package com.bycrm.util;

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.crypto.SecretKey;
import java.nio.charset.StandardCharsets;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * JWT 工具类
 */
@Component
public class JwtUtil {

    @Value("${jwt.secret}")
    private String secret;

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

    @Value("${jwt.remember-expiration:604800000}")
    private Long rememberExpiration;

    public Long getRememberExpiration() {
        return rememberExpiration;
    }

    /**
     * 生成 Token
     */
    public String generateToken(Long userId, String username, Integer role, Long dealerId) {
        return generateToken(userId, username, role, dealerId, expiration);
    }

    /**
     * 生成指定有效期的 Token（用于"记住我"延长有效期）
     */
    public String generateToken(Long userId, String username, Integer role, Long dealerId, long expirationMillis) {
        Map<String, Object> claims = new HashMap<>();
        claims.put("userId", userId);
        claims.put("username", username);
        claims.put("role", role);
        claims.put("dealerId", dealerId);
        return generateToken(claims, expirationMillis);
    }

    /**
     * 生成 Token
     */
    public String generateToken(Map<String, Object> claims) {
        return generateToken(claims, expiration);
    }

    /**
     * 生成指定有效期的 Token
     */
    public String generateToken(Map<String, Object> claims, long expirationMillis) {
        Date now = new Date();
        Date expiryDate = new Date(now.getTime() + expirationMillis);

        return Jwts.builder()
                .setClaims(claims)
                .setIssuedAt(now)
                .setExpiration(expiryDate)
                .signWith(getSigningKey(), SignatureAlgorithm.HS512)
                .compact();
    }

    /**
     * 从 Token 中获取 Claims
     */
    public Claims getClaimsFromToken(String token) {
        return Jwts.parserBuilder()
                .setSigningKey(getSigningKey())
                .build()
                .parseClaimsJws(token)
                .getBody();
    }

    /**
     * 从 Token 中获取用户ID
     */
    public Long getUserIdFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("userId", Long.class);
    }

    /**
     * 从 Token 中获取用户名
     */
    public String getUsernameFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("username", String.class);
    }

    /**
     * 从 Token 中获取角色
     */
    public Integer getRoleFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("role", Integer.class);
    }

    /**
     * 从 Token 中获取经销商ID
     */
    public Long getDealerIdFromToken(String token) {
        Claims claims = getClaimsFromToken(token);
        return claims.get("dealerId", Long.class);
    }

    /**
     * 验证 Token 是否过期
     */
    public boolean isTokenExpired(String token) {
        try {
            Date expiration = getClaimsFromToken(token).getExpiration();
            return expiration.before(new Date());
        } catch (Exception e) {
            return true;
        }
    }

    /**
     * 验证 Token
     */
    public boolean validateToken(String token) {
        try {
            return !isTokenExpired(token);
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * 获取签名密钥
     */
    private SecretKey getSigningKey() {
        byte[] keyBytes = secret.getBytes(StandardCharsets.UTF_8);
        return Keys.hmacShaKeyFor(keyBytes);
    }
}