class CKEditor4To5UpgradePluginManager

class CKEditor4To5UpgradePluginManager extends DefaultPluginManager {
    
    /**
     * A map of CKEditor 4 buttons to an upgrade plugin ID.
     *
     * @var array
     */
    protected $cke4ButtonsMap;
    
    /**
     * A map of CKEditor 4 plugins with settings to an upgrade plugin ID.
     *
     * @var array
     */
    protected $cke4PluginSettingsMap;
    
    /**
     * A map of CKEditor 5 plugins with configurable subset to upgrade plugin ID.
     *
     * @var array
     */
    protected $cke5SubsetConfigurationMap;
    
    /**
     * Constructs a CKEditor4To5UpgradePluginManager object.
     *
     * @param \Traversable $namespaces
     *   An object that implements \Traversable which contains the root paths
     *   keyed by the corresponding namespace to look for plugin implementations.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   Cache backend instance to use.
     * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
     *   The module handler to invoke the alter hook with.
     */
    public function __construct(\Traversable $namespaces, CacheBackendInterface $cache_backend, ModuleHandlerInterface $module_handler) {
        parent::__construct('Plugin/CKEditor4To5Upgrade', $namespaces, $module_handler, CKEditor4To5UpgradePluginInterface::class, CKEditor4To5Upgrade::class);
        $this->alterInfo('ckeditor4to5upgrade_plugin_info');
        $this->setCacheBackend($cache_backend, 'ckeditor4to5upgrade_plugins');
    }
    
    /**
     * Validates plugin definitions: avoids conflicts. Builds maps for later use.
     */
    protected function validateAndBuildMaps() : void {
        if ($this->cke4ButtonsMap !== NULL) {
            return;
        }
        foreach ($this->getDefinitions() as $upgrade_plugin_id => $definition) {
            // Only one CKEditor4To5Upgrade plugin can define the upgrade path for a
            // CKEditor 4 button.
            if (isset($definition['cke4_buttons'])) {
                assert(Inspector::assertAllStrings($definition['cke4_buttons']));
                foreach ($definition['cke4_buttons'] as $cke4_button_id) {
                    if (isset($this->cke4ButtonsMap[$cke4_button_id])) {
                        throw new \OutOfBoundsException(sprintf('The "%s" CKEditor 4 button is already being upgraded by the "%s" CKEditor4To5Upgrade plugin, the "%s" plugin is as well. This conflict needs to be resolved.', $cke4_button_id, $this->cke4ButtonsMap[$cke4_button_id], $upgrade_plugin_id));
                    }
                    $this->cke4ButtonsMap[$cke4_button_id] = $upgrade_plugin_id;
                }
            }
            // Only one CKEditor4To5Upgrade plugin can define the upgrade path for a
            // CKEditor 4 plugin's settings.
            if (isset($definition['cke4_plugin_settings'])) {
                assert(Inspector::assertAllStrings($definition['cke4_plugin_settings']));
                foreach ($definition['cke4_plugin_settings'] as $cke4_plugin_id) {
                    if (isset($this->cke4PluginSettingsMap[$cke4_plugin_id])) {
                        throw new \OutOfBoundsException(sprintf('The "%s" CKEditor 4 plugin\'s settings are already being upgraded by the "%s" CKEditor4To5Upgrade plugin, the "%s" plugin is as well. This conflict needs to be resolved.', $cke4_plugin_id, $this->cke4PluginSettingsMap[$cke4_plugin_id], $upgrade_plugin_id));
                    }
                    $this->cke4PluginSettingsMap[$cke4_plugin_id] = $upgrade_plugin_id;
                }
            }
            // Only one CKEditor4To5Upgrade plugin can define the upgrade path for a
            // CKEditor 5 plugin's elements subset configuration.
            if (isset($definition['cke5_plugin_elements_subset_configuration'])) {
                assert(Inspector::assertAllStrings($definition['cke5_plugin_elements_subset_configuration']));
                foreach ($definition['cke5_plugin_elements_subset_configuration'] as $cke5_plugin_id) {
                    if (isset($this->cke5SubsetConfigurationMap[$cke5_plugin_id])) {
                        throw new \OutOfBoundsException(sprintf('The "%s" CKEditor 5 plugin\'s elements subset configuration is already being computed by the "%s" CKEditor4To5Upgrade plugin, the "%s" plugin is as well. This conflict needs to be resolved.', $cke5_plugin_id, $this->cke5SubsetConfigurationMap[$cke5_plugin_id], $upgrade_plugin_id));
                    }
                    $this->cke5SubsetConfigurationMap[$cke5_plugin_id] = $upgrade_plugin_id;
                }
            }
        }
    }
    
