class IconExtractorSettingsForm

class IconExtractorSettingsForm {
    protected const COLOR_TYPE = 'color';
    
    /**
     * Create the Drupal Form API element from the settings.
     *
     * The generated form support default from the 'saved_value' key in the form
     * state. This value is set in IconPackManager::getExtractorPluginForms().
     *
     * @param array $settings
     *   The settings from the icon pack definition.
     * @param \Drupal\Core\Form\FormStateInterface|null $form_state
     *   The from state used to get values if no form context.
     *
     * @return array
     *   The form API generated.
     */
    public static function generateSettingsForm(array $settings, ?FormStateInterface $form_state = NULL) : array {
        $saved_values = $form_state ? $form_state->getCompleteFormState()
            ->getValue('saved_values') ?? [] : [];
        $form = [];
        foreach ($settings as $setting_id => $setting) {
            if (isset($setting['enum']) && is_array($setting['enum']) && !empty($setting['enum'])) {
                $form[$setting_id] = self::buildEnumForm($setting_id, $setting, $saved_values);
                continue;
            }
            // Settings format is a subset of JSON Schema, with only the scalars.
            $form[$setting_id] = match ($setting['type']) {    'boolean' => self::buildBooleanForm($setting_id, $setting, $saved_values),
                'number' => self::buildNumberForm($setting_id, $setting, $saved_values),
                'integer' => self::buildNumberForm($setting_id, $setting, $saved_values),
                'string' => self::buildStringForm($setting_id, $setting, $saved_values),
                default => self::buildStringForm($setting_id, $setting, $saved_values),
            
            };
        }
        return array_filter($form);
    }
    
    /**
     * Init setting from common JSON Schema properties.
     *
     * @param string $setting_id
     *   The setting id from the icon pack definition.
     * @param array $setting
     *   The settings from the icon pack definition.
     * @param array $saved_values
     *   The default saved values if any.
     *
     * @return array
     *   The form API generated with minimal keys.
     */
    protected static function initSettingForm(string $setting_id, array $setting, array $saved_values) : array {
        $form = [
            '#title' => $setting['title'] ?? $setting_id,
        ];
        if (isset($setting['description'])) {
            $form['#description'] = $setting['description'];
        }
        if (isset($setting['default'])) {
            $form['#default_value'] = $setting['default'];
        }
        if (isset($saved_values[$setting_id])) {
            $form['#default_value'] = $saved_values[$setting_id];
        }
        return $form;
    }
    
    /**
     * Build Drupal form for an enumerations to a select.
     *
     * @param string $setting_id
     *   The setting id from the icon pack definition.
     * @param array $setting
     *   The settings from the icon pack definition.
     * @param array $saved_values
     *   The default saved values if any.
     *
     * @return array
     *   The form API generated for enum as select.
     */
    protected static function buildEnumForm(string $setting_id, array $setting, array $saved_values) : array {
        $form = self::initSettingForm($setting_id, $setting, $saved_values);
        $form['#type'] = 'select';
        $form['#options'] = self::getOptions($setting);
        return $form;
    }
    
    /**
     * Get option list for enumerations.
     *
     * @param array $setting
     *   The settings from the icon pack definition.
     *
     * @return array
     *   The enum options for select.
     */
    protected static function getOptions(array $setting) : array {
        $options = array_combine($setting['enum'], $setting['enum']);
        foreach ($options as $key => $label) {
            if (is_string($label)) {
                $options[$key] = Unicode::ucwords($label);
            }
        }
        // Key meta:enum is used to provide a description for the enum list.
        // There is currently no official JSON Schema specification for enum
        // description, meta:enum is adopted by Adobe in
        // https://github.com/adobe/jsonschema2md and Coveo Open-Source in
        // https://github.com/coveooss/json-schema-for-humans.
        if (!isset($setting['meta:enum'])) {
            return $options;
        }
        $meta = $setting['meta:enum'];
        // Remove meta:enum items not found in options.
        return array_intersect_key($meta, $options);
    }
    
    /**
     * Build Drupal form for a boolean setting to a checkbox.
     *
     * @param string $setting_id
     *   The setting id from the icon pack definition.
     * @param array $setting
     *   The settings from the icon pack definition.
     * @param array $saved_values
     *   The default saved values if any.
     *
     * @return array
     *   The form API generated for enum as checkbox.
     */
    protected static function buildBooleanForm(string $setting_id, array $setting, array $saved_values) : array {
        $form = self::initSettingForm($setting_id, $setting, $saved_values);
        $form['#type'] = 'checkbox';
        return $form;
    }
    
    /**
     * Build Drupal form for a string setting to a textfield.
     *
     * @param string $setting_id
     *   The setting id from the icon pack definition.
     * @param array $setting
     *   The settings from the icon pack definition.
     * @param array $saved_values
     *   The default saved values if any.
     *
     * @return array
     *   The form API generated for enum as textfield.
     */
    protected static function buildStringForm(string $setting_id, array $setting, array $saved_values) : array {
        $form = self::initSettingForm($setting_id, $setting, $saved_values);
        if (isset($setting['format']) && $setting['format'] === self::COLOR_TYPE) {
            $form['#type'] = self::COLOR_TYPE;
            return $form;
        }
        $form['#type'] = 'textfield';
        if (isset($setting['pattern']) && !empty($setting['pattern'])) {
            $form['#pattern'] = $setting['pattern'];
        }
        if (isset($setting['maxLength'])) {
            $form['#maxlength'] = $setting['maxLength'];
        }
        // We don't support minLength and pattern together because it is not
        // possible to safely merge regular expressions.
        if (!isset($setting['pattern']) && isset($setting['minLength'])) {
            $form['#pattern'] = '^.{' . $setting['minLength'] . ',}$';
        }
        return $form;
    }
    
    /**
     * Build Drupal form for a number or integer setting.
     *
     * @param string $setting_id
     *   The setting id from the icon pack definition.
     * @param array $setting
     *   The settings from the icon pack definition.
     * @param array $saved_values
     *   The default saved values if any.
     *
     * @return array
     *   The form API generated for enum as number.
     */
    protected static function buildNumberForm(string $setting_id, array $setting, array $saved_values) : array {
        $form = self::initSettingForm($setting_id, $setting, $saved_values);
        $form['#type'] = 'number';
        if ($setting['type'] === 'integer') {
            $form['#step'] = 1;
        }
        if (isset($setting['multipleOf'])) {
            $form['#step'] = $setting['multipleOf'];
        }
        if (isset($setting['minimum'])) {
            $form['#min'] = $setting['minimum'];
        }
        if (isset($setting['maximum'])) {
            $form['#max'] = $setting['maximum'];
        }
        return $form;
    }

}