<?php
/**
 * @file
 * Adds a "Table" format to Field Groups.
 */

define('FIELD_GROUP_TABLE_LABEL_HIDDEN', 1);
define('FIELD_GROUP_TABLE_LABEL_ABOVE', 2);
define('FIELD_GROUP_TABLE_LABEL_CAPTION', 3);
define('FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP', 1);
define('FIELD_GROUP_TABLE_EMPTY_LABEL_MERGE', 2);

/**
 * Implements hook_ctools_plugin_api().
 */
function field_group_table_ctools_plugin_api($owner, $api) {
  if ($owner == 'field_group' && $api == 'field_group') {
    return array('version' => 1);
  }
}

/**
 * Implements hook_theme().
 */
function field_group_table_theme() {
  return array(
    'field_group_table_wrapper' => array(
      'render element' => 'element',
    ),
  );
}

/**
 * Implements hook_field_group_formatter_info().
 */
function field_group_table_field_group_formatter_info() {
  return array(
    'display' => array(
      'table' => array(
        'label' => t('Table'),
        'description' => t('This fieldgroup renders fields in a 2-column table with the label in the left column, and the value in the right column.'),
        'instance_settings' => array(
          'label_visibility' => FIELD_GROUP_TABLE_LABEL_CAPTION,
          'desc' => '',
          'first_column' => '',
          'second_column' => '',
          'empty_label_behavior' => FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP,
          'table_row_striping' => FALSE,
          'always_show_field_label' => FALSE,
          'classes' => '',
        ),
      ),
    ),
    'form' => array(
      'table' => array(
        'label' => t('Table'),
        'description' => t('This fieldgroup renders fields in a 2-column table with the label in the left column, and the value in the right column.'),
        'instance_settings' => array(
          'label_visibility' => FIELD_GROUP_TABLE_LABEL_CAPTION,
          'desc' => '',
          'first_column' => '',
          'second_column' => '',
          'empty_label_behavior' => FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP,
          'table_row_striping' => FALSE,
          'always_show_field_label' => FALSE,
          'classes' => '',
        ),
      ),
    ),
  );
}

/**
 * Implements hook_field_group_format_settings().
 */
function field_group_table_field_group_format_settings($group) {
  // Add a wrapper for extra settings to use by others.
  $form = array(
    'instance_settings' => array(
      '#tree' => TRUE,
      '#weight' => 2,
    ),
  );

  $field_group_types = field_group_formatter_info();
  $mode = $group->mode == 'form' ? 'form' : 'display';
  $formatter = $field_group_types[$mode][$group->format_type];
  $settings = $group->format_settings['instance_settings'];

  // Add optional instance_settings.
  switch ($group->format_type) {
    case 'table':
      $form['instance_settings']['label_visibility'] = array(
        '#title' => t('Label visibility'),
        '#description' => t('This option determines how to display the Field group label and description.'),
        '#type' => 'select',
        '#options' => array(
          FIELD_GROUP_TABLE_LABEL_HIDDEN => t('Hidden'),
          FIELD_GROUP_TABLE_LABEL_ABOVE => t('Above table'),
          FIELD_GROUP_TABLE_LABEL_CAPTION => t('Table caption'),
        ),
        '#default_value' => isset($settings['label_visibility']) ? $settings['label_visibility'] : $formatter['instance_settings']['label_visibility'],
      );
      $form['instance_settings']['desc'] = array(
        '#title' => t('Description for the group.'),
        '#type' => 'textarea',
        '#default_value' => isset($settings['desc']) ? $settings['desc'] : $formatter['instance_settings']['desc'],
      );
      $form['instance_settings']['first_column'] = array(
        '#title' => t('First column header'),
        '#description' => t('Use this field to add a table header.'),
        '#type' => 'textfield',
        '#default_value' => isset($settings['first_column']) ? $settings['first_column'] : $formatter['instance_settings']['first_column'],
      );
      $form['instance_settings']['second_column'] = array(
        '#title' => t('Second column header'),
        '#description' => t('Use this field to add a table header.'),
        '#type' => 'textfield',
        '#default_value' => isset($settings['second_column']) ? $settings['second_column'] : $formatter['instance_settings']['second_column'],
      );
      $form['instance_settings']['empty_label_behavior'] = array(
        '#title' => t('Empty label behavior'),
        '#type' => 'select',
        '#options' => array(
          FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP => t('Keep empty label cell'),
          FIELD_GROUP_TABLE_EMPTY_LABEL_MERGE => t('Merge cells'),
        ),
        '#default_value' => isset($settings['empty_label_behavior']) ? $settings['empty_label_behavior'] : $formatter['instance_settings']['empty_label_behavior'],
      );
      $form['instance_settings']['table_row_striping'] = array(
        '#title' => t('Table row striping'),
        '#description' => t('Adds zebra striping on the table rows.'),
        '#type' => 'checkbox',
        '#default_value' => isset($settings['table_row_striping']) ? $settings['table_row_striping'] : $formatter['instance_settings']['table_row_striping'],
      );
      $form['instance_settings']['always_show_field_label'] = array(
        '#title' => t('Always show field label'),
        '#description' => t('Forces the field label to always display in the first column and renders the field normally.'),
        '#type' => 'checkbox',
        '#default_value' => isset($settings['always_show_field_label']) ? $settings['always_show_field_label'] : $formatter['instance_settings']['always_show_field_label'],
      );

