<?php

/*
  ----------------------------------------------------------------------
  LICENSE

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License (GPL)
  as published by the Free Software Foundation; either version 2
  of the License, or (at your option) any later version.

  This program 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.

  To read the license please visit http://www.gnu.org/copyleft/gpl.html
  ----------------------------------------------------------------------
*/

/**
 * This class manage web-cron tasks
 * 
 * @copyright AlternC-Team 2000-2017 https://alternc.com/
 */
class m_cron {

    const MAX_SOCKETS = 8;
    const DEFAULT_CAFILE = "/etc/ssl/certs/ca-certificates.crt";


    /**
     * 
     */
    function schedule() {
        return Array(
            Array('unit' => 1440, 'name' => _("Daily")),
            Array('unit' => 60, 'name' => _("Hour")),
            Array('unit' => 30, 'name' => _("Half Hour")),
        );
    }


    /** 
     * List the crontab for the current user.
     * @return array an hash for each crontab.
     */
    function lst_cron() {
        global $cuid, $db, $msg;
        $msg->log("cron", "lst_cron");
        $db->query("SELECT * FROM cron WHERE uid = ? ORDER BY url;", array($cuid));
        $r = Array();
        while ($db->next_record()) {
            $tmp = Array();
            $tmp['id'] = $db->f('id');
            $tmp['url'] = urldecode($db->f('url'));
            $tmp['user'] = urldecode($db->f('user'));
            $tmp['password'] = urldecode($db->f('password'));
            $tmp['schedule'] = $db->f('schedule');
            $tmp['email'] = urldecode($db->f('email'));
            $tmp['next_execution'] = $db->f('next_execution');
            $r[] = $tmp;
        }
        return $r;
    }

    /**
     * Hook called by menu class to add menu to the left panel
     */
    function hook_menu() {
        $obj = array(
            'title' => _("Scheduled tasks"),
            'link' => 'cron.php',
            'pos' => 120,
        );

        return $obj;
    }


    /** 
     * update the crontab 
     * @param $arr array the crontab information, including its ID
     * @return boolean TRUE if the crontab has been edited
     */
    function update($arr) {
        $ok = true;
        foreach ($arr as $a) {
            if (!isset($a['id'])) {
                $a['id'] = null;
            }
            if (empty($a['url']) && is_null($a['id'])) {
                continue;
            }
            if (!$this->_update_one($a['url'], $a['user'], $a['password'], $a['email'], $a['schedule'], $a['id'])) {
                $ok = false;
            }
        }
        return $ok;
    }


    /** 
     * delete a crontab 
     * @param $id the id of the crontab to delete
     * @return boolean TRUE if the crontab has been deleted
     */
    function delete_one($id) {
        global $db, $msg, $cuid;
        $msg->log("cron", "delete_one");
        return $db->query("DELETE FROM cron WHERE id= ? AND uid= ? LIMIT 1;", array(intval($id), $cuid));
    }


    /** 
     * update a crontab, 
     * @return boolean TRUE if the crontab has been edited
     */
    private function _update_one($url, $user, $password, $email, $schedule, $id = null) {
        global $db, $msg, $quota, $cuid;
        $msg->log("cron", "update_one");

        if (empty($url) && !is_null($id)) {
            return $this->delete_one($id);
        }


        if (filter_var($url, FILTER_VALIDATE_URL) === false) {
            $msg->raise("ERROR", "cron", _("URL not valid"));
            return false;
        }
        $url = urlencode($url);
        $user = urlencode($user);
        if (empty($user)) {
            $password = '';
        }
        $password = urlencode($password);

        //@todo remove checkmail cf functions.php
        if (!empty($email) && !checkmail($email) == 0) {
            $msg->raise("ERROR", "cron", _("Email address is not valid"));
            return false;
        }
        $email = urlencode($email);
        if (!$this->valid_schedule($schedule)) {
            return false;
        }

        if (is_null($id)) { // if a new insert, quotacheck
            $q = $quota->getquota("cron");
            if ($q["u"] >= $q["t"]) {
                $msg->raise("ERROR", "cron", _("You quota of cron entries is over. You cannot create more cron entries"));
                return false;
            }
        } else { // if not a new insert, check the $cuid
            $db->query("SELECT uid FROM cron WHERE id = ? ;", array($id));
            if (!$db->next_record()) {
                return "false";
            } // return false if pb
            if ($db->f('uid') != $cuid) {
                $msg->raise("ERROR", "cron", _("Identity problem"));
                return false;
            }
        }
        return $db->query("REPLACE INTO cron (id, uid, url, user, password, schedule, email) VALUES (?, ?, ?, ?, ?, ?, ?) ;" , array($id, $cuid, $url, $user, $password, $schedule, $email));
    }


