<?php
/**
 * $Id: cronplus.module,v 1.10 2008/12/19 10:09:27 syscrusher Exp $
 *
 * CronPlus enhances the Drupal cron feature to provide specific calls to
 * other modules at on demand, hourly, daily, weekly, monthly, and yearly intervals.
 *
 * Author: Syscrusher (Scott Courtney)    License: GPL
 */

$stop_cron = 0;

/**
 * Implements hook_help().
 */
function cronplus_help($section) {
  switch ($section) {
    case 'admin/modules#description':
      return t('Calls module-specific on demand, hourly, daily, weekly, monthly, and yearly functions.');
      break;
  }
}

/**
 * Implements hook_menu().
 */
function cronplus_menu() {
  $items = array();
  $items['admin/settings/cronplus'] = array(
    'title' => t('cronplus'),
    'page callback' => 'cronplus_settings_main',
    'description' => 'Select which hour and on what day you would like houly and daily crons to run. Also see the status of cronplus',
    'access callback' => 'user_access',
    'access arguments' => array('administer site configuration'),
//    'type' => MENU_LOCAL_TASK,
  );
  $items['admin/settings/cronplus/main'] = array(
    'title' => t('configuration'),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'access callback' => 'user_access',
    'access arguments' => array('administer site configuration'),
    'weight' => -10,
  );
  $items['admin/settings/cronplus/status'] = array(
    'title' => t('status report'),
    'page callback' => 'cronplus_settings_status',
	'access' => user_access('administer site configuration'),
    'access callback' => 'user_access',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_LOCAL_TASK,
	'weight' => 10
  );
  $items['admin/settings/cronplus/run'] = array(
    'title' => t('run now'),
    'page callback' => 'cronplus_run_on_demand',
    'access callback' => 'user_access',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_LOCAL_TASK,
	'weight' => 20
  );
  return $items;
}

/**
 * Handle validation of the settings form
 *
 * Right now, all the fields are dropdown/select, so validation errors are
 * unlikely.
 */
function cronplus_settings_form_validate($form_id, $form_values) {
  $cronplus_preferred_hour = intval($form_values['cronplus_preferred_hour']);
  if ($cronplus_preferred_hour < 0 || $cronplus_preferred_hour > 23) {
    form_set_error('cronplus_preferred_hour', t('Hour must be 0 to 23 inclusive'));
  }
  $cronplus_preferred_wkdy = intval($form_values['cronplus_preferred_wkdy']);
  if ($cronplus_preferred_wkdy < 0 || $cronplus_preferred_wkdy > 6) {
    form_set_error('cronplus_preferred_wkdy', t('Weekday must be 0 to 6 (Sunday through Saturday, respectively) inclusive'));
  }
}

/**
 * Handle submission of the settings form
 */
function cronplus_settings_form_submit($form_id, $form_values) {
  $cronplus_preferred_hour = intval($form_values['cronplus_preferred_hour']);
  $cronplus_preferred_wkdy = intval($form_values['cronplus_preferred_wkdy']);
  variable_set('cronplus_preferred_hour', $cronplus_preferred_hour);
  variable_set('cronplus_preferred_wkdy', $cronplus_preferred_wkdy);
  drupal_set_message(t('Cronplus settings saved'), 'info');
}

/**
 * Handle the module's settings.
 */
function cronplus_settings_main() {  
  return drupal_get_form('cronplus_settings_form');
}

function cronplus_settings_form() {
  $form = array();
  $form['cronplus_preferred_hour'] = array(
    '#type' => 'select',
    '#title' => t('Preferred hour'),
    '#description' => t('Preferred hour of the day at which daily, weekly, monthly, and yearly jobs will run, if possible. Not guaranteed.'),
    '#default_value' => intval(variable_get('cronplus_preferred_hour', 0)),
    '#options' => _cronplus_int_options(0, 23),
  );
  $form['cronplus_preferred_wkdy'] = array(
    '#type' => 'select',
    '#title' => t('Preferred weekday'),
    '#description' => t('Preferred day of the week on which weekly, monthly, and yearly jobs will run, if possible. Not guaranteed.'),
    '#default_value' => intval(variable_get('cronplus_preferred_wkdy', 0)),
    '#options' => _cronplus_int_options(0, 6, array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'), TRUE),
  );
  $form['cronplus_submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save settings'),
  );
  return system_settings_form($form);
}

function cronplus_run_on_demand() {  
  return drupal_get_form('cronplus_run_on_demand_form');
}

function cronplus_run_on_demand_form() {
  $form_now = array();
  $form_now['run_now_submit'] = array(
    '#type' => 'submit',
    '#title' => t('Run now'),
    '#description' => t('This will force a cron run right now.'),
    '#value' => t('Run now'),
  );
  return $form_now;
}

function cronplus_run_on_demand_form_submit() {
  global $stop_cron;
  $stop_cron = 1;
  drupal_set_message(t('Cronplus ran successfully.'), 'info');
  return drupal_cron_run();
}