      break;
  }

  return $form;
}

/**
 * Implements hook_field_group_pre_render().
 */
function field_group_table_field_group_pre_render(&$element, $group, &$form) {
  // We only process the 'table' group type.
  if ($group->format_type != 'table') {
    return;
  }

  $mode = $group->mode == 'form' ? 'form' : 'display';
  $settings = $group->format_settings['instance_settings'];
  $label = check_plain($group->label);

  // Build the caption and description of this group.
  $caption = array();
  if ($settings['label_visibility'] == FIELD_GROUP_TABLE_LABEL_ABOVE) {
    $caption = array(
      '#type' => 'item',
      '#title' => $label,
      '#description' => field_filter_xss($settings['desc']),
    );
  }

  // Build the table header if necessary.
  $header = array();
  if ($settings['first_column'] || $settings['second_column']) {
    $header = array(
      check_plain($settings['first_column']),
      check_plain($settings['second_column']),
    );
  }

  // Create the element.
  $element += array(
    '#theme' => 'field_group_table_wrapper',
    '#title' => $group->label,
    '#mode' => $mode,
    '#groups' => array_keys($form['#groups']),
    '#settings' => $settings,
    '#attributes' => array(
      'class' => array_merge(array('field-group-table', $group->group_name), explode(' ', $settings['classes'])),
    ),
    '#caption' => $caption,
    // We will add the table rows upon rendering, as doing it here means
    // messing up the field group hierarchy, which causes issues.
    '#field_group_table' => array(
      '#theme' => "table__field_group_table__$group->group_name",
      '#header' => $header,
      '#caption' => ($settings['label_visibility'] == FIELD_GROUP_TABLE_LABEL_CAPTION) ? $label : NULL,
      '#attributes' => array(
        'class' => array('field-group-format', $group->group_name),
      ),
    ),
  );
}

/**
 * Returns HTML for a field_group_table_wrapper.
 */
function theme_field_group_table_wrapper($variables) {
  $element = $variables['element'];
  $mode = $element['#mode'];
  $settings = $element['#settings'];

  // Allow modules to alter the rows, useful for removing empty rows.
  $children = element_children($element, TRUE);
  drupal_alter('field_group_table_rows', $element, $children);

  // Build the table rows.
  $rows = array();
  foreach ($children as $child) {
    $variables = array(
      'element' => $element[$child],
      'settings' => $settings,
      'mode' => $mode,
    );
    unset($element[$child]);

    $rows[] = _field_group_table_row_build($variables);
  }

  $element['#field_group_table']['#rows'] = $rows;

  $render = array(
    '#theme' => 'container',
    '#attributes' => array(
      'id' => isset($element['#id']) ? $element['#id'] : '',
    ) + $element['#attributes'],
  );

  $render['#children'] = drupal_render($element['#caption']) . "\n";
  $render['#children'] .= drupal_render($element['#field_group_table']) . "\n";

  return drupal_render($render);
}

/**
 * Builds a table row for rendering.
 */
function _field_group_table_row_build($variables) {
  // Merge defaults.
  $variables += array(
    'row_class' => array(),
    'content_attributes' => array(),
  );

