#!/usr/bin/perl -w
#
# Copyright (c) 2015  Sulev-Madis Silber <ketas@si.pri.ee>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#


use strict;
use warnings FATAL => 'all';

use Data::Dumper;
use Device::SerialPort;


$| = 1;


my ($device) = @ARGV;


die 'no device' unless $device;


my $serialport;


sub serial_connected ()
{
	return defined $serialport ? 1 : undef;
}


sub serial_open ()
{
	$serialport = new Device::SerialPort($device) || die(sprintf "can't open serial port %s: %s", $device, $!);
	
	
	$serialport->baudrate(9600);
	
	$serialport->databits(8);
	$serialport->parity('none');
	$serialport->stopbits(1);
	
	$serialport->handshake('none');
	
	
	if (0)
	{
		$serialport->read_interval(100);
		$serialport->read_char_time(50);
		$serialport->read_const_time(1000);
		$serialport->write_char_time(5);
		$serialport->write_const_time(1000);
	}
	
	
	if (0)
	{
		$serialport->{C_IFLAG} &= ~(BRKINT|ICRNL|IGNCR|INLCR|INPCK|ISTRIP|IXON|IXOFF|PARMRK);
		$serialport->{C_IFLAG} |= IGNBRK|IGNPAR;
		$serialport->{C_OFLAG} &= ~(OPOST);
		$serialport->{C_CFLAG} &= ~(CSIZE|HUPCL|PARENB);
		$serialport->{C_CFLAG} |= (CLOCAL|CS8|CREAD);
		$serialport->{C_LFLAG} &= ~(ECHO|ECHOE|ECHOK|ECHONL|ICANON|IEXTEN|ISIG);
		$serialport->{C_VMIN} = 0;
		$serialport->{C_VTIME} = 3;
	}
	
	
	$serialport->write_settings;
	$serialport->purge_all;
}


sub serial_close ()
{
	if (serial_connected)
	{
		$serialport->close || warn "close failed\n";
		
		undef $serialport;
	}
}


sub purge_all ()
{
	return undef unless serial_connected;
	
	
	$serialport->purge_all;
}


sub serial_write ($)
{
	my ($string) = @_;
	
	
	return undef unless serial_connected;
	
	
	purge_all;
	
	
	my $count = $serialport->write($string);
	
	
	if (0)
	{
		select undef, undef, undef, (11 * 1000 / 10 ** 6);
	}
	
	
	unless ($count)
	{
		warn "write failed\n";
		
		return undef;
	}
	
	unless ($count == length $string)
	{
		warn "write incomplete\n";
		
		return undef;
	}
	
	
	$serialport->write_drain;
	
	
	return 1;
}


sub serial_read ($)
{
	my ($bytes) = @_;
	
	
	return undef unless serial_connected;
	
	
	$serialport->read_char_time(10);
	
	
	while (my ($count, $string) = $serialport->read($bytes))
	{
		warn "read incomplete\n" unless $count == $bytes;
		
		
		return $string;
	}
}


sub clean_exit ()
{
	serial_close;
	
	exit;
}


$SIG{$_} = \&clean_exit foreach qw(HUP INT TERM);


serial_open;


$0 = sprintf "serial %s", $device;


print STDERR "READY\n";


while (<STDIN>)
{
	if (/^\s*write\s+(.+)\s*$/i)
	{
		serial_write $1;
	}
	elsif (/^\s*read\s+(\d+)\s*$/i)
	{
		printf "read %s %s\n",
			$device,
			serial_read $1;
	}
}


clean_exit;