# generate gerrit changeId here, since husky overwrite .git/hooks/commit-msg
if test "$#" != 1 ; then
  echo "$0 requires an argument."
  exit 1
fi

if test ! -f "$1" ; then
  echo "file does not exist: $1"
  exit 1
fi

# Do not create a change id if requested
if test "false" = "`git config --bool --get gerrit.createChangeId`" ; then
  exit 0
fi

# $RANDOM will be undefined if not using bash, so don't use set -u
random=$( (whoami ; hostname ; date; cat $1 ; echo $RANDOM) | git hash-object --stdin)
dest="$1.tmp.${random}"

trap 'rm -f "${dest}"' EXIT

if ! git stripspace --strip-comments < "$1" > "${dest}" ; then
   echo "cannot strip comments from $1"
   exit 1
fi

if test ! -s "${dest}" ; then
  echo "file is empty: $1"
  exit 1
fi

# Avoid the --in-place option which only appeared in Git 2.8
# Avoid the --if-exists option which only appeared in Git 2.15
if ! git -c trailer.ifexists=doNothing interpret-trailers \
      --trailer "Change-Id: I${random}" < "$1" > "${dest}" ; then
  echo "cannot insert change-id line in $1"
  exit 1
fi

if ! mv "${dest}" "$1" ; then
  echo "cannot mv ${dest} to $1"
  exit 1
fi