ckeditor/ckeditor5-list

/**
 * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */

/**
 * @module list/todolistcheckedcommand
 */

import Command from '@ckeditor/ckeditor5-core/src/command';

const attributeKey = 'todoListChecked';

/**
 * The to-do check command.
 *
 * The command is registered by the {@link module:list/todolistediting~TodoListEditing} as
 * the `'todoListCheck'` editor command.
 *
 * @extends module:core/command~Command
 */
export default class TodoListCheckCommand extends Command {
    /**
     * @inheritDoc
     */
    constructor( editor ) {
        super( editor );

        /**
         * A flag indicating whether the command is active. The command is active when at least one of
         * {@link module:engine/model/selection~Selection selected} elements is a to-do list item.
         *
         * @observable
         * @readonly
         * @member {Boolean} #isEnabled
         */

        /**
         * A list of to-do list items selected by the {@link module:engine/model/selection~Selection}.
         *
         * @observable
         * @readonly
         * @member {Array.<module:engine/model/element~Element>} #value
         */

        /**
         * A list of to-do list items selected by the {@link module:engine/model/selection~Selection}.
         *
         * @protected
         * @type {Array.<module:engine/model/element~Element>}
         */
        this._selectedElements = [];

        // Refresh command before executing to be sure all values are up to date.
        // It is needed when selection has changed before command execution, in the same change block.
        this.on( 'execute', () => {
            this.refresh();
        }, { priority: 'highest' } );
    }

    /**
     * Updates the command's {@link #value} and {@link #isEnabled} properties based on the current selection.
     */
    refresh() {
        this._selectedElements = this._getSelectedItems();
        this.value = this._selectedElements.every( element => !!element.getAttribute( 'todoListChecked' ) );
        this.isEnabled = !!this._selectedElements.length;
    }

    /**
     * Gets all to-do list items selected by the {@link module:engine/model/selection~Selection}.
     *
     * @private
     * @returns {Array.<module:engine/model/element~Element>}
     */
    _getSelectedItems() {
        const model = this.editor.model;
        const schema = model.schema;

        const selectionRange = model.document.selection.getFirstRange();
        const startElement = selectionRange.start.parent;
        const elements = [];

        if ( schema.checkAttribute( startElement, attributeKey ) ) {
            elements.push( startElement );
        }

        for ( const item of selectionRange.getItems() ) {
            if ( schema.checkAttribute( item, attributeKey ) && !elements.includes( item ) ) {
                elements.push( item );
            }
        }

        return elements;
    }

    /**
     * Executes the command.
     *
     * @param {Object} [options]
     * @param {Boolean} [options.forceValue] If set, it will force the command behavior. If `true`, the command will apply
     * the attribute. Otherwise, the command will remove the attribute. If not set, the command will look for its current
     * value to decide what it should do.
     */
    execute( options = {} ) {
        this.editor.model.change( writer => {
            for ( const element of this._selectedElements ) {
                const value = ( options.forceValue === undefined ) ? !this.value : options.forceValue;

                if ( value ) {
                    writer.setAttribute( attributeKey, true, element );
                } else {
                    writer.removeAttribute( attributeKey, element );
                }
            }
        } );
    }
}