lib.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/>.
/**
 * Stripe enrolment plugin.
 *
 * This plugin allows you to set up paid courses.
 *
 * @package    enrol_stripepayment
 * @copyright  2015 Dualcube, Arkaprava Midya, Parthajeet Chakraborty
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
defined('MOODLE_INTERNAL') || die();
/**
 * Stripe enrolment plugin implementation.
 * @copyright  2015 Dualcube, Arkaprava Midya, Parthajeet Chakraborty
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
class enrol_stripepayment_plugin extends enrol_plugin {
    /**
     * Lists all currencies available for plugin.
     * @return $currencies
     */
    public function get_currencies() {
        // See https://www.stripe.com/cgi-bin/webscr?cmd=p/sell/mc/mc_intro-outside,
        // 3-character ISO-4217: https://cms.stripe.com/us/cgi-bin/?cmd=
        // _render-content&content_ID=developer/e_howto_api_currency_codes.
        $codes = array(
            'AUD', 'BRL', 'CAD', 'CHF', 'CZK', 'DKK', 'EUR', 'GBP', 'HKD', 'HUF', 'ILS', 'JPY',
            'MXN', 'MYR', 'NOK', 'NZD', 'PHP', 'PLN', 'RUB', 'SEK', 'SGD', 'THB', 'TRY', 'TWD', 'USD');
        $currencies = array();
        foreach ($codes as $c) {
            $currencies[$c] = new lang_string($c, 'core_currencies');
        }
        return $currencies;
    }

