[project/link.git] / link.module

<?php
// $Id$

/**
 * @file
 * Defines simple link field types.
 */

define('LINK_EXTERNAL', 'external');
define('LINK_INTERNAL', 'internal');
define('LINK_FRONT', 'front');
define('LINK_EMAIL', 'email');
define('LINK_DOMAINS', 'aero|arpa|asia|biz|com|cat|coop|edu|gov|info|int|jobs|mil|museum|name|nato|net|org|pro|travel|mobi|local');

define('LINK_TARGET_DEFAULT', 'default');
define('LINK_TARGET_NEW_WINDOW', '_blank');
define('LINK_TARGET_TOP', '_top');
define('LINK_TARGET_USER', 'user');

/**
 * Maximum URLs length.
 */
define('LINK_URL_MAX_LENGTH', 2048);

/**
 * Implements hook_field_info().
 */
function link_field_info() {
  return array(
    'link_field' => array(
      'label' => t('Link'),
      'description' => t('Store a title, href, and attributes in the database to assemble a link.'),
      'settings' => array(
        'target' => LINK_TARGET_DEFAULT,
        'class' => '',
        'rel' => '',
      ),
      'default_widget' => 'link_field',
      'default_formatter' => 'default',
    ),
  );
}

/**
 * Implements hook_field_schema().
 */
function link_field_schema($field) {
  return array(
    'columns' => array(
      'url' => array(
        'type' => 'varchar',
        'length' => LINK_URL_MAX_LENGTH,
        'not null' => FALSE,
        'sortable' => TRUE
      ),
      'title' => array(
        'type' => 'varchar',
        'length' => 255,
        'not null' => FALSE,
        'sortable' => TRUE
      ),
      'attributes' => array(
        'type' => 'text',
        'size' => 'medium',
        'not null' => FALSE
      ),
    ),
  );
}

/**
 * Implements hook_field_settings_form().
 */
function link_field_settings_form($field, $instance, $has_data) {
  $form = array(
    '#element_validate' => array('link_field_settings_form_validate'),
/*     '#theme' => 'link_field_settings', */
  );

  $form['url'] = array(
    '#type' => 'checkbox',
    '#title' => t('Optional URL'),
    '#default_value' => isset($field['settings']['url']) ? $field['settings']['url'] : '',
    '#return_value' => 'optional',
    '#description' => t('If checked, the URL field is optional and submitting a title alone will be acceptable. If the URL is omitted, the title will be displayed as plain text.'),
  );

  $title_options = array(
    'optional' => t('Optional Title'),
    'required' => t('Required Title'),
    'value' => t('Static Title'),
    'none' => t('No Title'),
  );

  $form['title'] = array(
    '#type' => 'radios',
    '#title' => t('Link Title'),
    '#default_value' => isset($field['settings']['title']) ? $field['settings']['title'] : 'optional',
    '#options' => $title_options,
    '#description' => t('If the link title is optional or required, a field will be displayed to the end user. If the link title is static, the link will always use the same title. If <a href="http://drupal.org/project/token">token module</a> is installed, the static title value may use any other node field as its value. Static and token-based titles may include most inline XHTML tags such as <em>strong</em>, <em>em</em>, <em>img</em>, <em>span</em>, etc.'),
  );

  $form['title_value'] = array(
    '#type' => 'textfield',
    '#title' => t('Static title'),
    '#default_value' => isset($field['settings']['title_value']) ? $field['settings']['title_value'] : '',
/*     '#size' => '46', */
    '#description' => t('This title will always be used if &ldquo;Static Title&rdquo; is selected above.'),
  );

 // Add token module replacements if available
  if (module_exists('token')) {
    $form['tokens'] = array(
      '#type' => 'fieldset',
      '#collapsible' => TRUE,
      '#collapsed' => TRUE,
      '#title' => t('Placeholder tokens'),
      '#description' => t("The following placeholder tokens can be used in both paths and titles. When used in a path or title, they will be replaced with the appropriate values."),
    );
    $form['tokens']['help'] = array(
      '#value' => theme('token_help', 'node'),
    );

