<?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/>.

/**
 * Cron functions.
 *
 * @package    core
 * @subpackage admin
 * @copyright  1999 onwards Martin Dougiamas  http://dougiamas.com
 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

/**
 * Execute cron tasks
 */
function cron_run() {
    global $DB, $CFG, $OUTPUT;

    if (CLI_MAINTENANCE) {
        echo "CLI maintenance mode active, cron execution suspended.\n";
        exit(1);
    }

    if (moodle_needs_upgrading()) {
        echo "Moodle upgrade pending, cron execution suspended.\n";
        exit(1);
    }

    require_once($CFG->libdir.'/adminlib.php');

    if (!empty($CFG->showcronsql)) {
        $DB->set_debug(true);
    }
    if (!empty($CFG->showcrondebugging)) {
        set_debugging(DEBUG_DEVELOPER, true);
    }

    core_php_time_limit::raise();
    $starttime = microtime();

    // Increase memory limit
    raise_memory_limit(MEMORY_EXTRA);

    // Emulate normal session - we use admin accoutn by default
    cron_setup_user();

    // Start output log
    $timenow  = time();
    mtrace("Server Time: ".date('r', $timenow)."\n\n");

    // Run all scheduled tasks.
    while (!\core\task\manager::static_caches_cleared_since($timenow) &&
           $task = \core\task\manager::get_next_scheduled_task($timenow)) {
        mtrace("Execute scheduled task: " . $task->get_name());
        cron_trace_time_and_memory();
        $predbqueries = null;
        $predbqueries = $DB->perf_get_queries();
        $pretime      = microtime(1);
        try {
            $task->execute();
            if (isset($predbqueries)) {
                mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");
                mtrace("... used " . (microtime(1) - $pretime) . " seconds");
            }
            mtrace("Scheduled task complete: " . $task->get_name());
            \core\task\manager::scheduled_task_complete($task);
        } catch (Exception $e) {
            if ($DB && $DB->is_transaction_started()) {
                error_log('Database transaction aborted automatically in ' . get_class($task));
                $DB->force_transaction_rollback();
            }
            if (isset($predbqueries)) {
                mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");
                mtrace("... used " . (microtime(1) - $pretime) . " seconds");
            }
            mtrace("Scheduled task failed: " . $task->get_name() . "," . $e->getMessage());
            \core\task\manager::scheduled_task_failed($task);
        }
        unset($task);
    }

    // Run all adhoc tasks.
    while (!\core\task\manager::static_caches_cleared_since($timenow) &&
           $task = \core\task\manager::get_next_adhoc_task($timenow)) {
        mtrace("Execute adhoc task: " . get_class($task));
        cron_trace_time_and_memory();
        $predbqueries = null;
        $predbqueries = $DB->perf_get_queries();
        $pretime      = microtime(1);
        try {
            $task->execute();
            if (isset($predbqueries)) {
                mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");
                mtrace("... used " . (microtime(1) - $pretime) . " seconds");
            }
            mtrace("Adhoc task complete: " . get_class($task));
            \core\task\manager::adhoc_task_complete($task);
        } catch (Exception $e) {
            if ($DB && $DB->is_transaction_started()) {
                error_log('Database transaction aborted automatically in ' . get_class($task));
                $DB->force_transaction_rollback();
            }
            if (isset($predbqueries)) {
                mtrace("... used " . ($DB->perf_get_queries() - $predbqueries) . " dbqueries");
                mtrace("... used " . (microtime(1) - $pretime) . " seconds");
            }
            mtrace("Adhoc task failed: " . get_class($task) . "," . $e->getMessage());
            \core\task\manager::adhoc_task_failed($task);
        }
        unset($task);
    }

    mtrace("Cron script completed correctly");

    gc_collect_cycles();
    mtrace('Cron completed at ' . date('H:i:s') . '. Memory used ' . display_size(memory_get_usage()) . '.');
    $difftime = microtime_diff($starttime, microtime());
    mtrace("Execution took ".$difftime." seconds");
}

/**
 * Output some standard information during cron runs. Specifically current time
 * and memory usage. This method also does gc_collect_cycles() (before displaying
 * memory usage) to try to help PHP manage memory better.
 */
function cron_trace_time_and_memory() {
    gc_collect_cycles();
    mtrace('... started ' . date('H:i:s') . '. Current memory use ' . display_size(memory_get_usage()) . '.');
}