    /**
     * Maps a CKEditor 4 button to the CKEditor 5 equivalent, if it exists.
     *
     * Generated by inspecting all \Drupal\ckeditor\CKEditorPluginButtonsInterface
     * implementations.
     *
     * @param string $cke4_button
     *   A valid CKEditor 4 button name.
     * @param \Drupal\ckeditor5\HTMLRestrictions $text_format_html_restrictions
     *   The restrictions of the text format, to allow an upgrade plugin to
     *   inspect the text format's HTML restrictions to make a decision.
     *
     * @return string[]|null
     *   The equivalent CKEditor 5 toolbar items, or NULL if no equivalent exists.
     *
     * @throws \OutOfBoundsException
     *   Thrown when no upgrade path exists.
     * @throws \LogicException
     *   Thrown when a plugin claims to provide an upgrade path but does not.
     *
     * @see \Drupal\ckeditor\CKEditorPluginButtonsInterface
     */
    public function mapCKEditor4ToolbarButtonToCKEditor5ToolbarItem(string $cke4_button, HTMLRestrictions $text_format_html_restrictions) : ?array {
        $this->validateAndBuildMaps();
        if (!isset($this->cke4ButtonsMap[$cke4_button])) {
            throw new \OutOfBoundsException(sprintf('No upgrade path found for the "%s" button.', $cke4_button));
        }
        $plugin_id = $this->cke4ButtonsMap[$cke4_button];
        try {
            return $this->createInstance($plugin_id)
                ->mapCKEditor4ToolbarButtonToCKEditor5ToolbarItem($cke4_button, $text_format_html_restrictions);
        } catch (\OutOfBoundsException $e) {
            throw new \LogicException(sprintf('The "%s" CKEditor4To5Upgrade plugin claims to provide an upgrade path for the "%s" CKEditor 4 button but does not.', $plugin_id, $cke4_button));
        }
    }
    
    /**
     * Maps CKEditor 4 settings to the CKEditor 5 equivalent, if needed.
     *
     * Not every CKEditor 5 plugin has settings; some CKEditor 5 plugins may have
     * settings that the CKEditor 4 equivalent did not and vice versa. Therefore
     * the complete CKEditor 4 settings are provided, and any CKEditor 5 setting
     * can be set.
     *
     * @param string $cke4_plugin_id
     *   The CKEditor 4 plugin whose settings need to be mapped.
     * @param array $cke4_plugin_settings
     *   The settings for this CKEditor 4 plugin.
     *
     * @return array|null
     *   NULL if not needed, otherwise an array with a single key-value pair:
     *   - key: the plugin ID of the equivalent CKEditor 5 plugin
     *   - value: the equivalent settings
     *
     * @throws \OutOfBoundsException
     *   Thrown when no upgrade path exists.
     * @throws \LogicException
     *   Thrown when a plugin claims to provide an upgrade path but does not.
     *
     * @see \Drupal\ckeditor\CKEditorPluginConfigurableInterface
     */
    public function mapCKEditor4SettingsToCKEditor5Configuration(string $cke4_plugin_id, array $cke4_plugin_settings) : ?array {
        $this->validateAndBuildMaps();
        if (!isset($this->cke4PluginSettingsMap[$cke4_plugin_id])) {
            throw new \OutOfBoundsException(sprintf('No upgrade path found for the "%s" plugin settings.', $cke4_plugin_id));
        }
        $plugin_id = $this->cke4PluginSettingsMap[$cke4_plugin_id];
        try {
            return $this->createInstance($plugin_id)
                ->mapCKEditor4SettingsToCKEditor5Configuration($cke4_plugin_id, $cke4_plugin_settings);
        } catch (\OutOfBoundsException $e) {
            throw new \LogicException(sprintf('The "%s" CKEditor4To5Upgrade plugin claims to provide an upgrade path for the "%s" CKEditor 4 plugin settings but does not.', $plugin_id, $cke4_plugin_id));
        }
    }
    
    /**
     * Computes elements subset configuration for CKEditor 5 plugin.
     *
     * Every CKEditor 5 plugin that implements the elements subset interface must
     * implement this as well, to ensure a smooth upgrade path.
     *
     * @param string $cke5_plugin_id
     *   The CKEditor 5 plugin whose subset configuration needs to be computed.
     * @param \Drupal\filter\FilterFormatInterface $text_format
     *   The text format based on whose restrictions this should be computed.
     *
     * @return array|null
     *   NULL if not needed, otherwise a configuration array (which can itself be
     *   a subset of the default configuration of this CKEditor 5 plugin: perhaps
     *   only some of the configuration values determine the subset).
     *
     * @throws \OutOfBoundsException
     *   Thrown when no upgrade path exists.
     * @throws \LogicException
     *   Thrown when a plugin claims to provide an upgrade path but does not.
     *
     * @see \Drupal\ckeditor5\Plugin\CKEditor5PluginElementsSubsetInterface
     */
    public function computeCKEditor5PluginSubsetConfiguration(string $cke5_plugin_id, FilterFormatInterface $text_format) : ?array {
        $this->validateAndBuildMaps();
        if (!isset($this->cke5SubsetConfigurationMap[$cke5_plugin_id])) {
            throw new \OutOfBoundsException(sprintf('No upgrade path found for the "%s" elements subset configuration.', $cke5_plugin_id));
        }
        $plugin_id = $this->cke5SubsetConfigurationMap[$cke5_plugin_id];
        try {
            return $this->createInstance($plugin_id)
                ->computeCKEditor5PluginSubsetConfiguration($cke5_plugin_id, $text_format);
        } catch (\OutOfBoundsException $e) {
            throw new \LogicException(sprintf('The "%s" CKEditor4To5Upgrade plugin claims to provide an upgrade path for the "%s" CKEditor 4 plugin settings but does not.', $plugin_id, $cke5_plugin_id));
        }
    }

}