    $form['enable_tokens'] = array(
      '#type' => 'checkbox',
      '#title' => t('Allow user-entered tokens'),
      '#default_value' => isset($field['settings']['enable_tokens']) ? $field['settings']['enable_tokens'] : 1,
      '#description' => t('Checking will allow users to enter tokens in URLs and Titles on the node edit form. This does not affect the field settings on this page.'),
    );
  }

  $form['display'] = array(
    '#tree' => TRUE,
  );
  $form['display']['url_cutoff'] = array(
    '#type' => 'textfield',
    '#title' => t('URL Display Cutoff'),
    '#default_value' => isset($field['settings']['display']['url_cutoff']) ? $field['settings']['display']['url_cutoff'] : '80',
    '#description' => t('If the user does not include a title for this link, the URL will be used as the title. When should the link title be trimmed and finished with an elipsis (&hellip;)? Leave blank for no limit.'),
    '#maxlength' => 3,
   '#size' => 3,
  );

  $target_options = array(
    LINK_TARGET_DEFAULT => t('Default (no target attribute)'),
    LINK_TARGET_TOP => t('Open link in window root'),
    LINK_TARGET_NEW_WINDOW => t('Open link in new window'),
    LINK_TARGET_USER => t('Allow the user to choose'),
  );
  $form['attributes'] = array(
    '#tree' => TRUE,
  );
  $form['attributes']['target'] = array(
    '#type' => 'radios',
    '#title' => t('Link Target'),
    '#default_value' => empty($field['settings']['attributes']['target']) ? LINK_TARGET_DEFAULT : $field['settings']['attributes']['target'],
    '#options' => $target_options,
  );
  $form['attributes']['rel'] = array(
    '#type' => 'textfield',
    '#title' => t('Rel Attribute'),
    '#description' => t('When output, this link will have this rel attribute. The most common usage is <a href="http://en.wikipedia.org/wiki/Nofollow">rel=&quot;nofollow&quot;</a> which prevents some search engines from spidering entered links.'),
    '#default_value' => empty($field['settings']['attributes']['rel']) ? '' : $field['settings']['attributes']['rel'],
    '#field_prefix' => 'rel = "',
    '#field_suffix' => '"',
    '#size' => 20,
  );
  $form['attributes']['class'] = array(
    '#type' => 'textfield',
    '#title' => t('Additional CSS Class'),
    '#description' => t('When output, this link will have have this class attribute. Multiple classes should be separated by spaces.'),
    '#default_value' => empty($field['settings']['attributes']['class']) ? '' : $field['settings']['attributes']['class'],
  );
  return $form;
}

/**
 * Validate the field settings form.
 */
function link_field_settings_form_validate($element, &$form_state, $complete_form) {
  if ($form_state['values']['field']['settings']['title'] === 'value' && empty($form_state['values']['field']['settings']['title_value'])) {
    form_set_error('title_value', t('A default title must be provided if the title is a static value.'));
  }
}

/**
 * Implementation of hook_field_settings().
 */
function link_field_settings($op, $field) {
  switch ($op) {
    case 'form':
      $form = array(
        '#theme' => 'link_field_settings',
      );

      $form['url'] = array(
        '#type' => 'checkbox',
        '#title' => t('Optional URL'),
        '#default_value' => $field['url'],
        '#return_value' => 'optional',
        '#description' => t('If checked, the URL field is optional and submitting a title alone will be acceptable. If the URL is omitted, the title will be displayed as plain text.'),
      );

      $title_options = array(
        'optional' => t('Optional Title'),
        'required' => t('Required Title'),
        'value' => t('Static Title: '),
        'none' => t('No Title'),
      );

      $form['title'] = array(
        '#type' => 'radios',
        '#title' => t('Link Title'),
        '#default_value' => isset($field['title']) ? $field['title'] : 'optional',
        '#options' => $title_options,
        '#description' => t('If the link title is optional or required, a field will be displayed to the end user. If the link title is static, the link will always use the same title. If <a href="http://drupal.org/project/token">token module</a> is installed, the static title value may use any other node field as its value. Static and token-based titles may include most inline XHTML tags such as <em>strong</em>, <em>em</em>, <em>img</em>, <em>span</em>, etc.'),
      );

      $form['title_value'] = array(
        '#type' => 'textfield',
        '#default_value' => $field['title_value'],
        '#size' => '46',
      );

