<%#
 Copyright 2013-2018 the original author or authors from the JHipster project.

 This file is part of the JHipster project, see https://www.jhipster.tech/
 for more information.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-%>
package <%=packageName%>.security.jwt;

import io.github.jhipster.config.JHipsterProperties;

import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.stream.Collectors;
import javax.annotation.PostConstruct;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.stereotype.Component;

import io.jsonwebtoken.*;

@Component
public class TokenProvider {

    private final Logger log = LoggerFactory.getLogger(TokenProvider.class);

    private static final String AUTHORITIES_KEY = "auth";

    private final Base64.Encoder encoder = Base64.getEncoder();

    private String secretKey;

    private long tokenValidityInMilliseconds;

    private long tokenValidityInMillisecondsForRememberMe;

    private final JHipsterProperties jHipsterProperties;

    public TokenProvider(JHipsterProperties jHipsterProperties) {
        this.jHipsterProperties = jHipsterProperties;
    }

    @PostConstruct
    public void init() {
        this.secretKey = encoder.encodeToString(jHipsterProperties.getSecurity().getAuthentication().getJwt()
            .getSecret().getBytes(StandardCharsets.UTF_8));

        this.tokenValidityInMilliseconds =
            1000 * jHipsterProperties.getSecurity().getAuthentication().getJwt().getTokenValidityInSeconds();
        this.tokenValidityInMillisecondsForRememberMe =
            1000 * jHipsterProperties.getSecurity().getAuthentication().getJwt()
                .getTokenValidityInSecondsForRememberMe();
    }

    public String createToken(Authentication authentication, boolean rememberMe) {
        String authorities = authentication.getAuthorities().stream()
            .map(GrantedAuthority::getAuthority)
            .collect(Collectors.joining(","));

        long now = (new Date()).getTime();
        Date validity;
        if (rememberMe) {
            validity = new Date(now + this.tokenValidityInMillisecondsForRememberMe);
        } else {
            validity = new Date(now + this.tokenValidityInMilliseconds);
        }

        return Jwts.builder()
            .setSubject(authentication.getName())
            .claim(AUTHORITIES_KEY, authorities)
            .signWith(SignatureAlgorithm.HS512, secretKey)
            .setExpiration(validity)
            .compact();
    }

    public Authentication getAuthentication(String token) {
        Claims claims = Jwts.parser()
            .setSigningKey(secretKey)
            .parseClaimsJws(token)
            .getBody();

        Collection<? extends GrantedAuthority> authorities =
            Arrays.stream(claims.get(AUTHORITIES_KEY).toString().split(","))
                .map(SimpleGrantedAuthority::new)
                .collect(Collectors.toList());

        User principal = new User(claims.getSubject(), "", authorities);

        return new UsernamePasswordAuthenticationToken(principal, token, authorities);
    }

    public boolean validateToken(String authToken) {
        try {
            Jwts.parser().setSigningKey(secretKey).parseClaimsJws(authToken);
            return true;
        } catch (SignatureException e) {
            log.info("Invalid JWT signature.");
            log.trace("Invalid JWT signature trace: {}", e);
        } catch (MalformedJwtException e) {
            log.info("Invalid JWT token.");
            log.trace("Invalid JWT token trace: {}", e);
        } catch (ExpiredJwtException e) {
            log.info("Expired JWT token.");
            log.trace("Expired JWT token trace: {}", e);
        } catch (UnsupportedJwtException e) {
            log.info("Unsupported JWT token.");
            log.trace("Unsupported JWT token trace: {}", e);
        } catch (IllegalArgumentException e) {
            log.info("JWT token compact of handler are invalid.");
            log.trace("JWT token compact of handler are invalid trace: {}", e);
        }
        return false;
    }
}