//
// Copyright 2014-2024 Cristian Maglie. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//

package serial

import (
	"regexp"

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

const devFolder = "/dev"

var osPortFilter = regexp.MustCompile("^(cu|tty)\\..*")

// termios manipulation functions

var baudrateMap = map[int]uint32{
	0:      unix.B9600, // Default to 9600
	50:     unix.B50,
	75:     unix.B75,
	110:    unix.B110,
	134:    unix.B134,
	150:    unix.B150,
	200:    unix.B200,
	300:    unix.B300,
	600:    unix.B600,
	1200:   unix.B1200,
	1800:   unix.B1800,
	2400:   unix.B2400,
	4800:   unix.B4800,
	9600:   unix.B9600,
	19200:  unix.B19200,
	38400:  unix.B38400,
	57600:  unix.B57600,
	115200: unix.B115200,
	230400: unix.B230400,
	460800: unix.B460800,
	921600: unix.B921600,
}

var databitsMap = map[int]uint32{
	0: unix.CS8, // Default to 8 bits
	5: unix.CS5,
	6: unix.CS6,
	7: unix.CS7,
	8: unix.CS8,
}

const tcCMSPAR uint32 = 0 // may be CMSPAR or PAREXT
const tcIUCLC uint32 = 0

const tcCCTS_OFLOW uint32 = 0x00010000
const tcCRTS_IFLOW uint32 = 0x00020000

const tcCRTSCTS uint32 = tcCCTS_OFLOW

const ioctlTcgetattr = unix.TIOCGETA
const ioctlTcsetattr = unix.TIOCSETA
const ioctlTcflsh = unix.TIOCFLUSH
const ioctlTioccbrk = unix.TIOCCBRK
const ioctlTiocsbrk = unix.TIOCSBRK

func toTermiosSpeedType(speed uint32) uint32 {
	return speed
}

func setTermSettingsBaudrate(speed int, settings *unix.Termios) (error, bool) {
	baudrate, ok := baudrateMap[speed]
	if !ok {
		return nil, true
	}
	// XXX: Is Cflag really needed
	// revert old baudrate
	for _, rate := range baudrateMap {
		settings.Cflag &^= rate
	}
	// set new baudrate
	settings.Cflag |= baudrate

	settings.Ispeed = toTermiosSpeedType(baudrate)
	settings.Ospeed = toTermiosSpeedType(baudrate)
	return nil, false
}

func (port *unixPort) setSpecialBaudrate(speed uint32) error {
	// TODO: unimplemented
	return &PortError{code: InvalidSpeed}
}
