class Internal

class Internal extends CKEditorPluginBase implements ContainerFactoryPluginInterface, CKEditorPluginContextualInterface {
    
    /**
     * The cache backend.
     *
     * @var \Drupal\Core\Cache\CacheBackendInterface
     */
    protected $cache;
    
    /**
     * Constructs a \Drupal\ckeditor\Plugin\CKEditorPlugin\Internal object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin_id for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Cache\CacheBackendInterface $cache_backend
     *   The cache backend.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, CacheBackendInterface $cache_backend) {
        $this->cache = $cache_backend;
        parent::__construct($configuration, $plugin_id, $plugin_definition);
    }
    
    /**
     * Creates an instance of the plugin.
     *
     * @param \Symfony\Component\DependencyInjection\ContainerInterface $container
     *   The container to pull out services used in the plugin.
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin ID for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     *
     * @return static
     *   Returns an instance of this plugin.
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('cache.default'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function isInternal() {
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function isEnabled(Editor $editor) {
        // This plugin represents the core CKEditor plugins. They're always enabled:
        // its configuration is always necessary.
        return TRUE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getFile() {
        // This plugin is already part of Drupal core's CKEditor build.
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getConfig(Editor $editor) {
        // Reasonable defaults that provide expected basic behavior.
        $config = [
            // Don't load CKEditor's config.js file.
'customConfig' => '',
            'pasteFromWordPromptCleanup' => TRUE,
            'resize_dir' => 'vertical',
            'justifyClasses' => [
                'text-align-left',
                'text-align-center',
                'text-align-right',
                'text-align-justify',
            ],
            'entities' => FALSE,
            'disableNativeSpellChecker' => FALSE,
        ];
        // Add the allowedContent setting, which ensures CKEditor only allows tags
        // and attributes that are allowed by the text format for this text editor.
        list($config['allowedContent'], $config['disallowedContent']) = $this->generateACFSettings($editor);
        // Add the format_tags setting, if its button is enabled.
        $toolbar_buttons = CKEditorPluginManager::getEnabledButtons($editor);
        if (in_array('Format', $toolbar_buttons)) {
            $config['format_tags'] = $this->generateFormatTagsSetting($editor);
        }
        return $config;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getButtons() {
        $button = function ($name, $direction = 'ltr') {
            // In the markup below, we mostly use the name (which may include spaces),
            // but in one spot we use it as a CSS class, so strip spaces.
            // Note: this uses str_replace() instead of Html::cleanCssIdentifier()
            // because we must provide these class names exactly how CKEditor expects
            // them in its library, which cleanCssIdentifier() does not do.
            $class_name = str_replace(' ', '', $name);
            return [
                '#type' => 'inline_template',
                '#template' => '<a href="#" class="cke-icon-only cke_{{ direction }}" role="button" title="{{ name }}" aria-label="{{ name }}"><span class="cke_button_icon cke_button__{{ classname }}_icon">{{ name }}</span></a>',
                '#context' => [
                    'direction' => $direction,
                    'name' => $name,
                    'classname' => $class_name,
                ],
            ];
        };
        return [
            // "basicstyles" plugin.
'Bold' => [
                'label' => $this->t('Bold'),
                'image_alternative' => $button('bold'),
                'image_alternative_rtl' => $button('bold', 'rtl'),
            ],
            'Italic' => [
                'label' => $this->t('Italic'),
                'image_alternative' => $button('italic'),
                'image_alternative_rtl' => $button('italic', 'rtl'),
            ],
            'Underline' => [
                'label' => $this->t('Underline'),
                'image_alternative' => $button('underline'),
                'image_alternative_rtl' => $button('underline', 'rtl'),
            ],
            'Strike' => [
                'label' => $this->t('Strike-through'),
                'image_alternative' => $button('strike'),
                'image_alternative_rtl' => $button('strike', 'rtl'),
            ],
            'Superscript' => [
                'label' => $this->t('Superscript'),
                'image_alternative' => $button('super script'),
                'image_alternative_rtl' => $button('super script', 'rtl'),
            ],
            'Subscript' => [
                'label' => $this->t('Subscript'),
                'image_alternative' => $button('sub script'),
                'image_alternative_rtl' => $button('sub script', 'rtl'),
            ],
            // "removeformat" plugin.
