import Element from '../nodes/element/Element.js';
import * as PropertySymbol from '../PropertySymbol.js';
import DOMStringMapUtility from './DOMStringMapUtility.js';

/**
 * Dataset factory.
 *
 * Reference:
 * https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/dataset
 */
export default class DOMStringMap {
	[key: string]: string;

	/**
	 * Constructor.
	 *
	 * @param illegalConstructorSymbol Illegal constructor symbol.
	 * @param element Element.
	 */
	constructor(illegalConstructorSymbol: symbol, element: Element) {
		if (illegalConstructorSymbol !== PropertySymbol.illegalConstructor) {
			throw new TypeError('Illegal constructor');
		}

		// Documentation for Proxy:
		// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy
		return new Proxy(this, {
			get(_target, property: string): string {
				const attribute = element[PropertySymbol.attributes][PropertySymbol.namedItems].get(
					'data-' + DOMStringMapUtility.camelCaseToKebab(property)
				);
				if (attribute) {
					return attribute[PropertySymbol.value];
				}
			},
			set(_target, property: string, value: string): boolean {
				element.setAttribute('data-' + DOMStringMapUtility.camelCaseToKebab(property), value);
				return true;
			},
			deleteProperty(_target, property: string): boolean {
				element.removeAttribute('data-' + DOMStringMapUtility.camelCaseToKebab(property));
				return true;
			},
			ownKeys(_target): string[] {
				// According to Mozilla we have to update the dataset object (target) to contain the same keys as what we return:
				// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy/Proxy/ownKeys
				// "The result List must contain the keys of all non-configurable own properties of the target object."
				const keys = [];
				for (const item of element[PropertySymbol.attributes][PropertySymbol.namedItems].values()) {
					if (item[PropertySymbol.name].startsWith('data-')) {
						keys.push(
							DOMStringMapUtility.kebabToCamelCase(item[PropertySymbol.name].replace('data-', ''))
						);
					}
				}
				return keys;
			},
			has(_target, property: string): boolean {
				return element[PropertySymbol.attributes][PropertySymbol.namedItems].has(
					'data-' + DOMStringMapUtility.camelCaseToKebab(property)
				);
			},
			defineProperty(_target, property: string, descriptor): boolean {
				if (descriptor.value === undefined) {
					return false;
				}

				element.setAttribute(
					'data-' + DOMStringMapUtility.camelCaseToKebab(property),
					descriptor.value
				);

				return true;
			},
			getOwnPropertyDescriptor(_target, property: string): PropertyDescriptor {
				const attribute = element[PropertySymbol.attributes][PropertySymbol.namedItems].get(
					'data-' + DOMStringMapUtility.camelCaseToKebab(property)
				);
				if (!attribute) {
					return;
				}
				return {
					value: attribute[PropertySymbol.value],
					writable: true,
					enumerable: true,
					configurable: true
				};
			}
		});
	}
}