/**
 * Returns an array of the time periods supported by the module. This can
 * be used by other modules to offer administrators or users options of
 * which time period should be attached to a particular feature of the
 * application.
 *
 * The index of the array is the raw period-name as applicable to hook
 * functions. The values are the translated version of that name.
 */
function cronplus_periods() {
  $periods = array();
  foreach (array('on_demand', 'hourly', 'daily', 'weekly', 'monthly', 'yearly') as $period) {
    $periods[$period] = t($period);
  }
  return $periods;
}

/**
 * Returns a really simple form for viewing the cronplus log entries.
 */
function cronplus_logview_form() {
  $form = array(
     'submit' => array(
       '#type' => 'submit',
       '#value' => t('View cronplus log'),
     ),
  );
  return $form;
}

/**
 * Handles submit of the log view form
 */
function cronplus_logview_form_submit($form_id, $form_values) {
  $_SESSION['watchdog_overview_filter'] = 'cronplus';
  drupal_goto('admin/reports/dblog');
}

/**
 * Shows a page listing all the places that implement each of the cronplus
 * hooks.
 */
function cronplus_settings_status() {
  $html = '<p>'. t('This section lists modules implementing the cronplus hook for each available time period. The listing is purely informational; there are no settings to change here.');
  $html .= '<p>' . drupal_get_form('cronplus_logview_form');
  $periods =& cronplus_periods();
  // Add one special case.
  $periods['cronplus'] = 'cronplus '. t('(multiplex hook)');
  foreach ($periods as $period => $period_t) {
    $html .= '<h2>'. $period_t .'</h2>';
    $html .= '<div class="cronplus_status">';
    $hook = ($period == 'cronplus') ? 'cronplus' : 'cronplus_'. $period;
    $group = '<p>'. t('Hook: {module}_%hook()', array('%hook' => $hook)) .'<p>'. t('Implemented by: ');
    $modules = module_implements($hook);
    if (count($modules) > 0) {
      $group .= '<span class="cronplus_modules">'. implode(', ', $modules) .'</span>';
    }
      else {
      $group .= t('None');
    }
    $group .= '<p>'. t('Last invoked: ');
    if ($period == 'cronplus') {
      $group .= t('Invoked along with each of the above');
    }
      else {
      $last_invoked = intval(variable_get('cronplus_'. $period .'_last', 0));
      $group .= $last_invoked ? gmdate('Y-m-d H:i:s', $last_invoked) .'&nbsp;UTC' : t('Never');
    }
    $html .= $group .'</div>';
  }
  $html .= '<p>';
  print theme("page", $html);
}

/**
 * Implements hook_cron. Examines the current date and time, and makes the
 * appropriate calls to other modules based on what parts of the date and
 * time have changed since the last run.
 */
function cronplus_cron() {
  global $stop_cron;
  // Gather information...
  $last_cron = intval(variable_get('cronplus_last_cron', 0));
  $now = time();
  $now_wkdy  = intval(gmdate('w', $now)); // 0=Sunday
  // For the $now_week, weeks start on Monday, not Sunday. This is a mismatch
  // against $now_wkdy, but it doesn't matter because all we are looking for
  // in $now_week is a *change* -- we don't care about the actual value.
  $now_week  = intval(gmdate('W', $now));
  $now_month = gmdate('Y-m', $now);
  $now_year  = intval(gmdate('Y', $now));
  $now_date  = gmdate('Y-m-d', $now);
  $now_hour  = intval(gmdate('H', $now));
  $now_on_demand  = intval(gmdate('s', $now));
  
  // Gather the last time each cronplus hook was invoked
  $cronplus_on_demand_last  = intval(variable_get('cronplus_on_demand_last', 0));
  $cronplus_hourly_last  = intval(variable_get('cronplus_hourly_last', 0));
  $cronplus_daily_last   = intval(variable_get('cronplus_daily_last', 0));
  $cronplus_weekly_last  = intval(variable_get('cronplus_weekly_last', 0));
  $cronplus_monthly_last = intval(variable_get('cronplus_monthly_last', 0));
  $cronplus_yearly_last  = intval(variable_get('cronplus_yearly_last', 0));
  
