file_importer.php

<?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/>.

/**
 * @package    mod_coursework
 * @copyright  2017 University of London Computer Centre {@link https://www.cosector.com}
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

namespace mod_coursework;

use mod_coursework\models\coursework;
use mod_coursework\models\submission;
use mod_coursework\export;

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

class coursework_file_zip_importer {

    public function extract_zip_file($filename, $contextid) {

        global $USER;

        // raise_memory_limit(MEMORY_EXTRA);
        // @set_time_limit(ASSIGNFEEDBACK_FILE_MAXFILEUNZIPTIME);

        $packer = get_file_packer('application/zip');

        return $packer->extract_to_storage($filename,
            $contextid,
            'coursework_temp_feedback_file',
            'coursework_feedback_file',
            $USER->id,
            'import');
    }

    public function get_import_files($contextid) {
        global $USER;

        $fs = get_file_storage();
        $files = $fs->get_directory_files($contextid,
            'coursework_temp_feedback_file',
            'coursework_feedback_file',
            $USER->id,
            '/import/');

        $keys = array_keys($files);

        if (count($files) == 1 && $files[$keys[0]]->is_directory()) {
            // An entire folder was zipped, rather than its contents.
            // We need to return the contents of the folder instead, so the import can continue.
            $files = $fs->get_directory_files($contextid,
                'coursework_temp_feedback_file',
                'coursework_feedback_file',
                $USER->id,
                $files[$keys[0]]->get_filepath());
        }

        return $files;
    }

    /**
     * Delete all temp files used when importing a zip
     *
     * @param int $contextid - The context id of this assignment instance
     * @return bool true if all files were deleted
     */
    public function delete_import_files($contextid) {
        global $USER;

        $fs = get_file_storage();

        return $fs->delete_area_files($contextid,
            'coursework_temp_feedback_file',
            'coursework_feedback_file',
            $USER->id);
    }

    /**
     * Process an uploaded zip file
     *
     * @param coursework $coursework
     * @return string - The html response
     */
    public function import_zip_files($coursework, $feedbackstage, $overwritecurrent) {
        global $CFG, $PAGE, $DB, $USER;

        @set_time_limit(ASSIGNFEEDBACK_FILE_MAXFILEUNZIPTIME);

        $results = [];

        $feedbackfilesupdated = 0;
        $feedbackfilesadded = 0;
        $userswithnewfeedback = [];
        $contextid = $coursework->get_context_id();

        $fs = get_file_storage();
        $feedbackfiles = $this->get_import_files($contextid);

        $participants = $coursework->get_allocatables();

        foreach ($feedbackfiles as $file) {

            $filename = $file->get_filename();

            if ($allocatableid = $this->is_valid_feedback_file_filename($coursework, $file, $participants) ) {

                $subdbrecord = $DB->get_record('coursework_submissions', ['courseworkid' => $coursework->id(), 'allocatableid' => $allocatableid, 'allocatabletype' => $coursework->get_allocatable_type()]);

                $submission = \mod_coursework\models\submission::find($subdbrecord);

                if ($submission->get_state() < \mod_coursework\models\submission::PUBLISHED) {

                    // If only add/edit initial capability then workout stage identifier
                    if ($feedbackstage == 'initialassessor') {

                        $feedback = $DB->get_record('coursework_feedbacks', ['submissionid' => $submission->id, 'assessorid' => $USER->id ]);

                        if ($feedback) {
                            $feedbackstage = $feedback->stage_identifier;

                        } else {
                            $results[$filename] = get_string('assessorfeedbacknotfound', 'mod_coursework');
                        }
                    }

                    if ($feedback = $this->feedback_exists($coursework, $submission, $feedbackstage)) {

                        if ($oldfile = $fs->get_file($contextid,
                            'mod_coursework',
                            'feedback',
                            $feedback->id,
                            '/',
                            $filename
                        )
                        ) {
                            if (!empty($overwritecurrent)) {
                                // Update existing feedback file.
                                $oldfile->replace_file_with($file);
                                $feedbackfilesupdated++;

                                $results[$filename] = get_string('feedbackfileupdated', 'mod_coursework');
                            } else {
                                $results[$filename] = get_string('feedbackcurrentfileexist', 'mod_coursework');
                            }
                        } else {
                            // Create a new feedback file.
                            $newfilerecord = new \stdClass();
                            $newfilerecord->contextid = $contextid;
                            $newfilerecord->component = 'mod_coursework';
                            $newfilerecord->filearea = 'feedback';
                            $newfilerecord->filename = $filename;
                            $newfilerecord->filepath = '/';
                            $newfilerecord->itemid = $feedback->id;
                            $fs->create_file_from_storedfile($newfilerecord, $file);
                            $feedbackfilesadded++;
                            $results[$filename] = get_string('feedbackfilecreated', 'mod_coursework');
                        }

                    } else {
                        $results[$filename] = get_string('assessorfeedbacknotfound', 'mod_coursework');
                    }
                } else {
                    $results[$filename] = get_string('feedbacksubmissionpublished', 'mod_coursework');
                }

            } else {
                $results[$filename] = get_string('feedbacknotfound', 'mod_coursework');
            }
        }

        // Clear up the files that have not been moved to the mod_coursework area
        $this->delete_import_files($contextid);

        return $results;

    }

    public function is_valid_feedback_file_filename($coursework, $feedbackfile, $participants) {

        $result = false;

        $filename = explode('.', $feedbackfile->get_filename());
        $filename = $filename[0];

        if ($feedbackfile->is_directory()) {
            return $result;
        }

        // Ignore hidden files.
        if (strpos($filename, '.') === 0) {
            return $result;
        }
        // Ignore hidden files.
        if (strpos($filename, '~') === 0) {
            return $result;
        }

        foreach ($participants as $user) {
            if ($filename == $coursework->get_username_hash($user->id)) {
                $result = $user->id;
                break;
            }
        }

        return $result;

    }

    public function feedback_exists($coursework, $submission, $stageidentifier) {

        global $DB, $USER;

        $sql = "SELECT     *
                     FROM       {coursework_feedbacks}
                     WHERE      submissionid = :submissionid
                     AND        stage_identifier = :stage
                     ";

        $params = ['submissionid' => $submission->id,
                              'stage' => $stageidentifier];

        if (!has_capability('mod/coursework:administergrades', $coursework->get_context())) {
            $sql .= "AND        (assessorid = :assessorid || lasteditedbyuser = :lasteditedbyuser)";
            $params['assessorid'] = $USER->id;
            $params['lasteditedbyuser'] = $USER->id;
        }

        return   $DB->get_record_sql($sql, $params);

    }

}