Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle 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 General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Contains the user_favourite_service class, part of the service layer for the favourites subsystem.

 *

 * @package   core_favourites

 * @copyright 2018 Jake Dallimore <jrhdallimore@gmail.com>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

namespace core_favourites\local\service;

use \core_favourites\local\entity\favourite;

use \core_favourites\local\repository\favourite_repository_interface;

defined('MOODLE_INTERNAL') || die();

/**

 * Class service, providing an single API for interacting with the favourites subsystem for a SINGLE USER.

 *

 * This class is responsible for exposing key operations (add, remove, find) and enforces any business logic necessary to validate

 * authorization/data integrity for these operations.

 *

 * All object persistence is delegated to the favourite_repository_interface object.

 *

 * @copyright 2018 Jake Dallimore <jrhdallimore@gmail.com>

 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

class user_favourite_service {

    /** @var favourite_repository_interface $repo the favourite repository object. */

    protected $repo;

    /** @var int $userid the id of the user to which this favourites service is scoped. */

    protected $userid;

    /**

     * The user_favourite_service constructor.

     *

     * @param \context_user $usercontext The context of the user to which this service operations are scoped.

     * @param \core_favourites\local\repository\favourite_repository_interface $repository a favourites repository.

     */

    public function __construct(\context_user $usercontext, favourite_repository_interface $repository) {

        $this->repo = $repository;

        $this->userid = $usercontext->instanceid;

    }

    /**

     * Favourite an item defined by itemid/context, in the area defined by component/itemtype.

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the item being favourited.

     * @param int $itemid the id of the item which is to be favourited.

     * @param \context $context the context in which the item is to be favourited.

     * @param int|null $ordering optional ordering integer used for sorting the favourites in an area.

     * @return favourite the favourite, once created.

     * @throws \moodle_exception if the component name is invalid, or if the repository encounters any errors.

     */

    public function create_favourite(string $component, string $itemtype, int $itemid, \context $context,

            int $ordering = null): favourite {

        // Access: Any component can ask to favourite something, we can't verify access to that 'something' here though.

        // Validate the component name.

        if (!in_array($component, \core_component::get_component_names())) {

            throw new \moodle_exception("Invalid component name '$component'");

        }

        $favourite = new favourite($component, $itemtype, $itemid, $context->id, $this->userid);

        $favourite->ordering = $ordering > 0 ? $ordering : null;

        return $this->repo->add($favourite);

    }

    /**

     * Find a list of favourites, by type, where type is the component/itemtype pair.

     *

     * E.g. "Find all favourite courses" might result in:

     * $favcourses = find_favourites_by_type('core_course', 'course');

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param int $limitfrom optional pagination control for returning a subset of records, starting at this point.

     * @param int $limitnum optional pagination control for returning a subset comprising this many records.

     * @return array the list of favourites found.

     * @throws \moodle_exception if the component name is invalid, or if the repository encounters any errors.

     */

    public function find_favourites_by_type(string $component, string $itemtype, int $limitfrom = 0, int $limitnum = 0): array {

        if (!in_array($component, \core_component::get_component_names())) {

            throw new \moodle_exception("Invalid component name '$component'");

        }

        return $this->repo->find_by(

            [

                'userid' => $this->userid,

                'component' => $component,

                'itemtype' => $itemtype

            ],

            $limitfrom,

            $limitnum

        );

    }

    /**

     * Find a list of favourites, by multiple types within a component.

     *

     * E.g. "Find all favourites in the activity chooser" might result in:

     * $favcourses = find_all_favourites('core_course', ['contentitem_mod_assign');

     *

     * @param string $component the frankenstyle component name.

     * @param array $itemtypes optional the type of the favourited item.

     * @param int $limitfrom optional pagination control for returning a subset of records, starting at this point.

     * @param int $limitnum optional pagination control for returning a subset comprising this many records.

     * @return array the list of favourites found.

     * @throws \moodle_exception if the component name is invalid, or if the repository encounters any errors.

     */

    public function find_all_favourites(string $component, array $itemtypes = [], int $limitfrom = 0, int $limitnum = 0): array {

        if (!in_array($component, \core_component::get_component_names())) {

            throw new \moodle_exception("Invalid component name '$component'");

        }

        $params = [

            'userid' => $this->userid,

            'component' => $component,

        ];

        if ($itemtypes) {

            $params['itemtype'] = $itemtypes;

        }

        return $this->repo->find_by(

            $params,

            $limitfrom,

            $limitnum

        );

    }

    /**

     * Returns the SQL required to include favourite information for a given component/itemtype combination.

