const { __ } = wp.i18n;
const { Toolbar, withAPIData, Dropdown, Dashicon } = wp.components;

/**
 * Product data cache.
 * Reduces the number of API calls and makes UI smoother and faster.
 */
const PRODUCT_DATA = {};

/**
 * When the display mode is 'Specific products' search for and add products to the block.
 *
 * @todo Add the functionality and everything.
 */
export class ProductsSpecificSelect extends React.Component {

	/**
	 * Constructor.
	 */
	constructor( props ) {
		super( props );

		this.state = {
			selectedProducts: props.selected_display_setting || [],
		}
	}

	/**
	 * Add a product to the list of selected products.
	 *
	 * @param id int Product ID.
	 */
	addOrRemoveProduct( id ) {
		let selectedProducts = this.state.selectedProducts;

		if ( ! selectedProducts.includes( id ) ) {
			selectedProducts.push( id );
		} else {
			selectedProducts = selectedProducts.filter( product => product !== id );
		}

		this.setState( {
			selectedProducts: selectedProducts
		} );

		/**
		 * We need to copy the existing data into a new array.
		 * We can't just push the new product onto the end of the existing array because Gutenberg seems
		 * to do some sort of check by reference to determine whether to *actually* update the attribute
		 * and will not update it if we just pass back the same array with an extra element on the end.
		 */
		this.props.update_display_setting_callback( selectedProducts.slice() );
	}

	/**
	 * Render the product specific select screen.
	 */
	render() {
		return (
			<div className="wc-products-list-card wc-products-list-card--specific">
				<ProductsSpecificSearchField
					addOrRemoveProductCallback={ this.addOrRemoveProduct.bind( this ) }
					selectedProducts={ this.state.selectedProducts }
				/>
				<ProductSpecificSelectedProducts
					columns={ this.props.attributes.columns }
					productIds={ this.state.selectedProducts }
					addOrRemoveProduct={ this.addOrRemoveProduct.bind( this ) }
				/>
			</div>
		);
	}
}

/**
 * Product search area
 */
class ProductsSpecificSearchField extends React.Component {

	/**
	 * Constructor.
	 */
	constructor( props ) {
		super( props );

		this.state = {
			searchText: '',
		}

		this.updateSearchResults = this.updateSearchResults.bind( this );
		this.setWrapperRef = this.setWrapperRef.bind( this );
		this.handleClickOutside = this.handleClickOutside.bind( this );
	}

	/**
	 * Hook in the listener for closing menu when clicked outside.
	 */
	componentDidMount() {
		document.addEventListener( 'mousedown', this.handleClickOutside );
	}

	/**
	 * Remove the listener for closing menu when clicked outside.
	 */
	componentWillUnmount() {
		document.removeEventListener( 'mousedown', this.handleClickOutside );
	}

	/**
	 * Set the wrapper reference.
	 *
	 * @param node DOMNode
	 */
	setWrapperRef( node ) {
		this.wrapperRef = node;
	}

	/**
	 * Close the menu when user clicks outside the search area.
	 */
	handleClickOutside( evt ) {
        if ( this.wrapperRef && ! this.wrapperRef.contains( event.target ) ) {
            this.setState( {
            	searchText: '',
            } );
        }
	}

	/**
	 * Event handler for updating results when text is typed into the input.
	 *
	 * @param evt Event object.
	 */
	updateSearchResults( evt ) {
		this.setState( {
			searchText: evt.target.value,
		} );
	}

	/**
	 * Render the product search UI.
	 */
	render() {
		return (
			<div className="wc-products-list-card__search-wrapper" ref={ this.setWrapperRef }>
				<div className="wc-products-list-card__input-wrapper">
					<Dashicon icon="search" />
					<input type="search"
						className="wc-products-list-card__search"
						value={ this.state.searchText }
						placeholder={ __( 'Search for products to display' ) }
						onChange={ this.updateSearchResults }
					/>
				</div>
				<ProductSpecificSearchResults
					searchString={ this.state.searchText }
					addOrRemoveProductCallback={ this.props.addOrRemoveProductCallback }
					selectedProducts={ this.props.selectedProducts }
				/>
			</div>
		);
	}
}

