<?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/>.

/**
 * A scheduled task.
 *
 * @package    core
 * @copyright  2015 Josh Willcock
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */
namespace core\task;

/**
 * Simple task to run the regular completion cron.
 * @copyright  2015 Josh Willcock
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later.
 */
class completion_regular_task extends scheduled_task {

    /**
     * Get a descriptive name for this task (shown to admins).
     *
     * @return string
     */
    public function get_name() {
        return get_string('taskcompletionregular', 'admin');
    }

    /**
     * Do the job.
     * Throw exceptions on errors (the job will be retried).
     */
    public function execute() {
        global $CFG, $COMPLETION_CRITERIA_TYPES, $DB;

        if ($CFG->enablecompletion) {
            require_once($CFG->libdir . "/completionlib.php");

            // Process each criteria type.
            foreach ($COMPLETION_CRITERIA_TYPES as $type) {
                $object = 'completion_criteria_'.$type;
                require_once $CFG->dirroot.'/completion/criteria/'.$object.'.php';
                $class = new $object();
                // Run the criteria type's cron method, if it has one
                if (method_exists($class, 'cron')) {
                    if (debugging()) {
                        mtrace('Running '.$object.'->cron()');
                    }
                    $class->cron();
                }
            }

            if (debugging()) {
                mtrace('Aggregating completions');
            }
            // Save time started
            $timestarted = time();
            // Grab all criteria and their associated criteria completions
            $sql = '
                SELECT DISTINCT
                    c.id AS course,
                    cr.id AS criteriaid,
                    crc.userid AS userid,
                    cr.criteriatype AS criteriatype,
                    cc.timecompleted AS timecompleted
                FROM
                    {course_completion_criteria} cr
                INNER JOIN
                    {course} c
                 ON cr.course = c.id
                INNER JOIN
                    {course_completions} crc
                 ON crc.course = c.id
                LEFT JOIN
                    {course_completion_crit_compl} cc
                 ON cc.criteriaid = cr.id
                AND crc.userid = cc.userid
                WHERE
                    c.enablecompletion = 1
                AND crc.timecompleted IS NULL
                AND crc.reaggregate > 0
                AND crc.reaggregate < :timestarted
                ORDER BY
                    course,
                    userid
            ';
            $rs = $DB->get_recordset_sql($sql, array('timestarted' => $timestarted));
            // Check if result is empty
            if (!$rs->valid()) {
                $rs->close(); // Not going to iterate (but exit), close rs
                return;
            }
            $current_user = null;
            $current_course = null;
            $completions = array();
            while (1) {
                // Grab records for current user/course
                foreach ($rs as $record) {
                    // If we are still grabbing the same users completions
                    if ($record->userid === $current_user && $record->course === $current_course) {
                        $completions[$record->criteriaid] = $record;
                    } else {
                        break;
                    }
                }
                // Aggregate
                if (!empty($completions)) {
                    if (debugging()) {
                        mtrace('Aggregating completions for user '.$current_user.' in course '.$current_course);
                    }
                    // Get course info object
                    $info = new \completion_info((object)array('id' => $current_course));
                    // Setup aggregation
                    $overall = $info->get_aggregation_method();
                    $activity = $info->get_aggregation_method(COMPLETION_CRITERIA_TYPE_ACTIVITY);
                    $prerequisite = $info->get_aggregation_method(COMPLETION_CRITERIA_TYPE_COURSE);
                    $role = $info->get_aggregation_method(COMPLETION_CRITERIA_TYPE_ROLE);
                    $overall_status = null;
                    $activity_status = null;
                    $prerequisite_status = null;
                    $role_status = null;
                    // Get latest timecompleted
                    $timecompleted = null;
                    // Check each of the criteria
                    foreach ($completions as $params) {
                        $timecompleted = max($timecompleted, $params->timecompleted);
                        $completion = new \completion_criteria_completion((array)$params, false);
                        // Handle aggregation special cases
                        if ($params->criteriatype == COMPLETION_CRITERIA_TYPE_ACTIVITY) {
                            completion_cron_aggregate($activity, $completion->is_complete(), $activity_status);
                        } else if ($params->criteriatype == COMPLETION_CRITERIA_TYPE_COURSE) {
                            completion_cron_aggregate($prerequisite, $completion->is_complete(), $prerequisite_status);
                        } else if ($params->criteriatype == COMPLETION_CRITERIA_TYPE_ROLE) {
                            completion_cron_aggregate($role, $completion->is_complete(), $role_status);
                        } else {
                            completion_cron_aggregate($overall, $completion->is_complete(), $overall_status);
                        }
                    }
                    // Include role criteria aggregation in overall aggregation
                    if ($role_status !== null) {
                        completion_cron_aggregate($overall, $role_status, $overall_status);
                    }
                    // Include activity criteria aggregation in overall aggregation
                    if ($activity_status !== null) {
                        completion_cron_aggregate($overall, $activity_status, $overall_status);
                    }
                    // Include prerequisite criteria aggregation in overall aggregation
                    if ($prerequisite_status !== null) {
                        completion_cron_aggregate($overall, $prerequisite_status, $overall_status);
                    }
                    // If aggregation status is true, mark course complete for user
                    if ($overall_status) {
                        if (debugging()) {
                            mtrace('Marking complete');
                        }
                        $ccompletion = new \completion_completion(array('course' => $params->course, 'userid' => $params->userid));
                        $ccompletion->mark_complete($timecompleted);
                    }
                }
                // If this is the end of the recordset, break the loop
                if (!$rs->valid()) {
                    $rs->close();
                    break;
                }
                // New/next user, update user details, reset completions
                $current_user = $record->userid;
                $current_course = $record->course;
                $completions = array();
                $completions[$record->criteriaid] = $record;
            }
            // Mark all users as aggregated
            $sql = "
                UPDATE
                    {course_completions}
                SET
                    reaggregate = 0
                WHERE
                    reaggregate < :timestarted
                AND reaggregate > 0
            ";
            $DB->execute($sql, array('timestarted' => $timestarted));
        }
    }

}