ckeditor/ckeditor5-engine

/**
 * @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 engine/model/operation/attributeoperation
 */

import Operation from './operation';
import Range from '../range';
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
import { _setAttribute } from './utils';
import { isEqual } from 'lodash-es';

/**
 * Operation to change nodes' attribute.
 *
 * Using this class you can add, remove or change value of the attribute.
 *
 * @extends module:engine/model/operation/operation~Operation
 */
export default class AttributeOperation extends Operation {
    /**
     * Creates an operation that changes, removes or adds attributes.
     *
     * If only `newValue` is set, attribute will be added on a node. Note that all nodes in operation's range must not
     * have an attribute with the same key as the added attribute.
     *
     * If only `oldValue` is set, then attribute with given key will be removed. Note that all nodes in operation's range
     * must have an attribute with that key added.
     *
     * If both `newValue` and `oldValue` are set, then the operation will change the attribute value. Note that all nodes in
     * operation's ranges must already have an attribute with given key and `oldValue` as value
     *
     * @param {module:engine/model/range~Range} range Range on which the operation should be applied. Must be a flat range.
     * @param {String} key Key of an attribute to change or remove.
     * @param {*} oldValue Old value of the attribute with given key or `null`, if attribute was not set before.
     * @param {*} newValue New value of the attribute with given key or `null`, if operation should remove attribute.
     * @param {Number|null} baseVersion Document {@link module:engine/model/document~Document#version} on which operation
     * can be applied or `null` if the operation operates on detached (non-document) tree.
     */
    constructor( range, key, oldValue, newValue, baseVersion ) {
        super( baseVersion );

        /**
         * Range on which operation should be applied.
         *
         * @readonly
         * @member {module:engine/model/range~Range}
         */
        this.range = range.clone();

        /**
         * Key of an attribute to change or remove.
         *
         * @readonly
         * @member {String}
         */
        this.key = key;

        /**
         * Old value of the attribute with given key or `null`, if attribute was not set before.
         *
         * @readonly
         * @member {*}
         */
        this.oldValue = oldValue === undefined ? null : oldValue;

        /**
         * New value of the attribute with given key or `null`, if operation should remove attribute.
         *
         * @readonly
         * @member {*}
         */
        this.newValue = newValue === undefined ? null : newValue;
    }

    /**
     * @inheritDoc
     */
    get type() {
        if ( this.oldValue === null ) {
            return 'addAttribute';
        } else if ( this.newValue === null ) {
            return 'removeAttribute';
        } else {
            return 'changeAttribute';
        }
    }

    /**
     * Creates and returns an operation that has the same parameters as this operation.
     *
     * @returns {module:engine/model/operation/attributeoperation~AttributeOperation} Clone of this operation.
     */
    clone() {
        return new AttributeOperation( this.range, this.key, this.oldValue, this.newValue, this.baseVersion );
    }

    /**
     * See {@link module:engine/model/operation/operation~Operation#getReversed `Operation#getReversed()`}.
     *
     * @returns {module:engine/model/operation/attributeoperation~AttributeOperation}
     */
    getReversed() {
        return new AttributeOperation( this.range, this.key, this.newValue, this.oldValue, this.baseVersion + 1 );
    }

    /**
     * @inheritDoc
     */
    toJSON() {
        const json = super.toJSON();

        json.range = this.range.toJSON();

        return json;
    }

    /**
     * @inheritDoc
     */
    _validate() {
        if ( !this.range.isFlat ) {
            /**
             * The range to change is not flat.
             *
             * @error attribute-operation-range-not-flat
             */
            throw new CKEditorError( 'attribute-operation-range-not-flat: The range to change is not flat.', this );
        }

        for ( const item of this.range.getItems( { shallow: true } ) ) {
            if ( this.oldValue !== null && !isEqual( item.getAttribute( this.key ), this.oldValue ) ) {
                /**
                 * Changed node has different attribute value than operation's old attribute value.
                 *
                 * @error attribute-operation-wrong-old-value
                 * @param {module:engine/model/item~Item} item
                 * @param {String} key
                 * @param {*} value
                 */
                throw new CKEditorError(
                    'attribute-operation-wrong-old-value: Changed node has different attribute value than operation\'s ' +
                    'old attribute value.',
                    this,
                    { item, key: this.key, value: this.oldValue }
                );
            }

            if ( this.oldValue === null && this.newValue !== null && item.hasAttribute( this.key ) ) {
                /**
                 * The attribute with given key already exists for the given node.
                 *
                 * @error attribute-operation-attribute-exists
                 * @param {module:engine/model/node~Node} node
                 * @param {String} key
                 */
                throw new CKEditorError(
                    'attribute-operation-attribute-exists: The attribute with given key already exists.',
                    this,
                    { node: item, key: this.key }
                );
            }
        }
    }

    /**
     * @inheritDoc
     */
    _execute() {
        // If value to set is same as old value, don't do anything.
        if ( !isEqual( this.oldValue, this.newValue ) ) {
            // Execution.
            _setAttribute( this.range, this.key, this.newValue );
        }
    }

    /**
     * @inheritDoc
     */
    static get className() {
        return 'AttributeOperation';
    }

    /**
     * Creates `AttributeOperation` object from deserilized object, i.e. from parsed JSON string.
     *
     * @param {Object} json Deserialized JSON object.
     * @param {module:engine/model/document~Document} document Document on which this operation will be applied.
     * @returns {module:engine/model/operation/attributeoperation~AttributeOperation}
     */
    static fromJSON( json, document ) {
        return new AttributeOperation( Range.fromJSON( json.range, document ), json.key, json.oldValue, json.newValue, json.baseVersion );
    }

    // @if CK_DEBUG_ENGINE // toString() {
    // @if CK_DEBUG_ENGINE //     return `AttributeOperation( ${ this.baseVersion } ): ` +
    // @if CK_DEBUG_ENGINE //        `"${ this.key }": ${ JSON.stringify( this.oldValue ) }` +
    // @if CK_DEBUG_ENGINE //        ` -> ${ JSON.stringify( this.newValue ) }, ${ this.range }`;
    // @if CK_DEBUG_ENGINE // }
}