<?php

/**
 * @file
 * FVL module file.
 */

/**
 * Implements hook_menu().
 */
function fvl_menu() {
  $items = array();
  $items['admin/config/content/fvl'] = array(
    'title' => 'Field Value Loader',
    'description' => 'Configure which fields should be hidden when viewing entity for manual loading them later (using AJAX). Separately for each bundle of an entity.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('fvl_admin_settings'),
    'access arguments' => array('administer site configuration'),
    'file' => 'fvl.admin.inc',
  );
  $items['fvl/%/%/%/%/%/%'] = array(
    'page callback' => 'fvl_get_field_value',
    'page arguments' => array(1, 2, 3, 4, 5, 6),
    'access arguments' => array('access content'),
  );
  return $items;
}

/**
 * Implements hook_entity_view().
 */
function fvl_entity_view($entity, $type, $view_mode, $langcode) {
  $settings = variable_get('fvl_fields', array());
  $ids = entity_extract_ids($type, $entity);
  if (isset($settings[$type][$ids[2]])) {
    foreach (array_keys($settings[$type][$ids[2]]) as $field) {
      if (isset($entity->content[$field])) {
        if (isset($entity->content[$field][1])) {
          foreach (array_keys($entity->content[$field]) as $delta) {
            if (is_numeric($delta)) {
              unset($entity->content[$field][$delta]);
            }
          }
        }
        // If revision is null set it as zero.
        $ids[1] = is_null($ids[1]) ? 0 : $ids[1];
        // Adding wrapper for ajax.
        $wrapper_id = "fvl-$type-$ids[0]-$field-$view_mode";
        $entity->content[$field]['#prefix'] = '<div id="' . $wrapper_id . '" class="fvl-ajax-container">';
        $entity->content[$field]['#suffix'] = '</div>';
        // Replacement of the field data to a link(like "Show").
        $replacement_text = empty($settings[$type][$ids[2]][$field]) ? variable_get('fvl_show_link_text', 'Show') : $settings[$type][$ids[2]][$field];
        $entity->content[$field][0] = array(
          '#type' => 'link',
          '#title' => t($replacement_text),
          '#href' => "fvl/$type/" . implode('/', $ids) . "/$field/$view_mode/nojs",
          '#ajax' => array(
            'wrapper' => $wrapper_id,
          ),
          '#attributes' => array(
            'rel' => 'nofollow',
            'class' => array('fvl-ajax-link'),
          ),
        );
      }
    }
  }
}

/**
 * Handler for ajax-request on field value.
 */
function fvl_get_field_value($entity_type, $entity_id, $rev_id, $bundle, $field, $view_mode, $mode = '') {
  if ($mode != 'ajax') {
    return fvl_nojs();
  }
  $settings = variable_get('fvl_fields', array());
  $conditions = $rev_id && $entity_type == 'node' ? array('vid' => $rev_id) : array();

  if (isset($settings[$entity_type][$bundle][$field]) && $entity = entity_load($entity_type, array($entity_id), $conditions)) {
    $entity = $entity[$entity_id];
    // Checking access to the entity and the field (protection for bypass attacks).
    $field_info = field_info_field($field);
    if (!field_access('view', $field_info, $entity_type, $entity) || !fvl_entity_view_access($entity_type, $entity)) {
      return MENU_ACCESS_DENIED;
    }
    // Getting display settings for field.
    $instance = field_info_instance($entity_type, $field, $bundle);
    // Assign default display.
    $view_mode = isset($instance['display'][$view_mode]) ? $view_mode : 'default';
    $display = $instance['display'][$view_mode];
    $output = field_view_field($entity_type, $entity, $field, $display);

    ajax_deliver($output);
    exit;
  }
  return MENU_NOT_FOUND;
}

/**
 * Getting access flag for an entity.
 */
function fvl_entity_view_access($entity_type, $entity) {
  if (module_exists('entity')) {
    global $user;
    return entity_access('view', $entity_type, $entity, $user);
  }
  switch ($entity_type) {
    case 'comment':
      return user_access('access comments');

    case 'node':
      return node_access('view', $entity);

    case 'user':
      return user_view_access($entity);

    default:
      return user_access('access content');
  }
}

/**
 * Helper function that generates the response when
 *  JavaScript is disabled.
 */
function fvl_nojs() {
  $path = '<front>';
  $base_url = str_replace('/', '\/', $GLOBALS['base_url']);
  if (isset($_SERVER['HTTP_REFERER']) && preg_match("/$base_url/", $_SERVER['HTTP_REFERER'])) {
    $path = $_SERVER['HTTP_REFERER'];
  }
  drupal_set_message(t('Please <a href="@how-to-yahoo-link" target="_blank">enable JavaScript</a> in your browser to view this data.', array('@how-to-yahoo-link' => 'http://help.yahoo.com/l/us/yahoo/help/faq/browsers/browsers-63474.html')), 'warning');
  drupal_goto($path);
}