#!/bin/sh
#
# This pre-commit hook checks if any versions of clang-format
# are installed, and if so, uses the installed version to format
# the staged changes.

base=clang-format-5.0
format=""

# Redirect output to stderr.
exec 1>&2

 # check if clang-format is installed
type "$base" >/dev/null 2>&1 && format="$base"

# no versions of clang-format are installed
if [ -z "$format" ]
then
    echo "$base is not installed. Pre-commit hook will not be executed."
    exit 0
fi

# Do everything from top - level
cd $(git rev-parse --show-toplevel)

if git rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=16bbb57
fi

# do the formatting
for file in $(git diff-index --cached --name-only $against | grep -E '\.h$|\.hpp$|\.cpp$|\.cl$|\.h\.in$|\.hpp\.in$|\.cpp\.in$')
do
    if [ -e "$file" ]
    then
        echo "$format $file"
        "$format" -i -style=file "$file"
    fi
done