      // Add token module replacements if available
      if (module_exists('token')) {
        $form['tokens'] = array(
          '#type' => 'fieldset',
          '#collapsible' => TRUE,
          '#collapsed' => TRUE,
          '#title' => t('Placeholder tokens'),
          '#description' => t("The following placeholder tokens can be used in both paths and titles. When used in a path or title, they will be replaced with the appropriate values."),
        );
        $form['tokens']['help'] = array(
          '#value' => theme('token_help', 'node'),
        );

        $form['enable_tokens'] = array(
          '#type' => 'checkbox',
          '#title' => t('Allow user-entered tokens'),
          '#default_value' => isset($field['enable_tokens']) ? $field['enable_tokens'] : 1,
          '#description' => t('Checking will allow users to enter tokens in URLs and Titles on the node edit form. This does not affect the field settings on this page.'),
        );
      }

      $form['display'] = array(
        '#tree' => TRUE,
      );
      $form['display']['url_cutoff'] = array(
        '#type' => 'textfield',
        '#title' => t('URL Display Cutoff'),
        '#default_value' => isset($field['display']['url_cutoff']) ? $field['display']['url_cutoff'] : '80',
        '#description' => t('If the user does not include a title for this link, the URL will be used as the title. When should the link title be trimmed and finished with an elipsis (&hellip;)? Leave blank for no limit.'),
        '#maxlength' => 3,
        '#size' => 3,
      );

      $target_options = array(
        LINK_TARGET_DEFAULT => t('Default (no target attribute)'),
        LINK_TARGET_TOP => t('Open link in window root'),
        LINK_TARGET_NEW_WINDOW => t('Open link in new window'),
        LINK_TARGET_USER => t('Allow the user to choose'),
      );
      $form['attributes'] = array(
        '#tree' => TRUE,
      );
      $form['attributes']['target'] = array(
        '#type' => 'radios',
        '#title' => t('Link Target'),
        '#default_value' => empty($field['attributes']['target']) ? LINK_TARGET_DEFAULT : $field['attributes']['target'],
        '#options' => $target_options,
      );
      $form['attributes']['rel'] = array(
        '#type' => 'textfield',
        '#title' => t('Rel Attribute'),
        '#description' => t('When output, this link will have this rel attribute. The most common usage is <a href="http://en.wikipedia.org/wiki/Nofollow">rel=&quot;nofollow&quot;</a> which prevents some search engines from spidering entered links.'),
        '#default_value' => empty($field['attributes']['rel']) ? '' : $field['attributes']['rel'],
        '#field_prefix' => 'rel = "',
        '#field_suffix' => '"',
        '#size' => 20,
      );
      $form['attributes']['class'] = array(
        '#type' => 'textfield',
        '#title' => t('Additional CSS Class'),
        '#description' => t('When output, this link will have have this class attribute. Multiple classes should be separated by spaces.'),
        '#default_value' => empty($field['attributes']['class']) ? '' : $field['attributes']['class'],
      );
      return $form;

    case 'validate':
      if ($field['title'] == 'value' && empty($field['title_value'])) {
        form_set_error('title_value', t('A default title must be provided if the title is a static value'));
      }
      break;

    case 'save':
      return array('attributes', 'display', 'url', 'title', 'title_value', 'enable_tokens');

    case 'database columns':
      return array(
        'url' => array('type' => 'varchar', 'length' => 255, 'not null' => FALSE, 'sortable' => TRUE),
        'title' => array('type' => 'varchar', 'length' => 255, 'not null' => FALSE, 'sortable' => TRUE),
        'attributes' => array('type' => 'text', 'size' => 'medium', 'not null' => FALSE),
      );

    case 'views data':
      module_load_include('inc', 'link', 'views/link.views');
      return link_views_content_field_data($field);
  }
}

/**
 * Theme the settings form for the link field.
 */
/*
function theme_link_field_settings($form) {
  $title_value = drupal_render($form['title_value']);
  $title_checkbox = drupal_render($form['title']['value']);

  // Set Static Title radio option to include the title_value textfield.
  $form['title']['value'] = array('#value' => '<div class="container-inline">'. $title_checkbox . $title_value .'</div>');

  // Reprint the title radio options with the included textfield.
  return drupal_render($form);
}

