import { I18nConfig, I18n } from './I18n';
import { I18nPolyfill } from './I18nPolyfill';

type HasDefault<T> = {
	[key in keyof T]: T[key] extends undefined
		? never
		: T[key] extends (...args: infer P) => any
		? undefined extends P[0]
			? key
			: never
		: key;
}[keyof T];

type NoDefault<T> = {
	[key in keyof T]: T[key] extends undefined
		? key
		: T[key] extends (...args: infer P) => any
		? undefined extends P[0]
			? never
			: key
		: never;
}[keyof T];

type ParameterType<T> = T extends undefined ? string | number : T extends (...args: infer P) => any ? P[0] : T;

export type Locale<U extends object> = {
	[key in keyof U]: U[key] extends Array<any>
		? Extract<U[key][number], object> extends infer R
			? NoDefault<R> extends never
				? HasDefault<R> extends never
					? () => string
					: (params?: { [p in HasDefault<R>]?: ParameterType<R[p]> }) => string
				: HasDefault<R> extends never
				? (params: { [p in NoDefault<R>]: ParameterType<R[p]> }) => string
				: (
						params: { [p in NoDefault<R>]: ParameterType<R[p]> } &
							{ [p in HasDefault<R>]?: ParameterType<R[p]> }
				  ) => string
			: never
		: U[key] extends object
		? Locale<U[key]>
		: U[key];
};

export type I18nInstance<U extends object = object, T = object> = T & {
	_: Omit<I18n<U, T>, 'chain'>;
};

export function createPolyfillI18n<U extends object, T = Locale<U>>(config: I18nConfig<U>): I18nInstance<U, T> {
	const instance = new I18nPolyfill<U, T>(config);
	const data = {};

	Object.defineProperty(data, '_', {
		value: instance,
	});

	Object.keys(config.defaultLocale.values).forEach((property) => {
		Object.defineProperty(data, property, {
			get: () => {
				return instance.chain()[property];
			},
		});
	});

	// @ts-ignore
	return data;
}

export function createI18n<U extends object, T = Locale<U>>(config: I18nConfig<U>): I18nInstance<U, T> {
	if (typeof Proxy === 'function') {
		const instance = new I18n<U, T>(config);

		// @ts-ignore
		return new Proxy(
			{},
			{
				get: (_, property) => {
					if (property === '_') {
						return instance;
					}

					return instance.chain()[property];
				},
			}
		);
	}

	return createPolyfillI18n(config);
}