'RemoveFormat' => [
                'label' => $this->t('Remove format'),
                'image_alternative' => $button('remove format'),
                'image_alternative_rtl' => $button('remove format', 'rtl'),
            ],
            // "justify" plugin.
'JustifyLeft' => [
                'label' => $this->t('Align left'),
                'image_alternative' => $button('justify left'),
                'image_alternative_rtl' => $button('justify left', 'rtl'),
            ],
            'JustifyCenter' => [
                'label' => $this->t('Align center'),
                'image_alternative' => $button('justify center'),
                'image_alternative_rtl' => $button('justify center', 'rtl'),
            ],
            'JustifyRight' => [
                'label' => $this->t('Align right'),
                'image_alternative' => $button('justify right'),
                'image_alternative_rtl' => $button('justify right', 'rtl'),
            ],
            'JustifyBlock' => [
                'label' => $this->t('Justify'),
                'image_alternative' => $button('justify block'),
                'image_alternative_rtl' => $button('justify block', 'rtl'),
            ],
            // "list" plugin.
'BulletedList' => [
                'label' => $this->t('Bullet list'),
                'image_alternative' => $button('bulleted list'),
                'image_alternative_rtl' => $button('bulleted list', 'rtl'),
            ],
            'NumberedList' => [
                'label' => $this->t('Numbered list'),
                'image_alternative' => $button('numbered list'),
                'image_alternative_rtl' => $button('numbered list', 'rtl'),
            ],
            // "indent" plugin.
'Outdent' => [
                'label' => $this->t('Outdent'),
                'image_alternative' => $button('outdent'),
                'image_alternative_rtl' => $button('outdent', 'rtl'),
            ],
            'Indent' => [
                'label' => $this->t('Indent'),
                'image_alternative' => $button('indent'),
                'image_alternative_rtl' => $button('indent', 'rtl'),
            ],
            // "undo" plugin.
'Undo' => [
                'label' => $this->t('Undo'),
                'image_alternative' => $button('undo'),
                'image_alternative_rtl' => $button('undo', 'rtl'),
            ],
            'Redo' => [
                'label' => $this->t('Redo'),
                'image_alternative' => $button('redo'),
                'image_alternative_rtl' => $button('redo', 'rtl'),
            ],
            // "blockquote" plugin.
'Blockquote' => [
                'label' => $this->t('Blockquote'),
                'image_alternative' => $button('blockquote'),
                'image_alternative_rtl' => $button('blockquote', 'rtl'),
            ],
            // "horizontalrule" plugin
'HorizontalRule' => [
                'label' => $this->t('Horizontal rule'),
                'image_alternative' => $button('horizontal rule'),
                'image_alternative_rtl' => $button('horizontal rule', 'rtl'),
            ],
            // "clipboard" plugin.
'Cut' => [
                'label' => $this->t('Cut'),
                'image_alternative' => $button('cut'),
                'image_alternative_rtl' => $button('cut', 'rtl'),
            ],
            'Copy' => [
                'label' => $this->t('Copy'),
                'image_alternative' => $button('copy'),
                'image_alternative_rtl' => $button('copy', 'rtl'),
            ],
            'Paste' => [
                'label' => $this->t('Paste'),
                'image_alternative' => $button('paste'),
                'image_alternative_rtl' => $button('paste', 'rtl'),
            ],
            // "pastetext" plugin.
'PasteText' => [
                'label' => $this->t('Paste Text'),
                'image_alternative' => $button('paste text'),
                'image_alternative_rtl' => $button('paste text', 'rtl'),
            ],
            // "pastefromword" plugin.
'PasteFromWord' => [
                'label' => $this->t('Paste from Word'),
                'image_alternative' => $button('paste from word'),
                'image_alternative_rtl' => $button('paste from word', 'rtl'),
            ],
            // "specialchar" plugin.
