<?php

/**

 * WordPress CRON API

 *

 * @package WordPress

 */

/**

 * Schedules a hook to run only once.

 *

 * Schedules a hook which will be executed once by the WordPress actions core at

 * a time which you specify. The action will fire off when someone visits your

 * WordPress site, if the schedule time has passed.

 *

 * @since 2.1.0

 * @link http://codex.wordpress.org/Function_Reference/wp_schedule_single_event

 *

 * @param int $timestamp Timestamp for when to run the event.

 * @param string $hook Action hook to execute when cron is run.

 * @param array $args Optional. Arguments to pass to the hook's callback function.

 */

function wp_schedule_single_event( $timestamp, $hook, $args = array()) {

	// don't schedule a duplicate if there's already an identical event due in the next 10 minutes

	$next = wp_next_scheduled($hook, $args);

	if ( $next && $next <= $timestamp + 600 )

		return;

	$crons = _get_cron_array();

	$key = md5(serialize($args));

	$crons[$timestamp][$hook][$key] = array( 'schedule' => false, 'args' => $args );

	uksort( $crons, "strnatcasecmp" );

	_set_cron_array( $crons );

}

/**

 * Schedule a periodic event.

 *

 * Schedules a hook which will be executed by the WordPress actions core on a

 * specific interval, specified by you. The action will trigger when someone

 * visits your WordPress site, if the scheduled time has passed.

 *

 * Valid values for the recurrence are hourly, daily and twicedaily.  These can

 * be extended using the cron_schedules filter in wp_get_schedules().

 *

 * @since 2.1.0

 *

 * @param int $timestamp Timestamp for when to run the event.

 * @param string $recurrence How often the event should recur.

 * @param string $hook Action hook to execute when cron is run.

 * @param array $args Optional. Arguments to pass to the hook's callback function.

 * @return bool|null False on failure, null when complete with scheduling event.

 */

function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {

	$crons = _get_cron_array();

	$schedules = wp_get_schedules();

	$key = md5(serialize($args));

	if ( !isset( $schedules[$recurrence] ) )

		return false;

	$crons[$timestamp][$hook][$key] = array( 'schedule' => $recurrence, 'args' => $args, 'interval' => $schedules[$recurrence]['interval'] );

	uksort( $crons, "strnatcasecmp" );

	_set_cron_array( $crons );

}

/**

 * Reschedule a recurring event.

 *

 * @since 2.1.0

 *

 * @param int $timestamp Timestamp for when to run the event.

 * @param string $recurrence How often the event should recur.

 * @param string $hook Action hook to execute when cron is run.

 * @param array $args Optional. Arguments to pass to the hook's callback function.

 * @return bool|null False on failure. Null when event is rescheduled.

 */

function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array()) {

	$crons = _get_cron_array();

	$schedules = wp_get_schedules();

	$key = md5(serialize($args));

	$interval = 0;

	// First we try to get it from the schedule

	if ( 0 == $interval )

		$interval = $schedules[$recurrence]['interval'];

	// Now we try to get it from the saved interval in case the schedule disappears

	if ( 0 == $interval )

		$interval = $crons[$timestamp][$hook][$key]['interval'];

	// Now we assume something is wrong and fail to schedule

	if ( 0 == $interval )

		return false;

	$now = time();

    if ( $timestamp >= $now )

        $timestamp = $now + $interval;

    else

        $timestamp = $now + ($interval - (($now - $timestamp) % $interval));

	wp_schedule_event( $timestamp, $recurrence, $hook, $args );

}

/**

 * Unschedule a previously scheduled cron job.

 *

 * The $timestamp and $hook parameters are required, so that the event can be

 * identified.

 *

 * @since 2.1.0

 *

 * @param int $timestamp Timestamp for when to run the event.

 * @param string $hook Action hook, the execution of which will be unscheduled.

 * @param array $args Arguments to pass to the hook's callback function.

 * Although not passed to a callback function, these arguments are used

 * to uniquely identify the scheduled event, so they should be the same

 * as those used when originally scheduling the event.

