#!/bin/bash

##
## The cleanup-commit script
## -------------------------
## This little script will cleanup your commit before you send it. You need to add the files to the staged area and
## run this script. It will automatically cleanup tabs and trailing spaces for the files you added and then add the
## clean versions to the staging area.
##
## Use at your own risk, I spent some time making the script error-proof so it will abort if sees any inconsistency,
## but of course playing around with your commit might break things. Btw, it saves the original file to file.bak.
##
## Happy hacking!
##

ABORT="Ab0rT0p3r4+|0n"

#
# Cleanup function
#
function cleanup {
  echo Cleaning up $1...
  # prepare the ground
  rm -rf $1.bak
  # compress <TAB> into double <BLANK> and eliminate trailing <BLANC>s
  sed -i.bak -e 's/\t/  /g' -e 's/ *$//' $1
}


#
# Get the git status for the current staged commit
#
FULLSTATUS=`git status --porcelain`

if [ $? -ne 0 ]
then
  echo "Unable to run git. Check if:"
  echo " -- git is installed (you can run git in the command line)"
  echo " -- the current directory is a valid git repository"
  exit 1
fi

echo

#
# Based on the status decide what files will get cleaned up
#
CLEANUP_FILES=`echo "$FULLSTATUS" | while read LINE
do

  STATUS=$(echo $LINE | sed 's/^\(..\).*$/\1/')
  if [ $? -ne 0 ]
  then
    echo "Could not get the status for line: $LINE"
    echo " -- you have the basic unix tools installed (grep, cut, sed)"
    echo $ABORT # This goes to CLEANUP_FILES
    exit 1
  fi

  FILES=$(echo $LINE | sed 's/^..//')
  FILE1=$(echo $FILES | cut -d ' ' -f 1)
  FILE2=$(echo $FILES | cut -d ' ' -f 3)

  case "$STATUS" in
  [AMRDC]" ")
    case "$STATUS" in
      "A "|"M ")
         echo $FILE1
         ;;
      "R ")
         echo $FILE2
         ;;
      "D ")
         #nothing to do
         ;;
      "C ")
         echo $FILE1
         echo $FILE2
         ;;
    esac
    ;;
  "??")
    # File is not tracked, no need to do anything about it
    # echo Untracked: $FILE1
    ;;
  *)
    echo "Unstable status of file $FILE1 (\"$STATUS\")" >&2
    echo "Aborting cleanup!" >&2
    echo $ABORT # This goes to CLEANUP_FILES
    exit 1
  esac
done; echo $CLEANUP_FILES`


#
# Perform actual cleanup
#
case $CLEANUP_FILES in
*"$ABORT")
  echo
  exit 1
  ;;
"")
  echo Nothing to do!
  ;;
*)
  cd $(git rev-parse --show-toplevel)

  if [ $? -ne 0 ]
  then
    echo Unexpected error: cannot cd to the repository root
    echo Aborting cleanup!
    exit 1
  fi

  echo "$CLEANUP_FILES" | while read FILE
  do
    cleanup $FILE
  done

  cd - &>/dev/null

  echo
  echo "Cleanup done: "
  echo " - original files saved as .bak"
  echo " - you can do \"git diff\" to see the changes the script did"
  echo " - you can do \"git commit -a\" to commit the cleaned up files"
  echo
  ;;
esac