    /**
     * Returns optional enrolment information icons.
     *
     * This is used in course list for quick overview of enrolment options.
     *
     * We are not using single instance parameter because sometimes
     * we might want to prevent icon repetition when multiple instances
     * of one type exist. One instance may also produce several icons.
     *
     * @param array $instances all enrol instances of this type in one course
     * @return array of pix_icon
     */
    public function get_info_icons(array $instances) {
        $found = false;
        foreach ($instances as $instance) {
            if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
                continue;
            }
            if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
                continue;
            }
            $found = true;
            break;
        }
        if ($found) {
            return array(new pix_icon('icon', get_string('pluginname', 'enrol_stripepayment'), 'enrol_stripepayment'));
        }
        return array();
    }
    /**
     * Lists all protected user roles.
     * @return bool(true or false)
     */
    public function roles_protected() {
        // Users with role assign cap may tweak the roles later.
        return false;
    }
    /**
     * Defines if user can be unenrolled.
     * @param stdClass $instance of the plugin
     * @return bool(true or false)
     */
    public function allow_unenrol(stdClass $instance) {
        // Users with unenrol cap may unenrol other users manually - requires enrol/stripe:unenrol.
        return true;
    }
    /**
     * Defines if user can be managed from admin.
     * @param stdClass $instance of the plugin
     * @return bool(true or false)
     */
    public function allow_manage(stdClass $instance) {
        // Users with manage cap may tweak period and status - requires enrol/stripe:manage.
        return true;
    }
    /**
     * Defines if 'enrol me' link will be shown on course page.
     * @param stdClass $instance of the plugin
     * @return bool(true or false)
     */
    public function show_enrolme_link(stdClass $instance) {
        return ($instance->status == ENROL_INSTANCE_ENABLED);
    }
    /**
     * Sets up navigation entries.
     *
     * @param navigation_node $instancesnode
     * @param stdClass $instance
     * @return void
     */
    public function add_course_navigation($instancesnode, stdClass $instance) {
        if ($instance->enrol !== 'stripepayment') {
             throw new coding_exception('Invalid enrol instance type!');
        }
        $context = context_course::instance($instance->courseid);
        if (has_capability('enrol/stripepayment:config', $context)) {
            $managelink = new moodle_url('/enrol/stripepayment/edit.php', array('courseid' => $instance->courseid, 'id' => $instance->id));
            $instancesnode->add($this->get_instance_name($instance), $managelink, navigation_node::TYPE_SETTING);
        }
    }
    /**
     * Returns edit icons for the page with list of instances
     * @param stdClass $instance
     * @return array
     */
    public function get_action_icons(stdClass $instance) {
        global $OUTPUT;
        if ($instance->enrol !== 'stripepayment') {
            throw new coding_exception('invalid enrol instance!');
        }
        $context = context_course::instance($instance->courseid);
        $icons = array();
        if (has_capability('enrol/stripepayment:config', $context)) {
            $editlink = new moodle_url("/enrol/stripepayment/edit.php", array('courseid' => $instance->courseid, 'id' => $instance->id));
            $icons[] = $OUTPUT->action_icon($editlink, new pix_icon('t/edit', get_string('edit'), 'core',
                    array('class' => 'iconsmall')));
        }
        return $icons;
    }
    /**
     * Returns link to page which may be used to add new instance of enrolment plugin in course.
     * @param int $courseid
     * @return moodle_url page url
     */
    public function get_newinstance_link($courseid) {
        $context = context_course::instance($courseid, MUST_EXIST);
        if (!has_capability('moodle/course:enrolconfig', $context) or !has_capability('enrol/stripepayment:config', $context)) {
            return null;
        }
        // Multiple instances supported - different cost for different roles.
        return new moodle_url('/enrol/stripepayment/edit.php', array('courseid' => $courseid));
    }
    /**
     * Creates course enrol form, checks if form submitted
     * and enrols user if necessary. It can also redirect.
     *
     * @param stdClass $instance
     * @return string html text, usually a form in a text box
     */
    public function enrol_page_hook(stdClass $instance) {
        global $CFG, $USER, $OUTPUT, $PAGE, $DB;
        $enrolstatus = $this->can_stripepayment_enrol($instance);
        if (!$enrolstatus) {
            return get_string('maxenrolledreached', 'enrol_stripepayment');
        }
        ob_start();
        if ($DB->record_exists('user_enrolments', array('userid' => $USER->id, 'enrolid' => $instance->id))) {
            return ob_get_clean();
        }
        if ($instance->enrolstartdate != 0 && $instance->enrolstartdate > time()) {
            return ob_get_clean();
        }
        if ($instance->enrolenddate != 0 && $instance->enrolenddate < time()) {
            return ob_get_clean();
        }
        $course = $DB->get_record('course', array('id' => $instance->courseid));
        $context = context_course::instance($course->id);
        $shortname = format_string($course->shortname, true, array('context' => $context));
        $strloginto = get_string("loginto", "", $shortname);
        $strcourses = get_string("courses");
        // Pass $view=true to filter hidden caps if the user cannot see them.
        if ($users = get_users_by_capability($context, 'moodle/course:update', 'u.*', 'u.id ASC',
                                             '', '', '', '', false, true)) {
            $users = sort_by_roleassignment_authority($users, $context);
            $teacher = array_shift($users);
        } else {
            $teacher = false;
        }
        $publishablekey = $this->get_config('publishablekey');
        if ( (float) $instance->cost <= 0 ) {
            $cost = (float) $this->get_config('cost');
        } else {
            $cost = (float) $instance->cost;
        }
        if (abs($cost) < 0.01) { // No cost, other enrolment methods (instances) should be used.
            echo '<p>'.get_string('nocost', 'enrol_stripepayment').'</p>';
        } else {
            // Calculate localised and "." cost, make sure we send Stripe the same value,
            // please note Stripe expects amount with 2 decimal places and "." separator.
            $localisedcost = format_float($cost, 2, true);
            $cost = format_float($cost, 2, false);
            if (isguestuser()) { // Force login only for guest user, not real users with guest role.
                if (empty($CFG->loginhttps)) {
                    $wwwroot = $CFG->wwwroot;
                } else {
                    // This actually is not so secure ;-), 'cause we're
                    // in unencrypted connection...
                    $wwwroot = str_replace("http://", "https://", $CFG->wwwroot);
                }
                echo '<div class="mdl-align"><p>'.get_string('paymentrequired').'</p>';
                echo '<p><b>'.get_string('cost').": $instance->currency $localisedcost".'</b></p>';
                echo '<p><a href="'.$wwwroot.'/login/">'.get_string('loginsite').'</a></p>';
                echo '</div>';
            } else {
                // Sanitise some fields before building the Stripe form.
                $coursefullname  = format_string($course->fullname, true, array('context' => $context));
                $courseshortname = $shortname;
                $userfullname    = fullname($USER);
                $userfirstname   = $USER->firstname;
                $userlastname    = $USER->lastname;
                $useraddress     = $USER->address;
                $usercity        = $USER->city;
                $useremail       = $USER->email;
                $instancename    = $this->get_instance_name($instance);
                if (!empty($instance->customtext1)) {
                    $message = format_string($instance->customtext1);
                } else {
                    $message = get_string("paymentrequired");
                }
                $validatezipcode = $this->get_config('validatezipcode');
                $billingaddress = $this->get_config('billingaddress');
                
