package com.t2404e.aihealthcoach.config;

import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.util.Date;
import java.util.Map;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtException;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.security.Keys;

@Component
public class JwtUtil {

    private final Key key;
    private final long expirationMs;

    public JwtUtil(@Value("${app.jwt.secret}") String secret,
                   @Value("${app.jwt.expiration-minutes}") long expMinutes) {
        this.key = Keys.hmacShaKeyFor(secret.getBytes(StandardCharsets.UTF_8));
        this.expirationMs = expMinutes * 60 * 1000;
    }

    public String generateToken(Long userId, String email, String role, String fullName) {
        Date now = new Date();
        Date expiry = new Date(now.getTime() + expirationMs);

        return Jwts.builder()
                .subject(email)
                .claims(Map.of(
                        "userId", userId,
                        "role", role,
                        "fullName", fullName
                ))
                .issuedAt(now)
                .expiration(expiry)
                .signWith(key)
                .compact();
    }

    public Claims parseClaims(String token) {
        return Jwts.parser()
                .verifyWith((javax.crypto.SecretKey) key)
                .build()
                .parseSignedClaims(token)
                .getPayload();
    }

    public boolean isTokenValid(String token) {
        try {
            parseClaims(token);
            return true;
        } catch (JwtException | IllegalArgumentException ex) {
            return false;
        }
    }
}