<?php

/**
 * @file
 * Provides the Views' administrative interface.
 */

use Drupal\Component\Utility\NestedArray;
use Drupal\views\ViewExecutable;
use Drupal\views\Views;

/**
 * Converts a form element in the add view wizard to be AJAX-enabled.
 *
 * This function takes a form element and adds AJAX behaviors to it such that
 * changing it triggers another part of the form to update automatically. It
 * also adds a submit button to the form that appears next to the triggering
 * element and that duplicates its functionality for users who do not have
 * JavaScript enabled (the button is automatically hidden for users who do have
 * JavaScript).
 *
 * To use this function, call it directly from your form builder function
 * immediately after you have defined the form element that will serve as the
 * JavaScript trigger. Calling it elsewhere (such as in hook_form_alter()) may
 * mean that the non-JavaScript fallback button does not appear in the correct
 * place in the form.
 *
 * @param $wrapping_element
 *   The element whose child will server as the AJAX trigger. For example, if
 *   $form['some_wrapper']['triggering_element'] represents the element which
 *   will trigger the AJAX behavior, you would pass $form['some_wrapper'] for
 *   this parameter.
 * @param $trigger_key
 *   The key within the wrapping element that identifies which of its children
 *   serves as the AJAX trigger. In the above example, you would pass
 *   'triggering_element' for this parameter.
 * @param $refresh_parents
 *   An array of parent keys that point to the part of the form that will be
 *   refreshed by AJAX. For example, if triggering the AJAX behavior should
 *   cause $form['dynamic_content']['section'] to be refreshed, you would pass
 *   array('dynamic_content', 'section') for this parameter.
 */
function views_ui_add_ajax_trigger(&$wrapping_element, $trigger_key, $refresh_parents) {
  $seen_ids = &drupal_static(__FUNCTION__ . ':seen_ids', array());
  $seen_buttons = &drupal_static(__FUNCTION__ . ':seen_buttons', array());

  // Add the AJAX behavior to the triggering element.
  $triggering_element = &$wrapping_element[$trigger_key];
  $triggering_element['#ajax']['callback'] = 'views_ui_ajax_update_form';
  // We do not use drupal_html_id() to get an ID for the AJAX wrapper, because
  // it remembers IDs across AJAX requests (and won't reuse them), but in our
  // case we need to use the same ID from request to request so that the
  // wrapper can be recognized by the AJAX system and its content can be
  // dynamically updated. So instead, we will keep track of duplicate IDs
  // (within a single request) on our own, later in this function.
  $triggering_element['#ajax']['wrapper'] = 'edit-view-' . implode('-', $refresh_parents) . '-wrapper';

  // Add a submit button for users who do not have JavaScript enabled. It
  // should be displayed next to the triggering element on the form.
  $button_key = $trigger_key . '_trigger_update';
  $wrapping_element[$button_key] = array(
    '#type' => 'submit',
    // Hide this button when JavaScript is enabled.
    '#attributes' => array('class' => array('js-hide')),
    '#submit' => array('views_ui_nojs_submit'),
    // Add a process function to limit this button's validation errors to the
    // triggering element only. We have to do this in #process since until the
    // form API has added the #parents property to the triggering element for
    // us, we don't have any (easy) way to find out where its submitted values
    // will eventually appear in $form_state['values'].
    '#process' => array_merge(array('views_ui_add_limited_validation'), element_info_property('submit', '#process', array())),
    // Add an after-build function that inserts a wrapper around the region of
    // the form that needs to be refreshed by AJAX (so that the AJAX system can
    // detect and dynamically update it). This is done in #after_build because
    // it's a convenient place where we have automatic access to the complete
    // form array, but also to minimize the chance that the HTML we add will
    // get clobbered by code that runs after we have added it.
    '#after_build' => array_merge(element_info_property('submit', '#after_build', array()), array('views_ui_add_ajax_wrapper')),
  );
  // Copy #weight and #access from the triggering element to the button, so
  // that the two elements will be displayed together.
  foreach (array('#weight', '#access') as $property) {
    if (isset($triggering_element[$property])) {
      $wrapping_element[$button_key][$property] = $triggering_element[$property];
    }
  }
  // For easiest integration with the form API and the testing framework, we
  // always give the button a unique #value, rather than playing around with
  // #name.
  $button_title = !empty($triggering_element['#title']) ? $triggering_element['#title'] : $trigger_key;
  if (empty($seen_buttons[$button_title])) {
    $wrapping_element[$button_key]['#value'] = t('Update "@title" choice', array(
      '@title' => $button_title,
    ));
    $seen_buttons[$button_title] = 1;
  }
  else {
    $wrapping_element[$button_key]['#value'] = t('Update "@title" choice (@number)', array(
      '@title' => $button_title,
      '@number' => ++$seen_buttons[$button_title],
    ));
  }

