Suggest Block patterns in block placeholder states

packages/base-styles/_z-index.scss

@@ -76,6 +76,11 @@ $z-layers: (
 	// should overlap most block content.
 	".block-editor-block-list__block.is-{selected,hovered} .block-editor-block-mover": 61,
 
+	// Query block setup state.
+	".block-editor-block-pattern-setup .pattern-slide": 100,
+	".block-editor-block-pattern-setup .{next,previous}-slide": 101,
+	".block-editor-block-pattern-setup .active-slide": 102,
+
 	// Show sidebar above wp-admin navigation bar for mobile viewports:
 	// #wpadminbar { z-index: 99999 }
 	".interface-interface-skeleton__sidebar": 100000,

packages/block-editor/src/components/block-pattern-setup/constants.js

@@ -0,0 +1,4 @@
+export const VIEWMODES = {
+	carousel: 'carousel',
+	grid: 'grid',
+};

packages/block-editor/src/components/block-pattern-setup/index.js

@@ -0,0 +1,184 @@
+/**
+ * WordPress dependencies
+ */
+import { useDispatch } from '@wordpress/data';
+import { cloneBlock } from '@wordpress/blocks';
+import {
+	VisuallyHidden,
+	__unstableComposite as Composite,
+	__unstableUseCompositeState as useCompositeState,
+	__unstableCompositeItem as CompositeItem,
+} from '@wordpress/components';
+
+import { useState } from '@wordpress/element';
+import { useInstanceId } from '@wordpress/compose';
+import { __ } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import { store as blockEditorStore } from '../../store';
+import BlockPreview from '../block-preview';
+import SetupToolbar from './setup-toolbar';
+import usePatternsSetup from './use-patterns-setup';
+import { VIEWMODES } from './constants';
+
+const SetupContent = ( {
+	viewMode,
+	activeSlide,
+	patterns,
+	onBlockPatternSelect,
+} ) => {
+	const composite = useCompositeState();
+	const containerClass = 'block-editor-block-pattern-setup__container';
+	if ( viewMode === VIEWMODES.carousel ) {
+		const slideClass = new Map( [
+			[ activeSlide, 'active-slide' ],
+			[ activeSlide - 1, 'previous-slide' ],
+			[ activeSlide + 1, 'next-slide' ],
+		] );
+		return (
+			<div className={ containerClass }>
+				<ul className="carousel-container">
+					{ patterns.map( ( pattern, index ) => (
+						<BlockPatternSlide
+							className={ slideClass.get( index ) || '' }
+							key={ pattern.name }
+							pattern={ pattern }
+						/>
+					) ) }
+				</ul>
+			</div>
+		);
+	}
+	return (
+		<Composite
+			{ ...composite }
+			role="listbox"
+			className={ containerClass }
+			aria-label={ __( 'Patterns list' ) }
+		>
+			{ patterns.map( ( pattern ) => (
+				<BlockPattern
+					key={ pattern.name }
+					pattern={ pattern }
+					onSelect={ onBlockPatternSelect }
+					composite={ composite }
+				/>
+			) ) }
+		</Composite>
+	);
+};
+
+function BlockPattern( { pattern, onSelect, composite } ) {
+	const baseClassName = 'block-editor-block-pattern-setup-list';
+	const { blocks, title, description, viewportWidth = 700 } = pattern;
+	const descriptionId = useInstanceId(
+		BlockPattern,
+		`${ baseClassName }__item-description`
+	);
+	return (
+		<div
+			className={ `${ baseClassName }__list-item` }
+			aria-label={ pattern.title }
+			aria-describedby={ pattern.description ? descriptionId : undefined }
+		>
+			<CompositeItem
+				role="option"
+				as="div"
+				{ ...composite }
+				className={ `${ baseClassName }__item` }
+				onClick={ () => onSelect( blocks ) }
+			>
+				<BlockPreview
+					blocks={ blocks }
+					viewportWidth={ viewportWidth }
+				/>
+				<div className={ `${ baseClassName }__item-title` }>
+					{ title }
+				</div>
+			</CompositeItem>
+			{ !! description && (
+				<VisuallyHidden id={ descriptionId }>
+					{ description }
+				</VisuallyHidden>
+			) }
+		</div>
+	);
+}
+
+function BlockPatternSlide( { className, pattern } ) {
+	const { blocks, title, description } = pattern;
+	const descriptionId = useInstanceId(
+		BlockPatternSlide,
+		'block-editor-block-pattern-setup-list__item-description'
+	);
+	return (
+		<li
+			className={ `pattern-slide ${ className }` }
+			aria-label={ title }
+			aria-describedby={ description ? descriptionId : undefined }
+		>
+			<BlockPreview blocks={ blocks } __experimentalLive />
+			{ !! description && (
+				<VisuallyHidden id={ descriptionId }>
+					{ description }
+				</VisuallyHidden>
+			) }
+		</li>
+	);
+}
+
+const BlockPatternSetup = ( {
+	clientId,
+	blockName,
+	filterPatternsFn,
+	startBlankComponent,
+} ) => {
+	const [ viewMode, setViewMode ] = useState( VIEWMODES.carousel );
+	const [ activeSlide, setActiveSlide ] = useState( 0 );
+	const [ showBlank, setShowBlank ] = useState( false );
+	const { replaceBlock } = useDispatch( blockEditorStore );
+	const patterns = usePatternsSetup( clientId, blockName, filterPatternsFn );
+
+	if ( ! patterns?.length || showBlank ) {
+		return startBlankComponent;
+	}
+
+	const onBlockPatternSelect = ( blocks ) => {
+		const clonedBlocks = blocks.map( ( block ) => cloneBlock( block ) );
+		replaceBlock( clientId, clonedBlocks );
+	};
+	return (
+		<div
+			className={ `block-editor-block-pattern-setup view-mode-${ viewMode }` }
+		>
+			<SetupToolbar
+				viewMode={ viewMode }
+				setViewMode={ setViewMode }
+				activeSlide={ activeSlide }
+				totalSlides={ patterns.length }
+				handleNext={ () => {
+					setActiveSlide( ( active ) => active + 1 );
+				} }
+				handlePrevious={ () => {
+					setActiveSlide( ( active ) => active - 1 );
+				} }
+				onBlockPatternSelect={ () => {
+					onBlockPatternSelect( patterns[ activeSlide ].blocks );
+				} }
+				onStartBlank={ () => {
+					setShowBlank( true );
+				} }
+			/>
+			<SetupContent
+				viewMode={ viewMode }
+				activeSlide={ activeSlide }
+				patterns={ patterns }
+				onBlockPatternSelect={ onBlockPatternSelect }
+			/>
+		</div>
+	);
+};
+
+export default BlockPatternSetup;

