1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * H5P autoloader management class.
19 *
20 * @package    core_h5p
21 * @copyright  2019 Sara Arjona <sara@moodle.com>
22 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
23 */
24
25namespace core_h5p\local\library;
26
27/**
28 * H5P autoloader management class.
29 *
30 * @package    core_h5p
31 * @copyright  2019 Sara Arjona <sara@moodle.com>
32 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
33 */
34class autoloader {
35
36    /**
37     * Returns the list of plugins that can work as H5P library handlers (have class PLUGINNAME\local\library\handler)
38     * @return array with the format: pluginname => class
39     */
40    public static function get_all_handlers(): array {
41        $handlers = [];
42        $plugins = \core_component::get_plugin_list_with_class('h5plib', 'local\library\handler') +
43            \core_component::get_plugin_list_with_class('h5plib', 'local_library_handler');
44        // Allow plugins to have the class either with namespace or without (useful for unittest).
45        foreach ($plugins as $pname => $class) {
46            $handlers[$pname] = $class;
47        }
48
49        return $handlers;
50    }
51
52    /**
53     * Returns the default H5P library handler class.
54     *
55     * @return string|null H5P library handler class
56     */
57    public static function get_default_handler(): ?string {
58        $default = null;
59        $handlers = self::get_all_handlers();
60        if (!empty($handlers)) {
61            // The default handler will be the first value in the list.
62            $default = array_shift($handlers);
63        }
64
65        return $default;
66    }
67
68    /**
69     * Returns the default H5P library handler.
70     *
71     * @return string|null H5P library handler
72     */
73    public static function get_default_handler_library(): ?string {
74        $default = null;
75        $handlers = self::get_all_handlers();
76        if (!empty($handlers)) {
77            // The default handler will be the first in the list.
78            $keys = array_keys($handlers);
79            $default = array_shift($keys);
80        }
81
82        return $default;
83    }
84
85    /**
86     * Returns the current H5P library handler class.
87     *
88     * @return string H5P library handler class
89     * @throws \moodle_exception
90     */
91    public static function get_handler_classname(): string {
92        global $CFG;
93
94        $handlers = self::get_all_handlers();
95        if (!empty($CFG->h5plibraryhandler)) {
96            if (isset($handlers[$CFG->h5plibraryhandler])) {
97                return $handlers[$CFG->h5plibraryhandler];
98            }
99        }
100
101        // If no handler has been defined, return the default one.
102        $defaulthandler = self::get_default_handler();
103        if (empty($defaulthandler)) {
104            // If there is no default handler, throw an exception.
105            throw new \moodle_exception('noh5plibhandlerdefined', 'core_h5p');
106        }
107
108        return $defaulthandler;
109    }
110
111    /**
112     * Get the current version of the H5P core library.
113     *
114     * @return string
115     */
116    public static function get_h5p_version(): string {
117        return component_class_callback(self::get_handler_classname(), 'get_h5p_version', []);
118    }
119
120    /**
121     * Get a URL for the current H5P Core Library.
122     *
123     * @param string $filepath The path within the h5p root
124     * @param array $params these params override current params or add new
125     * @return null|moodle_url
126     */
127    public static function get_h5p_core_library_url(?string $filepath = null, ?array $params = null): ?\moodle_url {
128        return component_class_callback(self::get_handler_classname(), 'get_h5p_core_library_url', [$filepath, $params]);
129    }
130
131    /**
132     * Get a URL for the current H5P Editor Library.
133     *
134     * @param string $filepath The path within the h5p root.
135     * @param array $params These params override current params or add new.
136     * @return null|\moodle_url The moodle_url instance to a file in the H5P Editor library.
137     */
138    public static function get_h5p_editor_library_url(?string $filepath = null, ?array $params = null): ?\moodle_url {
139        return component_class_callback(self::get_handler_classname(), 'get_h5p_editor_library_url', [$filepath, $params]);
140    }
141
142    /**
143     * Get the base path for the current H5P Editor Library.
144     *
145     * @param string $filepath The path within the h5p root.
146     * @return string  Path to a file in the H5P Editor library.
147     */
148    public static function get_h5p_editor_library_base(?string $filepath = null): string {
149        return component_class_callback(self::get_handler_classname(), 'get_h5p_editor_library_base', [$filepath]);
150    }
151
152    /**
153     * Returns a localized string, if it exists in the h5plib plugin and the value it's different from the English version.
154     *
155     * @param string $identifier The key identifier for the localized string
156     * @param string $language Language to get the localized string.
157     * @return string|null The localized string or null if it doesn't exist in this H5P library plugin.
158     */
159    public static function get_h5p_string(string $identifier, string $language): ?string {
160        return component_class_callback(self::get_handler_classname(), 'get_h5p_string', [$identifier, $language]);
161    }
162
163    /**
164     * Register the H5P autoloader.
165     */
166    public static function register(): void {
167        component_class_callback(self::get_handler_classname(), 'register', []);
168    }
169}
170