<?php
/**
 * SPDX-FileCopyrightText: 2017 Nextcloud GmbH and Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */
namespace OCA\User_LDAP;

use OC\User\Backend;
use OCP\Server;
use Psr\Log\LoggerInterface;

class UserPluginManager {
	private int $respondToActions = 0;

	private array $which = [
		Backend::CREATE_USER => null,
		Backend::SET_PASSWORD => null,
		Backend::GET_HOME => null,
		Backend::GET_DISPLAYNAME => null,
		Backend::SET_DISPLAYNAME => null,
		Backend::PROVIDE_AVATAR => null,
		Backend::COUNT_USERS => null,
		'deleteUser' => null
	];

	private bool $suppressDeletion = false;

	/**
	 * @return int All implemented actions, except for 'deleteUser'
	 */
	public function getImplementedActions() {
		return $this->respondToActions;
	}

	/**
	 * Registers a user plugin that may implement some actions, overriding User_LDAP's user actions.
	 *
	 * @param ILDAPUserPlugin $plugin
	 */
	public function register(ILDAPUserPlugin $plugin) {
		$respondToActions = $plugin->respondToActions();
		$this->respondToActions |= $respondToActions;

		foreach ($this->which as $action => $v) {
			if (is_int($action) && (bool)($respondToActions & $action)) {
				$this->which[$action] = $plugin;
				Server::get(LoggerInterface::class)->debug('Registered action ' . $action . ' to plugin ' . get_class($plugin), ['app' => 'user_ldap']);
			}
		}
		if (method_exists($plugin, 'deleteUser')) {
			$this->which['deleteUser'] = $plugin;
			Server::get(LoggerInterface::class)->debug('Registered action deleteUser to plugin ' . get_class($plugin), ['app' => 'user_ldap']);
		}
	}

	/**
	 * Signal if there is a registered plugin that implements some given actions
	 * @param int $actions Actions defined in \OC\User\Backend, like Backend::CREATE_USER
	 * @return bool
	 */
	public function implementsActions($actions) {
		return ($actions & $this->respondToActions) == $actions;
	}

	/**
	 * Create a new user in LDAP Backend
	 *
	 * @param string $username The username of the user to create
	 * @param string $password The password of the new user
	 * @return string | false The user DN if user creation was successful.
	 * @throws \Exception
	 */
	public function createUser($username, $password) {
		$plugin = $this->which[Backend::CREATE_USER];

		if ($plugin) {
			return $plugin->createUser($username, $password);
		}
		throw new \Exception('No plugin implements createUser in this LDAP Backend.');
	}

	/**
	 * Change the password of a user*
	 * @param string $uid The username
	 * @param string $password The new password
	 * @return bool
	 * @throws \Exception
	 */
	public function setPassword($uid, $password) {
		$plugin = $this->which[Backend::SET_PASSWORD];

		if ($plugin) {
			return $plugin->setPassword($uid, $password);
		}
		throw new \Exception('No plugin implements setPassword in this LDAP Backend.');
	}

	/**
	 * checks whether the user is allowed to change their avatar in Nextcloud
	 * @param string $uid the Nextcloud user name
	 * @return boolean either the user can or cannot
	 * @throws \Exception
	 */
	public function canChangeAvatar($uid) {
		$plugin = $this->which[Backend::PROVIDE_AVATAR];

		if ($plugin) {
			return $plugin->canChangeAvatar($uid);
		}
		throw new \Exception('No plugin implements canChangeAvatar in this LDAP Backend.');
	}

	/**
	 * Get the user's home directory
	 * @param string $uid the username
	 * @return boolean
	 * @throws \Exception
	 */
	public function getHome($uid) {
		$plugin = $this->which[Backend::GET_HOME];

		if ($plugin) {
			return $plugin->getHome($uid);
		}
		throw new \Exception('No plugin implements getHome in this LDAP Backend.');
	}

	/**
	 * Get display name of the user
	 * @param string $uid user ID of the user
	 * @return string display name
	 * @throws \Exception
	 */
	public function getDisplayName($uid) {
		$plugin = $this->which[Backend::GET_DISPLAYNAME];

		if ($plugin) {
			return $plugin->getDisplayName($uid);
		}
		throw new \Exception('No plugin implements getDisplayName in this LDAP Backend.');
	}

	/**
	 * Set display name of the user
	 * @param string $uid user ID of the user
	 * @param string $displayName new user's display name
	 * @return string display name
	 * @throws \Exception
	 */
	public function setDisplayName($uid, $displayName) {
		$plugin = $this->which[Backend::SET_DISPLAYNAME];

		if ($plugin) {
			return $plugin->setDisplayName($uid, $displayName);
		}
		throw new \Exception('No plugin implements setDisplayName in this LDAP Backend.');
	}

	/**
	 * Count the number of users
	 * @return int|false
	 * @throws \Exception
	 */
	public function countUsers() {
		$plugin = $this->which[Backend::COUNT_USERS];

		if ($plugin) {
			return $plugin->countUsers();
		}
		throw new \Exception('No plugin implements countUsers in this LDAP Backend.');
	}

	/**
	 * @return bool
	 */
	public function canDeleteUser() {
		return !$this->suppressDeletion && $this->which['deleteUser'] !== null;
	}

	/**
	 * @param $uid
	 * @return bool
	 * @throws \Exception
	 */
	public function deleteUser($uid) {
		$plugin = $this->which['deleteUser'];
		if ($plugin) {
			if ($this->suppressDeletion) {
				return false;
			}
			return $plugin->deleteUser($uid);
		}
		throw new \Exception('No plugin implements deleteUser in this LDAP Backend.');
	}

	/**
	 * @param bool $value
	 * @return bool – the value before the change
	 */
	public function setSuppressDeletion(bool $value): bool {
		$old = $this->suppressDeletion;
		$this->suppressDeletion = $value;
		return $old;
	}
}