/**
 * Implement hook_field_is_empty().
 */
function link_field_is_empty($item, $field) {
  return empty($item['title']) && empty($item['url']);
}

function link_field_load($entity_type, $entities, $field, $instances, $langcode, &$items, $age) {
  foreach ($entities as $id => $entity) {
    foreach ($items[$id] as $delta => $item) {
      $items[$id][$delta]['attributes'] = _link_load($field, $item);
    }
  }
}

/**
 * Implements hook_field_validate().
 */
function link_field_validate($entity_type, $entity, $field, $instance, $langcode, $items, &$errors) {
  $optional_field_found = FALSE;
  foreach ($items as $delta => $value) {
    _link_validate($items[$delta], $delta, $field, $entity, $instance, $optional_field_found);
  }
}

/**
 * Implements hook_field_presave().
 */
function link_field_presave($entity_type, $entity, $field, $instance, $langcode, &$items) {
  foreach ($items as $delta => $value) {
    _link_sanitize($items[$delta], $delta, $field, $entity);
    _link_process($items[$delta], $delta, $field, $entity);
  }
}

/**
 * Implements hook_field_widget_info().
 */
function link_field_widget_info() {
  return array(
    'link_field' => array(
      'label' => 'Link',
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
  );
}

/**
 * Implements hook_field_widget_form().
 */
function link_field_widget_form(&$form, &$form_state, $field, $instance, $langcode, $items, $delta, $element) {
  $element += array(
    '#type' => $instance['widget']['type'],
    '#default_value' => isset($items[$delta]) ? $items[$delta] : '',
  );
  return $element;
}

/**
 * Implements hook_field_formatter_view().
 */
/*function link_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();
  if ($display['type'] === 'link_default') {
    foreach ($items as $delta => $item) {
      $element[$delta] = array(
        '#markup' => theme('link_field', $item),
      );
    }
  }
  return $element;
}*/

function _link_load($field, &$item) {
  return $item['attributes'] = isset($item['attributes']) ? unserialize($item['attributes']) : $field['settings']['attributes'];
}

function _link_process(&$item, $delta = 0, $field, $entity) {
  // Trim whitespace from URL.
  $item['url'] = trim($item['url']);

  // if no attributes are set then make sure $item['attributes'] is an empty array - this lets $field['attributes'] override it.
  if (empty($item['attributes'])) {
    $item['attributes'] = array();
  }

  // Serialize the attributes array.
  $item['attributes'] = serialize($item['attributes']);

  // Don't save an invalid default value (e.g. 'http://').
  if ((isset($field['widget']['default_value'][$delta]['url']) && $item['url'] == $field['widget']['default_value'][$delta]['url'])
      && is_object($node)) {
    if (!link_validate_url($item['url'])) {
      unset($item['url']);
    }
  }
}

function _link_validate(&$item, $delta, $field, $node, $instance, &$optional_field_found) {
  if ($item['url'] && !(isset($field['widget']['default_value'][$delta]['url']) && $item['url'] === $field['widget']['default_value'][$delta]['url'] && !$item['required'])) {
    // Validate the link.
    if (link_validate_url(trim($item['url'])) == FALSE) {
      form_set_error($field['field_name'] .']['. $delta .'][url', t('Not a valid URL.'));
    }
    // Require a title for the link if necessary.
    if ($field['settings']['title'] == 'required' && strlen(trim($item['title'])) == 0) {
      form_set_error($field['field_name'] .']['. $delta .'][title', t('Titles are required for all links.'));
    }
  }
  // Require a link if we have a title.
  if ($field['settings']['url'] !== 'optional' && strlen(isset($item['title']) ? $item['title'] : NULL) > 0 && strlen(trim($item['url'])) == 0) {
    form_set_error($field['field_name'] .']['. $delta .'][url', t('You cannot enter a title without a link url.'));
  }
  // In a totally bizzaro case, where URLs and titles are optional but the field is required, ensure there is at least one link.
  if ($field['settings']['url'] === 'optional' && $field['settings']['title'] === 'optional' && (strlen(trim($item['url'])) !== 0 || strlen(trim($item['title'])) !== 0)) {
    $optional_field_found = TRUE;
  }
  // Require entire field
  if ($field['settings']['url'] === 'optional'
    && $field['settings']['title'] === 'optional'
    && $instance['required'] == 1 && !$optional_field_found && isset($instance['id'])) {
    form_set_error($instance['field_name'] .'][0][title',
                   t('At least one title or URL must be entered.'));
  }
}

