import { useState } from '@wordpress/element';
import type { Link } from '../../shared/api/types/links';

function withLinkSelected(
	selectedIds: ReadonlySet< number >,
	linkId: number,
	isSelected: boolean
): ReadonlySet< number > {
	const nextIds = new Set( selectedIds );

	if ( isSelected ) {
		nextIds.add( linkId );
	} else {
		nextIds.delete( linkId );
	}

	return nextIds;
}

export function useLinkSelection( shownLinks: readonly Link[] ) {
	const [ selectedIds, setSelectedIds ] = useState< ReadonlySet< number > >(
		() => new Set()
	);
	const selectedLinks = shownLinks.filter( ( link ) =>
		selectedIds.has( link.id )
	);

	const select = ( linkId: number, isSelected: boolean ) => {
		setSelectedIds( ( previousIds ) =>
			withLinkSelected( previousIds, linkId, isSelected )
		);
	};

	const selectAll = () => {
		setSelectedIds( new Set( shownLinks.map( ( link ) => link.id ) ) );
	};

	const clear = () => {
		setSelectedIds( new Set() );
	};

	return { selectedIds, selectedLinks, select, selectAll, clear };
}

export type LinkSelection = ReturnType< typeof useLinkSelection >;