text: /**
   * @license Copyright (c) 2003-2020, CKSource - Frederico Knabben. All rights reserved.
   * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
   */
  
  import ClassicTestEditor from '@ckeditor/ckeditor5-core/tests/_utils/classictesteditor';
  import Paragraph from '@ckeditor/ckeditor5-paragraph/src/paragraph';
  import Bold from '@ckeditor/ckeditor5-basic-styles/src/bold';
  import Italic from '@ckeditor/ckeditor5-basic-styles/src/italic';
  import LinkEditing from '@ckeditor/ckeditor5-link/src/linkediting';
  import Input from '../../src/input';
  
  import ViewText from '@ckeditor/ckeditor5-engine/src/view/text';
  import ViewElement from '@ckeditor/ckeditor5-engine/src/view/element';
  import ViewContainerElement from '@ckeditor/ckeditor5-engine/src/view/containerelement';
  import MutationObserver from '@ckeditor/ckeditor5-engine/src/view/observer/mutationobserver';
  
  import { getData as getModelData, setData as setModelData } from '@ckeditor/ckeditor5-engine/src/dev-utils/model';
  import { getData as getViewData } from '@ckeditor/ckeditor5-engine/src/dev-utils/view';
  
  /* global document */
  
  // NOTE: In all these tests we need to simulate the mutations. However, it's really tricky to tell what
  // should be in "newChildren" because we don't have yet access to these nodes. We pass new instances,
  // but this means that DomConverter which is used somewhere internally may return a different instance
  // (which wouldn't happen in practice because it'd cache it). Besides, it's really hard to tell if the
  // browser will keep the instances of the old elements when modifying the tree when the user is typing
  // or if it will create new instances itself too.
  // However, the code handling these mutations doesn't really care what's inside new/old children. It
  // just needs the mutations common ancestor to understand how big fragment of the tree has changed.
  describe( 'Bug ckeditor5-typing#100', () => {
  	let domElement, domRoot, editor, model, view, viewDocument, viewRoot;
  
  	beforeEach( () => {
  		domElement = document.createElement( 'div' );
  		document.body.appendChild( domElement );
  
  		return ClassicTestEditor.create( domElement, { plugins: [ Input, Paragraph, Bold, Italic, LinkEditing ] } )
  			.then( newEditor => {
  				editor = newEditor;
  				model = editor.model;
  				view = editor.editing.view;
  				viewDocument = view.document;
  				viewRoot = viewDocument.getRoot();
  				domRoot = view.getDomRoot();
  
  				// Mock image feature.
  				newEditor.model.schema.register( 'image', { allowWhere: '$text' } );
  
  				editor.conversion.for( 'downcast' ).elementToElement( {
  					model: 'image',
  					view: 'img'
  				} );
  
  				editor.conversion.for( 'upcast' ).elementToElement( {
  					view: 'img',
  					model: 'image'
  				} );
  
  				// Disable MO completely and in a way it won't be reenabled on some Document#render() call.
  				const mutationObserver = view.getObserver( MutationObserver );
  
  				mutationObserver.disable();
  				mutationObserver.enable = () => {};
  			} );
  	} );
  
  	afterEach( () => {
  		domElement.remove();
  
  		return editor.destroy();
  	} );
  
  	// This happens when browser automatically switches parent and child nodes.
  	it( 'should handle mutations switching inner and outer node when adding new text node after', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text italic="true" bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><i><strong>text{}</strong></i></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const italic = paragraph.getChild( 0 );
  		const strong = italic.getChild( 0 );
  		const text = strong.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong><i>text</i>x</strong>';
  		viewDocument.fire( 'mutations', [
  			// First mutation - remove all children from link element.
  			{
  				type: 'children',
  				node: italic,
  				oldChildren: [ strong ],
  				newChildren: []
  			},
  
  			// Second mutation - remove link from paragraph and put italic there.
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ italic ],
  				newChildren: [ new ViewElement( viewDocument, 'i' ) ]
  			},
  
  			// Third mutation - italic's new children.
  			{
  				type: 'children',
  				node: strong,
  				oldChildren: [ text ],
  				newChildren: [ new ViewElement( viewDocument, 'a', null, text._clone() ), new ViewText( viewDocument, 'x' ) ]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p><i><strong>textx{}</strong></i></p>' );
  	} );
  
  	it( 'should handle mutations switching inner and outer node when adding new text node before', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text italic="true" bold="true">' +
  			'[]text' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><i><strong>{}text</strong></i></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const italic = paragraph.getChild( 0 );
  		const strong = italic.getChild( 0 );
  		const text = strong.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>x<i>text</i></strong>';
  		viewDocument.fire( 'mutations', [
  			// First mutation - remove all children from link element.
  			{
  				type: 'children',
  				node: italic,
  				oldChildren: [ strong ],
  				newChildren: []
  			},
  
  			// Second mutation - remove link from paragraph and put italic there.
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ italic ],
  				newChildren: [ new ViewElement( viewDocument, 'i' ) ]
  			},
  
  			// Third mutation - italic's new children.
  			{
  				type: 'children',
  				node: strong,
  				oldChildren: [ text ],
  				newChildren: [ new ViewText( viewDocument, 'x' ), new ViewElement( viewDocument, 'a', null, 'text' ) ]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p><i><strong>x{}text</strong></i></p>' );
  	} );
  
  	it( 'should handle mutations switching inner and outer node - with text before', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'xxx<$text italic="true" bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p>xxx<i><strong>text{}</strong></i></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const textBefore = paragraph.getChild( 0 );
  		const link = paragraph.getChild( 1 );
  		const italic = link.getChild( 0 );
  		const text = italic.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = 'xxx<strong><i>text</i>x</strong>';
  		viewDocument.fire( 'mutations', [
  			// First mutation - remove all children from link element.
  			{
  				type: 'children',
  				node: link,
  				oldChildren: [ italic ],
  				newChildren: []
  			},
  