    /** 
     * validate a crontab schedule
     * @param $s array schedule paramters
     * @return boolean TRUE if the schedule is valid
     */
    function valid_schedule($s) {
        $s2 = intval($s);
        if ($s2 != $s) {
            return false;
        }
        $r = false;
        foreach ($this->schedule() as $cs) {
            if ($cs['unit'] == $s) {
                return true;
            }
        }
        return $r;
    }


    /** 
     * hook for quota computation
     */
    function hook_quota_get() {
        global $cuid, $db, $msg;
        $msg->log("cron", "alternc_get_quota");
        $q = Array("name" => "cron", "description" => _("Scheduled tasks"), "used" => 0);
        $db->query("select count(*) as cnt from cron where uid = ? ;", array($cuid));
        if ($db->next_record()) {
            $q['used'] = $db->f('cnt');
        }
        return $q;
    }


    /**
     * Execute the required crontab of AlternC users
     * this function EXIT at the end.
     */
    function execute_cron() {
        global $db;

        if (!isset($GLOBALS["DEBUG"])) {
            $GLOBALS["DEBUG"] = false;
        }
        $db->query("SELECT id, url, email, schedule, user, password FROM cron WHERE next_execution <= NOW();");
        $urllist = array();

        while ($db->next_record()) {
            $db->Record["url"] = urldecode($db->Record["url"]);
            $db->Record["user"] = urldecode($db->Record["user"]);
            $db->Record["email"] = urldecode($db->Record["email"]);
            $db->Record["password"] = urldecode($db->Record["password"]);

            // we support only http or https schemes:
            if (substr($db->Record["url"], 0, 7) == "http://" || substr($db->Record["url"], 0, 8) == "https://") {
                $u = array(
                    "url" => $db->Record["url"],
                    "id" => $db->Record["id"], "email" => $db->Record["email"],
                );

                if ($db->Record["user"] && $db->Record["password"]) {
                    $u["login"] = $db->Record["user"];
                    $u["password"] = $db->Record["password"];
                }
                if ($GLOBALS["DEBUG"])
                    echo "Will run cron :\n" . print_r($u, true) . "\n";
                $urllist[] = $u;
            }

            if (empty($urllist)) { // nothing to do : 
                exit(0);
            }
        }
        // cron_callback($url, $content, $curlobj) will be called at the end of each http call.
        $this->rolling_curl($urllist, array("m_cron", "cron_callback"));
    }


    /**
     * Callback function called by rolling_curl when a cron resulr has been received
     * schedule it for next run and send the mail if needed
     */
    function cron_callback($url, $content, $curl) {
        global $db, $L_FQDN;
        if (empty($url["id"])) {
            return; // not normal...
        }
        $id = intval($url["id"]);

        if ($curl["http_code"] == 200) {
            $ok = true;
        } else {
            $ok = false;
        }
        if (isset($url["email"]) && $url["email"] && $content) {
            if (!mail($url["email"], "AlternC Cron #$id - Report " . date("r"), "Please find below the stdout content produced by your cron task.\n------------------------------------------------------------\n\n" . $content, "From: postmaster@$L_FQDN")) {
                echo "Error sending mail for cron #$id to address '" . $url["email"] . "'\n";
            }
        }
        // now schedule it for next run:
        $db->query("UPDATE cron SET next_execution=FROM_UNIXTIME( UNIX_TIMESTAMP(NOW()) + schedule * 60) WHERE id= ?", array($id));
    }


    /**
     * Launch parallel (using MAX_SOCKETS sockets maximum) retrieval
     * of URL using CURL 
     * @param $urls array of associative array, each having the following keys : 
     *  url = url to get (of the form http[s]://login:password@host/path/file?querystring )
     *  login & password = if set, tell the login and password to use as simple HTTP AUTH.
     *  - any other key will be sent as it is to the callback function
     * @param $callback function called for each request when completing. First argument is the $url object, second is the content (output)
     *  third is the info structure from curl for the returned page. 200 for OK, 403 for AUTH FAILED, 0 for timeout, dump it to know it ;) 
     *  this function should return as soon as possible to allow other curl calls to complete properly.
     * @param $cursom_options array of custom CURL options for all transfers
     */
    function rolling_curl($urls, $callback, $custom_options = null) {
        // make sure the rolling window isn't greater than the # of urls
        if (!isset($GLOBALS["DEBUG"]))
            $GLOBALS["DEBUG"] = false;
        $rolling_window = m_cron::MAX_SOCKETS;
        $rolling_window = (count($urls) < $rolling_window) ? count($urls) : $rolling_window;

