class ImageStyleEditForm

class ImageStyleEditForm extends ImageStyleFormBase {
    
    /**
     * The image effect manager service.
     *
     * @var \Drupal\image\ImageEffectManager
     */
    protected $imageEffectManager;
    
    /**
     * Constructs an ImageStyleEditForm object.
     *
     * @param \Drupal\Core\Entity\EntityStorageInterface $image_style_storage
     *   The storage.
     * @param \Drupal\image\ImageEffectManager $image_effect_manager
     *   The image effect manager service.
     */
    public function __construct(EntityStorageInterface $image_style_storage, ImageEffectManager $image_effect_manager) {
        parent::__construct($image_style_storage);
        $this->imageEffectManager = $image_effect_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container) {
        return new static($container->get('entity_type.manager')
            ->getStorage('image_style'), $container->get('plugin.manager.image.effect'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function form(array $form, FormStateInterface $form_state) {
        $user_input = $form_state->getUserInput();
        $form['#title'] = $this->t('Edit style %name', [
            '%name' => $this->entity
                ->label(),
        ]);
        $form['#tree'] = TRUE;
        $form['#attached']['library'][] = 'image/admin';
        // Show the thumbnail preview.
        $preview_arguments = [
            '#theme' => 'image_style_preview',
            '#style' => $this->entity,
        ];
        $form['preview'] = [
            '#type' => 'item',
            '#title' => $this->t('Preview (Click for actual images)'),
            '#markup' => \Drupal::service('renderer')->render($preview_arguments),
            // Render preview above parent elements.
'#weight' => -5,
        ];
        // Build the list of existing image effects for this image style.
        $form['effects'] = [
            '#type' => 'table',
            '#header' => [
                $this->t('Effect'),
                $this->t('Weight'),
                $this->t('Operations'),
            ],
            '#tabledrag' => [
                [
                    'action' => 'order',
                    'relationship' => 'sibling',
                    'group' => 'image-effect-order-weight',
                ],
            ],
            '#attributes' => [
                'id' => 'image-style-effects',
            ],
            '#empty' => $this->t('There are currently no effects in this style. Add one by selecting an option below.'),
            // Render effects below parent elements.
'#weight' => 5,
        ];
        foreach ($this->entity
            ->getEffects() as $effect) {
            $key = $effect->getUuid();
            $form['effects'][$key]['#attributes']['class'][] = 'draggable';
            $form['effects'][$key]['#weight'] = isset($user_input['effects']) ? $user_input['effects'][$key]['weight'] : NULL;
            $form['effects'][$key]['effect'] = [
                '#tree' => FALSE,
                'data' => [
                    'label' => [
                        '#plain_text' => $effect->label(),
                    ],
                ],
            ];
            $summary = $effect->getSummary();
            if (!empty($summary)) {
                $summary['#prefix'] = ' ';
                $form['effects'][$key]['effect']['data']['summary'] = $summary;
            }
            $form['effects'][$key]['weight'] = [
                '#type' => 'weight',
                '#title' => $this->t('Weight for @title', [
                    '@title' => $effect->label(),
                ]),
                '#title_display' => 'invisible',
                '#default_value' => $effect->getWeight(),
                '#attributes' => [
                    'class' => [
                        'image-effect-order-weight',
                    ],
                ],
            ];
            $links = [];
            $is_configurable = $effect instanceof ConfigurableImageEffectInterface;
            if ($is_configurable) {
                $links['edit'] = [
                    'title' => $this->t('Edit'),
                    'url' => Url::fromRoute('image.effect_edit_form', [
                        'image_style' => $this->entity
                            ->id(),
                        'image_effect' => $key,
                    ]),
                ];
            }
            $links['delete'] = [
                'title' => $this->t('Delete'),
                'url' => Url::fromRoute('image.effect_delete', [
                    'image_style' => $this->entity
                        ->id(),
                    'image_effect' => $key,
                ]),
            ];
            $form['effects'][$key]['operations'] = [
                '#type' => 'operations',
                '#links' => $links,
            ];
        }
        // Build the new image effect addition form and add it to the effect list.
        $new_effect_options = [];
        $effects = $this->imageEffectManager
            ->getDefinitions();
        uasort($effects, function ($a, $b) {
            return Unicode::strcasecmp($a['label'], $b['label']);
        });
        foreach ($effects as $effect => $definition) {
            $new_effect_options[$effect] = $definition['label'];
        }
        $form['effects']['new'] = [
            '#tree' => FALSE,
            '#weight' => $user_input['weight'] ?? NULL,
            '#attributes' => [
                'class' => [
                    'draggable',
                ],
            ],
        ];
        $form['effects']['new']['effect'] = [
            'data' => [
                'new' => [
                    '#type' => 'select',
                    '#title' => $this->t('Effect'),
                    '#title_display' => 'invisible',
                    '#options' => $new_effect_options,
                    '#empty_option' => $this->t('Select a new effect'),
                ],
                [
                    'add' => [
                        '#type' => 'submit',
                        '#value' => $this->t('Add'),
                        '#validate' => [
                            '::effectValidate',
                        ],
                        '#submit' => [
                            '::submitForm',
                            '::effectSave',
                        ],
                    ],
                ],
            ],
            '#prefix' => '<div class="image-style-new">',
            '#suffix' => '</div>',
        ];
        $form['effects']['new']['weight'] = [
            '#type' => 'weight',
            '#title' => $this->t('Weight for new effect'),
            '#title_display' => 'invisible',
            '#default_value' => count($this->entity
                ->getEffects()) + 1,
            '#attributes' => [
                'class' => [
                    'image-effect-order-weight',
                ],
            ],
        ];
        $form['effects']['new']['operations'] = [
            'data' => [],
        ];
        return parent::form($form, $form_state);
    }
    
