import { inject } from '@loopback/context';
import { HttpErrors } from '@loopback/rest';
import { TokenService } from './types';
import { TokenServiceBindings } from './keys';
import { UserProfile } from '../data';


const jwt = require('jsonwebtoken');
const jwtSign = jwt.sign, jwtVerify = jwt.verify;

export class AppJWTTokenService implements TokenService
{
  constructor(
		@inject(TokenServiceBindings.SECRET) private _jwtSecret: string,
		@inject(TokenServiceBindings.ISSUER) private _jwtIssuer: string,
		@inject(TokenServiceBindings.AUDIENCE) private _jwtAudience: string,
		@inject(TokenServiceBindings.EXPIRES_IN) private _jwtExpiresIn: string,
	) {}

	async verifyToken (token: string): Promise<UserProfile>
	{
		try {

			const userProfile: UserProfile = jwtVerify
			(
				token,
				this._jwtSecret,
				{
					issuer: this._jwtIssuer,
					audience: this._jwtAudience,
				}
			);

			return userProfile;

		} catch (err) {

			throw new HttpErrors.Unauthorized(`Error: verifying token ${err}`);
		}
	}

	async generateToken (userProfile: UserProfile): Promise<string>
	{
		try {

			const token = jwtSign
			(
				userProfile,
				this._jwtSecret,
				{
					issuer: this._jwtIssuer,
					audience: this._jwtAudience,
					expiresIn: Number(this._jwtExpiresIn),
				}
			);

			return token;

		} catch (err) {

			throw new HttpErrors.Unauthorized(`Error: generate token ${err}`);
		}
	}
}