package serialport

import (
	"fmt"
	"os"

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

func Open115200(path string) (*os.File, error) {
	file, err := os.OpenFile(path, os.O_RDWR|unix.O_NOCTTY, 0)
	if err != nil {
		return nil, err
	}

	termios, err := unix.IoctlGetTermios(int(file.Fd()), unix.TCGETS)
	if err != nil {
		file.Close()
		return nil, err
	}

	termios.Iflag = 0
	termios.Oflag = 0
	termios.Lflag = 0
	termios.Cflag &^= unix.CSIZE | unix.PARENB | unix.CSTOPB | unix.CRTSCTS
	termios.Cflag |= unix.CS8 | unix.CREAD | unix.CLOCAL
	termios.Ispeed = unix.B115200
	termios.Ospeed = unix.B115200
	termios.Cc[unix.VMIN] = 1
	termios.Cc[unix.VTIME] = 0

	if err := unix.IoctlSetTermios(int(file.Fd()), unix.TCSETS, termios); err != nil {
		file.Close()
		return nil, fmt.Errorf("configure %s: %w", path, err)
	}
	return file, nil
}