<?php

/**
 * @file
 * Module file for block_example.
 */

use Drupal\Component\Utility\Unicode;
use Drupal\Core\Block\BlockPluginInterface;

/**
 * @defgroup block_example Example: Block
 * @ingroup examples
 * @{
 * Demonstrates code creation of blocks.
 *
 * This is an example outlining how a module can define blocks that can be
 * displayed on various pages of a site, or how to alter blocks provided by
 * other modules.
 */

/**
 * Implements hook_block_view_alter().
 *
 * This hook allows you to modify the output of any block in the system.
 *
 * In addition, instead of hook_block_view_alter(), which is called for all
 * blocks, you can also use hook_block_view_MODULE_DELTA_alter() to alter a
 * specific block. To change only our block using
 * hook_block_view_MODULE_DELTA_alter, we would use the function:
 * block_example_block_view_block_example_example_configurable_text_alter()
 *
 * We are going to uppercase the subject (the title of the block as shown to the
 * user) of any block if the string "uppercase" appears in the block title or
 * subject. Default block titles are set programmatically in the subject key;
 * titles created through the UI are saved in the title key. This module creates
 * an example block to demonstrate this effect (default title set
 * programmatically as subject).  You can also demonstrate the effect of this
 * hook by creating a new block whose title has the string 'uppercase' in it
 * (set as title through the UI).
 */
function block_example_block_view_alter(array &$build, BlockPluginInterface $block) {
  // We'll search for the string 'uppercase'.
  $definition = $block->getPluginDefinition();
  if ((!empty($build['#configuration']['label']) && stristr($build['#configuration']['label'], 'uppercase')) || (!empty($definition['subject']) && stristr($definition['subject'], 'uppercase'))) {
    // This will uppercase the block title.
    $build['#configuration']['label'] = Unicode::strtoupper($build['#configuration']['label']);
  }
}

/**
 * @} End of "defgroup block_example".
 */