/**
 * Cleanup user-entered values for a link field according to field settings.
 *
 * @param $item
 *   A single link item, usually containing url, title, and attributes.
 * @param $delta
 *   The delta value if this field is one of multiple fields.
 * @param $field
 *   The CCK field definition.
 * @param $node
 *   The node containing this link.
 */
function _link_sanitize(&$item, $delta, &$field, &$node) {
  // Don't try to process empty links.
  if (empty($item['url']) && empty($item['title'])) {
    return;
  }

  // Replace URL tokens.
  if (module_exists('token') && $field['enable_tokens']) {
    // Load the node if necessary for nodes in views.
    $token_node = isset($node->nid) ? node_load($node->nid) : $node;
    $item['url'] = token_replace($item['url'], 'node', $token_node);
  }

  $type = link_validate_url($item['url']);
  $url = link_cleanup_url($item['url']);

  // Separate out the anchor if any.
  if (strpos($url, '#') !== FALSE) {
    $item['fragment'] = substr($url, strpos($url, '#') + 1);
    $url = substr($url, 0, strpos($url, '#'));
  }
  // Separate out the query string if any.
  if (strpos($url, '?') !== FALSE) {
    $query = substr($url, strpos($url, '?') + 1);
    parse_str($query, $query_array);
    $item['query'] = $query_array;
    $url = substr($url, 0, strpos($url, '?'));
  }

  // Create a shortened URL for display.
  $display_url = $type == LINK_EMAIL ? str_replace('mailto:', '', $url) : url($url, array('query' => isset($item['query']) ? $item['query'] : NULL, 'fragment' => isset($item['fragment']) ? $item['fragment'] : NULL, 'absolute' => TRUE));
  if ($field['settings']['display']['url_cutoff'] && strlen($display_url) > $field['settings']['display']['url_cutoff']) {
    $display_url = substr($display_url, 0, $field['settings']['display']['url_cutoff']) ."...";
  }
  $item['display_url'] = $display_url;

  // Use the title defined at the field level.
  if ($field['settings']['title'] == 'value' && strlen(trim($field['settings']['title_value']))) {
    $title = $field['settings']['title_value'];
  }
  // Use the title defined by the user at the widget level.
  else if (isset($item['title'])) {
    $title = $item['title'];
  }
  
  // Replace tokens.
  if (module_exists('token') && ($field['title'] == 'value' || $field['enable_tokens'])) {
    // Load the node if necessary for nodes in views.
    $token_node = isset($node->nid) ? node_load($node->nid) : $node;
    $title = filter_xss(token_replace($title, 'node', $token_node), array('b', 'br', 'code', 'em', 'i', 'img', 'span', 'strong', 'sub', 'sup', 'tt', 'u'));
    $item['html'] = TRUE;
  }
  $item['title'] = empty($title) ? $item['display_url'] : $title;

  if (!isset($item['attributes'])) {
    $item['attributes'] = array();
  }

  // Unserialize attributtes array if it has not been unserialized yet.
  if (!is_array($item['attributes'])) {
    $item['attributes'] = (array)unserialize($item['attributes']);
  }

  // Add default attributes.
  $field['settings']['attributes'] += _link_default_attributes();

  // Merge item attributes with attributes defined at the field level.
  $item['attributes'] += $field['settings']['attributes'];

  // If user is not allowed to choose target attribute, use default defined at
  // field level.
  if ($field['settings']['attributes']['target'] != LINK_TARGET_USER) {
    $item['attributes']['target'] = $field['settings']['attributes']['target'];
  }

  // Remove the target attribute if the default (no target) is selected.
  if (empty($item['attributes']) || $item['attributes']['target'] == LINK_TARGET_DEFAULT) {
    unset($item['attributes']['target']);
  }

  // Remove the rel=nofollow for internal links.
  if ($type != LINK_EXTERNAL && strpos($item['attributes']['rel'], 'nofollow') !== FALSE) {
    $item['attributes']['rel'] = str_replace('nofollow', '', $item['attributes']);
  }

