/**
* {@inheritdoc}
*/
protected function preprocessVariables(Variables $variables, $hook, array $info)
{
// Retrieve the ID, generating one if needed.
$id = $variables->getAttribute('id', Html::getUniqueId($variables->offsetGet('id', 'bootstrap-panel')));
unset($variables['id']);
// Handle collapsible state.
if ($variables['heading'] && $variables['collapsible']) {
// Retrieve the body ID attribute.
if ($body_id = $variables->getAttribute('id', "{$id}--content", 'body_attributes')) {
// Ensure the target is set.
if ($variables['target'] = $variables->offsetGet('target', "#{$body_id}")) {
// Set additional necessary attributes to the heading.
$variables->setAttributes(['aria-controls' => preg_replace('/^#/', '', $variables['target']), 'aria-expanded' => !$variables['collapsed'] ? 'true' : 'false', 'aria-pressed' => !$variables['collapsed'] ? 'true' : 'false', 'data-toggle' => 'collapse', 'role' => 'button'], 'heading_attributes');
}
}
}
// Ensure there is a valid panel state.
if (!$variables->offsetGet('panel_type')) {
$variables->offsetSet('panel_type', 'default');
}
// Convert the description variable.
$this->preprocessDescription($variables, $hook, $info);
// Ensure all attributes are proper objects.
$this->preprocessAttributes($variables, $hook, $info);
}
