<?php

/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2016 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE.txt
 */

namespace Joomla\CMS\Helper;

use Joomla\CMS\Factory;
use Joomla\Database\ParameterType;

// phpcs:disable PSR1.Files.SideEffects
\defined('_JEXEC') or die;
// phpcs:enable PSR1.Files.SideEffects

/**
 * Helper to deal with user groups.
 *
 * @since  3.6.3
 */
final class UserGroupsHelper
{
    /**
     * Indicates the current helper instance is the singleton instance.
     *
     * @var    integer
     * @since  3.6.3
     */
    public const MODE_SINGLETON = 1;

    /**
     * Indicates the current helper instance is a standalone class instance.
     *
     * @var    integer
     * @since  3.6.3
     */
    public const MODE_INSTANCE = 2;

    /**
     * Singleton instance.
     *
     * @var    UserGroupsHelper
     * @since  3.6.3
     */
    private static $instance;

    /**
     * Available user groups
     *
     * @var    array
     * @since  3.6.3
     */
    private $groups = [];

    /**
     * Mode this class is working: singleton or std instance
     *
     * @var    integer
     * @since  3.6.3
     */
    private $mode;

    /**
     * Total available groups
     *
     * @var    integer
     * @since  3.6.3
     */
    private $total;

    /**
     * Constructor
     *
     * @param   array    $groups  Array of groups
     * @param   integer  $mode    Working mode for this class
     *
     * @since   3.6.3
     */
    public function __construct(array $groups = [], $mode = self::MODE_INSTANCE)
    {
        $this->mode = (int) $mode;

        if ($groups) {
            $this->setGroups($groups);
        }
    }

    /**
     * Count loaded user groups.
     *
     * @return  integer
     *
     * @since   3.6.3
     */
    public function count()
    {
        return \count($this->groups);
    }

    /**
     * Get the helper instance.
     *
     * @return  self
     *
     * @since   3.6.3
     */
    public static function getInstance()
    {
        if (static::$instance === null) {
            // Only here to avoid code style issues...
            $groups = [];

            static::$instance = new static($groups, static::MODE_SINGLETON);
        }

        return static::$instance;
    }

    /**
     * Get a user group by its id.
     *
     * @param   integer  $id  Group identifier
     *
     * @return  mixed  stdClass on success. False otherwise
     *
     * @since   3.6.3
     */
    public function get($id)
    {
        if ($this->has($id)) {
            return $this->groups[$id];
        }

        // Singleton will load groups as they are requested
        if ($this->isSingleton()) {
            $this->groups[$id] = $this->load($id);

            return $this->groups[$id];
        }

        return false;
    }

    /**
     * Get the list of existing user groups.
     *
     * @return  array
     *
     * @since   3.6.3
     */
    public function getAll()
    {
        if ($this->isSingleton() && $this->total() !== $this->count()) {
            $this->loadAll();
        }

        return $this->groups;
    }

    /**
     * Check if a group is in the list.
     *
     * @param   integer  $id  Group identifier
     *
     * @return  boolean
     *
     * @since   3.6.3
     */
    public function has($id)
    {
        return (\array_key_exists($id, $this->groups) && $this->groups[$id] !== false);
    }

    /**
     * Check if this instance is a singleton.
     *
     * @return  boolean
     *
     * @since   3.6.3
     */
    private function isSingleton()
    {
        return $this->mode === static::MODE_SINGLETON;
    }

    /**
     * Get total available user groups in database.
     *
     * @return  integer
     *
     * @since   3.6.3
     */
    public function total()
    {
        if ($this->total === null) {
            $db = Factory::getDbo();

            $query = $db->getQuery(true)
                ->select('COUNT(' . $db->quoteName('id') . ')')
                ->from($db->quoteName('#__usergroups'));

            $db->setQuery($query);

            $this->total = (int) $db->loadResult();
        }

        return $this->total;
    }

    /**
     * Load a group from database.
     *
     * @param   integer  $id  Group identifier
     *
     * @return  mixed
     *
     * @since   3.6.3
     */
    public function load($id)
    {
        // Cast as integer until method is typehinted.
        $id = (int) $id;

        $db = Factory::getDbo();

        $query = $db->getQuery(true)
            ->select('*')
            ->from($db->quoteName('#__usergroups'))
            ->where($db->quoteName('id') . ' = :id')
            ->bind(':id', $id, ParameterType::INTEGER);

        $db->setQuery($query);

        $group = $db->loadObject();

        if (!$group) {
            return false;
        }

        return $this->populateGroupData($group);
    }

    /**
     * Load all user groups from the database.
     *
     * @return  self
     *
     * @since   3.6.3
     */
    public function loadAll()
    {
        $this->groups = [];

        $db = Factory::getDbo();

        $query = $db->getQuery(true)
            ->select('*')
            ->from($db->quoteName('#__usergroups'))
            ->order($db->quoteName('lft') . ' ASC');

        $db->setQuery($query);

        $groups = $db->loadObjectList('id');

        $this->groups = $groups ?: [];
        $this->populateGroupsData();

        return $this;
    }

    /**
     * Populates extra information for groups.
     *
     * @return  array
     *
     * @since   3.6.3
     */
    private function populateGroupsData()
    {
        foreach ($this->groups as $group) {
            $this->populateGroupData($group);
        }

        return $this->groups;
    }

    /**
     * Populate data for a specific user group.
     *
     * @param   \stdClass  $group  Group
     *
     * @return  \stdClass
     *
     * @since   3.6.3
     */
    public function populateGroupData($group)
    {
        if (!$group || property_exists($group, 'path')) {
            return $group;
        }

        $parentId = (int) $group->parent_id;

        if ($parentId === 0) {
            $group->path  = [$group->id];
            $group->level = 0;

            return $group;
        }

        $parentGroup = $this->has($parentId) ? $this->get($parentId) : $this->load($parentId);

        if (!property_exists($parentGroup, 'path')) {
            $parentGroup = $this->populateGroupData($parentGroup);
        }

        $group->path  = array_merge($parentGroup->path, [$group->id]);
        $group->level = \count($group->path) - 1;

        return $group;
    }

    /**
     * Set the groups to be used as source.
     *
     * @param   array  $groups  Array of user groups.
     *
     * @return  self
     *
     * @since   3.6.3
     */
    public function setGroups(array $groups)
    {
        $this->groups = $groups;
        $this->populateGroupsData();
        $this->total  = \count($groups);

        return $this;
    }
}