 */

function wp_unschedule_event( $timestamp, $hook, $args = array() ) {

	$crons = _get_cron_array();

	$key = md5(serialize($args));

	unset( $crons[$timestamp][$hook][$key] );

	if ( empty($crons[$timestamp][$hook]) )

		unset( $crons[$timestamp][$hook] );

	if ( empty($crons[$timestamp]) )

		unset( $crons[$timestamp] );

	_set_cron_array( $crons );

}

/**

 * Unschedule all cron jobs attached to a specific hook.

 *

 * @since 2.1.0

 *

 * @param string $hook Action hook, the execution of which will be unscheduled.

 * @param mixed $args,... Optional. Event arguments.

 */

function wp_clear_scheduled_hook( $hook ) {

	$args = array_slice( func_get_args(), 1 );

	while ( $timestamp = wp_next_scheduled( $hook, $args ) )

		wp_unschedule_event( $timestamp, $hook, $args );

}

/**

 * Retrieve the next timestamp for a cron event.

 *

 * @since 2.1.0

 *

 * @param string $hook Action hook to execute when cron is run.

 * @param array $args Optional. Arguments to pass to the hook's callback function.

 * @return bool|int The UNIX timestamp of the next time the scheduled event will occur.

 */

function wp_next_scheduled( $hook, $args = array() ) {

	$crons = _get_cron_array();

	$key = md5(serialize($args));

	if ( empty($crons) )

		return false;

	foreach ( $crons as $timestamp => $cron ) {

		if ( isset( $cron[$hook][$key] ) )

			return $timestamp;

	}

	return false;

}

/**

 * Send request to run cron through HTTP request that doesn't halt page loading.

 *

 * @since 2.1.0

 *

 * @return null Cron could not be spawned, because it is not needed to run.

 */

function spawn_cron( $local_time = 0 ) {

	if ( !$local_time )

		$local_time = time();

	if ( defined('DOING_CRON') || isset($_GET['doing_wp_cron']) )

		return;

	/*

	 * do not even start the cron if local server timer has drifted

	 * such as due to power failure, or misconfiguration

	 */

	$timer_accurate = check_server_timer( $local_time );

	if ( !$timer_accurate )

		return;

	/*

	* multiple processes on multiple web servers can run this code concurrently

	* try to make this as atomic as possible by setting doing_cron switch

	*/

	$flag = get_transient('doing_cron');

	if ( $flag > $local_time + 10*60 )

		$flag = 0;

	// don't run if another process is currently running it or more than once every 60 sec.

	if ( $flag + 60 > $local_time )

		return;

	//sanity check

	$crons = _get_cron_array();

	if ( !is_array($crons) )

		return;

	$keys = array_keys( $crons );

	if ( isset($keys[0]) && $keys[0] > $local_time )

		return;

	if ( defined('ALTERNATE_WP_CRON') && ALTERNATE_WP_CRON ) {

		if ( !empty($_POST) || defined('DOING_AJAX') )

			return;

		set_transient( 'doing_cron', $local_time );

		ob_start();

		wp_redirect( add_query_arg('doing_wp_cron', '', stripslashes($_SERVER['REQUEST_URI'])) );

		echo ' ';

		// flush any buffers and send the headers

		while ( @ob_end_flush() );

		flush();

		@include_once(ABSPATH . 'wp-cron.php');

		return;

	}

	set_transient( 'doing_cron', $local_time );

	$cron_url = get_option( 'siteurl' ) . '/wp-cron.php?doing_wp_cron';

	wp_remote_post( $cron_url, array('timeout' => 0.01, 'blocking' => false, 'sslverify' => apply_filters('https_local_ssl_verify', true)) );

}

/**

 * Run scheduled callbacks or spawn cron for all scheduled events.

 *

 * @since 2.1.0

 *

 * @return null When doesn't need to run Cron.

 */

function wp_cron() {

	// Prevent infinite loops caused by lack of wp-cron.php

	if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false || ( defined('DISABLE_WP_CRON') && DISABLE_WP_CRON ) )

		return;

	if ( false === $crons = _get_cron_array() )

		return;

	$local_time = time();

	$keys = array_keys( $crons );

	if ( isset($keys[0]) && $keys[0] > $local_time )

		return;

	$schedules = wp_get_schedules();

	foreach ( $crons as $timestamp => $cronhooks ) {

		if ( $timestamp > $local_time ) break;

		foreach ( (array) $cronhooks as $hook => $args ) {

			if ( isset($schedules[$hook]['callback']) && !call_user_func( $schedules[$hook]['callback'] ) )

				continue;

			spawn_cron( $local_time );

			break 2;

		}

	}

}

/**

 * Retrieve supported and filtered Cron recurrences.