                require_once('Stripe/vendor/autoload.php');
                
                $plugin = enrol_get_plugin('stripepayment');
                \Stripe\Stripe::setApiKey($plugin->get_config('secretkey'));
                
                $customer_id = \Stripe\Customer::create([
                    "name" => $userfullname,
                    "email" => $useremail,
                    "description" => get_string('charge_description1', 'enrol_stripepayment')
                ]);
                $session_success_url = "$CFG->wwwroot/enrol/stripepayment/charge.php?session={CHECKOUT_SESSION_ID}&u={$USER->id}&c={$course->id}&i={$instance->id}";
                $source_success_url = "$CFG->wwwroot/enrol/stripepayment/charge.php?u={$USER->id}&c={$course->id}&i={$instance->id}";
                $session_cancel_url = $session_success_url;

                $session = \Stripe\Checkout\Session::create([
                  'payment_method_types' => ['card'],
                  'customer' => $customer_id,
                  'submit_type' => 'pay',
                  'locale' => current_language(),
                  'line_items' => [[
                    'name' => $courseshortname,
                    'description' => $coursefullname,
                    'amount' => $cost * 100,
                    'currency' => $instance->currency,
                    'quantity' => 1,
                  ]],
                  'success_url' => $session_success_url,
                  'cancel_url' => $session_cancel_url,
                  ]);

                $source = \Stripe\Source::create([
                    'type' => 'bancontact',
                    'amount' => $cost * 100,
                    'currency' => $instance->currency,
                    'owner' => [
                        'name' => $userfullname,
                        ],
                    'redirect' => [
                        'return_url' => $source_success_url,
                        ],
                    'statement_descriptor' => $coursefullname,
                    ]);


                $button_name = $this->generate_random_string(6);

                $accepted_debit_card = [];
                // add the accepted debit card methods 
                // see https://stripe.com/docs/payments/local-payment-methods
                if ($USER->country == 'BE') {
                    $accepted_debit_card[] = 'bancontact';
                }

                if (isset($source->redirect)) {
                    $source_url = $source->redirect->url;
                } else {
                    $accepted_debit_card = [];
                }

