/**
 * External dependencies
 */
import { useEffect, useRef, useState } from '@wordpress/element';
import { getAttributes, getTerms } from '@woocommerce/editor-components/utils';
import {
	AttributeObject,
	AttributeTerm,
	AttributeWithTerms,
} from '@woocommerce/types';
import { formatError } from '@woocommerce/base-utils';

export default function useProductAttributes( shouldLoadAttributes: boolean ) {
	const [ errorLoadingAttributes, setErrorLoadingAttributes ] =
		useState< Awaited< ReturnType< typeof formatError > > | null >( null );
	const [ isLoadingAttributes, setIsLoadingAttributes ] = useState( false );
	const [ productsAttributes, setProductsAttributes ] = useState<
		AttributeWithTerms[]
	>( [] );
	const hasLoadedAttributes = useRef( false );

	useEffect( () => {
		if (
			! shouldLoadAttributes ||
			isLoadingAttributes ||
			hasLoadedAttributes.current
		)
			return;

		async function fetchAttributesWithTerms() {
			setIsLoadingAttributes( true );

			try {
				const attributes: AttributeObject[] = await getAttributes();
				const attributesWithTerms: AttributeWithTerms[] = [];

				for ( const attribute of attributes ) {
					const terms: AttributeTerm[] = await getTerms(
						attribute.id
					);

					attributesWithTerms.push( {
						...attribute,
						// Manually adding the parent id because of a Rest API bug
						// returning always `0` as parent.
						// see https://github.com/woocommerce/woocommerce-blocks/issues/8501
						parent: 0,
						terms: terms.map( ( term ) => ( {
							...term,
							attr_slug: attribute.taxonomy,
							parent: attribute.id,
						} ) ),
					} );
				}

				setProductsAttributes( attributesWithTerms );
				hasLoadedAttributes.current = true;
			} catch ( e ) {
				if ( e instanceof Error ) {
					setErrorLoadingAttributes( await formatError( e ) );
				}
			} finally {
				setIsLoadingAttributes( false );
			}
		}

		fetchAttributesWithTerms();

		return () => {
			hasLoadedAttributes.current = true;
		};
	}, [ isLoadingAttributes, shouldLoadAttributes ] );

	return {
		errorLoadingAttributes,
		isLoadingAttributes,
		productsAttributes,
	};
}