package auth

import (
	"errors"
	"time"

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

type Claims struct {
	AdminID int    `json:"admin_id"`
	Email   string `json:"email"`
	jwt.RegisteredClaims
}

func SignAdmin(secret string, adminID int, email string, ttl time.Duration) (string, error) {
	claims := Claims{
		AdminID: adminID,
		Email:   email,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(ttl)),
			IssuedAt:  jwt.NewNumericDate(time.Now()),
			Issuer:    IssuerAdmin,
		},
	}
	t := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
	return t.SignedString([]byte(secret))
}

func ParseAdmin(secret, token string) (*Claims, error) {
	claims := &Claims{}
	parsed, err := jwt.ParseWithClaims(token, claims, func(t *jwt.Token) (any, error) {
		if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, errors.New("unexpected signing method")
		}
		return []byte(secret), nil
	})
	if err != nil {
		return nil, err
	}
	if !parsed.Valid || claims.Issuer != IssuerAdmin || claims.AdminID <= 0 {
		return nil, errors.New("invalid token")
	}
	return claims, nil
}