#! /bin/bash
#
#  bash is used for simplicity.  Any language will do,
#  use whatever you feel is best suited to the problem.
#
#  if you choose bash, remember that any system that
#  supports inotify/gidget will also have the highly
#  efficient double-bracket and double-parentheses
#  syntaxes available for if/else testing.  Those
#  methods are preferable when available but do not
#  necessarily work on older systems.  I have used
#  the older portable syntax below, and made other
#  questionable choices in order to provide strong
#  examples.
#
#  --Charlie Brooks 2011
#
#
#  We should get passed a file name or the string UC4
#
#
if [ "x$1" == "x" ] ; then
    echo No file or command. Confused, exiting.
    exit 1
fi
#
#  do all the work in the folder where the file
#  we are processing was found.  This is actually a
#  really bad idea since that folder is almost
#  certainly being watched by gidget - we are going
#  to generate event traffic and will have to code
#  very carefully to avoid a resource destroying
#  infinite loop!  I did it this way for demonstration
#  purposes only, do not do this in production code.
#
workFolder=`dirname "$1"`
if test ! -d "$workFolder" ; then
    echo Folder $workFolder does not exist.  Unable to continue.
    echo File $1 will not be processed!
    exit 1
fi
#
# prevent md5 recursion from eating entire filesystem
#
if [ "${1##*\.}" == "md5" ] ; then
    echo MD5 file.  Exiting.
    exit 0
fi
#
#  Race conditions are always a serious threat on
#  modern multiprocessor systems with redundant
#  disk storage, and naive mutex mechanisms that
#  assume nothing can happen between testing for
#  a flag and creating a flag will always fail.
#
set -o noclobber
(md5sum "$1" >"$1.md5" ) 2>/dev/null 1>&2
MDSTATUS=$?
set +o noclobber

if [ "$MDSTATUS" != "0" ]  ; then
    if test -e "$1.md5" ; then
        if md5sum "$1" | diff -a -q - -- "$1.md5" ; then
            echo $1 has already been processed!
            exit 0
        else
            echo WARNING! $1 does not match $1.md5!
            echo Duplicate file name without duplicate data
            echo unable to proceed!
        fi
    else
      echo error $MDSTATUS
      echo Unable to create $1.md5
      echo process aborting!
    fi
    exit 2
# in a real gidget proc, comment out the next 4 lines
else
    echo built $1.md5 for transfer integrity checking
    echo hospital can use this for HIPAA assurance
    echo and we can use it for dupe checking
fi
#
#  do appropriate processing for all files we know about
#  Note that in a real gidget proc, success generates no
#  output.  You only write output if you want an error
#  email to be generated.

case $1 in

  recon.20??-??-??.txt)
      echo "Reconcilitation file.  Kicking off UC4 recon job!"
      ;;

  cash.20??-??-??.txt)
      echo "Cash file.  Kicking off UC4 cash job!"
      ;;


  nubiz.20??-??-??.txt)
      echo "New Business file.  Kicking off UC4 nubus job!"
      ;;


  legal.20??-??-??.txt)
      echo "legal file.  Kicking off UC4 legal job!"
      ;;

  *)
      echo "Unrecognized file $1 - alerting operations!"
      echo mail mail mail mail
      ;;

esac

exit 0