dlzLogoSwap.module

<?php

/**
 * Implements hook_preprocess_page().
 */
function dlzLogoSwap_preprocess_page(&$variables) {
  $default = $variables['logo'];
  if (_dlzLogoSwap_checkIsLogoSwapped()) {
    $variables['logo'] = variable_get("dlzLogoSwap_logo_path", $default); //"themes/bartik/logo2.png";
  }
}


/**
 * Implements hook_cron().
 */
function dlzLogoSwap_cron() {
  $start_date = variable_get("dlzLogoSwap_start_date", -1);
  $end_date = variable_get("dlzLogoSwap_end_date", -1);
  $no_end_date = variable_get("dlzLogoSwap_no_end_date", FALSE);

  $start = strtotime($start_date);
  $end = strtotime($end_date);

  // If the start time is now or in the past...
  if ($start <= time()) {
    // If there is no end time configured...
    if ($no_end_date == TRUE) {
      // Then we need to make sure the logo swap is enabled.
      _dlzLogoSwap_enableLogoSwap();
      return;
    }

    // If the end time is now or in the past...
    if ($end <= time()) {
      // Then we need to disable the logo swap.
      _dlzLogoSwap_disableLogoSwap();
      return;
    }
    else { // If the end time is in the future... ($end > time())
    // Then we need to enable the logo swap.
    _dlzLogoSwap_enableLogoSwap();
    return;
    }
  }
  else { // If the start time is not now, or in the past... (then it must be in the future...)
    // Then we need to disable the logo swap.
    _dlzLogoSwap_disableLogoSwap();
    return;
  }
}


/**
 * Implements hook_menu()
 */
function dlzLogoSwap_menu() {
  $items = array();

  $items['admin/config/content/dlzlogoswap'] = array(
    'title' => 'Subscribe',
    'description' => 'Subscribe to this node',
    'page callback' => 'drupal_get_form',
    'page arguments' => array("dlzLogoSwap_schedule_form"),
    'access arguments' => array('create dlzLogoSwap schedules'),
    'type' => MENU_LOCAL_TASK
  );

  return $items;
}


/**
 * Implements Form API
 */
function dlzLogoSwap_schedule_form($node, &$form_state) {
  if (!is_array($node)) {
    $node = array();
  }

  $theme_settings = variable_get("theme_settings", -1);
  $default_logo = (is_array($theme_settings) && isset($theme_settings['logo_path'])) ? $theme_settings['logo_path'] : "";

  $node['dlzLogoSwap_logo_path'] = array(
    '#title' => t('Path to alternate logo'),
    '#type' => 'textfield',
    '#description' => t('Specify the path to the alternate logo to be displayed.'),
    '#default_value' => variable_get("dlzLogoSwap_logo_path", $default_logo),
    '#required' => TRUE,
  );

  $node['dlzLogoSwap_start_date'] = array(
    '#title' => t('Schedule Logo Swap Start'),
    '#type' => 'date_popup',
    '#description' => t('Specify the date when the alternate logo should be displayed.'),
    '#default_value' => variable_get("dlzLogoSwap_start_date", ""),
    '#required' => TRUE,
  );

  $node['dlzLogoSwap_end_date'] = array(
    '#title' => t('Schedule Logo Swap End'),
    '#type' => 'date_popup',
    '#description' => t('Specify the date when the alternate logo should no longer be displayed.'),
    '#required' => TRUE,
    '#default_value' => variable_get("dlzLogoSwap_end_date", ""),
  );

  $node['dlzLogoSwap_no_end_date'] = array(
    '#title' => t('No End Date.'),
    '#type' => 'checkbox',
    '#description' => t('Specify that the alternate logo should not swap out.'),
    '#default_value' => variable_get("dlzLogoSwap_no_end_date", FALSE),
  );

  return system_settings_form($node);
  /*
   * system_setting_form($form) automatically does this for us:
   *
      $node['#submit'][] = 'system_settings_form_submit';
      $node['submit'] = array(
         '#type' => 'submit',
         '#value' => t("Save Schedule"),
      );

      return $node;
   *
   */
}


/**
 * Form Validation Handler
 */
function dlzLogoSwap_schedule_form_validate($form, &$form_state) {
  $start = $form_state['values']['dlzLogoSwap_start_date'];
  $end = $form_state['values']['dlzLogoSwap_end_date'];

  $start_ts = strtotime($start);
  $end_ts = strtotime($end);

  if ($end_ts <= $start_ts) {
    $map = array("%end_date" => $end, "%start_date" => $start);
    $msg = t("The scheduled end date (%end_date) is on or before the schedule start date (%start_date).", $map);
    form_set_error("dlzLogoSwap_end_date", $msg);
  }

  if ($start_ts < time()) {
    $map = array("%start_date" => $start);
    $msg = t("The scheduled start date (%start_date) has already passed.", $map);
    form_set_error("dlzLogoSwap_start_date", $msg);
  }
}



/**
 * Implements hook_permission()
 */
function dlzLogoSwap_permission() {
  return array(
    'create dlzLogoSwap schedules' => array(
      'title' => t('Create Logo Swap Schedules'),
      'description' => t('Schedule swapping the default site logo for an alternative one.'),
    ),
  );
}


/**
 * Private Methods
 */
function _dlzLogoSwap_checkIsLogoSwapped() {
  $is_enabled = variable_get("dlzLogoSwap_enabled", FALSE);
  return (bool) ($is_enabled == TRUE);
}

function _dlzLogoSwap_disableLogoSwap() {
  if (_dlzLogoSwap_checkIsLogoSwapped() == TRUE) {
    variable_set("dlzLogoSwap_enabled", FALSE);
  }
}

function _dlzLogoSwap_enableLogoSwap() {
  if(_dlzLogoSwap_checkIsLogoSwapped() == FALSE){
    variable_set("dlzLogoSwap_enabled", TRUE);
  }
}