  // Attach custom data to the triggering element and submit button, so we can
  // use it in both the process function and AJAX callback.
  $ajax_data = array(
    'wrapper' => $triggering_element['#ajax']['wrapper'],
    'trigger_key' => $trigger_key,
    'refresh_parents' => $refresh_parents,
    // Keep track of duplicate wrappers so we don't add the same wrapper to the
    // page more than once.
    'duplicate_wrapper' => !empty($seen_ids[$triggering_element['#ajax']['wrapper']]),
  );
  $seen_ids[$triggering_element['#ajax']['wrapper']] = TRUE;
  $triggering_element['#views_ui_ajax_data'] = $ajax_data;
  $wrapping_element[$button_key]['#views_ui_ajax_data'] = $ajax_data;
}

/**
 * Processes a non-JavaScript fallback submit button to limit its validation errors.
 */
function views_ui_add_limited_validation($element, &$form_state) {
  // Retrieve the AJAX triggering element so we can determine its parents. (We
  // know it's at the same level of the complete form array as the submit
  // button, so all we have to do to find it is swap out the submit button's
  // last array parent.)
  $array_parents = $element['#array_parents'];
  array_pop($array_parents);
  $array_parents[] = $element['#views_ui_ajax_data']['trigger_key'];
  $ajax_triggering_element = NestedArray::getValue($form_state['complete_form'], $array_parents);

  // Limit this button's validation to the AJAX triggering element, so it can
  // update the form for that change without requiring that the rest of the
  // form be filled out properly yet.
  $element['#limit_validation_errors'] = array($ajax_triggering_element['#parents']);

  // If we are in the process of a form submission and this is the button that
  // was clicked, the form API workflow in form_builder() will have already
  // copied it to $form_state['triggering_element'] before our #process
  // function is run. So we need to make the same modifications in $form_state
  // as we did to the element itself, to ensure that #limit_validation_errors
  // will actually be set in the correct place.
  if (!empty($form_state['triggering_element'])) {
    $clicked_button = &$form_state['triggering_element'];
    if ($clicked_button['#name'] == $element['#name'] && $clicked_button['#value'] == $element['#value']) {
      $clicked_button['#limit_validation_errors'] = $element['#limit_validation_errors'];
    }
  }

  return $element;
}

/**
 * After-build function that adds a wrapper to a form region (for AJAX refreshes).
 *
 * This function inserts a wrapper around the region of the form that needs to
 * be refreshed by AJAX, based on information stored in the corresponding
 * submit button form element.
 */
function views_ui_add_ajax_wrapper($element, &$form_state) {
  // Don't add the wrapper <div> if the same one was already inserted on this
  // form.
  if (empty($element['#views_ui_ajax_data']['duplicate_wrapper'])) {
    // Find the region of the complete form that needs to be refreshed by AJAX.
    // This was earlier stored in a property on the element.
    $complete_form = &$form_state['complete_form'];
    $refresh_parents = $element['#views_ui_ajax_data']['refresh_parents'];
    $refresh_element = NestedArray::getValue($complete_form, $refresh_parents);

    // The HTML ID that AJAX expects was also stored in a property on the
    // element, so use that information to insert the wrapper <div> here.
    $id = $element['#views_ui_ajax_data']['wrapper'];
    $refresh_element += array(
      '#prefix' => '',
      '#suffix' => '',
    );
    $refresh_element['#prefix'] = '<div id="' . $id . '" class="views-ui-ajax-wrapper">' . $refresh_element['#prefix'];
    $refresh_element['#suffix'] .= '</div>';

    // Copy the element that needs to be refreshed back into the form, with our
    // modifications to it.
    NestedArray::setValue($complete_form, $refresh_parents, $refresh_element);
  }

  return $element;
}

/**
 * Updates a part of the add view form via AJAX.
 *
 * @return
 *   The part of the form that has changed.
 */
function views_ui_ajax_update_form($form, $form_state) {
  // The region that needs to be updated was stored in a property of the
  // triggering element by views_ui_add_ajax_trigger(), so all we have to do is
  // retrieve that here.
  return NestedArray::getValue($form, $form_state['triggering_element']['#views_ui_ajax_data']['refresh_parents']);
}

/**
 * Non-Javascript fallback for updating the add view form.
 */
function views_ui_nojs_submit($form, &$form_state) {
  $form_state['rebuild'] = TRUE;
}