'SpecialChar' => [
                'label' => $this->t('Character map'),
                'image_alternative' => $button('special char'),
                'image_alternative_rtl' => $button('special char', 'rtl'),
            ],
            'Format' => [
                'label' => $this->t('HTML block format'),
                'image_alternative' => [
                    '#type' => 'inline_template',
                    '#template' => '<a href="#" role="button" aria-label="{{ format_text }}"><span class="ckeditor-button-dropdown">{{ format_text }}<span class="ckeditor-button-arrow"></span></span></a>',
                    '#context' => [
                        'format_text' => $this->t('Format'),
                    ],
                ],
            ],
            // "table" plugin.
'Table' => [
                'label' => $this->t('Table'),
                'image_alternative' => $button('table'),
                'image_alternative_rtl' => $button('table', 'rtl'),
            ],
            // "showblocks" plugin.
'ShowBlocks' => [
                'label' => $this->t('Show blocks'),
                'image_alternative' => $button('show blocks'),
                'image_alternative_rtl' => $button('show blocks', 'rtl'),
            ],
            // "sourcearea" plugin.
'Source' => [
                'label' => $this->t('Source code'),
                'image_alternative' => $button('source'),
                'image_alternative_rtl' => $button('source', 'rtl'),
            ],
            // "maximize" plugin.
'Maximize' => [
                'label' => $this->t('Maximize'),
                'image_alternative' => $button('maximize'),
                'image_alternative_rtl' => $button('maximize', 'rtl'),
            ],
            // No plugin, separator "button" for toolbar builder UI use only.
'-' => [
                'label' => $this->t('Separator'),
                'image_alternative' => [
                    '#type' => 'inline_template',
                    '#template' => '<a href="#" role="button" aria-label="{{ button_separator_text }}" class="ckeditor-separator"></a>',
                    '#context' => [
                        'button_separator_text' => $this->t('Button separator'),
                    ],
                ],
                'attributes' => [
                    'class' => [
                        'ckeditor-button-separator',
                    ],
                    'data-drupal-ckeditor-type' => 'separator',
                ],
                'multiple' => TRUE,
            ],
        ];
    }
    
    /**
     * Builds the "format_tags" configuration part of the CKEditor JS settings.
     *
     * @see getConfig()
     *
     * @param \Drupal\editor\Entity\Editor $editor
     *   A configured text editor object.
     *
     * @return array
     *   An array containing the "format_tags" configuration.
     */
    protected function generateFormatTagsSetting(Editor $editor) {
        // When no text format is associated yet, assume no tag is allowed.
        // @see \Drupal\editor\EditorInterface::hasAssociatedFilterFormat()
        if (!$editor->hasAssociatedFilterFormat()) {
            return [];
        }
        $format = $editor->getFilterFormat();
        $cid = 'ckeditor_internal_format_tags:' . $format->id();
        if ($cached = $this->cache
            ->get($cid)) {
            $format_tags = $cached->data;
        }
        else {
            // The <p> tag is always allowed — HTML without <p> tags is nonsensical.
            $format_tags = [
                'p',
            ];
            // Given the list of possible format tags, automatically determine whether
            // the current text format allows this tag, and thus whether it should show
            // up in the "Format" dropdown.
            $possible_format_tags = [
                'h1',
                'h2',
                'h3',
                'h4',
                'h5',
                'h6',
                'pre',
            ];
            foreach ($possible_format_tags as $tag) {
                $input = '<' . $tag . '>TEST</' . $tag . '>';
                $output = trim(check_markup($input, $editor->id()));
                if (Html::load($output)->getElementsByTagName($tag)->length !== 0) {
                    $format_tags[] = $tag;
                }
            }
            $format_tags = implode(';', $format_tags);
            // Cache the "format_tags" configuration. This cache item is infinitely
            // valid; it only changes whenever the text format is changed, hence it's
            // tagged with the text format's cache tag.
            $this->cache
                ->set($cid, $format_tags, Cache::PERMANENT, $format->getCacheTags());
        }
        return $format_tags;
    }
    
    /**
     * Builds the ACF part of the CKEditor JS settings.