        $master = curl_multi_init();

        // add additional curl options here
        $std_options = array(CURLOPT_RETURNTRANSFER => true,
        CURLOPT_FOLLOWLOCATION => false,
        CURLOPT_CONNECTTIMEOUT => 5,
        CURLOPT_TIMEOUT => 240, // 4 minutes timeout for a page
        CURLOPT_USERAGENT => "AlternC (Cron Daemon)",
        CURLOPT_MAXREDIRS => 0);

        if ($GLOBALS["DEBUG"]) {
            $std_options[CURLOPT_VERBOSE] = true;
        }
        $options = ($custom_options) ? ($std_options + $custom_options) : $std_options;

        // start the first batch of requests
        for ($i = 0; $i < $rolling_window; $i++) {
            $ch = curl_init();
            $options[CURLOPT_URL] = $urls[$i]["url"];
            if ($GLOBALS["DEBUG"]) {
                echo "URL: " . $urls[$i]["url"] . "\n";
            }
            curl_setopt_array($ch, $options);
            // Handle custom cafile for some https url
            if (strtolower(substr($options[CURLOPT_URL], 0, 5)) == "https") {
                curl_setopt($ch, CURLOPT_CAINFO, m_cron::DEFAULT_CAFILE);
                if ($GLOBALS["DEBUG"]) {
                    echo "cainfo set to DEFAULT\n";
                }
            }
            if (isset($urls[$i]["login"]) && isset($urls[$i]["password"])) { // set basic http authentication
                curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
                curl_setopt($ch, CURLOPT_USERPWD, $urls[$i]["login"] . ":" . $urls[$i]["password"]);
                if ($GLOBALS["DEBUG"]) {
                    echo "set basic auth\n";
                }
            }
            curl_multi_add_handle($master, $ch);
        }

        do {
            while (($execrun = curl_multi_exec($master, $running)) == CURLM_CALL_MULTI_PERFORM);
            if ($execrun != CURLM_OK) {
                break;
            }
            // a request was just completed -- find out which one
            while ($done = curl_multi_info_read($master)) {
                $info = curl_getinfo($done['handle']);
                // TODO : since ssl_verify_result is buggy, if we have [header_size] => 0  && [request_size] => 0 && [http_code] => 0, AND https, we can pretend the SSL certificate is buggy.
                if ($GLOBALS["DEBUG"]) {
                    echo "Info for " . $done['handle'] . " \n";
                    print_r($info);
                }
                if ($info['http_code'] == 200) {
                    $output = curl_multi_getcontent($done['handle']);
                } else {
                    // request failed.  add error handling.
                    $output = "";
                }
                // request terminated.  process output using the callback function.
                // Pass the url array to the callback, so we need to search it
                foreach ($urls as $url) {
                    if ($url["url"] == $info["url"]) {
                        call_user_func($callback, $url, $output, $info);
                        break;
                    }
                }

                // If there is more: start a new request
                // (it's important to do this before removing the old one)
                if ($i < count($urls)) {
                    $ch = curl_init();
                    $options[CURLOPT_URL] = $urls[$i++];  // increment i
                    curl_setopt_array($ch, $options);
                    if (strtolower(substr($options[CURLOPT_URL], 0, 5)) == "https") {
                        curl_setopt($ch, CURLOPT_CAINFO, m_cron::DEFAULT_CAFILE);
                        if ($GLOBALS["DEBUG"]) {
                            echo "cainfo set to DEFAULT\n";
                        }
                    }
                    if (isset($urls[$i]["login"]) && isset($urls[$i]["password"])) {  // set basic http authentication
                        curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
                        curl_setopt($ch, CURLOPT_USERPWD, urlencode($urls[$i]["login"]) . ":" . urlencode($urls[$i]["password"]));
                        if ($GLOBALS["DEBUG"]) {
                            echo "set basic auth\n";
                        }
                    }
                    curl_multi_add_handle($master, $ch);
                }
                // remove the curl handle that just completed
                curl_multi_remove_handle($master, $done['handle']);
            }
        } while ($running);

        curl_multi_close($master);
        return true;
    }

} /* Class cron */
