SkycrateBackend/src/main/java/com/skycrate/backend/skycrateBackend/services/JwtService.java

package com.skycrate.backend.skycrateBackend.services;

import com.skycrate.backend.skycrateBackend.entity.User;
import io.jsonwebtoken.*;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.security.Keys;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Service;

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

@Service
public class JwtService {

    @Value("${security.jwt.secret-key}")
    private String secretKey;

    @Value("${security.jwt.expiration-time}")
    private long expirationTime;

    private static final String SECRET_KEY = "PPp27xSTfBwOpRn4/AV6gPzQSnQg+Oi80KdWfCcuAHs=";

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

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

    public Date extractExpiration(String token) {
        return extractClaim(token, Claims::getExpiration);
    }

    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
        Claims claims = Jwts.parserBuilder()
                .setSigningKey(getSigningKey())
                .build()
                .parseClaimsJws(token)
                .getBody();
        return claimsResolver.apply(claims);
    }

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

    public boolean isTokenExpired(String token) {
        return extractExpiration(token).before(new Date());
    }

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

    public String generateToken(User user) {
        return generateToken((UserDetails) user);
    }
}