import jwt, { JwtPayload, SignOptions } from 'jsonwebtoken';
import crypto from 'crypto';
import config from '../config';

// ─── OTP ─────────────────────────────────────────────────────────────────────

export const generateOTP = (length = 6): string =>
  Array.from({ length }, () => Math.floor(Math.random() * 10)).join('');

// ─── Random ──────────────────────────────────────────────────────────────────

export const generateRandomString = (length = 10): string =>
  crypto.randomBytes(length).toString('hex').slice(0, length);

// ─── Validation ──────────────────────────────────────────────────────────────

export const isValidEmail = (email: string): boolean =>
  /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(email);

export const isValidPhone = (phone: string): boolean =>
  /^\+?[0-9]{10,15}$/.test(phone);

export const check_Input_isPhone_Or_isEmail = (
  input: string
): { type: 'email' | 'phone'; value: string } => {
  if (isValidEmail(input)) return { type: 'email', value: input };
  if (isValidPhone(input)) return { type: 'phone', value: input };
  throw new Error('Input is neither a valid email nor phone number');
};

// ─── Masking ─────────────────────────────────────────────────────────────────

export const maskSensitiveInfo = (
  value: string,
  type: 'email' | 'phone'
): string => {
  if (type === 'email') {
    const [user, domain] = value.split('@');
    return `${user.slice(0, 3)}***@${domain}`;
  }
  return value.slice(0, 3) + '****' + value.slice(-3);
};

// ─── JWT ─────────────────────────────────────────────────────────────────────

export const createToken = (
  payload: object,
  secret: string,
  expiresIn: string
): string => jwt.sign(payload, secret, { expiresIn } as SignOptions);

export const verifyToken = (token: string, secret: string): JwtPayload =>
  jwt.verify(token, secret) as JwtPayload;

export const createAccessToken = (payload: object): string =>
  createToken(
    payload,
    config.jwt_access_token_secret,
    config.jwt_access_token_expires_in
  );

export const createRefreshToken = (payload: object): string =>
  createToken(
    payload,
    config.jwt_refresh_token_secret,
    config.jwt_refresh_token_expires_in
  );

// ─── Transaction ID ──────────────────────────────────────────────────────────

export const generateTransactionId = (length = 12): string =>
  crypto.randomBytes(length).toString('hex').toUpperCase().slice(0, length);