packages/block-editor/src/components/block-pattern-setup/setup-toolbar.js

@@ -0,0 +1,97 @@
+/**
+ * WordPress dependencies
+ */
+import { __ } from '@wordpress/i18n';
+import { Button } from '@wordpress/components';
+import {
+	chevronRight,
+	chevronLeft,
+	grid,
+	stretchFullWidth,
+} from '@wordpress/icons';
+
+/**
+ * Internal dependencies
+ */
+import { VIEWMODES } from './constants';
+
+const Actions = ( { onStartBlank, onBlockPatternSelect } ) => (
+	<div className="block-editor-block-pattern-setup__actions">
+		<Button onClick={ onStartBlank }>{ __( 'Start blank' ) }</Button>
+		<Button isPrimary onClick={ onBlockPatternSelect }>
+			{ __( 'Choose' ) }
+		</Button>
+	</div>
+);
+
+const CarouselNavigation = ( {
+	handlePrevious,
+	handleNext,
+	activeSlide,
+	totalSlides,
+} ) => (
+	<div className="block-editor-block-pattern-setup__navigation">
+		<Button
+			icon={ chevronLeft }
+			label={ __( 'Previous pattern' ) }
+			onClick={ handlePrevious }
+			disabled={ activeSlide === 0 }
+		/>
+		<Button
+			icon={ chevronRight }
+			label={ __( 'Next pattern' ) }
+			onClick={ handleNext }
+			disabled={ activeSlide === totalSlides - 1 }
+		/>
+	</div>
+);
+
+const SetupToolbar = ( {
+	viewMode,
+	setViewMode,
+	handlePrevious,
+	handleNext,
+	activeSlide,
+	totalSlides,
+	onBlockPatternSelect,
+	onStartBlank,
+} ) => {
+	const isCarouselView = viewMode === VIEWMODES.carousel;
+	const displayControls = (
+		<div className="block-editor-block-pattern-setup__display-controls">
+			<Button
+				icon={ stretchFullWidth }
+				label={ __( 'Carousel view' ) }
+				onClick={ () => setViewMode( VIEWMODES.carousel ) }
+				isPressed={ isCarouselView }
+			/>
+			<Button
+				icon={ grid }
+				label={ __( 'Grid view' ) }
+				onClick={ () => setViewMode( VIEWMODES.grid ) }
+				isPressed={ viewMode === VIEWMODES.grid }
+			/>
+		</div>
+	);
+	return (
+		<div className="block-editor-block-pattern-setup__toolbar">
+			{ isCarouselView && (
+				<CarouselNavigation
+					handlePrevious={ handlePrevious }
+					handleNext={ handleNext }
+					activeSlide={ activeSlide }
+					totalSlides={ totalSlides }
+				/>
+			) }
+			{ displayControls }
+			{ isCarouselView && (
+				<Actions
+					onBlockPatternSelect={ onBlockPatternSelect }
+					onStartBlank={ onStartBlank }
+				/>
+			) }
+		</div>
+	);
+};
+
+export default SetupToolbar;