// SPDX-FileCopyrightText: (C) Copyright 2026 Pim van Pelt <pim@ipng.ch>
// SPDX-License-Identifier: Apache-2.0

//go:build openbsd || freebsd || netbsd || dragonfly || darwin

package keypress

import "golang.org/x/sys/unix"

// cbreak puts the terminal into cbreak mode (no canonical input/echo) so a
// single keystroke is available, leaving output post-processing intact. The
// BSDs use the TIOCGETA/TIOCSETA termios ioctls (Linux uses TCGETS/TCSETS). It
// returns the previous termios for restore, or an error if fd is not a tty.
func cbreak(fd int) (*unix.Termios, error) {
	old, err := unix.IoctlGetTermios(fd, unix.TIOCGETA)
	if err != nil {
		return nil, err
	}
	t := *old
	t.Lflag &^= unix.ICANON | unix.ECHO | unix.ECHOE | unix.ECHOK | unix.ECHONL
	t.Cc[unix.VMIN] = 1
	t.Cc[unix.VTIME] = 0
	if err := unix.IoctlSetTermios(fd, unix.TIOCSETA, &t); err != nil {
		return nil, err
	}
	return old, nil
}

// restore reverts the terminal to the settings captured by cbreak.
func restore(fd int, old *unix.Termios) error {
	return unix.IoctlSetTermios(fd, unix.TIOCSETAF, old)
}