  // Remove empty attributes.
  $item['attributes'] = array_filter($item['attributes']);

  // Sets title to trimmed url if one exists
  // @TODO: Do we need this?  It seems not.
  if(!empty($item['display_url']) && empty($item['title'])) {
    $item['title'] = $item['display_url'];
  }
  elseif(!isset($item['title'])) {
    $item['title'] = $item['url'];
  }
  
}

/**
 * Implements hook_theme().
 */
function link_theme() {
  return array(
    /*'link_field_settings' => array(
      'variables' => array('element' => NULL),
    ),*/
    'link_formatter_default' => array(
      'variables' => array('element' => NULL),
    ),
    'link_formatter_plain' => array(
      'variables' => array('element' => NULL),
    ),
    'link_formatter_url' => array(
      'variables' => array('element' => NULL),
    ),
    'link_formatter_short' => array(
      'variables' => array('element' => NULL),
    ),
    'link_formatter_label' => array(
      'variables' => array('element' => NULL),
    ),
    'link_formatter_separate' => array(
      'variables' => array('element' => NULL),
    ),
    'link_field' => array(
      'render element' => 'element',
    ),
  );
}

/**
 * FAPI theme for an individual text elements.
 */
function theme_link_field($vars) {
  drupal_add_css(drupal_get_path('module', 'link') .'/link.css');

  $element = $vars['element'];
  // Prefix single value link fields with the name of the field.
  if (empty($element['#field']['multiple'])) {
    if (isset($element['url']) && !isset($element['title'])) {
      unset($element['url']['#title']);
    }
  }

  $output = '';
  $output .= '<div class="link-field-subrow clearfix">';
  if (isset($element['title'])) {
    $output .= '<div class="link-field-title link-field-column">'. drupal_render($element['title']) .'</div>';
  }
  $output .= '<div class="link-field-url'. (isset($element['title']) ? ' link-field-column' : '') .'">'. drupal_render($element['url']) .'</div>';
  $output .= '</div>';
  if (!empty($element['attributes']['target'])) {
    $output .= '<div class="link-attributes">'. drupal_render($element['attributes']['target']) .'</div>';
  }
  return $output;
}

/**
 * Implements hook_element_info().
 */
function link_element_info() {
  $elements = array();
  $elements['link_field'] =  array(
    '#input' => TRUE,
    '#process' => array('link_field_process'),
    '#theme' => 'link_field',
    '#theme_wrappers' => array('form_element'),
  );
  return $elements;
}

function _link_default_attributes() {
  return array(
    'target' => LINK_TARGET_DEFAULT,
    'class' => '',
    'rel' => '',
  );
}

/**
 * Process the link type element before displaying the field.
 *
 * Build the form element. When creating a form using FAPI #process,
 * note that $element['#value'] is already set.
 *
 * The $fields array is in $form['#field_info'][$element['#field_name']].
 */
function link_field_process($element, $form_state, $form) {
  $settings = &$form_state['field'][$element['#field_name']][$element['#language']]['field']['settings'];
  $element['url'] = array(
    '#type' => 'textfield',
    '#maxlength' => LINK_URL_MAX_LENGTH,
    '#title' => t('URL'),
    '#required' => ($element['#delta'] == 0 && $settings['url'] !== 'optional') ? $element['#required'] : FALSE,
    '#default_value' => isset($element['#value']['url']) ? $element['#value']['url'] : NULL,
  );
  if ($settings['title'] !== 'none' && $settings['title'] !== 'value') {
    $element['title'] = array(
      '#type' => 'textfield',
      '#maxlength' => '255',
      '#title' => t('Title'),
      '#required' => ($settings['title'] == 'required' && !empty($element['#value']['url'])) ? TRUE : FALSE,
      '#default_value' => isset($element['#value']['title']) ? $element['#value']['title'] : NULL,
    );
  }