     *
     * This ensures that CKEditor obeys the HTML restrictions defined by Drupal's
     * filter system, by enabling CKEditor's Advanced Content Filter (ACF)
     * functionality: http://ckeditor.com/blog/CKEditor-4.1-RC-Released.
     *
     * @see getConfig()
     *
     * @param \Drupal\editor\Entity\Editor $editor
     *   A configured text editor object.
     *
     * @return array
     *   An array with two values:
     *   - the first value is the "allowedContent" setting: a well-formatted array
     *     or TRUE. The latter indicates that anything is allowed.
     *   - the second value is the "disallowedContent" setting: a well-formatted
     *     array or FALSE. The latter indicates that nothing is disallowed.
     */
    protected function generateACFSettings(Editor $editor) {
        // When no text format is associated yet, assume nothing is disallowed, so
        // set allowedContent to true.
        if (!$editor->hasAssociatedFilterFormat()) {
            return TRUE;
        }
        $format = $editor->getFilterFormat();
        $filter_types = $format->getFilterTypes();
        // When nothing is disallowed, set allowedContent to true.
        if (!in_array(FilterInterface::TYPE_HTML_RESTRICTOR, $filter_types)) {
            return [
                TRUE,
                FALSE,
            ];
        }
        else {
            $get_attribute_values = function ($attribute_values, $allowed_values) {
                $values = array_keys(array_filter($attribute_values, function ($value) use ($allowed_values) {
                    if ($allowed_values) {
                        return $value !== FALSE;
                    }
                    else {
                        return $value === FALSE;
                    }
                }));
                if (count($values)) {
                    return implode(',', $values);
                }
                else {
                    return NULL;
                }
            };
            $html_restrictions = $format->getHtmlRestrictions();
            // When all HTML is allowed, also set allowedContent to true and
            // disallowedContent to false.
            if ($html_restrictions === FALSE) {
                return [
                    TRUE,
                    FALSE,
                ];
            }
            $allowed = [];
            $disallowed = [];
            if (isset($html_restrictions['forbidden_tags'])) {
                foreach ($html_restrictions['forbidden_tags'] as $tag) {
                    $disallowed[$tag] = TRUE;
                }
            }
            foreach ($html_restrictions['allowed'] as $tag => $attributes) {
                // Tell CKEditor the tag is allowed, but no attributes.
                if ($attributes === FALSE) {
                    $allowed[$tag] = [
                        'attributes' => FALSE,
                        'styles' => FALSE,
                        'classes' => FALSE,
                    ];
                }
                elseif ($attributes === TRUE) {
                    $allowed[$tag] = [
                        'attributes' => TRUE,
                        'styles' => TRUE,
                        'classes' => TRUE,
                    ];
                    // We've just marked that any value for the "style" and "class"
                    // attributes is allowed. However, that may not be the case: the "*"
                    // tag may still apply restrictions.
                    // Since CKEditor's ACF follows the following principle:
                    //     Once validated, an element or its property cannot be
                    //     invalidated by another rule.
                    // That means that the most permissive setting wins. Which means that
                    // it will still be allowed by CKEditor, for instance, to define any
                    // style, no matter what the "*" tag's restrictions may be. If there
                    // is a setting for either the "style" or "class" attribute, it cannot
                    // possibly be more permissive than what was set above. Hence, inherit
                    // from the "*" tag where possible.
                    if (isset($html_restrictions['allowed']['*'])) {
                        $wildcard = $html_restrictions['allowed']['*'];
                        if (isset($wildcard['style'])) {
                            if (!is_array($wildcard['style'])) {
                                $allowed[$tag]['styles'] = $wildcard['style'];
                            }
                            else {
                                $allowed_styles = $get_attribute_values($wildcard['style'], TRUE);
                                if (isset($allowed_styles)) {
                                    $allowed[$tag]['styles'] = $allowed_styles;
                                }
                                else {
                                    unset($allowed[$tag]['styles']);
                                }
                            }
                        }
                        if (isset($wildcard['class'])) {
                            if (!is_array($wildcard['class'])) {
                                $allowed[$tag]['classes'] = $wildcard['class'];
                            }
                            else {
                                $allowed_classes = $get_attribute_values($wildcard['class'], TRUE);
                                if (isset($allowed_classes)) {
                                    $allowed[$tag]['classes'] = $allowed_classes;
                                }
                                else {
                                    unset($allowed[$tag]['classes']);
                                }
                            }
                        }
                    }
                }
                elseif (is_array($attributes)) {
                    // Set defaults (these will be overridden below if more specific
                    // values are present).
