#!/bin/bash

# The vehicle's VIN is available from message ID $380.
# Due to it's length, it is split across three messages.
# The first character contains the messge ID [0-2]
# The next seven characters holds ASCII character (in hexadecimal)
# Each part of the message is sent 0.1 seconds apart.

# We need to combine all three parts, convert them to ASCII,
# and store them in the variable $VIN

# We'll wait up to 0.35 seconds for three message to arrive
# (in any order).

# We'll create an array called $message
declare -a message

# We're going to store the VIN number in a variable called $vin
vin=$( timeout -s 9 0.35 /usr/bin/candump -L can0,03E0:0fff | \
       cut -d# -f2 | while read a
do
  # Extract the message ID number [0-3]
  id="$( echo $a | cut -c1-2 )"
  id=$( printf "%d" $id)

  # Extract the data, convert to ASCII, remove trailing NULL characters.
  data="$( echo $a | cut -c3- )"
  data="$( echo $data | fold -w2 | paste -sd ' ' | sed -e 's/\( 00\)*$//g' )"
  data="$( bindechexascii --h2a $data 2>/dev/null | cut -d: -f2 |  cut -c2- )"

  # Assign the data to an array called $message
  message[$id]="$data"

  # Print all three message parts, present or not.
  echo ${message[@]} | tr -d ' '

  # Exit the loop, only keeping the last line, which we
  # have set (above) to be stored in the variable $vin

done | tail -1 )

chars=$( echo -n "$vin" | wc -c )

# If there are no characters, no VIN was received. Print an error.

if [ $chars -eq 0 ]
  then
    echo "NOTFOUND"
    exit 2
  fi

# Check to see how many characters are in our reassembled VIN.
# If it is less than 17, exit the script with an error.

if [ $chars -lt 17 ]
  then
    # INVALID VIN, EXIT WITH RESULT CODE 1 TO SIGNIFY AN ERROR.
    echo "INVALID($vin)"
    exit 1
  fi

# Print the VIN to standard output
echo $vin