<?php
/**
 * @file
 * Globally available functions for Rules' Views integration.
 */

function rb_views_views_api() {
  return array(
    'api' => 3,
    'path' => drupal_get_path('module', 'rb_views') . '/views',
  );
}

/**
 * Implements of hook_views_pre_execute().
 *
 * @param $view
 *   The view object that is going to be executed.
 */
function rb_views_views_pre_build($view) {
  // Get a light-weight and easy-to-handle representation of the view.
  $view_representation = rb_views_create_view_representation($view);

  // Call the Rules event, passing along the view representation.
  rules_invoke_event('rb_views_event_view_execute', $view_representation);

  // Update the original view according to changes in the representation.
  rb_view_update_real_view($view, $view_representation);
}

/**
 * Implements of hook_views_pre_render().
 *
 * @param $view
 *   The view object that is going to be rendered.
 */
function rb_views_views_pre_render($view) {
  $view_representation = rb_views_create_view_representation($view);
  rules_invoke_event('rb_views_event_view_render', $view_representation);
  rb_view_update_real_view($view, $view_representation);
}

/**
 * Implements of hook_views_post_render().
 *
 * @param $view
 *   The view object that has been rendered.
 */
function rb_views_views_post_render($view, $output, $cache) {
  $view_representation = rb_views_create_view_representation($view);
  rules_invoke_event('rb_views_event_view_complete', $view_representation);
  rb_view_update_real_view($view, $view_representation);
}

/**
 * Creates a new view representation array from a given view object.
 *
 * This object is used to avoid having Rules copying the quite large view data
 * object when doing different operations. And also to make a few view
 * properties easier to access.
 *
 * @param $view
 *   The full view object. (This is passed by reference to avoid copying the
 *   actual view just for creating a light-weight representation.)
 * @return
 *   An array with a few view properties relevant for Rules.
 */
function rb_views_create_view_representation(view $view) {
  $view_representation = new stdClass();
  // Set all simple non-writable properties.
  foreach (rb_views_get_nonwritable_representation_properties() as $representation_property => $view_property) {
    $view_representation->$representation_property = $view->$view_property;
  }

  // Set all simple writable properties, too.
  foreach (rb_views_get_writable_representation_properties() as $representation_property => $view_property) {
    $view_representation->$representation_property = $view->$view_property;
  }

  // Set the handler properties.
  foreach (rb_views_get_views_handlers() as $handler_type => $handler_label) {
	if(isset($view->$handler_type)) {
      $view_representation->$handler_type = array_keys($view->$handler_type);
    }
  }

  return $view_representation;
}

/**
 * Updates a view object according to any changes made to a view representation.
 *
 * @param $view
 *   The view to update. Passed by argument.
 * @param $view_representation
 *   The view representation, containing information about any updates that
 *   should be make to the view.
 */
function rb_view_update_real_view(view $view, $view_representation) {
  // Update all simple (writable) properties.
  foreach (rb_views_get_writable_representation_properties() as $representation_property => $view_property) {
    $view->$view_property = $view_representation->$representation_property;
  }

  // Check each handler type, to see if any handler has been modified.
  foreach (rb_views_get_views_handlers() as $handler_name => $handler_label) {
    if (isset($view->{$handler_name}) && (array_keys($view->{$handler_name}) != $view_representation->{$handler_name})) {
      // If handlers of a type has been modified, build a new list of handler
      // instances according to the view representation, and update the real
      // view.
      $updated_handlers = array();
      foreach ($view_representation->{$handler_name} as $handler_id) {
        $updated_handlers[$handler_id] = $view->{$handler_name}[$handler_id];
      }
      $view->{$handler_name} = $updated_handlers;
    }
  }
}

/**
 * Returns an array of non-handler properties for view representations.
 *
 * The returned array is keyed with the representation name, with each value
 * being the property name used in the real view.
 */
function rb_views_get_nonwritable_representation_properties() {
  return array(
    'machine_name' => 'name',
    'display' => 'current_display',
    'human_name' => 'human_name',
    'base_table' => 'base_table',
    'total_rows' => 'total_rows',
  );
}

/**
 * Returns an array of non-handler properties for view representations.
 *
 * The returned array is keyed with the representation name, with each value
 * being the property name used in the real view.
 */
function rb_views_get_writable_representation_properties() {
  return array(
    'args' => 'args',
    'current_page' => 'current_page',
    'items_per_page' => 'items_per_page',
    'offset' => 'offset',
  );
}

/**
 * Returns a list of all handler types for Views, plus handler labels.
 */
function rb_views_get_views_handlers() {
  return array(
    'field' => t('View field'),
    'argument' => t('Contextual filter'),
    'sort' => t('Sort criteria'),
    'filter' => t('Filter'),
    'relationship' => t('Relationship'),
    'header' => t('Header'),
    'footer' => t('Footer'),
    'empty' => t('No result reaction'),
  );
}

/**
 * Class defining the Views argument validator plugin.
 */
class RbViewsArgumentValidator extends RulesRuleSet {

  protected $itemName = 'views argument validator';

  /**
   * Override to set the provided and required variables to fixed sets.
   */
  public function __construct($variables = array(), $providesVars = array()) {
    // Set some fixed variables used by this type of plugin. (Editing of these
    // is disabled.)
    $variables = array(
      'arg' => array(
        'type' => 'text',
        'label' => t('Argument'),
      ),
      'args' => array(
        'type' => 'list<text>',
        'label' => t('All arguments'),
      ),
      'validation' => array(
        'type' => 'boolean',
        'label' => t('Validation value'),
        'parameter' => FALSE,
      ),
    );

    $providesVars = array('arg', 'args', 'validation');

    parent::__construct($variables);
    // The provided vars of a component are the names of variables, which should
    // be provided to the caller. See rule().
    if ($providesVars) {
      $this->info['provides'] = $providesVars;
    }
  }
}

/**
 * Class defining the UI for the Views argument validator plugin.
 */
class RbViewsArgumentValidatorUI extends RulesRuleSetUI {
  // Override form to hide the variables settings.
  public function form(&$form, &$form_state, $options = array(), $iterator = NULL) {
    // Pass an iterator just iterating over the rules, thus no further child
    // elements will be displayed.
    parent::form($form, $form_state, $options, $this->element->getIterator());
    $form['settings']['vars']['#access'] = FALSE;
  }
}