/**
 * Form element validation handler for a taxonomy autocomplete field.
 *
 * This allows a taxonomy autocomplete field to be validated outside the
 * standard Field API workflow, without passing in a complete field widget.
 * Instead, all that is required is that $element['#field_name'] contain the
 * name of the taxonomy autocomplete field that is being validated.
 *
 * This function is currently not used for validation directly, although it
 * could be. Instead, it is only used to store the term IDs and vocabulary name
 * in the element value, based on the tags that the user typed in.
 *
 * @see taxonomy_autocomplete_validate()
 */
function views_ui_taxonomy_autocomplete_validate($element, &$form_state) {
  $value = array();
  if ($tags = $element['#value']) {
    // Get the machine names of the vocabularies we will search, keyed by the
    // vocabulary IDs.
    $field = field_info_field($element['#entity_type'], $element['#field_name']);
    $vocabularies = array();
    $allowed_values = $field->getSetting('allowed_values');
    if (!empty($allowed_values)) {
      foreach ($allowed_values as $tree) {
        if ($vocabulary = entity_load('taxonomy_vocabulary', $tree['vocabulary'])) {
          $vocabularies[$vocabulary->id()] = $tree['vocabulary'];
        }
      }
    }
    // Store the term ID of each (valid) tag that the user typed.
    $typed_terms = drupal_explode_tags($tags);
    foreach ($typed_terms as $typed_term) {
      if ($terms = entity_load_multiple_by_properties('taxonomy_term', array('name' => trim($typed_term), 'vid' => array_keys($vocabularies)))) {
        $term = array_pop($terms);
        $value['tids'][] = $term->id();
      }
    }
    // Store the term IDs along with the name of the vocabulary. Currently
    // Views (as well as the Field UI) assumes that there will only be one
    // vocabulary, although technically the API allows there to be more than
    // one.
    if (!empty($value['tids'])) {
      $value['tids'] = array_unique($value['tids']);
      $value['vocabulary'] = array_pop($vocabularies);
    }
  }
  form_set_value($element, $value, $form_state);
}

/**
 * Add a <select> dropdown for a given section, allowing the user to
 * change whether this info is stored on the default display or on
 * the current display.
 */
function views_ui_standard_display_dropdown(&$form, &$form_state, $section) {
  $view = $form_state['view'];
  $display_id = $form_state['display_id'];
  $executable = $view->getExecutable();
  $displays = $executable->displayHandlers;
  $current_display = $executable->display_handler;

  // @todo Move this to a separate function if it's needed on any forms that
  // don't have the display dropdown.
  $form['override'] = array(
    '#prefix' => '<div class="views-override clearfix container-inline" data-drupal-views-offset="top">',
    '#suffix' => '</div>',
    '#weight' => -1000,
    '#tree' => TRUE,
  );

  // Add the "2 of 3" progress indicator.
  if ($form_progress = $view->getFormProgress()) {
    $form['progress']['#markup'] = '<div id="views-progress-indicator">' . t('@current of @total', array('@current' => $form_progress['current'], '@total' => $form_progress['total'])) . '</div>';
    $form['progress']['#weight'] = -1001;
  }

  if ($current_display->isDefaultDisplay()) {
    return;
  }

  // Determine whether any other displays have overrides for this section.
  $section_overrides = FALSE;
  $section_defaulted = $current_display->isDefaulted($section);
  foreach ($displays as $id => $display) {
    if ($id === 'default' || $id === $display_id) {
      continue;
    }
    if ($display && !$display->isDefaulted($section)) {
      $section_overrides = TRUE;
    }
  }

  $display_dropdown['default'] = ($section_overrides ? t('All displays (except overridden)') : t('All displays'));
  $display_dropdown[$display_id] = t('This @display_type (override)', array('@display_type' => $current_display->getPluginId()));
  // Only display the revert option if we are in a overridden section.
  if (!$section_defaulted) {
    $display_dropdown['default_revert'] = t('Revert to default');
  }

  $form['override']['dropdown'] = array(
    '#type' => 'select',
    '#title' => t('For'), // @TODO: Translators may need more context than this.
    '#options' => $display_dropdown,
  );
  if ($current_display->isDefaulted($section)) {
    $form['override']['dropdown']['#default_value'] = 'defaults';
  }
  else {
    $form['override']['dropdown']['#default_value'] = $display_id;
  }

}

/**
 * Create the menu path for one of our standard AJAX forms based upon known
 * information about the form.
 */
function views_ui_build_form_path($form_state) {
  $ajax = empty($form_state['ajax']) ? 'nojs' : 'ajax';
  $name = $form_state['view']->id();
  $path = "admin/structure/views/$ajax/$form_state[form_key]/$name/$form_state[display_id]";
  if (isset($form_state['type'])) {
    $path .= '/' . $form_state['type'];
  }
  if (isset($form_state['id'])) {
    $path .= '/' . $form_state['id'];
  }
  return $path;
}

/**
 * #process callback for a button; determines if a button is the form's triggering element.
 *
 * The Form API has logic to determine the form's triggering element based on
 * the data in POST. However, it only checks buttons based on a single #value
 * per button. This function may be added to a button's #process callbacks to
 * extend button click detection to support multiple #values per button. If the
 * data in POST matches any value in the button's #values array, then the
 * button is detected as having been clicked. This can be used when the value
 * (label) of the same logical button may be different based on context (e.g.,
 * "Apply" vs. "Apply and continue").
 *
 * @see _form_builder_handle_input_element()
 * @see _form_button_was_clicked()
 */
function views_ui_form_button_was_clicked($element, &$form_state) {
  $process_input = empty($element['#disabled']) && ($form_state['programmed'] || ($form_state['process_input'] && (!isset($element['#access']) || $element['#access'])));
  if ($process_input && !isset($form_state['triggering_element']) && !empty($element['#is_button']) && isset($form_state['input'][$element['#name']]) && isset($element['#values']) && in_array($form_state['input'][$element['#name']], $element['#values'], TRUE)) {
    $form_state['triggering_element'] = $element;
  }
  return $element;
}