                    $allowed[$tag] = [
                        'attributes' => FALSE,
                        'styles' => FALSE,
                        'classes' => FALSE,
                    ];
                    // Configure allowed attributes, allowed "style" attribute values and
                    // allowed "class" attribute values.
                    // CKEditor only allows specific values for the "class" and "style"
                    // attributes; so ignore restrictions on other attributes, which
                    // Drupal filters may provide.
                    // NOTE: A Drupal contrib module can subclass this class, override the
                    // getConfig() method, and override the JavaScript at
                    // Drupal.editors.ckeditor to somehow make validation of values for
                    // attributes other than "class" and "style" work.
                    $allowed_attributes = array_filter($attributes, function ($value) {
                        return $value !== FALSE;
                    });
                    if (count($allowed_attributes)) {
                        $allowed[$tag]['attributes'] = implode(',', array_keys($allowed_attributes));
                    }
                    if (isset($allowed_attributes['style'])) {
                        if (is_bool($allowed_attributes['style'])) {
                            $allowed[$tag]['styles'] = $allowed_attributes['style'];
                        }
                        elseif (is_array($allowed_attributes['style'])) {
                            $allowed_classes = $get_attribute_values($allowed_attributes['style'], TRUE);
                            if (isset($allowed_classes)) {
                                $allowed[$tag]['styles'] = $allowed_classes;
                            }
                        }
                    }
                    if (isset($allowed_attributes['class'])) {
                        if (is_bool($allowed_attributes['class'])) {
                            $allowed[$tag]['classes'] = $allowed_attributes['class'];
                        }
                        elseif (is_array($allowed_attributes['class'])) {
                            $allowed_classes = $get_attribute_values($allowed_attributes['class'], TRUE);
                            if (isset($allowed_classes)) {
                                $allowed[$tag]['classes'] = $allowed_classes;
                            }
                        }
                    }
                    // Handle disallowed attributes analogously. However, to handle *dis-
                    // allowed* attribute values, we must look at *allowed* attributes'
                    // disallowed attribute values! After all, a disallowed attribute
                    // implies that all of its possible attribute values are disallowed,
                    // thus we must look at the disallowed attribute values on allowed
                    // attributes.
                    $disallowed_attributes = array_filter($attributes, function ($value) {
                        return $value === FALSE;
                    });
                    if (count($disallowed_attributes)) {
                        // No need to blacklist the 'class' or 'style' attributes; CKEditor
                        // handles them separately (if no specific class or style attribute
                        // values are allowed, then those attributes are disallowed).
                        if (isset($disallowed_attributes['class'])) {
                            unset($disallowed_attributes['class']);
                        }
                        if (isset($disallowed_attributes['style'])) {
                            unset($disallowed_attributes['style']);
                        }
                        $disallowed[$tag]['attributes'] = implode(',', array_keys($disallowed_attributes));
                    }
                    if (isset($allowed_attributes['style']) && is_array($allowed_attributes['style'])) {
                        $disallowed_styles = $get_attribute_values($allowed_attributes['style'], FALSE);
                        if (isset($disallowed_styles)) {
                            $disallowed[$tag]['styles'] = $disallowed_styles;
                        }
                    }
                    if (isset($allowed_attributes['class']) && is_array($allowed_attributes['class'])) {
                        $disallowed_classes = $get_attribute_values($allowed_attributes['class'], FALSE);
                        if (isset($disallowed_classes)) {
                            $disallowed[$tag]['classes'] = $disallowed_classes;
                        }
                    }
                }
            }
            ksort($allowed);
            ksort($disallowed);
            return [
                $allowed,
                $disallowed,
            ];
        }
    }

}