  // Initialize field attributes as an array if it is not an array yet.
  if (!is_array($settings['attributes'])) {
    $settings['attributes'] = array();
  }
  // Add default atrributes.
  $settings['attributes'] += _link_default_attributes();
  $attributes = isset($element['#value']['attributes']) ? $element['#value']['attributes'] : $settings['attributes'];
  if (!empty($settings['attributes']['target']) && $settings['attributes']['target'] == LINK_TARGET_USER) {
    $element['attributes']['target'] = array(
      '#type' => 'checkbox',
      '#title' => t('Open URL in a New Window'),
      '#return_value' => LINK_TARGET_NEW_WINDOW,
      '#default_value' => isset($attributes['target']) ? $attributes['target'] : FALSE,
    );
  }
  return $element;
}

/**
 * Implementation of hook_field_formatter_info().
 */
function link_field_formatter_info() {
  return array(
    'default' => array(
      'label' => t('Title, as link (default)'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
    'url' => array(
      'label' => t('URL, as link'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
    'plain' => array(
      'label' => t('URL, as plain text'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
    'short' => array(
      'label' => t('Short, as link with title "Link"'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
    'label' => array(
      'label' => t('Label, as link with label as title'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
    'separate' => array(
      'label' => t('Separate title and URL'),
      'field types' => array('link_field'),
      'multiple values' => FIELD_BEHAVIOR_DEFAULT,
    ),
  );
}

function link_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $elements = array();
  foreach ($items as $delta => $item) {
    $elements[$delta] = array(
      '#markup' => theme('link_formatter_'. $display['type'], array('element' => $item, 'field' => $instance)),
    );
  }
  return $elements;
}

/**
 * Theme function for 'default' text field formatter.
 */
function theme_link_formatter_default($element) {
  //drupal_set_message('<pre>'. print_r($element['element'], TRUE) .'</pre>');
  // Display a normal link if both title and URL are available.
  if (!empty($element['element']['title']) && !empty($element['element']['url'])) {
    return l($element['element']['title'], $element['element']['url'], array('attributes' => $element['element']['attributes']));
  }
  // If only a title, display the title.
  elseif (!empty($element['element']['title'])) {
    return check_plain($element['element']['title']);
  }
  elseif (!empty($element['element']['url'])) {
    return l($element['element']['title'], $element['element']['url'], array('attributes' => $element['element']['attributes']));
  }
}

/**
 * Theme function for 'plain' text field formatter.
 */
function theme_link_formatter_plain($element) {
  return empty($element['element']['url']) ? check_plain($element['element']['title']) : url($element['element']['url'], array('attributes' => $element['element']['attributes']));
}

/**
 * Theme function for 'url' text field formatter.
 */
/*
function theme_link_formatter_url($element) {
  return $element['element']['url'] ? l($element['element']['display_url'], $element['element']['url'], array('attributes' => $element['element']['attributes']) : '';
}
*/

/**
 * Theme function for 'short' text field formatter.
 */
function theme_link_formatter_short($element) {
  return $element['element']['url'] ? l(t('Link'), $element['element']['url'], array('attributes' => $element['element']['attributes'])) : '';
}

/**
 * Theme function for 'label' text field formatter.
 */
function theme_link_formatter_label($element) {
  return $element['element']['url'] ? l($element['field']['label'], $element['element']['url'], array('attributes' => $element['element']['attributes'])) : '';
}

/**
 * Theme function for 'separate' text field formatter.
 */

function theme_link_formatter_separate($element) {
  $class = empty($element['element']['attributes']['class']) ? '' : ' '. $element['element']['attributes']['class'];
  unset($element['element']['attributes']['class']);
  $title = empty($element['element']['title']) ? '' : check_plain($element['element']['title']);

  $output = '';
  $output .= '<div class="link-item '. $class .'">';
  if (!empty($title)) {
    $output .= '<div class="link-title">'. $title .'</div>';
  }
  $output .= '<div class="link-url">'. l($element['element']['url'], $element['element']['url'], array('attributes' => $element['element']['attributes'])) .'</div>';
  $output .= '</div>';
  return $output;
}


function link_token_list($type = 'all') {
  if ($type === 'field' || $type === 'all') {
    $tokens = array();

    $tokens['link']['url'] = t("Link URL");
    $tokens['link']['title'] = t("Link title");
    $tokens['link']['view'] = t("Formatted html link");

    return $tokens;
  }
}

function link_token_values($type, $object = NULL) {
  if ($type === 'field') {
    $item = $object[0];

