/**
 * External dependencies
 */
import { map, mapValues } from 'lodash';
import { EMPTY_ARRAY, EMPTY_OBJECT } from '@nelio-content/constants';
import { createIndexedSelector, isDefined } from '@nelio-content/utils';
import type {
	Maybe,
	PostId,
	PremiumItems,
	PremiumItemSummaries,
	PremiumItemType,
} from '@nelio-content/types';

/**
 * Internal dependencies
 */
import type { State } from '../../config';

type GetPremiumItem = typeof _getPremiumItem & {
	CurriedSignature: < Type extends PremiumItemType >(
		type: Type,
		id?: PremiumItems[ Type ][ 'id' ]
	) => Maybe< PremiumItems[ Type ] >;
};
export const getPremiumItem: GetPremiumItem = _getPremiumItem as GetPremiumItem;
function _getPremiumItem< Type extends PremiumItemType >(
	state: State,
	type: Type,
	id?: PremiumItems[ Type ][ 'id' ]
): Maybe< PremiumItems[ Type ] > {
	return id ? state.entities.premiumByType[ type ]?.byId[ id ] : undefined;
}

type GetAllPremiumItemsRelatedToPost =
	typeof _getAllPremiumItemsRelatedToPost & {
		CurriedSignature: ( postId?: PostId ) => Partial< {
			[ K in PremiumItemType ]: ReadonlyArray< PremiumItems[ K ] >;
		} >;
	};
const _getAllPremiumItemsRelatedToPost = createIndexedSelector(
	(
		state: State,
		postId?: PostId
	): Partial< {
		[ K in PremiumItemType ]: ReadonlyArray< PremiumItems[ K ] >;
	} > => {
		if ( ! postId ) {
			return EMPTY_OBJECT;
		}

		const summariesByType = mapValues(
			state.entities.premiumByType,
			( s ) => s?.byRelatedPost[ postId ] ?? EMPTY_ARRAY
		);

		return mapValues(
			summariesByType,
			< K extends PremiumItemType >(
				summaries: ReadonlyArray< PremiumItemSummaries[ K ] >,
				type: K
			) =>
				map( summaries, ( { id } ) =>
					getPremiumItem( state, type, id )
				).filter( isDefined )
		) as Partial< {
			[ K in PremiumItemType ]: ReadonlyArray< PremiumItems[ K ] >;
		} >;
	},
	( state: State, postId?: PostId ) => ( {
		key: postId || 0,
		dependants: [ state.entities.premiumByType ],
	} )
);
export const getAllPremiumItemsRelatedToPost =
	_getAllPremiumItemsRelatedToPost as GetAllPremiumItemsRelatedToPost;

type GetPremiumItemsRelatedToPost = typeof _getPremiumItemsRelatedToPost & {
	CurriedSignature: < Type extends PremiumItemType >(
		typeName: Type,
		postId?: PostId
	) => ReadonlyArray< PremiumItems[ Type ] >;
};
export const getPremiumItemsRelatedToPost =
	_getPremiumItemsRelatedToPost as GetPremiumItemsRelatedToPost;
function _getPremiumItemsRelatedToPost< Type extends PremiumItemType >(
	state: State,
	typeName: Type,
	postId?: PostId
): ReadonlyArray< PremiumItems[ Type ] > {
	const all = getAllPremiumItemsRelatedToPost( state, postId );
	return all[ typeName ] ?? EMPTY_ARRAY;
}