package mk.ukim.finki.predmeti.internettehnologii.jobvistabackend.service.impl;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.security.Keys;
import mk.ukim.finki.predmeti.internettehnologii.jobvistabackend.service.intef.JwtService;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Service;

import java.security.Key;
import java.util.Date;
import java.util.Map;
import java.util.function.Function;

@Service
public class JwtServiceImpl implements JwtService {
    private final static String SECRET_KEY = "7191b1d33668d4a2316a02f9a40798b77bccd22173bd882c93a0a916a5e921d1";

    public String generateToken(UserDetails userDetails) {
        return Jwts.builder().setSubject(userDetails.getUsername())
                .setIssuedAt(new Date())
                .setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 24))
                .signWith(getSigninKey(), SignatureAlgorithm.HS256)
                .compact();
    }

    @Override
    public String generateRefreshToken(Map<String, Object> extraClaims, UserDetails userDetails) {
        return Jwts.builder().setClaims(extraClaims).setSubject(userDetails.getUsername())
                .setIssuedAt(new Date())
                .setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 24 * 7))
                .signWith(getSigninKey(), SignatureAlgorithm.HS256)
                .compact();
    }

    private Key getSigninKey() {
        byte[] key = Decoders.BASE64.decode(SECRET_KEY);
        return Keys.hmacShaKeyFor(key);
    }

    public String extractUsername(String token) {
        return extractClaim(token, Claims::getSubject);
    }

    private Claims extractAllClaims(String token) {
        return Jwts.parserBuilder().setSigningKey(getSigninKey()).build().parseClaimsJws(token).getBody();
    }

    public  <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
        final Claims claims = extractAllClaims(token);
        return claimsResolver.apply(claims);
    }

    public boolean isTokenValid(String token, UserDetails userDetails) {
        final String username = extractUsername(token);
        return username.equals(userDetails.getUsername()) && !isTokenExpired(token);
    }


    private boolean isTokenExpired(String token) {
        return extractClaim(token, Claims::getExpiration).before(new Date());
    }
}