<?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/>.

/**
 * Defines backup_course_task
 *
 * @package     core_backup
 * @subpackage  moodle2
 * @category    backup
 * @copyright   2010 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
 * @license     http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * course task that provides all the properties and common steps to be performed
 * when one course is being backup
 *
 * TODO: Finish phpdocs
 */
class backup_course_task extends backup_task {

    protected $courseid;
    protected $contextid;

    /**
     * Constructor - instantiates one object of this class
     */
    public function __construct($name, $courseid, $plan = null) {

        $this->courseid   = $courseid;
        $this->contextid  = context_course::instance($this->courseid)->id;

        parent::__construct($name, $plan);
    }

    public function get_contextid() {
        return $this->contextid;
    }

    /**
     * Course tasks have their own directory to write files
     */
    public function get_taskbasepath() {

        return $this->get_basepath() . '/course';
    }

    /**
     * Create all the steps that will be part of this task
     */
    public function build() {

        // Add some extra settings that related processors are going to need
        $this->add_setting(new backup_activity_generic_setting(backup::VAR_COURSEID, base_setting::IS_INTEGER, $this->get_courseid()));
        $this->add_setting(new backup_activity_generic_setting(backup::VAR_CONTEXTID, base_setting::IS_INTEGER, $this->contextid));

        // Create the course directory
        $this->add_step(new create_taskbasepath_directory('create_course_directory'));

        // Create the course.xml file with course & category information
        // annotating some bits, tags and module restrictions
        $this->add_step(new backup_course_structure_step('course_info', 'course.xml'));

        // Generate the enrolment file (conditionally, prevent it in any IMPORT/HUB operation)
        if ($this->plan->get_mode() != backup::MODE_IMPORT && $this->plan->get_mode() != backup::MODE_HUB) {
            $this->add_step(new backup_enrolments_structure_step('course_enrolments', 'enrolments.xml'));
        }

        // Annotate enrolment custom fields.
        $this->add_step(new backup_enrolments_execution_step('annotate_enrol_custom_fields'));

        // Annotate all the groups and groupings belonging to the course. This can be optional.
        if ($this->get_setting_value('groups')) {
            $this->add_step(new backup_annotate_course_groups_and_groupings('annotate_course_groups'));
        }

        // Annotate the groups used in already annotated groupings (note this may be
        // unnecessary now that we are annotating all the course groups and groupings in the
        // step above). This is here to support course->defaultgroupingid.
        // This may not be required to annotate if groups are not being backed up.
        if ($this->get_setting_value('groups')) {
            $this->add_step(new backup_annotate_groups_from_groupings('annotate_groups_from_groupings'));
        }

        // Annotate the question_categories belonging to the course context (conditionally).
        if ($this->get_setting_value('questionbank')) {
            $this->add_step(new backup_calculate_question_categories('course_question_categories'));
        }

        // Generate the roles file (optionally role assignments and always role overrides)
        $this->add_step(new backup_roles_structure_step('course_roles', 'roles.xml'));

        // Generate the filter file (conditionally)
        if ($this->get_setting_value('filters')) {
            $this->add_step(new backup_filters_structure_step('course_filters', 'filters.xml'));
        }

        // Generate the comments file (conditionally)
        if ($this->get_setting_value('comments')) {
            $this->add_step(new backup_comments_structure_step('course_comments', 'comments.xml'));
        }

        // Generate the calender events file (conditionally)
        if ($this->get_setting_value('calendarevents')) {
            $this->add_step(new backup_calendarevents_structure_step('course_calendar', 'calendar.xml'));
        }

        // Generate the logs file (conditionally)
        if ($this->get_setting_value('logs')) {
            // Legacy logs.
            $this->add_step(new backup_course_logs_structure_step('course_logs', 'logs.xml'));
            // New log stores.
            $this->add_step(new backup_course_logstores_structure_step('course_logstores', 'logstores.xml'));
            // Last access to course logs.
            $this->add_step(new backup_course_loglastaccess_structure_step('course_loglastaccess', 'loglastaccess.xml'));
        }

        // Generate the course competencies.
        $this->add_step(new backup_course_competencies_structure_step('course_competencies', 'competencies.xml'));

        // Annotate activity completion defaults.
        $this->add_step(new backup_completion_defaults_structure_step('course_completion_defaults', 'completiondefaults.xml'));

        // Generate the inforef file (must be after ALL steps gathering annotations of ANY type)
        $this->add_step(new backup_inforef_structure_step('course', 'inforef.xml'));

        // Migrate the already exported inforef entries to final ones
        $this->add_step(new move_inforef_annotations_to_final('migrate_inforef'));

        // Generate the content bank file (conditionally).
        if ($this->get_setting_value('contentbankcontent')) {
            $this->add_step(new backup_contentbankcontent_structure_step('course_contentbank', 'contentbank.xml'));
        }

        // At the end, mark it as built
        $this->built = true;
    }

    /**
     * Code the transformations to perform in the course in
     * order to get transportable (encoded) links
     * @param string $content content in which to encode links.
     * @return string content with links encoded.
     */
    public static function encode_content_links($content) {

        // Link to the course main page (it also covers "&topic=xx" and "&week=xx"
        // because they don't become transformed (section number) in backup/restore.
        $content = self::encode_links_helper($content, 'COURSEVIEWBYID',       '/course/view.php?id=');
        $content = self::encode_links_helper($content, 'COURSESECTIONBYID',    '/course/section.php?id=');

        // A few other key course links.
        $content = self::encode_links_helper($content, 'GRADEINDEXBYID',       '/grade/index.php?id=');
        $content = self::encode_links_helper($content, 'GRADEREPORTINDEXBYID', '/grade/report/index.php?id=');
        $content = self::encode_links_helper($content, 'BADGESVIEWBYID',       '/badges/index.php?type=2&id=');
        $content = self::encode_links_helper($content, 'USERINDEXVIEWBYID',    '/user/index.php?id=');
        $content = self::encode_links_helper($content, 'PLUGINFILEBYCONTEXT',  '/pluginfile.php/');
        $content = self::encode_links_helper($content, 'PLUGINFILEBYCONTEXTURLENCODED', '/pluginfile.php/', true);

        return $content;
    }

    /**
     * Helper method, used by encode_content_links.
     * @param string $content content in which to encode links.
     * @param string $name the name of this type of encoded link.
     * @param string $path the path that identifies this type of link, up
     *      to the ?paramname= bit.
     * @param bool $urlencoded whether to use urlencode() before replacing the path.
     * @return string content with one type of link encoded.
     */
    private static function encode_links_helper(string $content, string $name, string $path, bool $urlencoded = false) {
        global $CFG;
        // We want to convert both http and https links.
        $root = $CFG->wwwroot;
        $httpsroot = str_replace('http://', 'https://', $root);
        $httproot = str_replace('https://', 'http://', $root);

        $httpsbase = $httpsroot . $path;
        $httpbase = $httproot . $path;

        if ($urlencoded) {
            $httpsbase = urlencode($httpsbase);
            $httpbase = urlencode($httpbase);
        }

        $httpsbase = preg_quote($httpsbase, '/');
        $httpbase = preg_quote($httpbase, '/');

        $return = preg_replace('/(' . $httpsbase . ')([0-9]+)/', '$@' . $name . '*$2@$', $content);
        $return = preg_replace('/(' . $httpbase . ')([0-9]+)/', '$@' . $name . '*$2@$', $return);

        return $return;
    }

// Protected API starts here

    /**
     * Define the common setting that any backup section will have
     */
    protected function define_settings() {

        // Nothing to add, sections doesn't have common settings (for now)

    }
}