    $tokens['url'] = $item['url'];
    $tokens['title'] = $item['title'];
    $tokens['view'] = isset($item['view']) ? $item['view'] : '';

    return $tokens;
  }
}

/**
 * Implements hook_views_api().
 */
function link_views_api() {
  return array(
    'api' => 2,
    'path' => drupal_get_path('module', 'link') .'/views',
  );
}

/**
 * Forms a valid URL if possible from an entered address.
 * Trims whitespace and automatically adds an http:// to addresses without a protocol specified
 *
 * @param string $url
 * @param string $protocol The protocol to be prepended to the url if one is not specified
 */
function link_cleanup_url($url, $protocol = "http") {
  $url = trim($url);
  $type = link_validate_url($url);

  if ($type === LINK_EXTERNAL) {
    // Check if there is no protocol specified.
    $protocol_match = preg_match("/^([a-z0-9][a-z0-9\.\-_]*:\/\/)/i", $url);
    if (empty($protocol_match)) {
      // But should there be? Add an automatic http:// if it starts with a domain name.
      $domain_match = preg_match('/^(([a-z0-9]([a-z0-9\-_]*\.)+)('. LINK_DOMAINS .'|[a-z]{2}))/i', $url);
      if (!empty($domain_match)) {
        $url = $protocol ."://". $url;
      }
    }
  }

  return $url;
}

/**
 * A lenient verification for URLs. Accepts all URLs following RFC 1738 standard
 * for URL formation and all email addresses following the RFC 2368 standard for
 * mailto address formation.
 *
 * @param string $text
 * @return mixed Returns boolean FALSE if the URL is not valid. On success, returns an object with
 * the following attributes: protocol, hostname, ip, and port.
 */
function link_validate_url($text) {

  $allowed_protocols = variable_get('filter_allowed_protocols', array('http', 'https', 'ftp', 'news', 'nntp', 'telnet', 'mailto', 'irc', 'ssh', 'sftp', 'webcal'));

  $protocol = '(('. implode("|", $allowed_protocols) .'):\/\/)';
  $authentication = '([a-z0-9]+(:[a-z0-9]+)?@)';
  $domain = '(([a-z0-9]([a-z0-9\-_\[\]])*)(\.(([a-z0-9\-_\[\]])+\.)*('. LINK_DOMAINS .'|[a-z]{2}))?)';
  $ipv4 = '([0-9]{1,3}(\.[0-9]{1,3}){3})';
  $ipv6 = '([0-9a-fA-F]{1,4}(\:[0-9a-fA-F]{1,4}){7})';
  $port = '(:([0-9]{1,5}))';

  // Pattern specific to eternal links.
  $external_pattern = '/^'. $protocol .'?'. $authentication .'?('. $domain .'|'. $ipv4 .'|'. $ipv6 .' |localhost)'. $port .'?';

  // Pattern specific to internal links.
  $internal_pattern = "/^([a-z0-9_\-+\[\]]+)";

  $directories = "(\/[a-z0-9_\-\.~+%=&,$'!():;*@\[\]]*)*";
  // Yes, four backslashes == a single backslash.
  $query = "(\/?\?([?a-z0-9+_|\-\.\/\\\\%=&,$'():;*@\[\]]*))";
  $anchor = "(#[a-z0-9_\-\.~+%=&,$'():;*@\[\]]*)";

  // The rest of the path for a standard URL.
  $end = $directories .'?'. $query .'?'. $anchor .'?'.'$/i';

  $user = '[a-zA-Z0-9_\-\.\+\^!#\$%&*+\/\=\?\`\|\{\}~\'\[\]]+';
  $email_pattern = '/^mailto:'. $user .'@'.'('. $domain .'|'. $ipv4 .'|'. $ipv6 .'|localhost)'. $query .'?$/';

  if (strpos($text, '<front>') === 0) {
    return LINK_FRONT;
  }
  if (in_array('mailto', $allowed_protocols) && preg_match($email_pattern, $text)) {
    return LINK_EMAIL;
  }
  if (preg_match($internal_pattern . $end, $text)) {
    return LINK_INTERNAL;
  }
  if (preg_match($external_pattern . $end, $text)) {
    return LINK_EXTERNAL;
  }

  return FALSE;
}