package com.example.security;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.security.Keys;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import java.security.Key;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Component
public class JwtTokenUtil {

    @Value("${jwt.secret:data-oracle-secret-key-for-jwt-token-generation}")
    private String secret;

    @Value("${jwt.expiration:86400000}")
    private Long expiration;

    private Key key;

    @PostConstruct
    public void init() {
        this.key = Keys.hmacShaKeyFor(secret.getBytes());
    }

    public String generateToken(Long userId, String username, String deptCode) {
        Map<String, Object> claims = new HashMap<>();
        claims.put("userId", userId);
        claims.put("username", username);
        claims.put("deptCode", deptCode);
        return createToken(claims, username);
    }

    private String createToken(Map<String, Object> claims, String subject) {
        return Jwts.builder()
                .setClaims(claims)
                .setSubject(subject)
                .setIssuedAt(new Date(System.currentTimeMillis()))
                .setExpiration(new Date(System.currentTimeMillis() + expiration))
                .signWith(key, SignatureAlgorithm.HS256)
                .compact();
    }

    public String getUsernameFromToken(String token) {
        return getClaimsFromToken(token).getSubject();
    }

    public Long getUserIdFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("userId", Long.class);
    }

    public String getDeptCodeFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("deptCode", String.class);
    }

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

    public boolean validateToken(String token) {
        try {
            getClaimsFromToken(token);
            return !isTokenExpired(token);
        } catch (Exception e) {
            return false;
        }
    }

    private boolean isTokenExpired(String token) {
        Date expiration = getClaimsFromToken(token).getExpiration();
        return expiration.before(new Date());
    }
}