  			// Second mutation - remove link from paragraph and put italic there.
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ textBefore, link ],
  				newChildren: [ new ViewText( viewDocument, 'xxx' ), new ViewElement( viewDocument, 'i' ) ]
  			},
  
  			// Third mutation - italic's new children.
  			{
  				type: 'children',
  				node: italic,
  				oldChildren: [ text ],
  				newChildren: [ new ViewElement( viewDocument, 'a', null, 'text' ), new ViewText( viewDocument, 'x' ) ]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p>xxx<i><strong>textx{}</strong></i></p>' );
  	} );
  
  	// This happens when spell checker is applied on <strong> element and changes it to <b>.
  	it( 'should handle mutations replacing node', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<b>fixed text</b>';
  		viewDocument.fire( 'mutations', [
  			// Replace `<strong>` with `<b>`.
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ strong ],
  				newChildren: [ new ViewElement( viewDocument, 'b', null, 'fixed text' ) ]
  			}
  		] );
  
  		expect( getViewData( view, { withoutSelection: true } ) ).to.equal( '<p><strong>fixed text</strong></p>' );
  	} );
  
  	// Spell checker splits text inside attributes to two text nodes.
  	it( 'should handle mutations inside attribute element', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'this is foo text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>this is foo text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  		const text = strong.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].childNodes[ 0 ].innerHTML = 'this is bar text';
  		viewDocument.fire( 'mutations', [
  			{
  				type: 'children',
  				node: strong,
  				oldChildren: [ text ],
  				newChildren: [ new ViewText( viewDocument, 'this is bar' ), new ViewText( viewDocument, ' text' ) ]
  			}
  		] );
  
  		expect( getViewData( view, { withoutSelection: true } ) ).to.equal( '<p><strong>this is bar text</strong></p>' );
  	} );
  
  	it( 'should do nothing if elements mutated', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>text</strong><img />';
  		viewDocument.fire( 'mutations', [
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ strong ],
  				newChildren: [
  					new ViewElement( viewDocument, 'strong', null, new ViewText( viewDocument, 'text' ) ),
  					new ViewElement( viewDocument, 'img' )
  				]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  	} );
  
  	it( 'should do nothing if text is not changed', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>text</strong>';
  		viewDocument.fire( 'mutations', [
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ strong ],
  				newChildren: [ new ViewElement( viewDocument, 'strong', null, new ViewText( viewDocument, 'text' ) ) ]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  	} );
  
  	it( 'should do nothing on empty mutations', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>text</strong>';
  		viewDocument.fire( 'mutations', [] );
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  	} );
  
  	it( 'should do nothing if mutations does not have common ancestor', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>text</strong>';
  		viewDocument.fire( 'mutations', [
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ strong ],
  				newChildren: [ strong ]
  			},
  			{
  				type: 'children',
  				node: new ViewContainerElement( 'div' ),
  				oldChildren: [],
  				newChildren: [ new ViewText( viewDocument, 'foo' ), new ViewText( viewDocument, 'bar' ) ]
  			}
  		] );
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  	} );
  
  	it( 'should handle view selection if one is returned from mutations', () => {
  		setModelData( model,
  			'<paragraph>' +
  			'<$text bold="true">' +
  			'text[]' +
  			'</$text>' +
  			'</paragraph>'
  		);
  
  		expect( getViewData( view ) ).to.equal( '<p><strong>text{}</strong></p>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  		const viewSelection = view.createSelection( paragraph, 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<b>textx</b>';
  		viewDocument.fire( 'mutations', [
  			// Replace `<strong>` with `<b>`.
  			{
  				type: 'children',
  				node: paragraph,
  				oldChildren: [ strong ],
  				newChildren: [ new ViewElement( viewDocument, 'b', null, new ViewText( viewDocument, 'textx' ) ) ]
  			}
  		], viewSelection );
  
  		expect( getModelData( model ) ).to.equal( '<paragraph><$text bold="true">[]textx</$text></paragraph>' );
  		expect( getViewData( view ) ).to.equal( '<p><strong>{}textx</strong></p>' );
  	} );
  
  	// #117.
  	it( 'should handle mixed mutations', () => {
  		setModelData( model, '<paragraph>[]<$text bold="true">Foo bar aple</$text></paragraph>' );
  
  		const paragraph = viewRoot.getChild( 0 );
  		const strong = paragraph.getChild( 0 );
  		const viewSelection = view.createSelection( paragraph, 0 );
  
  		// Simulate mutations and DOM change.
  		domRoot.childNodes[ 0 ].innerHTML = '<strong>Foo bar </strong><b>apple</b>';
  		viewDocument.fire( 'mutations', [
  			{
  				type: 'text',
  				oldText: 'Foo bar aple',
  				newText: 'Foo bar ',
  				node: viewRoot.getChild( 0 ).getChild( 0 )
  			},
  			{
  				type: 'children',
  				oldChildren: [ strong ],
  				newChildren: [ strong, new ViewElement( viewDocument, 'b', null, new ViewText( viewDocument, 'apple' ) ) ],
  				node: paragraph
  			}
  		], viewSelection );
  
  		expect( getModelData( model ) ).to.equal( '<paragraph><$text bold="true">[]Foo bar apple</$text></paragraph>' );
  		expect( getViewData( view ) ).to.equal( '<p><strong>{}Foo bar apple</strong></p>' );
  	} );
  } );
  