package auth

import (
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"

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

func createJWT(secret []byte) (token string, err error) {
	return jwt.NewWithClaims(jwt.SigningMethodHS512, jwt.MapClaims{
		"exp": time.Now().Add(time.Hour * 24).Unix(),
	}).SignedString(secret)
}

func validateJWT(tokenString string, secret []byte) (err error) {
	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
		// Don't forget to validate the alg is what you expect:
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}

		return secret, nil
	})
	if err != nil {
		return
	}
	if date, err := token.Claims.GetExpirationTime(); err == nil && date.After(time.Now()) {
		return nil
	}
	return errors.New("JWT not valid")
}

func extractToken(r *http.Request) (token string, err error) {
	tokenHeader := r.Header.Get("Authorization") // Grab the token from the header

	if tokenHeader == "" {
		err = errors.New("missing token")
		return
	}

	token = strings.TrimPrefix(tokenHeader, "Bearer ")

	if token == "" {
		err = errors.New("malformed token")
	}
	return
}