enter code here <?php  require_once 'connect.php';

// Check if username is empty
if(empty(trim($_POST["username"]))){
    $username_err = 'Please enter username.';
} else{
    $username = trim($_POST["username"]);
}

// Check if password is empty
if(empty(trim($_POST['password']))){
    $password_err = 'Please enter your password.';
} else{
    $password = trim($_POST['password']);
}

// Validate credentials
if(empty($username_err) && empty($password_err)){
    // Prepare a select statement
    $sql = "SELECT username,password FROM users WHERE username = '".$_POST['username']."'";

    if($stmt = mysqli_prepare($link, $sql)){
        // Bind variables to the prepared statement as parameters

// Set parameters
        $param_username = $username;
        //$param_password = password_hash($password, PASSWORD_DEFAULT);

        // Attempt to execute the prepared statement
        if(mysqli_stmt_execute($stmt)){
            // Store result
            mysqli_stmt_store_result($stmt);

            // Check if username exists, if yes then verify password
            if(mysqli_stmt_num_rows($stmt) == 1){
                // Bind result variables
                mysqli_stmt_bind_result($stmt, $username, $hashed_password);
                if(mysqli_stmt_fetch($stmt)){
                    if(password_verify($password, $hashed_password)){
                        /* Password is correct, so start a new session and
                        save the username to the session */
                        session_start();
                        $_SESSION['username'] = $username;
                        header("location: welcome.php");
                    } else{
                        // Display an error message if password is not valid
                        $password_err = 'The password you entered was not valid.';
                    }
                }
            } else{
                // Display an error message if username doesn't exist
                $username_err = 'No account found with that username.';
            }
        } else{
            echo "Oops! Something went wrong. Please try again later.";
        }
    }

    // Close statement
    //mysqli_stmt_close($stmt);
}

// Close connection
mysqli_close($link);