import { createHmac } from 'crypto';

/**
 * hmac加密用户绑定token
 * @param str
 */
export function encryptionUserToken(id: number, randomCode: string, time?: number): string {
	let now: string;
	if (!time) {
		const timestamp: number = Date.now();
		now = Math.round(timestamp / 1000 / 30).toString();
	} else {
		now = time.toString();
	}
	const originalToken = createHmac('sha256', now)
		.update(id + randomCode)
		.digest('hex');
	const token = originalToken.toUpperCase().substr(parseInt(now.charAt(now.length - 3), 10), 4);
	return token;
}


/**
 * 验证用户绑定token是否合法
 * @param id 用户id
 * @param randomCode 随机码
 * @param token 验证的token
 */
export async function verifyUserToken(id: number, randomCode: string, token: string): Promise<boolean> {
	const time = Math.round(Date.now() / 1000 / 30);
	if (
		token === encryptionUserToken(id, randomCode, time) ||
		token === encryptionUserToken(id, randomCode, time - 1)
	) {
		return true;
	} else {
		return false;
	}
}