#!/bin/bash
if [ -x /usr/lib/git-core/google_hook ]; then
  /usr/lib/git-core/google_hook pre-commit "$@"
else
  echo 'warning: Cannot run /usr/lib/git-core/google_hook.' \
    'If this is unexpected, please file a go/git-bug' >&2
fi

# Do not perform pre-commit on Windows
if [[ "$OSTYPE" == "win32" || "$OSTYPE" == "msys" ]]; then
    exit 0
fi

# Make a temporary directory
TMPDIR=$(mktemp -d -t gcp-$(date +%Y-%m-%d-%H-%M-%S)-XXXXXXXXXX)
diffFile=$(mktemp gpc-XXXXXXXXX --tmpdir=$TMPDIR)

# Get every source file that's been added, changed, or modified in the
# current index.
FILES=$(git diff --cached --name-only --diff-filter=ACM | grep '\.cpp$\|\.hpp$\|\.h$\|\.c$')

# Checkout a copy of current index into TMPDIR. This is necessary so that we
# only read the versions of files that are being committed, and not any changes
# to those files that haven't been added yet.
git checkout-index --prefix=$TMPDIR/ -af

# Everything else will now happen in TMPDIR
cd $TMPDIR

# Go through each file and test if clang-format modifies the file
pass=1
for FILE in $FILES
do
    tmpfile=$(mktemp gpc-XXXXXXXXX --tmpdir=$TMPDIR)
    FULLFILE="$TMPDIR/$FILE"
    clang-format --style=file $FULLFILE > "$tmpfile"
    diff "$FULLFILE" "$tmpfile" > "$diffFile"
    if [ -s "$diffFile" ]
    then
        echo "$FILE"
        pass=0
    fi
    rm "$tmpfile"
done

rm "$diffFile"
rm -rf "$TMPDIR"

if [ "$pass" != 1 ]
then
    echo "Please run src/clang-format-all.sh to correct the above files"
    exit 1
fi