<?php

/**
 * @file
 * Use field label as placeholder for all elements in choosen form.
 */

/**
 * Implements hook_menu().
 */
function form_placeholder_menu() {
  $items = array();
  $items['admin/config/user-interface/form-placeholder'] = array(
    'title' => 'Form Placeholder',
    'description' => 'Use field label as placeholder for all elements in choosen form.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('form_placeholder_admin_settings'),
    'access arguments' => array('administer form placeholder'),
    'file' => 'form_placeholder.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_permission().
 */
function form_placeholder_permission() {
  return array(
    'administer form placeholder' => array(
      'title' => t('Administer form placeholder settings'),
    ),
  );
}

/**
 * Implements hook_libraries_info().
 */
function form_placeholder_libraries_info() {
  $libraries['jquery.placeholder'] = array(
    'title' => 'jQuery Placeholder',
    'vendor url' => 'https://github.com/mathiasbynens/jquery-placeholder',
    'download url' => 'https://github.com/mathiasbynens/jquery-placeholder/archive/v2.0.8.zip',
    'version' => '2.0.8',
    'files' => array(
      'js' => array(
        'jquery.placeholder.js',
      ),
    ),
    'variants' => array(
      'source' => array(
        'files' => array(
          'js' => array(
            'jquery.placeholder.js',
          ),
        ),
      ),
    ),
  );
  return $libraries;
}

/**
 * Implements hook_element_info_alter().
 */
function form_placeholder_element_info_alter(&$types) {
  foreach (array_keys($types) as $type) {
    switch ($type) {
      case 'form':
      case 'textarea':
      case 'textfield':
      case 'password':
      case 'password_confirm':
        $types[$type]['#process'][] = 'form_placeholder_process_element';
        break;
    }
  }
}

/**
 * Element process callback.
 *
 * @param array $element
 *   The render array element.
 *
 * @return array
 *   The processed element.
 */
function form_placeholder_process_element($element) {
  if (isset($element['#form_placeholder'])) {
    $action = $element['#form_placeholder'] == TRUE ? 'include' : 'exclude';
    if ($element['#type'] == 'form') {
      $element['#attributes']['class'][] = 'form-placeholder-' . $action . '-children';
    }
    else {
      $element['#attributes']['class'][] = 'form-placeholder-' . $action;
    }
  }
  if ($element['#type'] == 'form') {
    form_placeholder_attach($element);
  }
  return $element;
}

/**
 * Adds placeholder to form element.
 *
 * @param array $element
 *   Form API element.
 */
function form_placeholder_attach(&$element) {
  // Adding jQuery Placeholder plugin library.
  if (module_exists('libraries') && ($path = libraries_get_path('jquery.placeholder'))) {
    $element['#attached']['js'][] = array(
      'type' => 'file',
      'data' => $path . '/jquery.placeholder.js',
    );
    $fallback_support = TRUE;
  }
  else {
    $fallback_support = FALSE;
  }
  // Adding settings.
  $whitechars = array("\r\n", "\r", "\n");
  $element['#attached']['js'][] = array(
    'type' => 'setting',
    'data' => array(
      'form_placeholder' => array(
        'fallback_support' => $fallback_support,
        'include' => str_replace($whitechars, ',', variable_get('form_placeholder_include', '')),
        'exclude' => str_replace($whitechars, ',', variable_get('form_placeholder_exclude', '')),
        'required_indicator' => variable_get('form_placeholder_required_indicator', 'append'),
      ),
    ),
  );
  // Adding module JS file.
  $element['#attached']['js'][] = array(
    'type' => 'file',
    'data' => drupal_get_path('module', 'form_placeholder') . '/form_placeholder.js',
  );
}

/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function form_placeholder_form_webform_client_form_alter(&$form, &$form_state, $form_id) {
  $form['#process'][] = 'form_placeholder_process_element';
}