ExifWidgetBase.php

<?php

namespace Drupal\exif\Plugin\Field\FieldWidget;

use Drupal;
use Drupal\Core\Field\WidgetBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\field\Entity\FieldConfig;

/**
 * Base class for 'Exif Field widget' plugin implementations.
 *
 * @ingroup field_widget
 */
abstract class ExifWidgetBase extends WidgetBase {
    const EXIF_BASE_DEFAULT_SETTINGS = [
        'image_field' => NULL,
    ];
    
    /**
     * {@inheritdoc}
     */
    public static function defaultSettings() {
        return ExifWidgetBase::EXIF_BASE_DEFAULT_SETTINGS + parent::defaultSettings();
    }
    
    /**
     * Validate field to ensure it is linked to a image field.
     *
     * Use in settingsForm callback.
     *
     * @param array $element
     *   A form element array containing basic properties for the widget.
     * @param \Drupal\Core\Form\FormStateInterface $form_state
     *   The current state of the form.
     * @param array $form
     *   The form structure where widgets are being attached to.
     */
    public static function validateImageField(array $element, FormStateInterface $form_state, array $form) {
        $elementSettings = $form_state->getValue($element['#parents']);
        if (!$elementSettings) {
            $field_storage_definitions = Drupal::getContainer()->get('entity_field.manager')
                ->getFieldStorageDefinitions($form['#entity_type']);
            $field_storage = $field_storage_definitions[$element['#field_name']];
            if ($field_storage) {
                $args = [
                    '%field' => $field_storage->getName(),
                ];
                $message = t('Field %field must be link to an image field.', $args);
            }
            else {
                $message = t('Field must be link to an image field.');
            }
            $form_state->setErrorByName('image_field', $message);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function settingsForm(array $form, FormStateInterface $form_state) {
        $element = parent::settingsForm($form, $form_state);
        if ($form['#entity_type'] == "node" || $form['#entity_type'] == "media") {
            $image_fields = $this->retrieveImageFieldFromBundle($form['#entity_type'], $form['#bundle']);
            $default_image_value = $this->retrieveImageFieldDefaultValue($element, $image_fields);
            $element['image_field'] = [
                '#type' => 'radios',
                '#title' => t('image field to use to retrieve data'),
                '#description' => t('determine the image used to look for exif and iptc metadata'),
                '#options' => $image_fields,
                '#default_value' => $default_image_value,
                '#element_validate' => [
                    [
                        get_class($this),
                        'validateImageField',
                    ],
                ],
            ];
        }
        if ($form['#entity_type'] == "file") {
            $element['image_field'] = [
                '#type' => 'hidden',
                '#default_value' => "file",
                '#value' => "file",
            ];
        }
        return $element;
    }
    
    /**
     * {@inheritdoc}
     */
    public function settingsSummary() {
        $summary = parent::settingsSummary();
        $image_field = $this->getSetting('image_field');
        if (isset($image_field)) {
            $bundle_name = $this->fieldDefinition
                ->getTargetBundle();
            $entity_type = $this->fieldDefinition
                ->getTargetEntityTypeId();
            $image_field_config = Drupal::getContainer()->get('entity_field.manager')
                ->getFieldDefinitions($entity_type, $bundle_name)[$image_field];
            if ($image_field_config instanceof FieldConfig) {
                if ($image_field_config->getType() == "image" || $image_field_config->getType() == "media") {
                    $label = t("'@image_linked_label' (id: @image_linked_id)", [
                        '@image_linked_label' => $image_field_config->getLabel(),
                        '@image_linked_id' => $image_field,
                    ]);
                }
                else {
                    $label = $image_field;
                }
            }
            $image_field_msg = t("exif will be extracted from image field @image", [
                '@image' => $label,
            ]);
        }
        else {
            $image_field_msg = t('No image chosen. field will stay empty.');
        }
        array_unshift($summary, $image_field_msg);
        return $summary;
    }
    
    /**
     * Retrieve list of image field labels by key of image field.
     *
     * @param string $entity_type
     *   Entity Type name.
     * @param string $bundle_name
     *   Name bundle.
     *
     * @return array
     *   Map of all images fields contained in this bundle by key and description.
     */
    protected function retrieveImageFieldFromBundle($entity_type, $bundle_name) {
        $fields_of_bundle = Drupal::getContainer()->get('entity_field.manager')
            ->getFieldDefinitions($entity_type, $bundle_name);
        $result = [];
        foreach ($fields_of_bundle as $key => $value) {
            if ($value instanceof FieldConfig) {
                if (in_array($value->getType(), [
                    'image',
                    'media',
                    'file',
                ])) {
                    $result[$key] = $value->getLabel() . " (" . $key . ")";
                }
            }
        }
        return $result;
    }
    
    /**
     * Calculate default value for settings form.
     *
     * More precisely, it calculate default value
     * for image_field setting of widget.
     *
     * simple implementation: Look for the first image field found.
     *
     * @param array $widget
     *   Widget we are checking.
     * @param array $image_fields
     *   Image fields links to this widget.
     *
     * @return string
     *   First image field found or NULL if none.
     */
    protected function retrieveImageFieldDefaultValue(array $widget, array $image_fields) {
        if (array_key_exists('settings', $widget) && array_key_exists('image_field', $widget['settings'])) {
            $result = $widget['settings']['image_field'];
        }
        else {
            $result = NULL;
        }
        if (empty($result)) {
            // Look for the first image field found.
            $temp = array_keys($image_fields);
            if (!empty($temp) && is_array($temp)) {
                $result = $temp[0];
            }
        }
        return $result;
    }

}