package utils

import (
	"errors"
	"time"

	"github.com/golang-jwt/jwt/v5"
)

// JWTClaims 自定义JWT声明
type JWTClaims struct {
	UserID   uint64 `json:"user_id"`
	Username string `json:"username"`
	Role     string `json:"role"`
	jwt.RegisteredClaims
}

// GenerateToken 生成JWT Token
// userID: 用户ID, username: 用户名, role: 角色, secret: 密钥, expirationHours: 过期时间(小时)
func GenerateToken(userID uint64, username, role, secret string, expirationHours int) (string, error) {
	claims := JWTClaims{
		UserID:   userID,
		Username: username,
		Role:     role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(expirationHours) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Issuer:    "seeyon-filesystem",
		},
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return token.SignedString([]byte(secret))
}

// ParseToken 解析JWT Token
func ParseToken(tokenString, secret string) (*JWTClaims, error) {
	token, err := jwt.ParseWithClaims(tokenString, &JWTClaims{}, func(token *jwt.Token) (interface{}, error) {
		return []byte(secret), nil
	})
	if err != nil {
		return nil, err
	}

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

	return nil, errors.New("invalid token")
}