<?php
/**
 * @copyright Copyright (c) 2021 Carl Schwan <carl@carlschwan.eu>
 *
 * @author Carl Schwan <carl@carlschwan.eu>
 *
 * @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 <https://www.gnu.org/licenses/>.
 *
 */

namespace OCA\Settings\Settings\Admin;

use OCA\Settings\AppInfo\Application;
use OCA\Settings\Service\AuthorizedGroupService;
use OCP\AppFramework\Http\TemplateResponse;
use OCP\AppFramework\Services\IInitialState;
use OCP\IGroupManager;
use OCP\Settings\IDelegatedSettings;
use OCP\Settings\IManager;
use OCP\Settings\ISettings;

class Delegation implements ISettings {
	/** @var IManager */
	private $settingManager;

	/** @var IInitialState $initialStateService */
	private $initialStateService;

	/** @var IGroupManager $groupManager */
	private $groupManager;

	/** @var AuthorizedGroupService $authorizedGroupService */
	private $authorizedGroupService;

	public function __construct(
		IManager $settingManager,
		IInitialState $initialStateService,
		IGroupManager $groupManager,
		AuthorizedGroupService $authorizedGroupService
	) {
		$this->settingManager = $settingManager;
		$this->initialStateService = $initialStateService;
		$this->groupManager = $groupManager;
		$this->authorizedGroupService = $authorizedGroupService;
	}

	/**
	 * Filter out the ISettings that are not IDelegatedSettings from $innerSection
	 * and add them to $settings.
	 *
	 * @param IDelegatedSettings[] $settings
	 * @param ISettings[] $innerSection
	 * @return IDelegatedSettings[]
	 */
	private function getDelegatedSettings(array $settings, array $innerSection): array {
		foreach ($innerSection as $setting) {
			if ($setting instanceof IDelegatedSettings) {
				$settings[] = $setting;
			}
		}
		return $settings;
	}

	private function initSettingState(): void {
		// Available settings page initialization
		$sections = $this->settingManager->getAdminSections();
		$settings = [];
		foreach ($sections as $sectionPriority) {
			foreach ($sectionPriority as $section) {
				$sectionSettings = $this->settingManager->getAdminSettings($section->getId());
				$sectionSettings = array_reduce($sectionSettings, [$this, 'getDelegatedSettings'], []);
				$settings = array_merge(
					$settings,
					array_map(function (IDelegatedSettings $setting) use ($section) {
						return [
							'class' => get_class($setting),
							'sectionName' => $section->getName() . ($setting->getName() !== null ? ' - ' . $setting->getName() : ''),
							'priority' => $section->getPriority(),
						];
					}, $sectionSettings)
				);
			}
		}
		usort($settings, function (array $a, array $b) {
			if ($a['priority'] == $b['priority']) {
				return 0;
			}
			return ($a['priority'] < $b['priority']) ? -1 : 1;
		});
		$this->initialStateService->provideInitialState('available-settings', $settings);
	}

	public function initAvailableGroupState(): void {
		// Available groups initialization
		$groups = [];
		$groupsClass = $this->groupManager->search('');
		foreach ($groupsClass as $group) {
			if ($group->getGID() === 'admin') {
				continue; // Admin already have access to everything
			}
			$groups[] = [
				'displayName' => $group->getDisplayName(),
				'gid' => $group->getGID(),
			];
		}
		$this->initialStateService->provideInitialState('available-groups', $groups);
	}

	public function initAuthorizedGroupState(): void {
		// Already set authorized groups
		$this->initialStateService->provideInitialState('authorized-groups', $this->authorizedGroupService->findAll());
	}

	public function getForm(): TemplateResponse {
		$this->initSettingState();
		$this->initAvailableGroupState();
		$this->initAuthorizedGroupState();

		return new TemplateResponse(Application::APP_ID, 'settings/admin/delegation', [], '');
	}

	/**
	 * @return string the section ID, e.g. 'sharing'
	 */
	public function getSection() {
		return 'admindelegation';
	}

	/*
	 * @inheritdoc
	 */
	public function getPriority() {
		return 75;
	}
}