  $last_cron_on_demand = intval(gmdate('s', $cronplus_on_demand_last));
  $last_cron_hour = intval(gmdate('H', $cronplus_hourly_last));
  $last_cron_day  = gmdate('Y-m-d', $cronplus_daily_last);
  $last_cron_week = intval(gmdate('W', $cronplus_weekly_last));
  $last_cron_month = gmdate('Y-m', $cronplus_monthly_last);
  $last_cron_year = intval(gmdate('Y', $cronplus_yearly_last));
  
  // Preferred hour affects daily, weekly, monthly, and yearly runs
  $prefer_hour = intval(variable_get('cronplus_preferred_hour', 0));
  // Preferred wkdy affects weekly, monthly, and yearly runs
  $prefer_wkdy = intval(variable_get('cronplus_preferred_wkdy', 0));
  $interval = $now - $last_cron;   // Seconds since last run

  // Make the appropriate runs. In each case, we try to run in the preferred
  // window, but if it's been too long since the last run, we toss the
  // preference and just get the job done. Note that those "too long" values
  // are just arbitrarily assigned. They need to be a little bigger than the
  // real length of the corresponding time interval so that the module will
  // tend to converge onto the preferred timings over the long term.

  // On Demand
  if ($now_second != $last_cron_second || $interval >= 10 && $stop_cron == 1) {
    cronplus_invoke_hook('on_demand', $now, $last_cron);
  }
  $stop_cron++;
  
  // Hourly
  if ($now_hour != $last_cron_hour || $interval >= 4000) {
    cronplus_invoke_hook('hourly', $now, $last_cron);
  }
  // Daily
  if (substr($last_cron_day, 0, 10) != $now_date && ($now_hour >= $prefer_hour || $interval > 96000)) {
    // The sleep() calls in the following logic ensure that calls to cronplus_invoke_hook()
    // cannot occur multiple times in the same second, no matter how fast the system is.
    // This is needed because log entries have a precision of only seconds, and we want
    // to ensure that they are displayed in a sensible order for the administrator.
    // Note that it's not needed for the hourly call.
    //
    // The maximum combined delay from the sleep() calls is 4 seconds, worst case,
    // and that is only possible one time per year.
    sleep(1);
    cronplus_invoke_hook('daily', $now, $last_cron);
  }
  // Weekly
  if ($now_week != $last_cron_week && (($now_wkdy >= $prefer_wkdy && $now_hour >= $prefer_hour) || $interval > (86400*8))) {
    sleep(1);
    cronplus_invoke_hook('weekly', $now, $last_cron);
  }
  // Monthly
  if ($now_month != $last_cron_month && (($now_wkdy >= $prefer_wkdy && $now_hour >= $prefer_hour) || $interval > 86400*35)) {
    sleep(1);
    cronplus_invoke_hook('monthly', $now, $last_cron);
  }
  // Yearly
  if ($now_year > $last_cron_year && (($now_wkdy >= $prefer_wkdy && $now_hour >= $prefer_hour) || $interval > (86400*380))) {
    sleep(1);
    cronplus_invoke_hook('yearly', $now, $last_cron);
  }

  // Record the current run time
  variable_set('cronplus_last_cron', $now);
}

/**
 * Invokes the proper functions in all other modules that define them. $now is passed
 * down the tree because that is the "official" timestamp for this cron run as a whole,
 * even though the execution start time of each function call may be a later.
 */
function cronplus_invoke_hook($period, $now, $last_cron) {
  $now_fmt = gmdate('Y-m-d H:i:s', $now);
  $function_name = 'cronplus_'. $period;
  $last_this = variable_get($function_name .'_last', 0);
  variable_set($function_name .'_last', $now);
  watchdog('cronplus', 'Processing %period cron for %d UTC, calling {module}_%func() for all modules', array('%d' => $now_fmt, '%period' => t($period), '%func' => $function_name), WATCHDOG_NOTICE);
  @module_invoke_all($function_name, $now, $last_cron, $last_this);
  @module_invoke_all('cronplus', $period, $now, $last_cron, $last_this);
} 

/**
 * Returns an associative array filled with integers pointing to themselves, or
 * to the corresponding values from the $values array, if specified. The values
 * are translated if $translate is TRUE.
 */
function _cronplus_int_options($min, $max, $values=NULL, $translate=FALSE) {
  $options = array();
  for ($i=$min; $i<=$max; $i++) {
    if (is_array($values) && isset($values[$i])) {
      $options[$i] = $translate ? t($values[$i]) : $values[$i];
    }
      else {
      $options[$i] = $i;
    }
  }
  return $options;
}