  $row = array(
    'data' => array(),
    'no_striping' => !$variables['settings']['table_row_striping'],
    'class' => $variables['row_class'],
  );

  switch ($variables['mode']) {
    case 'display':
      // In some cases (like with field extra fields) #title and #label_display
      // may not be set. In that case we try to use #label as the title instead,
      // as that is commonly used.
      $title = '';
      if (isset($variables['element']['#title'])) {
        $title = $variables['element']['#title'];
      }
      elseif (isset($variables['element']['#label'])) {
        $title = $variables['element']['#label'];
      }
      $label_display = isset($variables['element']['#label_display']) ? isset($variables['element']['#label_display']) : 'above';

      // Display the label in the first column, if 'always show field label' is
      // set.
      if ($variables['settings']['always_show_field_label']) {
        $row['data'][] = array(
          'data' => $title,
          'header' => TRUE,
          'class' => array('field-label'),
        );
      }
      // Display the label in the first column, if it's set to "above" and the
      // title isn't empty.
      elseif ($label_display == 'above' && $title != '') {
        $row['data'][] = array(
          'data' => $title,
          'header' => TRUE,
          'class' => array('field-label'),
        );

        // Do not display the label in the second column.
        $variables['element']['#label_display'] = 'hidden';
      }
      // Display an empty cell if we won't display the title and 'empty label
      // behavior' is set to keep empty label cells.
      elseif ($variables['settings']['empty_label_behavior'] == FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP) {
        $row['data'][] = array(
          'data' => '&nbsp;',
          'header' => TRUE,
          'class' => array('field-label', 'field-label-hidden'),
        );
      }
      // Otherwise we merge the cells.
      else {
        $variables['content_attributes']['colspan'] = 2;
      }

      break;

    case 'form':
      $class = array('field-label');

      list($title, $required) = field_group_table_find_element_title($variables['element']);

      if ($title != '' || ($title == '' && $variables['settings']['empty_label_behavior'] == FIELD_GROUP_TABLE_EMPTY_LABEL_KEEP)) {
        $row['data'][] = array(
          'data' => ($title == '') ? '&nbsp;' : array(
            '#type' => 'item',
            '#title' => $title,
            '#required' => $required,
          ),
          'header' => TRUE,
          'class' => $class,
        );
      }
      else {
        $variables['content_attributes']['colspan'] = 2;
      }

      break;
  }

  // Add the field's content.
  $row['data'][] = $variables['content_attributes'] + array(
    'data' => $variables['element'],
    'class' => array('field-content'),
  );

  return $row;
}

/**
 * Find first #title that is not that of a container, unset and return it.
 *
 * @param array $element
 * @return array(string, bool)|null
 */
function field_group_table_find_element_title(array &$element) {
  if (isset($element['#title']) && isset($element['#type']) && $element['#type'] !== 'container') {
    $title = $element['#title'];
    $required = $element['#required'];

    $element['#title'] = '';
    $element['#required'] = FALSE;

    return array($title, $required);
  }
  else {
    foreach (element_children($element) as $key) {
      if ($return = field_group_table_find_element_title($element[$key])) {
        return $return;
      }
    }
  }
}

/**
 * Implements hook_field_group_table_rows_alter().
 *
 * In some cases a child may be completely empty and therefore will be useless,
 * because it will render as an empty table row. See
 * http://drupal.org/node/1985606 for example. This function removes the most
 * common occurrences of empty rows.
 */
function field_group_table_field_group_table_rows_alter(&$element, &$children) {
  // Only operate on "display" mode.
  if ($element['#mode'] != 'display') {
    return;
  }

  $render_api_properties = array('#theme', '#markup', '#prefix', '#suffix');

  foreach ($children as $index => $child) {
    // A row containing another field group is not empty.
    if (in_array($child, $element['#groups'])) {
      continue;
    }

    // A row containing render API code is not empty.
    if (is_array($element[$child]) && array_intersect($render_api_properties, array_keys($element[$child]))) {
      continue;
    }

    // This an empty row, remove it.
    unset($children[$index]);
    unset($element[$child]);
  }
}