gradeimporter/forms/submission_form_functions.php

<?php
// This file is part of
//
// 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/>.

function create_submission($data, $gradeimporterid, $userid) {
    global $DB;
    $timenow = time();
    if (empty($data->id)) {
        // If is new db entry;
        $data->gradeimporterid = $gradeimporterid;
        $data->usermodified = $userid;
        $data->timecreated = $timenow;

        $isnewentry = true;
    } else {
        $isnewentry = false;
    }

    $data->descriptionformat = $data->description["format"];
    $data->description = $data->description["text"];
    $data->timemodified = $timenow;
    $data->position = -1; // Do later

    if ($isnewentry) {
        // If is new entry insert data into DB and gets id
        $data->id = $DB->insert_record('gradeimporter_submission', $data);
    }

    // If not new entry updates information
    // If new entry inserts id into DB
    $DB->update_record('gradeimporter_submission', $data);

    return $data;
}



function store_files($context, $cm, $data) {
    $fs = get_file_storage();
    $files = $fs->get_area_files($context->id, 'mod_gradeimporter',
                                'submissionfiles', $data->id
                            );
    foreach ($files as $file) {
        $extension = explode(".", $file->get_filename())[1];
        if ($extension == 'csv') {
            read_csv($file->get_content(), $context, $data);
            return;
        }
    }
}

function read_csv($content, $context, $data) {
    $csv = prepare_csv($content);
    foreach ($csv as $feedback) {
        if ($feedback['file'] != "") {
            // If feedback has associated file, insert it into pluginfile
            $feedbackfilepath = store_feedback_file($feedback, $context, $data, $filepath);
        }
        echo "Before store_feedback</br>";
        store_feedback($feedback, $context->id, $data->id);
        echo "After store_feedback</br>";
    }
}

function prepare_csv($content) {
    $csvlines = explode(PHP_EOL, $content);
    $csv = array();
    foreach ($csvlines as $line) {
        $csv[] = str_getcsv($line);
    }
    $header = array_shift($csv);

    $outputcsv = array();
    $outputcsv = array_map(
                            function($v)use($header){
                                return array_combine($header, $v);
                            },
                            $csv
                        );

    return $outputcsv;
}

function store_feedback($feedback, $contextid, $submissionid) {
    global $DB;
    // Prepare data to submit to gradeimporter_feedback table
    $entry = new stdClass();
    $entry->id = null;

    $entry->timecreated = time();
    $entry->timemodified = time();

    $entry->submissionid = $submissionid;
    $entry->studentid = $feedback['id'];
    $entry->grade = $feedback['grade'];
    $entry->comment = $feedback['comment'];
    $entry->name = $feedback['file'];
    $entry->fileid = 0;
    $entry->usermodified = 1;
    $entry->contextid = $contextid;

    // Insert data into gradeimporter_feedback table and gets ID
    $entry->id = $DB->insert_record('gradeimporter_feedback', $entry);

}

function store_feedback_file($feedback, $context, $data, $filepath) {
    // Prepare file
    $fs = get_file_storage();
    $fileinfo = array(
        'contextid' => $context->id,
        'component' => 'mod_gradeimporter',
        'filearea' => 'submissionfiles',
        'itemid' => 0,
        'filepath' => "/$data->id/{$feedback[id]}/",
        'filename' => $feedback['file'],
        'timecreated' => time(),
        'timemodified' => time()
    );

    // Move file from temp to pluginfile
    $fs->create_file_from_pathname($fileinfo, $filepath);

    return $fileinfo['filepath'];
}