                if (isset($session->id))  {
                    $session_id = $session->id;    
                    include($CFG->dirroot.'/enrol/stripepayment/enrol.html');
                } else {
                    echo get_string('error_with_stripe', 'enrol_stripepayment');
                }
            }
        }
        return $OUTPUT->box(ob_get_clean());
    }
    public function can_stripepayment_enrol(stdClass $instance) {
        global $CFG, $DB, $OUTPUT, $USER;
        if ($instance->customint3 > 0) {
            // Max enrol limit specified.
            $count = $DB->count_records('user_enrolments', array('enrolid' => $instance->id));
            if ($count >= $instance->customint3) {
                // Bad luck, no more stripepayment enrolments here.
                return false;
            }
        }
        return true;
    }
    /**
     * Returns localised name of enrol instance
     *
     * @param stdClass $instance (null is accepted too)
     * @return string
     */
    public function get_instance_name($instance) {
        global $DB;
        if (empty($instance->name)) {
            if (!empty($instance->roleid) and $role = $DB->get_record('role', array('id'=>$instance->roleid))) {
                $role = ' (' . role_get_name($role, context_course::instance($instance->courseid, IGNORE_MISSING)) . ')';
            } else {
                $role = '';
            }
            $enrol = $this->get_name();
            return get_string('pluginname', 'enrol_'.$enrol) . $role;
        } else {
            return format_string($instance->name);
        }
    }
    /**
     * Restore instance and map settings.
     *
     * @param restore_enrolments_structure_step $step
     * @param stdClass $data
     * @param stdClass $course
     * @param int $oldid
     */
    public function restore_instance(restore_enrolments_structure_step $step, stdClass $data, $course, $oldid) {
        global $DB;
        if ($step->get_task()->get_target() == backup::TARGET_NEW_COURSE) {
            $merge = false;
        } else {
            $merge = array(
                'courseid'   => $data->courseid,
                'enrol'      => $this->get_name(),
                'roleid'     => $data->roleid,
                'cost'       => $data->cost,
                'currency'   => $data->currency,
            );
        }
        if ($merge and $instances = $DB->get_records('enrol', $merge, 'id')) {
            $instance = reset($instances);
            $instanceid = $instance->id;
        } else {
            $instanceid = $this->add_instance($course, (array)$data);
        }
        $step->set_mapping('enrol', $oldid, $instanceid);
    }
    /**
     * Restore user enrolment.
     *
     * @param restore_enrolments_structure_step $step
     * @param stdClass $data
     * @param stdClass $instance
     * @param int $userid
     * @param int $oldinstancestatus
     */
    public function restore_user_enrolment(restore_enrolments_structure_step $step, $data, $instance, $userid, $oldinstancestatus) {
        $this->enrol_user($instance, $userid, null, $data->timestart, $data->timeend, $data->status);
    }
    /**
     * Gets an array of the user enrolment actions
     *
     * @param course_enrolment_manager $manager
     * @param stdClass $ue A user enrolment object
     * @return array An array of user_enrolment_actions
     */
    public function get_user_enrolment_actions(course_enrolment_manager $manager, $ue) {
        $actions = array();
        $context = $manager->get_context();
        $instance = $ue->enrolmentinstance;
        $params = $manager->get_moodlepage()->url->params();
        $params['ue'] = $ue->id;
        if ($this->allow_unenrol($instance) && has_capability("enrol/stripepayment:unenrol", $context)) {
            $url = new moodle_url('/enrol/unenroluser.php', $params);
            $actions[] = new user_enrolment_action(new pix_icon('t/delete', ''),
            get_string('unenrol', 'enrol'), $url, array('class' => 'unenrollink', 'rel' => $ue->id));
        }
        if ($this->allow_manage($instance) && has_capability("enrol/stripepayment:manage", $context)) {
            $url = new moodle_url('/enrol/editenrolment.php', $params);
            $actions[] = new user_enrolment_action(new pix_icon('t/edit', ''),
            get_string('edit'), $url, array('class' => 'editenrollink', 'rel' => $ue->id));
        }
        return $actions;
    }
    /**
     * Set up cron for the plugin (if any).
     *
     */
    public function cron() {
        $trace = new text_progress_trace();
        $this->process_expirations($trace);
    }
    /**
     * Execute synchronisation.
     * @param progress_trace $trace
     * @return int exit code, 0 means ok
     */
    public function sync(progress_trace $trace) {
        $this->process_expirations($trace);
        return 0;
    }
    /**
     * Is it possible to delete enrol instance via standard UI?
     *
     * @param stdClass $instance
     * @return bool
     */
    public function can_delete_instance($instance) {
        $context = context_course::instance($instance->courseid);
        return has_capability('enrol/stripepayment:config', $context);
    }
    /**
     * Is it possible to hide/show enrol instance via standard UI?
     *
     * @param stdClass $instance
     * @return bool
     */
    public function can_hide_show_instance($instance) {
        $context = context_course::instance($instance->courseid);
        return has_capability('enrol/stripepayment:config', $context);
    }
    /**
     * Get a random string (with letters and digits)
     *
     * @param int $length
     * @return string
     */ 
    private function generate_random_string($length = 10) {
        $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
        $characters_length = strlen($characters);
        $random_string = '';
        for ($i = 0; $i < $length; $i++) {
             $random_string .= $characters[rand(0, $characters_length - 1)];
             }
        return $random_string;
        }
}