package org.initialde.yakasave.Infrastructure.authentication.Jwt;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.io.Decoders;
import io.jsonwebtoken.security.Keys;
import org.initialde.yakasave.Api.Requests.LoginRequest;
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.HashMap;
import java.util.Map;
import java.util.function.Function;

@Service
public class JwtServiceImpl implements JwtService {
    @Value("${jwt.secret}")
    private String secretKey;
    @Value("${jwt.expiration}")
    private long jwtExpirationTime;

    @Override
    public String generateToken(LoginRequest loginRequest) {
        return generate(new HashMap<>(), loginRequest);
    }

    private String generate(Map<String, Object> extraClaims, LoginRequest loginRequest) {
        return buildToken(
                extraClaims,
                loginRequest,
                jwtExpirationTime
        );
    }

    private String buildToken(Map<String, Object> extraClaims, LoginRequest loginRequest, long expirationTime) {
        return Jwts
                .builder()
                .setClaims(extraClaims)
                .setSubject(loginRequest.username())
                .setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + expirationTime))
                .signWith(getSignInKey(), SignatureAlgorithm.HS256)
                .compact();
    }

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

    @Override
    public boolean isTokenValid(String jwt, UserDetails userDetails) {
        return true;
    }

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

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

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

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

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