/**
 * Executes cron functions for a specific type of plugin.
 *
 * @param string $plugintype Plugin type (e.g. 'report')
 * @param string $description If specified, will display 'Starting (whatever)'
 *   and 'Finished (whatever)' lines, otherwise does not display
 */
function cron_execute_plugin_type($plugintype, $description = null) {
    global $DB;

    // Get list from plugin => function for all plugins
    $plugins = get_plugin_list_with_function($plugintype, 'cron');

    // Modify list for backward compatibility (different files/names)
    $plugins = cron_bc_hack_plugin_functions($plugintype, $plugins);

    // Return if no plugins with cron function to process
    if (!$plugins) {
        return;
    }

    if ($description) {
        mtrace('Starting '.$description);
    }

    foreach ($plugins as $component=>$cronfunction) {
        $dir = core_component::get_component_directory($component);

        // Get cron period if specified in version.php, otherwise assume every cron
        $cronperiod = 0;
        if (file_exists("$dir/version.php")) {
            $plugin = new stdClass();
            include("$dir/version.php");
            if (isset($plugin->cron)) {
                $cronperiod = $plugin->cron;
            }
        }

        // Using last cron and cron period, don't run if it already ran recently
        $lastcron = get_config($component, 'lastcron');
        if ($cronperiod && $lastcron) {
            if ($lastcron + $cronperiod > time()) {
                // do not execute cron yet
                continue;
            }
        }

        mtrace('Processing cron function for ' . $component . '...');
        cron_trace_time_and_memory();
        $pre_dbqueries = $DB->perf_get_queries();
        $pre_time = microtime(true);

        $cronfunction();

        mtrace("done. (" . ($DB->perf_get_queries() - $pre_dbqueries) . " dbqueries, " .
                round(microtime(true) - $pre_time, 2) . " seconds)");

        set_config('lastcron', time(), $component);
        core_php_time_limit::raise();
    }

    if ($description) {
        mtrace('Finished ' . $description);
    }
}

/**
 * Used to add in old-style cron functions within plugins that have not been converted to the
 * new standard API. (The standard API is frankenstyle_name_cron() in lib.php; some types used
 * cron.php and some used a different name.)
 *
 * @param string $plugintype Plugin type e.g. 'report'
 * @param array $plugins Array from plugin name (e.g. 'report_frog') to function name (e.g.
 *   'report_frog_cron') for plugin cron functions that were already found using the new API
 * @return array Revised version of $plugins that adds in any extra plugin functions found by
 *   looking in the older location
 */
function cron_bc_hack_plugin_functions($plugintype, $plugins) {
    global $CFG; // mandatory in case it is referenced by include()d PHP script

    if ($plugintype === 'report') {
        // Admin reports only - not course report because course report was
        // never implemented before, so doesn't need BC
        foreach (core_component::get_plugin_list($plugintype) as $pluginname=>$dir) {
            $component = $plugintype . '_' . $pluginname;
            if (isset($plugins[$component])) {
                // We already have detected the function using the new API
                continue;
            }
            if (!file_exists("$dir/cron.php")) {
                // No old style cron file present
                continue;
            }
            include_once("$dir/cron.php");
            $cronfunction = $component . '_cron';
            if (function_exists($cronfunction)) {
                $plugins[$component] = $cronfunction;
            } else {
                debugging("Invalid legacy cron.php detected in $component, " .
                        "please use lib.php instead");
            }
        }
    } else if (strpos($plugintype, 'grade') === 0) {
        // Detect old style cron function names
        // Plugin gradeexport_frog used to use grade_export_frog_cron() instead of
        // new standard API gradeexport_frog_cron(). Also applies to gradeimport, gradereport
        foreach(core_component::get_plugin_list($plugintype) as $pluginname=>$dir) {
            $component = $plugintype.'_'.$pluginname;
            if (isset($plugins[$component])) {
                // We already have detected the function using the new API
                continue;
            }
            if (!file_exists("$dir/lib.php")) {
                continue;
            }
            include_once("$dir/lib.php");
            $cronfunction = str_replace('grade', 'grade_', $plugintype) . '_' .
                    $pluginname . '_cron';
            if (function_exists($cronfunction)) {
                $plugins[$component] = $cronfunction;
            }
        }
    }

    return $plugins;
}