<?php
session_start();


if ($_SERVER['REQUEST_METHOD'] == 'GET') {
    die("This page does not take GET request");
}
if ($_SERVER['REQUEST_METHOD'] == 'POST') {

    require_once('dbconfig.php');
    $loginUserName = $_POST['username'];
    $loginPassword = $_POST['password'];

    $mysqli_conn = new mysqli($servername, $username, $password, $dbname);
    if (mysqli_connect_errno()) {
        die("Failed to connect to database");
    }
    $sql = "select * from users where username='$loginUserName' and password='$loginPassword'";
    $result = $mysqli_conn->query($sql);
    $count = mysqli_num_rows($result);


    if (empty($_POST['username'])) {
        echo "Username cannot be empty";
    }
    if (empty($_POST['password'])) {
        echo "password is empty, try again";
    }
    if ($count > 0 && $row = $result->fetch_assoc()) {

        echo("$loginUserName has successfully logged in");

    } else if ($count == 0) {

        $sqlCheck = "select * from users";
        $checkResult = $mysqli_conn->query($sqlCheck);


        if ($checkResult->num_rows > 0) {
            while ($row = $result->fetch_assoc()) {
                if ($row['username'] == $loginUserName && $row['password'] != $loginPassword) {
                    echo "Invalid ID";
                }
                if ($row['username'] != $loginUserName && $row['password'] == $loginPassword) {
                    echo "Incorrect password";
                }
                if ($row['username'] != $loginUserName && $row['password'] != $loginPassword) {
                    echo "Your ID and password do not exist";
                }


            }
        }
    }




    $mysqli_conn->close();

}


?>