class ThemeSuggestionsAlterTest

class ThemeSuggestionsAlterTest extends BrowserTestBase {
  
  /**
   * Modules to enable.
   *
   * @var array
   */
  protected static $modules = [
    'theme_test',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * {@inheritdoc}
   */
  protected function setUp() : void {
    parent::setUp();
    \Drupal::service('theme_installer')->install([
      'test_theme',
    ]);
  }
  
  /**
   * Tests that hooks to provide theme suggestions work.
   */
  public function testTemplateSuggestions() {
    $this->drupalGet('theme-test/suggestion-provided');
    $this->assertSession()
      ->pageTextContains('Template for testing suggestions provided by the module declaring the theme hook.');
    // Install test_theme, it contains a template suggested by theme_test.module
    // in theme_test_theme_suggestions_theme_test_suggestion_provided().
    $this->config('system.theme')
      ->set('default', 'test_theme')
      ->save();
    $this->drupalGet('theme-test/suggestion-provided');
    $this->assertSession()
      ->pageTextContains('Template overridden based on suggestion provided by the module declaring the theme hook.');
  }
  
  /**
   * Tests hook_theme_suggestions_alter().
   */
  public function testGeneralSuggestionsAlter() {
    $this->drupalGet('theme-test/general-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Original template for testing hook_theme_suggestions_alter().');
    // Install test_theme and test that themes can alter template suggestions.
    $this->config('system.theme')
      ->set('default', 'test_theme')
      ->save();
    $this->drupalGet('theme-test/general-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template overridden based on new theme suggestion provided by the test_theme theme via hook_theme_suggestions_alter().');
    // Enable the theme_suggestions_test module to test modules implementing
    // suggestions alter hooks.
    \Drupal::service('module_installer')->install([
      'theme_suggestions_test',
    ]);
    $this->resetAll();
    $this->drupalGet('theme-test/general-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template overridden based on new theme suggestion provided by a module via hook_theme_suggestions_alter().');
  }
  
  /**
   * Tests that theme suggestion alter hooks work for templates.
   */
  public function testTemplateSuggestionsAlter() {
    $this->drupalGet('theme-test/suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Original template for testing hook_theme_suggestions_HOOK_alter().');
    // Install test_theme and test that themes can alter template suggestions.
    $this->config('system.theme')
      ->set('default', 'test_theme')
      ->save();
    $this->drupalGet('theme-test/suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template overridden based on new theme suggestion provided by the test_theme theme via hook_theme_suggestions_HOOK_alter().');
    // Enable the theme_suggestions_test module to test modules implementing
    // suggestions alter hooks.
    \Drupal::service('module_installer')->install([
      'theme_suggestions_test',
    ]);
    $this->resetAll();
    $this->drupalGet('theme-test/suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template overridden based on new theme suggestion provided by a module via hook_theme_suggestions_HOOK_alter().');
  }
  
  /**
   * Tests that theme suggestion alter hooks work for specific theme calls.
   */
  public function testSpecificSuggestionsAlter() {
    // Test that the default template is rendered.
    $this->drupalGet('theme-test/specific-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template for testing specific theme calls.');
    $this->config('system.theme')
      ->set('default', 'test_theme')
      ->save();
    // Test a specific theme call similar to '#theme' => 'node__article'.
    $this->drupalGet('theme-test/specific-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template matching the specific theme call.');
    $this->assertSession()
      ->pageTextContains('theme_test_specific_suggestions__variant');
    // Ensure that the base hook is used to determine the suggestion alter hook.
    \Drupal::service('module_installer')->install([
      'theme_suggestions_test',
    ]);
    $this->resetAll();
    $this->drupalGet('theme-test/specific-suggestion-alter');
    $this->assertSession()
      ->pageTextContains('Template overridden based on suggestion alter hook determined by the base hook.');
    $raw_content = $this->getSession()
      ->getPage()
      ->getContent();
    // Verify that a specific theme call is added to the suggestions array
    // before the suggestions alter hook.
    $this->assertLessThan(strpos($raw_content, 'theme_test_specific_suggestions__variant__foo'), strpos($raw_content, 'theme_test_specific_suggestions__variant'));
  }
  
  /**
   * Tests execution order of theme suggestion alter hooks.
   *
   * Hook hook_theme_suggestions_alter() should fire before
   * hook_theme_suggestions_HOOK_alter() within an extension (module or theme).
   */
  public function testExecutionOrder() {
    // Install our test theme and module.
    $this->config('system.theme')
      ->set('default', 'test_theme')
      ->save();
    \Drupal::service('module_installer')->install([
      'theme_suggestions_test',
    ]);
    $this->resetAll();
    // Send two requests so that we get all the messages we've set via
    // \Drupal\Core\Messenger\MessengerInterface::addStatus().
    $this->drupalGet('theme-test/suggestion-alter');
    // Ensure that the order is first by extension, then for a given extension,
    // the hook-specific one after the generic one.
    $expected_order = [
      'theme_suggestions_test_theme_suggestions_alter() executed.',
      'theme_suggestions_test_theme_suggestions_theme_test_suggestions_alter() executed.',
      'theme_test_theme_suggestions_alter() executed for theme_test_suggestions.',
      'theme_test_theme_suggestions_theme_test_suggestions_alter() executed.',
      'test_theme_theme_suggestions_alter() executed.',
      'test_theme_theme_suggestions_theme_test_suggestions_alter() executed.',
    ];
    $content = preg_replace('/\\s+/', ' ', Xss::filter($this->getSession()
      ->getPage()
      ->getContent(), []));
    $order = 0;
    foreach ($expected_order as $expected_string) {
      $this->assertGreaterThan($order, strpos($content, $expected_string));
      $order = strpos($content, $expected_string);
    }
  }

}