    /**
     * Validate handler for image effect.
     */
    public function effectValidate($form, FormStateInterface $form_state) {
        if (!$form_state->getValue('new')) {
            $form_state->setErrorByName('new', $this->t('Select an effect to add.'));
        }
    }
    
    /**
     * Submit handler for image effect.
     */
    public function effectSave($form, FormStateInterface $form_state) {
        $this->save($form, $form_state);
        // Check if this field has any configuration options.
        $effect = $this->imageEffectManager
            ->getDefinition($form_state->getValue('new'));
        // Load the configuration form for this option.
        if (is_subclass_of($effect['class'], '\\Drupal\\image\\ConfigurableImageEffectInterface')) {
            $form_state->setRedirect('image.effect_add_form', [
                'image_style' => $this->entity
                    ->id(),
                'image_effect' => $form_state->getValue('new'),
            ], [
                'query' => [
                    'weight' => $form_state->getValue('weight'),
                ],
            ]);
            $form_state->setIgnoreDestination();
        }
        else {
            $effect = [
                'id' => $effect['id'],
                'data' => [],
                'weight' => $form_state->getValue('weight'),
            ];
            $effect_id = $this->entity
                ->addImageEffect($effect);
            $this->entity
                ->save();
            if (!empty($effect_id)) {
                $this->messenger()
                    ->addStatus($this->t('The image effect was successfully applied.'));
            }
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function submitForm(array &$form, FormStateInterface $form_state) {
        // Update image effect weights.
        if (!$form_state->isValueEmpty('effects')) {
            $this->updateEffectWeights($form_state->getValue('effects'));
        }
        parent::submitForm($form, $form_state);
    }
    
    /**
     * {@inheritdoc}
     */
    public function save(array $form, FormStateInterface $form_state) {
        parent::save($form, $form_state);
        $this->messenger()
            ->addStatus($this->t('Changes to the style have been saved.'));
    }
    
    /**
     * Updates image effect weights.
     *
     * @param array $effects
     *   Associative array with effects having effect uuid as keys and array
     *   with effect data as values.
     */
    protected function updateEffectWeights(array $effects) {
        foreach ($effects as $uuid => $effect_data) {
            if ($this->entity
                ->getEffects()
                ->has($uuid)) {
                $this->entity
                    ->getEffect($uuid)
                    ->setWeight($effect_data['weight']);
            }
        }
    }

}