     *

     * Generally, find_favourites_by_type() is the recommended way to fetch favourites.

     *

     * This method is used to include favourite information in external queries, for items identified by their

     * component and itemtype, matching itemid to the $joinitemid, and for the user to which this service is scoped.

     *

     * It uses a LEFT JOIN to preserve the original records. If you wish to restrict your records, please consider using a

     * "WHERE {$tablealias}.id IS NOT NULL" in your query.

     *

     * Example usage:

     *

     * list($sql, $params) = $service->get_join_sql_by_type('core_message', 'message_conversations', 'myfavouritetablealias',

     *                                                      'conv.id');

     * Results in $sql:

     *     "LEFT JOIN {favourite} fav

     *             ON fav.component = :favouritecomponent

     *            AND fav.itemtype = :favouriteitemtype

     *            AND fav.userid = 1234

     *            AND fav.itemid = conv.id"

     * and $params:

     *     ['favouritecomponent' => 'core_message', 'favouriteitemtype' => 'message_conversations']

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param string $tablealias the desired alias for the favourites table.

     * @param string $joinitemid the table and column identifier which the itemid is joined to. E.g. conversation.id.

     * @return array the list of sql and params, in the format [$sql, $params].

     */

    public function get_join_sql_by_type(string $component, string $itemtype, string $tablealias, string $joinitemid): array {

        $sql = " LEFT JOIN {favourite} {$tablealias}

                        ON {$tablealias}.component = :favouritecomponent

                       AND {$tablealias}.itemtype = :favouriteitemtype

                       AND {$tablealias}.userid = {$this->userid}

                       AND {$tablealias}.itemid = {$joinitemid} ";

        $params = [

            'favouritecomponent' => $component,

            'favouriteitemtype' => $itemtype,

        ];

        return [$sql, $params];

    }

    /**

     * Delete a favourite item from an area and from within a context.

     *

     * E.g. delete a favourite course from the area 'core_course', 'course' with itemid 3 and from within the CONTEXT_USER context.

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param int $itemid the id of the item which was favourited (not the favourite's id).

     * @param \context $context the context of the item which was favourited.

     * @throws \moodle_exception if the user does not control the favourite, or it doesn't exist.

     */

    public function delete_favourite(string $component, string $itemtype, int $itemid, \context $context) {

        if (!in_array($component, \core_component::get_component_names())) {

            throw new \moodle_exception("Invalid component name '$component'");

        }

        // Business logic: check the user owns the favourite.

        try {

            $favourite = $this->repo->find_favourite($this->userid, $component, $itemtype, $itemid, $context->id);

        } catch (\moodle_exception $e) {

            throw new \moodle_exception("Favourite does not exist for the user. Cannot delete.");

        }

        $this->repo->delete($favourite->id);

    }

    /**

     * Check whether an item has been marked as a favourite in the respective area.

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param int $itemid the id of the item which was favourited (not the favourite's id).

     * @param \context $context the context of the item which was favourited.

     * @return bool true if the item is favourited, false otherwise.

     */

    public function favourite_exists(string $component, string $itemtype, int $itemid, \context $context): bool {

        return $this->repo->exists_by(

            [

                'userid' => $this->userid,

                'component' => $component,

                'itemtype' => $itemtype,

                'itemid' => $itemid,

                'contextid' => $context->id

            ]

        );

    }

    /**

     * Get the favourite.

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param int $itemid the id of the item which was favourited (not the favourite's id).

     * @param \context $context the context of the item which was favourited.

     * @return favourite|null

     */

    public function get_favourite(string $component, string $itemtype, int $itemid, \context $context) {

        try {

            return $this->repo->find_favourite(

                $this->userid,

                $component,

                $itemtype,

                $itemid,

                $context->id

            );

        } catch (\dml_missing_record_exception $e) {

            return null;

        }

    }

    /**

     * Count the favourite by item type.

     *

     * @param string $component the frankenstyle component name.

     * @param string $itemtype the type of the favourited item.

     * @param \context|null $context the context of the item which was favourited.

     * @return int

     */

    public function count_favourites_by_type(string $component, string $itemtype, \context $context = null) {

        $criteria = [

            'userid' => $this->userid,

            'component' => $component,

            'itemtype' => $itemtype

        ];

        if ($context) {

            $criteria['contextid'] = $context->id;

        }

        return $this->repo->count_by($criteria);

    }

}