import { type ObjectKey, parseObjectPath } from './parseObjectPath';

/**
 * get by path
 *
 * {@link https://github.com/developit/dlv dlv}
 */
export function get<O extends object, P extends ObjectKey, OrElse>(
	obj: O,
	key: P | P[],
	def?: OrElse,
): ResolveObjectPathType<O, P, OrElse> {
	const undef = undefined;
	const path = parseObjectPath(key);
	let out: any = obj;
	for (const i of path) {
		out = out ? out[i] : undef;
	}
	return out === undef ? (def as any) : out;
}

/**
 * It tries to resolve the path of the given object, otherwise it will return OrElse
 *
 * {@link https://github.com/Pouja/typescript-deep-path-safe typescript-deep-path-safe}
 */
export type ResolveObjectPathType<
	ObjectType,
	Path extends string | symbol | number,
	OrElse,
> = Path extends keyof ObjectType
	? ObjectType[Path]
	: Path extends `${infer LeftSide}.${infer RightSide}`
		? LeftSide extends keyof ObjectType
			? ResolveObjectPathType<ObjectType[LeftSide], RightSide, OrElse>
			: Path extends `${infer LeftSide}[${number}].${infer RightSide}`
				? LeftSide extends keyof ObjectType
					? ObjectType[LeftSide] extends Array<infer U>
						? ResolveObjectPathType<U, RightSide, OrElse>
						: OrElse
					: OrElse
				: OrElse
		: Path extends `${infer LeftSide}[${number}]`
			? LeftSide extends keyof ObjectType
				? ObjectType[LeftSide] extends Array<infer U>
					? U
					: OrElse
				: OrElse
			: OrElse;