<?php
/**
 * @copyright Copyright (c) 2016 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @author Christoph Wurst <christoph@owncloud.com>
 * @author Joas Schilling <coding@schilljs.com>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

namespace OC\Settings\Activity;

use InvalidArgumentException;
use OCP\Activity\IEvent;
use OCP\Activity\IManager;
use OCP\Activity\IProvider;
use OCP\IGroup;
use OCP\IGroupManager;
use OCP\IURLGenerator;
use OCP\IUser;
use OCP\IUserManager;
use OCP\L10N\IFactory as L10nFactory;

class GroupProvider implements IProvider {

	public const ADDED_TO_GROUP = 'group_added';
	public const REMOVED_FROM_GROUP = 'group_removed';

	/** @var L10nFactory */
	private $l10n;
	/** @var IURLGenerator */
	private $urlGenerator;
	/** @var IManager */
	private $activityManager;
	/** @var IUserManager */
	protected $userManager;
	/** @var IGroupManager */
	protected $groupManager;

	/** @var string[] */
	protected $groupDisplayNames = [];
	/** @var string[] */
	protected $userDisplayNames = [];


	public function __construct(L10nFactory $l10n,
								IURLGenerator $urlGenerator,
								IManager $activityManager,
								IUserManager $userManager,
								IGroupManager $groupManager) {
		$this->urlGenerator = $urlGenerator;
		$this->l10n = $l10n;
		$this->activityManager = $activityManager;
		$this->userManager = $userManager;
		$this->groupManager = $groupManager;
	}

	public function parse($language, IEvent $event, IEvent $previousEvent = null) {
		if ($event->getType() !== 'group_settings') {
			throw new InvalidArgumentException();
		}

		$l = $this->l10n->get('settings', $language);

		$params = $event->getSubjectParameters();
		$parsedParameters = [
			'user' => $this->generateUserParameter($params['user']),
			'group' => $this->generateGroupParameter($params['group']),
		];

		if (isset($params['actor'])) {
			$parsedParameters['actor'] = $this->generateUserParameter($params['actor']);
		}

		switch ($event->getSubject()) {
			case self::ADDED_TO_GROUP:
				if (isset($parsedParameters['actor'])) {
					if ($this->activityManager->getCurrentUserId() === $params['user']) {
						$subject = $l->t('{actor} added you to group {group}');
					} elseif (isset($params['actor']) && $this->activityManager->getCurrentUserId() === $params['actor']) {
						$subject = $l->t('You added {user} to group {group}');
					} else {
						$subject = $l->t('{actor} added {user} to group {group}');
					}
				} else if ($this->activityManager->getCurrentUserId() === $params['user']) {
					$subject = $l->t('An administrator added you to group {group}');
				} else {
					$subject = $l->t('An administrator added {user} to group {group}');
				}
				break;
			case self::REMOVED_FROM_GROUP:
				if (isset($parsedParameters['actor'])) {
					if ($this->activityManager->getCurrentUserId() === $params['user']) {
						$subject = $l->t('{actor} removed you from group {group}');
					} elseif (isset($params['actor']) && $this->activityManager->getCurrentUserId() === $params['actor']) {
						$subject = $l->t('You removed {user} from group {group}');
					} else {
						$subject = $l->t('{actor} removed {user} from group {group}');
					}
				} else if ($this->activityManager->getCurrentUserId() === $params['user']) {
					$subject = $l->t('An administrator removed you from group {group}');
				} else {
					$subject = $l->t('An administrator removed {user} from group {group}');
				}
				break;
			default:
				throw new InvalidArgumentException();
		}

		$this->setSubjects($event, $subject, $parsedParameters);

		return $event;
	}

	/**
	 * @param IEvent $event
	 * @param string $subject
	 * @param array $parameters
	 * @throws \InvalidArgumentException
	 */
	protected function setSubjects(IEvent $event, string $subject, array $parameters): void {
		$placeholders = $replacements = [];
		foreach ($parameters as $placeholder => $parameter) {
			$placeholders[] = '{' . $placeholder . '}';
			$replacements[] = $parameter['name'];
		}

		$event->setParsedSubject(str_replace($placeholders, $replacements, $subject))
			->setRichSubject($subject, $parameters);
	}

	/**
	 * @param string $gid
	 * @return array
	 */
	protected function generateGroupParameter(string $gid): array {
		if (!isset($this->groupDisplayNames[$gid])) {
			$this->groupDisplayNames[$gid] = $this->getGroupDisplayName($gid);
		}

		return [
			'type' => 'user-group',
			'id' => $gid,
			'name' => $this->groupDisplayNames[$gid],
		];
	}

	/**
	 * @param string $gid
	 * @return string
	 */
	protected function getGroupDisplayName(string $gid): string {
		$group = $this->groupManager->get($gid);
		if ($group instanceof IGroup) {
			return $group->getDisplayName();
		}
		return $gid;
	}

	/**
	 * @param string $uid
	 * @return array
	 */
	protected function generateUserParameter(string $uid): array {
		if (!isset($this->displayNames[$uid])) {
			$this->userDisplayNames[$uid] = $this->getDisplayName($uid);
		}

		return [
			'type' => 'user',
			'id' => $uid,
			'name' => $this->userDisplayNames[$uid],
		];
	}

	/**
	 * @param string $uid
	 * @return string
	 */
	protected function getDisplayName(string $uid): string {
		$user = $this->userManager->get($uid);
		if ($user instanceof IUser) {
			return $user->getDisplayName();
		} else {
			return $uid;
		}
	}
}