#!/bin/bash -e
# taken from: https://raw.githubusercontent.com/andrewseidl/githook-clang-format/master/clang-format.hook
# - with just added check for cpp file & check for proper version of clang-format
# - with use of clang-format diff.py - for changed chunk changes only
# might be worth to consider: https://github.com/Sarcasm/run-clang-format

set -o pipefail

# check if clang format is in proper version, version is 3rd column in `clang-format --version`
CVER=$(clang-format --version | cut -d ' ' -f 3 | cut -d '.' -f 1)
if [ $CVER -lt 9 ]; then
    echo "Install clang-format in at least verion 9 and set as default, on ubuntu:"
    echo 'Your clang format version used: '$(clang-format --version)
    echo "git commit aborted"
    exit 1
fi

# if clang-format-diff exists in path - then use it, if not - than try to use it from clang-format-${CVER}
L_CLANG_DIFF_TOOL=$( which clang-format-diff.py && echo "clang-format-diff.py" || echo "/usr/share/clang/clang-format-${CVER}/clang-format-diff.py" )
if [[ ! -f ${L_CLANG_DIFF_TOOL} ]]; then
    echo "Clang tool for git diff chunk formatting not found!"
    echo "path used: ${L_CLANG_DIFF_TOOL}"
    exit 1
fi

format_file() {
  file="${1}"
  if [ -f $file ]; then
    echo "Format file: ${1} diff"
    git diff -U0 --no-color --cached ${1} | ${L_CLANG_DIFF_TOOL} -p1 -i
    git add ${1}
  fi
}

case "${1}" in
  --about )
    echo "Runs clang-format on source files"
    ;;
  * )
    for file in `git diff-index --cached --name-only HEAD` ; do
        if [[ ${file} =~ ^.*\.(cpp|hpp|c|h|cxx|gcc|cc)$ ]]; then
            format_file "${file}"
        fi
    done
    ;;
esac