 *

 * The supported recurrences are 'hourly' and 'daily'. A plugin may add more by

 * hooking into the 'cron_schedules' filter. The filter accepts an array of

 * arrays. The outer array has a key that is the name of the schedule or for

 * example 'weekly'. The value is an array with two keys, one is 'interval' and

 * the other is 'display'.

 *

 * The 'interval' is a number in seconds of when the cron job should run. So for

 * 'hourly', the time is 3600 or 60*60. For weekly, the value would be

 * 60*60*24*7 or 604800. The value of 'interval' would then be 604800.

 *

 * The 'display' is the description. For the 'weekly' key, the 'display' would

 * be <code>__('Once Weekly')</code>.

 *

 * For your plugin, you will be passed an array. you can easily add your

 * schedule by doing the following.

 * <code>

 * // filter parameter variable name is 'array'

 *	$array['weekly'] = array(

 *		'interval' => 604800,

 *		'display' => __('Once Weekly')

 *	);

 * </code>

 *

 * @since 2.1.0

 *

 * @return array

 */

function wp_get_schedules() {

	$schedules = array(

		'hourly' => array( 'interval' => 3600, 'display' => __('Once Hourly') ),

		'twicedaily' => array( 'interval' => 43200, 'display' => __('Twice Daily') ),

		'daily' => array( 'interval' => 86400, 'display' => __('Once Daily') ),

	);

	return array_merge( apply_filters( 'cron_schedules', array() ), $schedules );

}

/**

 * Retrieve Cron schedule for hook with arguments.

 *

 * @since 2.1.0

 *

 * @param string $hook Action hook to execute when cron is run.

 * @param array $args Optional. Arguments to pass to the hook's callback function.

 * @return string|bool False, if no schedule. Schedule on success.

 */

function wp_get_schedule($hook, $args = array()) {

	$crons = _get_cron_array();

	$key = md5(serialize($args));

	if ( empty($crons) )

		return false;

	foreach ( $crons as $timestamp => $cron ) {

		if ( isset( $cron[$hook][$key] ) )

			return $cron[$hook][$key]['schedule'];

	}

	return false;

}

//

// Private functions

//

/**

 * Retrieve cron info array option.

 *

 * @since 2.1.0

 * @access private

 *

 * @return array CRON info array.

 */

function _get_cron_array()  {

	$cron = get_option('cron');

	if ( ! is_array($cron) )

		return false;

	if ( !isset($cron['version']) )

		$cron = _upgrade_cron_array($cron);

	unset($cron['version']);

	return $cron;

}

/**

 * Updates the CRON option with the new CRON array.

 *

 * @since 2.1.0

 * @access private

 *

 * @param array $cron Cron info array from {@link _get_cron_array()}.

 */

function _set_cron_array($cron) {

	$cron['version'] = 2;

	update_option( 'cron', $cron );

}

/**

 * Upgrade a Cron info array.

 *

 * This function upgrades the Cron info array to version 2.

 *

 * @since 2.1.0

 * @access private

 *

 * @param array $cron Cron info array from {@link _get_cron_array()}.

 * @return array An upgraded Cron info array.

 */

function _upgrade_cron_array($cron) {

	if ( isset($cron['version']) && 2 == $cron['version'])

		return $cron;

	$new_cron = array();

	foreach ( (array) $cron as $timestamp => $hooks) {

		foreach ( (array) $hooks as $hook => $args ) {

			$key = md5(serialize($args['args']));

			$new_cron[$timestamp][$hook][$key] = $args;

		}

	}

	$new_cron['version'] = 2;

	update_option( 'cron', $new_cron );

	return $new_cron;

}

// stub for checking server timer accuracy, using outside standard time sources

function check_server_timer( $local_time ) {

	return true;

}