/**
 * Render product search results based on the text entered into the textbox.
 */
const ProductSpecificSearchResults = withAPIData( ( props ) => {

		if ( ! props.searchString.length ) {
			return {
				products: []
			};
		}

		return {
			products: '/wc/v2/products?per_page=10&search=' + props.searchString,
		};
	} )( ( { products, addOrRemoveProductCallback, selectedProducts } ) => {
		if ( ! products.data ) {
			return null;
		}

		if ( 0 === products.data.length ) {
			return <span className="wc-products-list-card__search-no-results"> { __( 'No products found' ) } </span>;
		}

		// Populate the cache.
		for ( let product of products.data ) {
			PRODUCT_DATA[ product.id ] = product;
		}

		return <ProductSpecificSearchResultsDropdown
			products={ products.data }
			addOrRemoveProductCallback={ addOrRemoveProductCallback }
			selectedProducts={ selectedProducts }
		/>
	}
);

/**
 * The dropdown of search results.
 */
class ProductSpecificSearchResultsDropdown extends React.Component {

	/**
	 * Render dropdown.
	 */
	render() {
		const { products, addOrRemoveProductCallback, selectedProducts } = this.props;

		let productElements = [];

		for ( let product of products ) {
			productElements.push(
				<ProductSpecificSearchResultsDropdownElement
					product={product}
					addOrRemoveProductCallback={ addOrRemoveProductCallback }
					selected={ selectedProducts.includes( product.id ) }
				/>
			);
		}

		return (
			<div role="menu" className="wc-products-list-card__search-results" aria-orientation="vertical" aria-label={ __( 'Products list' ) }>
				<div>
					{ productElements }
				</div>
			</div>
		);
	}
}

/**
 * One search result.
 */
class ProductSpecificSearchResultsDropdownElement extends React.Component {

	/**
	 * Constructor.
	 */
	constructor( props ) {
		super( props );

		this.handleClick = this.handleClick.bind( this );
	}

	/**
	 * Add product to main list and change UI to show it was added.
	 */
	handleClick() {
		this.props.addOrRemoveProductCallback( this.props.product.id );
	}

	/**
	 * Render one result in the search results.
	 */
	render() {
		const product = this.props.product;
		let icon = this.props.selected ? <Dashicon icon="yes" /> : null;

		return (
			<div className={ 'wc-products-list-card__content' + ( this.props.selected ? ' wc-products-list-card__content--added' : '' ) } onClick={ this.handleClick }>
				<img src={ product.images[0].src } />
				<span className="wc-products-list-card__content-item-name">{ product.name }</span>
				{ icon }
			</div>
		);
	}
}

/**
 * List preview of selected products.
 */
const ProductSpecificSelectedProducts = withAPIData( ( props ) => {
		if ( ! props.productIds.length ) {
			return {
				products: []
			};
		}

		// Determine which products are not already in the cache and only fetch uncached products.
		let uncachedProducts = [];
		for( const productId of props.productIds ) {
			if ( ! PRODUCT_DATA.hasOwnProperty( productId ) ) {
				uncachedProducts.push( productId );
			}
		}

		return {
			products: uncachedProducts.length ? '/wc/v2/products?include=' + uncachedProducts.join( ',' ) : []
		};
	} )( ( { productIds, products, columns, addOrRemoveProduct } ) => {

		// Add new products to cache.
		if ( products.data ) {
			for ( const product of products.data ) {
				PRODUCT_DATA[ product.id ] = product;
			}
		}

		const productElements = [];

		for ( const productId of productIds ) {

			// Skip products that aren't in the cache yet or failed to fetch.
			if ( ! PRODUCT_DATA.hasOwnProperty( productId ) ) {
				continue;
			}

			const productData = PRODUCT_DATA[ productId ];

			productElements.push(
				<li className="wc-products-list-card__item">
					<div className="wc-products-list-card__content">
						<img src={ productData.images[0].src } />
						<span className="wc-products-list-card__content-item-name">{ productData.name }</span>
						<button
							type="button"
							id={ 'product-' + productData.id }
							onClick={ function() { addOrRemoveProduct( productData.id ) } } >
								<Dashicon icon="no-alt" />
						</button>
					</div>
				</li>
			);
		}

		return (
			<div className={ 'wc-products-list-card__results-wrapper wc-products-list-card__results-wrapper--cols-' + columns }>
				<div role="menu" className="wc-products-list-card__results" aria-orientation="vertical" aria-label={ __( 'Selected products' ) }>
					<h3>{ __( 'Selected products' ) }</h3>

					{ ! productElements.length && <span className="wc-products-list-card__search-no-selected">{ __( 'No products selected' ) }</span> }

					<ul>
						{ productElements }
					</ul>
				</div>
			</div>
		);
	}
);