package xin.merlin.myplayerbackend.utils;

import io.jsonwebtoken.*;
import io.jsonwebtoken.security.Keys;
import jakarta.annotation.PostConstruct;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Component;
import xin.merlin.myplayerbackend.config.security.JwtProperties;


import javax.crypto.SecretKey;
import java.nio.charset.StandardCharsets;
import java.util.Date;
import java.util.UUID;

@Component
@RequiredArgsConstructor
public class JwtUtil {

    private final JwtProperties jwtProperties;

    private SecretKey key;
    private JwtParser jwtParser;

    @PostConstruct
    public void init() {
        try {
            // 从配置文件密钥生成 SecretKey
            this.key = Keys.hmacShaKeyFor(jwtProperties.getSecret().getBytes(StandardCharsets.UTF_8));
            this.jwtParser = Jwts.parser()
                    .verifyWith(key)
                    .build();
        } catch (Exception e) {
            throw new RuntimeException("JWT 密钥初始化失败，请检查配置文件 jwt.secret", e);
        }
    }

    /**
     * 生成 JWT Token
     */
    public String generateToken(String uAccount, Integer uId) {
        Date now = new Date();
        Date expireDate = new Date(now.getTime() + jwtProperties.getExpire() * 1000L);

        return Jwts.builder()
                .subject(uAccount)
                .claim("id", uId)
                .claim("account", uAccount)
                .id(UUID.randomUUID().toString())
                .issuedAt(now)
                .expiration(expireDate)
                .issuer(jwtProperties.getIssuer())
                .signWith(key, Jwts.SIG.HS256) // JJWT 0.12.6推荐的写法
                .compact();
    }

    /**
     * 解析 Token 获取 Claims
     */
    public Claims getClaims(String token) {
        try {
            Jws<Claims> jws = jwtParser.parseSignedClaims(token);
            System.out.println(jws.getPayload());
            return jws.getPayload();
        } catch (ExpiredJwtException e) {
            throw new TokenExpiredException("Token 已过期", e);
        } catch (JwtException e) {
            throw new InvalidTokenException("无效的 Token", e);
        } catch (Exception e) {
            throw new InvalidTokenException("解析 Token 失败", e);
        }
    }

    /**
     * 判断 Token 是否过期
     */
    public boolean isTokenExpired(String token) {
        Claims claims = getClaims(token);
        return claims.getExpiration().before(new Date());
    }

    /**
     * 获取账号
     */
    public String getUAccount(String token) {
        Claims claims = getClaims(token);
        return claims.getSubject();
    }

    /**
     * 获取用户ID
     */
    public String getUId(String token) {
        Claims claims = getClaims(token);
        return claims.get("id", String.class);
    }

    // 自定义异常类
    public static class TokenExpiredException extends RuntimeException {
        public TokenExpiredException(String message, Throwable cause) {
            super(message, cause);
        }
    }

    public static class InvalidTokenException extends RuntimeException {
        public InvalidTokenException(String message, Throwable cause) {
            super(message, cause);
        }
    }
}