<?php
// $Id$

/**
 * @file
 * The Filter By Node Type module, which makes input filter configurable on a per-content-type basis.
 *
 * Drupal core gives you no possibility to limit given input filters to a defined set of
 * content types. This functionality is provided by the Filter By Node Type module. Common usage
 * examples are:
 *  - a designated filter for forums, blog entries etc. etc.
 */

/**
 * Implementation of hook_perm().
 */
function filterbynodetype_perm() {
  return array('bypass filter restrictions');
}

/**
 * Implementation of hook_form_alter().
 *
 * Allow users with the necessary permission to change what input formats
 * are allowed on a give node type.
 */
function filterbynodetype_form_node_type_form_alter(&$form, $form_state) {

  $options = array();
  foreach (filter_formats() as $format) {
    $options[$format->format] = $format->name;
  }

  $defaults = array();
  foreach (filter_formats() as $format) {
    $defaults[] = variable_get('filterbynodetype_' . $format->format . '_' . $form['#node_type']->type, 1);
  }

  $form['submission']['input_formats'] = array(
    '#type' => 'checkboxes',
    '#title' => t('Allowed input formats'),
    '#description' => t('Specify which input formats will be allowed on this node type\'s body field.  Note that a user must still have access to the appropriate input format in order to be able to use it.'),
    '#options' => $options,
    '#default_value' => $defaults,
    '#access' => user_access('adminster filters'),
  );

  // Attach our submit handler so we can save our extra values.
  $form['#submit'][] = 'filterbynodetype_node_type_form_submit';
}

/**
 * Submit function for our admin form additions
 *
 * @see filterbynodetype_form_node_type_form_alter()
 */
function filterbynodetype_node_type_form_submit($form, &$form_state) {
  $form_values = $form_state['values'];
  foreach (filter_formats() as $format) {
    variable_set('filterbynodetype_' . $format->format . '_' . $form_values['type'], $form_values['input_formats'][$format->format]);
  }
}

/**
 * Implementation of hook_form_alter().
 */
function filterbynodetype_form_alter(&$form, $form_state, $form_id) {

  // For node edit forms, filter out disallowed input formats.
  if (isset($form['#node']) && $form['#node']->type .'_node_form' == $form_id && !user_access('bypass filter restrictions')) {
    $type = $form['type']['#value'];
    $formats =& $form['body_field']['format'];
    foreach (element_children($formats) as $element) {
      if (isset($formats[$element]['#return_value']) && ! variable_get('filterbynodetype_' . $formats[$element]['#return_value'] . '_' . $type, 1)) {
        unset($formats[$element]);
      }
    }

    if (2 == count(element_children($formats))) { // 1 format and 1 extra item for the link
      // If there's only one filter left, fold it down to just the description
      $formats = $form['body_field']['format'];
      unset($form['body_field']['format']);
      // We don't know what the IDs are of the two fields, so we have to iterate to get them.
      foreach (element_children($formats) as $element) {
        if (isset($formats[$element]['#title'])) {
          // This is a filter, so we assign it to the filter set as the only option.
          $form['body_field']['format'][$element] = array(
            '#type' => 'value',
            '#value' => $element,
            '#parents' => array('format'),
          );
          $form['body_field']['format']['format'] = array( // I have no idea why it uses this structure, but this is what filter.module does.
            '#type' => 'item',
            '#description' => $formats[$element]['#description'],
          );
        }
        else {
          // It's the guidelines text.
          $form['body_field']['format']['guidelines_link'] = array(
            '#value' => $formats[$element]['#value'],
          );
        }
      }
    }
    if (1 == count(element_children($formats))) { // 1 extra item for the link, which means there's no filters left
      // Do nothing.  The form becomes unsubmittable all on its own.
    }
  }
}