package auth

import (
	"errors"
	"time"

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

const SessionTTL = 7 * 24 * time.Hour

type Claims struct {
	jwt.RegisteredClaims
	UserID       int64 `json:"uid"`
	TokenVersion int   `json:"ver"`
}

func IssueToken(secret []byte, userID int64, tokenVersion int, now time.Time) (string, error) {
	c := Claims{
		RegisteredClaims: jwt.RegisteredClaims{
			IssuedAt:  jwt.NewNumericDate(now),
			ExpiresAt: jwt.NewNumericDate(now.Add(SessionTTL)),
		},
		UserID:       userID,
		TokenVersion: tokenVersion,
	}
	return jwt.NewWithClaims(jwt.SigningMethodHS256, c).SignedString(secret)
}

func ParseToken(secret []byte, tok string) (*Claims, error) {
	var c Claims
	_, err := jwt.ParseWithClaims(tok, &c, func(t *jwt.Token) (any, error) { return secret, nil },
		jwt.WithValidMethods([]string{"HS256"}), jwt.WithExpirationRequired())
	if err != nil {
		return nil, err
	}
	if c.UserID == 0 {
		return nil, errors.New("missing uid")
	}
	return &c, nil
}