fungsi login

<?php

session_start();

require 'functions.php';

if (isset($_COOKIE["id"]) && isset($_COOKIE["key"])) {

    $id = $_COOKIE['id'];
    $key = $_COOKIE['key'];

    // ambil username berdasrkan id
    $result = mysqli_query("SELECT username FROM user WHERE id = $id");

    // ambil id saja
    $row = mysqli_fetch_assoc($result);

    // cek cookie dan username
    if ($key === hash('sha256', $row['username'])) {
        $_SESSION['login'] = true;
    }
}



if (isset($_SESSION["login"])) {
    header("Location: index.php");
}

if (isset($_POST["daftar"])) {
    header("Location: registrasi.php");
}



// cek tombol login sudah di tekan belum
if (isset($_POST["login"])) {

    $username = $_POST["username"];
    $password = $_POST["password"];

    // menampilkan data dari tabel user
    $result = mysqli_query($conn, "SELECT * FROM user WHERE username = '$username'");

    // cek ada tidak username
    if (mysqli_num_rows($result) === 1 ) {

        // cek password sama atau tidak
        $row = mysqli_fetch_assoc($result);

        if (password_verify($password, $row["password"])) {

            // seting session
            $_SESSION["login"] = true;

            // cek remember me
            if ($_POST["remember"]) {

                // seting cookie
                setcookie('id', $row['id'], time()+60);
                setcookie('key', hash('sha256', $row['username']), time()+60);
            }

            // jika password benar redirect ke halaman index.php
            header("Location: index.php");
            exit;
        }
    }

    $error = true;
}