import { MixedList } from '../common/MixedList';

export class ObjectUtils {
	/**
	 * Checks if given value is an object.
	 * We cannot use instanceof because it has problems when running on different contexts.
	 * And we don't simply use typeof because typeof null === "object".
	 */
	static isObject(val: any): val is Object {
		return val !== null && typeof val === 'object';
	}

	/**
	 * Checks if given value is an object.
	 * We cannot use instanceof because it has problems when running on different contexts.
	 * And we don't simply use typeof because typeof null === "object".
	 */
	static isObjectWithName(val: any): val is Object & { name: string } {
		return val !== null && typeof val === 'object' && val['name'] !== undefined;
	}

	/**
	 * Copy the values of all of the enumerable own properties from one or more source objects to a
	 * target object.
	 * @param target The target object to copy to.
	 * @param source The source object from which to copy properties.
	 */
	static assign<T, U>(target: T, source: U): void;

	/**
	 * Copy the values of all of the enumerable own properties from one or more source objects to a
	 * target object.
	 * @param target The target object to copy to.
	 * @param source1 The first source object from which to copy properties.
	 * @param source2 The second source object from which to copy properties.
	 */
	static assign<T, U, V>(target: T, source1: U, source2: V): void;

	/**
	 * Copy the values of all of the enumerable own properties from one or more source objects to a
	 * target object.
	 * @param target The target object to copy to.
	 * @param source1 The first source object from which to copy properties.
	 * @param source2 The second source object from which to copy properties.
	 * @param source3 The third source object from which to copy properties.
	 */
	static assign<T, U, V, W>(target: T, source1: U, source2: V, source3: W): void;

	/**
	 * Copy the values of all of the enumerable own properties from one or more source objects to a
	 * target object.
	 * @param target The target object to copy to.
	 * @param sources One or more source objects from which to copy properties
	 */
	static assign(target: object, ...sources: any[]): void {
		for (const source of sources) {
			for (const prop of Object.getOwnPropertyNames(source)) {
				(target as any)[prop] = source[prop];
			}
		}
	}

	/**
	 * Converts MixedList<T> to strictly an array of its T items.
	 */
	static mixedListToArray<T>(list: MixedList<T>): T[] {
		if (list !== null && typeof list === 'object') {
			return Object.keys(list).map((key) => (list as { [key: string]: T })[key]);
		} else {
			return list;
		}
	}
}