DataLink

#! /bin/bash

################################################################################
# Arduino Data Link                                                            #
################################################################################
#                                                                              #
# Version 1.0                                                                  #
# Written by: Tibor Áser Veres                                                 #
# Source: https://github.com/RPBCACUEAIIBH/Arduino-DataLink                    #
# License: BSD License 2.0 (see LICENSE.md file)                               #
#                                                                              #
################################################################################

# Constants
Files="/usr/share/DataLink"

if [[ -d $1 ]]
then
  RunDir=$1
  shift
  else
  RunDir=$(pwd)
fi

# Processing options
SendRequest=false
Quit=false
while [[ ! -z $@ ]]
do
  case $1 in
       --help ) cat $Files/Help.md
                exit
                ;;
    --version ) echo ''
                echo 'Arduino DataLink - Version 1.0'
                echo ''
                cat $Files/LICENSE.md
                echo ''
                exit
                ;;
           -s ) SendRequest=true
                shift
                Request=$1
                shift
                ;;
           -e ) Quit=true
                shift
                Over=$1
                shift
                ;;
            * ) if [[ -z $Port ]]
                then
                  Port=$1
                  shift
                else
                  Speed=$1
                  shift
                fi
                ;;
  esac
done

# Root check
if [[ $(whoami) != "root" ]]
then
  echo 'This script needs to run as root! Please use "sudo" in front.'
  exit
fi

# Checking and creating log file if necessary.
DT=$(date -Is)
Time=${DT:11:8}
Success=true
if [[ ! -f $RunDir/Log ]]
then
  touch $RunDir/Log
  chown $SUDO_USER:$SUDO_USER $RunDir/Log
  echo "$Time N: Starting log..." | tee $RunDir/Log
  DT=$(date -Is); echo "${DT:11:8} W: Log file was missing!" | tee -a $RunDir/Log
else
  echo "$Time N: Starting log..." | tee $RunDir/Log
fi

# Checking Parts and initialising
if [[ ! -f $RunDir/Controls ]]
then
  DT=$(date -Is); echo "${DT:11:8} W: Controls file missing!" | tee -a $RunDir/Log
  touch $RunDir/Controls
  chown $SUDO_USER:$SUDO_USER $RunDir/Controls
# Read is default, but may not be desired depending on your program to start reading immediately... Change "Read" to "Stop" to put it on stendby by default...(both the condition, and the default value.)
  echo -n "Read" > $RunDir/Controls # << Here
else
  State=$(cat $RunDir/Controls) # Reseting state to read...
  if [[ $State != "Read" ]] # << here 
  then
    echo -n "Read" > $RunDir/Controls # << here
  fi
fi

if [[ ! -f $RunDir/Input ]]
then
  DT=$(date -Is); echo "${DT:11:8} W: Input file missing!" | tee -a $RunDir/Log
  touch $RunDir/Input
  chown $SUDO_USER:$SUDO_USER $RunDir/Input
fi
if [[ ! -z $(cat $RunDir/Input) ]]
then
  DT=$(date -Is); echo "${DT:11:8} W: Input file not empty... Cleaning!" | tee -a $RunDir/Log
  echo -n "" > $RunDir/Input
fi

if [[ ! -f $RunDir/Output ]]
then
  DT=$(date -Is); echo "${DT:11:8} W: Output file missing!" | tee -a $RunDir/Log
  touch $RunDir/Output
  chown $SUDO_USER:$SUDO_USER $RunDir/Output
fi
if [[ ! -z $(cat $RunDir/Output) ]]
then
  DT=$(date -Is); echo "${DT:11:8} W: Output file not empty... Cleaning!" | tee -a $RunDir/Log
  echo -n "" > $RunDir/Output
fi

# Saving previous port configuration and reconfiguring port
PPC=$(stty -F $Port -g)

function Configure
{
  # Checking and setting port
  if [[ -z $Port ]]
  then
    Port=$(grep "Port:" $RunDir/Config | awk '{ print $2 }')
  fi
  if [[ -z $Port ]]
  then
    DT=$(date -Is); echo "${DT:11:8} E: Port not specified!" | tee -a $RunDir/Log
    Success=false
  else
    if [[ ! -e $Port ]]
    then
      DT=$(date -Is); echo "${DT:11:8} E: Device not found!" | tee -a $RunDir/Log
      Success=false
    fi
  fi

  # Checking baudrate
  if [[ -z $Speed ]]
  then
    Speed=$(grep "BaudRate:" $RunDir/Config | awk '{ print $2 }')
  fi
  if [[ ! -z $Speed ]]
  then
    case $Speed in
         300 ) Speed=300
               ;;
         600 ) Speed=600
               ;;
        1200 ) Speed=1200
               ;;
        2400 ) Speed=2400
               ;;
        4800 ) Speed=4800
               ;;
        9600 ) Speed=9600
               ;;
       19200 ) Speed=19200
               ;;
       57600 ) Speed=57600
               ;;
      115200 ) Speed=115200
               ;;
      500000 ) Speed=500000
               ;;
     1000000 ) Speed=1000000
               ;;
     2000000 ) Speed=2000000
               ;;
           * ) DT=$(date -Is); echo "${DT:11:8} W: Unkown baud rate! Falling back to 9600..." | tee -a $RunDir/Log
               Speed=9600
               ;;
    esac
  else
    Speed=9600
  fi

  if [[ ! -z $(grep "E:"  $RunDir/Log) ]]
  then
    DT=$(date -Is); echo "${DT:11:8} N: Fatal error happened! Aborting..." | tee -a $RunDir/Log
    sleep 5
    exit
  fi

