/*
 * This file is part of laurelin_api
 * Copyright (C) 2023 Jonni Liljamo <jonni@liljamo.com>
 *
 * Licensed under GPL-3.0-only.
 * See LICENSE for licensing information.
 */

package auth

import (
	"api/db"
	"errors"
	"os"
	"time"

	"github.com/golang-jwt/jwt/v4"
)

var JWTSecret = []byte(os.Getenv("LAURELINAPI_JWT_SECRET"))

type JWTClaims struct {
	Username string `json:"username"`
	Email    string `json:"email"`
	jwt.RegisteredClaims
}

func NewJWTToken(username string, email string) (token string, err error) {
	claims := JWTClaims{
		Username: username,
		Email:    email,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(1 * time.Hour)),
		},
	}
	jwtClaims := jwt.NewWithClaims(jwt.SigningMethodHS512, claims)
	token, err = jwtClaims.SignedString(JWTSecret)
	return
}

func ValidateJWTToken(userToken string) (claims *JWTClaims, err error) {
	token, err := jwt.ParseWithClaims(
		userToken,
		&JWTClaims{},
		func(token *jwt.Token) (interface{}, error) {
			return []byte(JWTSecret), nil
		},
	)

	if err != nil {
		return
	}

	if !token.Valid {
		err = errors.New("token not valid")
		return
	}

	claims, ok := token.Claims.(*JWTClaims)
	if !ok {
		err = errors.New("could not parse JWT claims")
		return
	}

	if claims.ExpiresAt.Unix() < time.Now().Local().Unix() {
		err = errors.New("token is expired")
		return
	}

	// Auth should match a registered user
	// NOTE: Technically auth should always match a registered user, but just in-case.
	// TOFIX: Or, now that I think about it, I should run some tests to see if this
	//        truly is just dumb to check.
	_, uerr := db.GetUserByEmail(claims.Email)
	if uerr != nil {
		err = errors.New("user does not exist")
		return
	}

	return
}