call array_values(array_filter()) on the
	 *               result of this function (FIXME).
	 */
	public function getSecondaryLinks() {
		return [];
	}

	/**
	 * Get the ID of the associated event
	 * @return int Event id
	 */
	public function getEventId() {
		return $this->event->getId();
	}

	/**
	 * @return array
	 * @throws TimestampException
	 */
	public function jsonSerialize() {
		$body = $this->getBodyMessage();

		return [
			'header' => $this->getHeaderMessage()->parse(),
			'compactHeader' => $this->getCompactHeaderMessage()->parse(),
			'body' => $body ? $body->escaped() : '',
			'icon' => $this->getIconType(),
			'links' => [
				'primary' => $this->getPrimaryLinkWithMarkAsRead() ?: [],
				'secondary' => array_values( array_filter( $this->getSecondaryLinks() ) ),
			],
		];
	}

	/**
	 * @param User $user
	 * @return string
	 */
	protected function getTruncatedUsername( User $user ) {
		return $this->language->embedBidi( $this->language->truncate( $user->getName(), self::USERNAME_RECOMMENDED_LENGTH, '...', false ) );
	}

	/**
	 * @param Title $title
	 * @param bool $includeNamespace
	 * @return string
	 */
	protected function getTruncatedTitleText( Title $title, $includeNamespace = false ) {
		$text = $includeNamespace ? $title->getPrefixedText() : $title->getText();
		return $this->language->embedBidi( $this->language->truncate( $text, self::PAGE_NAME_RECOMMENDED_LENGTH, '...', false ) );
	}

	/**
	 * @param User|null $user
	 * @return array|null
	 */
	final protected function getUserLink( $user ) {
		if ( !$user ) {
			return null;
		}

		if ( !$this->userCan( Revision::DELETED_USER ) ) {
			return null;
		}

		$url = $user->isAnon()
			? SpecialPage::getTitleFor( 'Contributions', $user->getName() )->getFullURL()
			: $user->getUserPage()->getFullURL();

		$label = $user->getName();
		$truncatedLabel = $this->language->truncate( $label, self::USERNAME_AS_LABEL_RECOMMENDED_LENGTH, '...', false );
		$isTruncated = $label !== $truncatedLabel;

		return [
			'url' => $url,
			'label' => $this->language->embedBidi( $truncatedLabel ),
			'tooltip' => $isTruncated ? $label : '',
			'description' => '',
			'icon' => 'userAvatar',
			'prioritized' => true,
		];
	}

	/**
	 * @param Title $title
	 * @param string $description
	 * @param bool $prioritized
	 * @param array $query
	 * @return array
	 */
	final protected function getPageLink( Title $title, $description, $prioritized, $query = [] ) {
		if ( $title->getNamespace() === NS_USER_TALK ) {
			$icon = 'userSpeechBubble';
		} elseif ( $title->isTalkPage() ) {
			$icon = 'speechBubbles';
		} else {
			$icon = 'article';
		}

		return [
			'url' => $title->getFullURL( $query ),
			'label' => $this->language->embedBidi(
				$this->language->truncate( $title->getText(), self::PAGE_NAME_AS_LABEL_RECOMMENDED_LENGTH, '...', false )
			),
			'tooltip' => $title->getPrefixedText(),
			'description' => $description,
			'icon' => $icon,
			'prioritized' => $prioritized,
		];
	}

	/**
	 * Get a dynamic action link
	 *
	 * @param Title $title Title relating to this action
	 * @param bool $icon Optional. Symbolic name of the OOUI icon to use
	 * @param string $label link text (non-escaped)
	 * @param string|null $description descriptive text (optional, non-escaped)
	 * @param array $data Action data
	 * @param array $query
	 * @return array Array compatible with the structure of
	 *  secondary links
	 */
	final protected function getDynamicActionLink( Title $title, $icon, $label, $description = null, $data = [], $query = [] ) {
		if ( !$icon && $title->getNamespace() === NS_USER_TALK ) {
			$icon = 'userSpeechBubble';
		} elseif ( !$icon && $title->isTalkPage() ) {
			$icon = 'speechBubbles';
		} elseif ( !$icon ) {
			$icon = 'article';
		}

		return [
			'type' => 'dynamic-action',
			'label' => $label,
			'description' => $description,
			'data' => $data,
			'url' => $title->getFullURL( $query ),
			'icon' => $icon,
		];
	}

	/**
	 * Get an 'watch' or 'unwatch' dynamic action link
	 *
	 * @param Title $title Title to watch or unwatch
	 * @return array Array compatible with dynamic action link
	 */
	final protected function getWatchActionLink( Title $title ) {
		$isTitleWatched = $this->getUser()->isWatched( $title );
		$availableAction = $isTitleWatched ? 'unwatch' : 'watch';

		$data = [
			'tokenType' => 'watch',
			'params' => [
				'action' => 'watch',
				'titles' => $title->getPrefixedText(),
			],
			'messages' => [
				'confirmation' => [
					// notification-dynamic-actions-watch-confirmation
					// notification-dynamic-actions-unwatch-confirmation
					'title' => $this
						->msg( 'notification-dynamic-actions-' . $availableAction . '-confirmation' )
						->params(
							$this->getTruncatedTitleText( $title ),
							$title->getFullURL(),
							$this->getUser()->getName()
						),
					// notification-dynamic-actions-watch-confirmation-description
					// notification-dynamic-actions-unwatch-confirmation-description
					'description' => $this
						->msg( 'notification-dynamic-actions-' . $availableAction . '-confirmation-description' )
						->params(
							$this->getTruncatedTitleText( $title ),
							$title->getFullURL(),
							$this->getUser()->getName()
						),
				],
			],
		];

		// "Unwatching" action requires another parameter
		if ( $isTitleWatched ) {
			$data[ 'params' ][ 'unwatch' ] = 1;
		}

		return $this->getDynamicActionLink(
			$title,
			// Design requirements are to flip the star icons
			// in their meaning; that is, for the 'unwatch' action
			// we should display an empty star, and for the 'watch'
			// action a full star. In OOUI icons, their names
			// are reversed.
			$isTitleWatched ? 'star' : 'unStar',
			// notification-dynamic-actions-watch
			// notification-dynamic-actions-unwatch
			$this->msg( 'notification-dynamic-actions-' . $availableAction )
				->params(
					$this->getTruncatedTitleText( $title ),
					$title->getFullURL( [ 'action' => $availableAction ] ),
					$this->getUser()->getName()
				),
			null,
			$data,
			[ 'action' => $availableAction ]
		);
	}
}