  # Configuring port
  stty -F $Port cs8 $Speed min 0 time 0 -parenb -parodd -cmspar -hupcl -cstopb cread clocal -crtscts ignbrk -brkint -ignpar -parmrk inpck -istrip -inlcr -igncr -icrnl -ixon -ixoff -iuclc -ixany -imaxbel -iutf8 -opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 -isig -icanon -iexten -echo -echoe -echok -echonl noflsh -xcase -tostop -echoprt -echoctl -echoke -flusho -extproc

  # Opening channel (It appears that "cat" command can read and clear the buffer but can not request data from the microcontroller. On the other hand "tail" does not seem to clear the buffer so neither will keep reading data indefinitely alone... They seem to work together just fine if tail is started first and keeps running in the background...
  tail -f $Port&
}

# Calling function Configure
Configure

if [[ $(cat $RunDir/Log) == "$Time N: Starting log..." ]]
then
  DT=$(date -Is); echo "${DT:11:8} N: Successful initialization!" | tee -a $RunDir/Log
else
  if [[ ! -z $(grep "E:" $RunDir/Log) ]]
  then
    DT=$(date -Is); echo "${DT:11:8} N: Fatal error happened! Aborting..." | tee -a $RunDir/Log
    exit
  else
    DT=$(date -Is); echo "${DT:11:8} N: One or more errors ware corrected!" | tee -a $RunDir/Log
  fi
fi

# -s option
if [[ $SendRequest == true ]]
then
  if [[ -z $Request ]]
  then
    DT=$(date -Is); echo "${DT:11:8} E: Request signal is not specified! Please edit the Output file!" | tee -a $RunDir/Log
  else
    DT=$(date -Is); echo "${DT:11:8} N: Requesting..." | tee -a $RunDir/Log
    echo $Request > $RunDir/Output
  fi
fi

# -e option
if [[ $Quit == true ]]
then
  if [[ -z $Over ]]
  then
    DT=$(date -Is); echo "${DT:11:8} E: Over signal is not specified! Please edit the Controls file!" | tee -a $RunDir/Log
  fi
fi

# Waiting for the arduino to reset
sleep 7 # my arduino runs at 16MHz it resets in somewhat less then 3s, but I'm not sure if a 8MHz one would reset so soon...

# Main section
State="Read"
while [[ $State != "Exit" ]]
do
  LastState=$State
  State=$(awk '{ print $1 }' $RunDir/Controls)
  if [[ $Quit == true ]] # -e option
  then
    if [[ ! -z $(grep "$Over" $RunDir/Input) ]]
    then
      State="Exit"
    fi
  fi
  if [[ ! -z $(cat $RunDir/Output) ]]
  then
      echo -n $(cat $RunDir/Output) > $Port # Remove the "-n" option for sending new line character...
      echo -n "" > $RunDir/Output
  fi
  if [[ $State == "Read" ]]
  then
    Discard=$(cat $Port) #The firts read stuff is junk in the buffer...
  fi
  if [[ $State == "Reading" ]]
  then
    cat $Port | tee -a $RunDir/Input
  else
    sleep 0.25
  fi
  case $State in
           Read ) echo "Reading" > $RunDir/Controls
                  DT=$(date -Is); echo "${DT:11:8} N: Reading..." >> $RunDir/Log
                  ;;
           Stop ) echo "Stopped" > $RunDir/Controls
                  DT=$(date -Is); echo "${DT:11:8} N: Stopping..." >> $RunDir/Log
                  ;;
           Exit ) DT=$(date -Is); echo "${DT:11:8} N: Exiting..." >> $RunDir/Log
                  ;;
          Clear ) echo -n "" > $RunDir/Input
                  State=$LastState
                  echo -n $State > $RunDir/Controls
                  ;;
        Reading ) :
                  ;;
    Reconfigure ) echo -n "Stopped" > $RunDir/Controls
                  kill $(ps -e | grep tail | awk '{ print $1 }')
                  Port=$(grep "Port:" $RunDir/Config | awk '{ print $2 }')
                  Speed=$(grep "BaudRate:" $RunDir/Config | awk '{ print $2 }')
                  Configure
                  echo -n " Reconfigured" >> $RunDir/Controls
                  ;;
        Stopped ) :
                  ;;
              * ) DT=$(date -Is); echo "${DT:11:8} W: Unknown state request! Falling back to previous state!" >> $RunDir/Log
                  State=$LastState
                  echo -n $State > $RunDir/Controls
                  ;;
  esac
done

# Closing channel
kill $(ps -e | grep tail | awk '{ print $1 }') #Fix this! It will kill all tail operations including non-related ones!

# Restoring previous port settings... (arduino IDE may have problem uploading or using serial monitor if not restored...)
stty $PPC -F $Port # It gives me an error like crazy. but it does what it supposed to do...

# Ending log and exiting
DT=$(date -Is); echo "${DT:11:8} N: Ending log!" >> $RunDir/Log
echo "Exited" > $RunDir/Controls