package service

import (
	"time"
	
	"github.com/golang-jwt/jwt/v4"
	
	"newaterobot-process/config"
)

// CustomClaims 自定义声明结构体
type CustomClaims struct {
	UserID   uint   `json:"user_id"`
	Username string `json:"username"`
	jwt.RegisteredClaims
}

// JWTService JWT服务
type JWTService struct{}

var jwtService = new(JWTService)

// GenerateToken 生成token
func (j *JWTService) GenerateToken(userID uint, username string) (string, error) {
	// 获取JWT配置
	jwtConfig := config.GlobalConfig.JWT
	
	// 创建声明
	claims := CustomClaims{
		userID,
		username,
		jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(jwtConfig.Expire) * time.Second)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			NotBefore: jwt.NewNumericDate(time.Now()),
		},
	}

	// 创建token
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

	// 签名token
	return token.SignedString([]byte(jwtConfig.Secret))
}

// ParseToken 解析token
func (j *JWTService) ParseToken(tokenString string) (*CustomClaims, error) {
	// 获取JWT配置
	jwtConfig := config.GlobalConfig.JWT
	
	// 解析token
	token, err := jwt.ParseWithClaims(tokenString, &CustomClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(jwtConfig.Secret), nil
	})

	if err != nil {
		return nil, err
	}

	if claims, ok := token.Claims.(*CustomClaims); ok && token.Valid {
		return claims, nil
	}

	return nil, err
}

// GetJWTService 获取JWT服务实例
func GetJWTService() *JWTService {
	return jwtService
}