package jwt

import (
	"errors"
	"time"

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

type Claims struct {
	UserID   uint   `json:"uid"`
	Username string `json:"username"`
	Role     string `json:"role"`
	jwt.RegisteredClaims
}

type Manager struct {
	Secret    []byte
	ExpireHrs int
}

func New(secret string, expireHrs int) *Manager {
	return &Manager{Secret: []byte(secret), ExpireHrs: expireHrs}
}

func (m *Manager) Generate(userID uint, username, role string) (string, error) {
	claims := Claims{
		UserID:   userID,
		Username: username,
		Role:     role,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(time.Duration(m.ExpireHrs) * time.Hour)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
		},
	}
	t := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return t.SignedString(m.Secret)
}

func (m *Manager) Parse(tokenStr string) (*Claims, error) {
	claims := &Claims{}
	t, err := jwt.ParseWithClaims(tokenStr, claims, func(t *jwt.Token) (interface{}, error) {
		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return m.Secret, nil
	})
	if err != nil {
		return nil, err
	}
	if !t.Valid {
		return nil, errors.New("invalid token")
	}
	return claims, nil
}