import crypto, { KeyObject } from 'crypto';
import util from 'util';
import type { TapoDeviceKey } from '../types/raw-types';

const RSA_CIPHER_ALGORITHM = 'rsa';
const AES_CIPHER_ALGORITHM = 'aes-128-cbc';
const PASSPHRASE = 'top secret';

export const generateKeyPair = async () => {
	const RSA_OPTIONS = {
		modulusLength: 1024,
		publicKeyEncoding: {
			type: 'spki',
			format: 'pem',
		},
		privateKeyEncoding: {
			type: 'pkcs1',
			format: 'pem',
			cipher: 'aes-256-cbc',
			passphrase: PASSPHRASE,
		},
	};
	const generateKeyPair = util.promisify(crypto.generateKeyPair);
	return generateKeyPair(RSA_CIPHER_ALGORITHM, RSA_OPTIONS);
};

export const encrypt = (data: any, deviceKey: TapoDeviceKey): string => {
	var cipher = crypto.createCipheriv(AES_CIPHER_ALGORITHM, deviceKey.key, deviceKey.iv);
	var ciphertext = cipher.update(Buffer.from(JSON.stringify(data)));
	return Buffer.concat([ciphertext, cipher.final()]).toString('base64');
};

export const decrypt = (data: string, deviceKey: TapoDeviceKey): any => {
	var cipher = crypto.createDecipheriv(AES_CIPHER_ALGORITHM, deviceKey.key, deviceKey.iv);
	var ciphertext = cipher.update(Buffer.from(data, 'base64'));
	return JSON.parse(Buffer.concat([ciphertext, cipher.final()]).toString());
};

export const readDeviceKey = (pemKey: string, privateKey: KeyObject): Buffer => {
	const keyBytes = Buffer.from(pemKey, 'base64');
	const deviceKey = crypto.privateDecrypt(
		{
			key: privateKey,
			padding: crypto.constants.RSA_PKCS1_PADDING,
			passphrase: PASSPHRASE,
		},
		keyBytes,
	);

	return deviceKey;
};

export const base64Encode = (data: string): string => {
	return Buffer.from(data).toString('base64');
};

export const base64Decode = (data: string): string => {
	return Buffer.from(data, 'base64').toString();
};

export const shaDigest = (data: string): string => {
	var shasum = crypto.createHash('sha1');
	shasum.update(data);
	return shasum.digest('hex');
};