#!/bin/bash
#
# To enable this hook, rename this file to "pre-commit" and copy into the
# ../.git/hooks directory.


# Cross platform projects tend to avoid non-ASCII filenames; prevent
# them from being added to the repository. We exploit the fact that the
# printable range starts at the space character and ends with tilde.
function check_no_nonascii_characters {
  if [ "${allownonascii}" == "true" ]; then
    return
  fi

  # Note that the use of brackets around a tr range is ok here, (it's
  # even required, for portability to Solaris 10's /usr/bin/tr), since
  # the square bracket bytes happen to fall in the designated range.
  if test $(git diff --cached --name-only --diff-filter=A -z "${against}" |
	      LC_ALL=C tr -d '[ -~]\0' | wc -c) != 0
  then
    cat <<\EOF
Error: Attempt to add a non-ASCII file name.

This can cause problems if you want to work with people on other platforms.

To be portable it is advisable to rename the file.

If you know what you are doing you can disable this check using:

  git config hooks.allownonascii true
EOF
    exit 1
  fi
}


function check_no_diffmarkers_or_whitespace_errors {
  # If there are whitespace errors, print the offending file names and fail.
  set -e
  git diff-index --check --cached "${against}" --
  set +e
}


function run_clang_format {
  echo "${changed_c_filenames}" | grep -v '3rdparty'
  if [[ "${changed_c_filenames}" == "" ]]; then
    return
  fi
  # Run clang-format against any changed C++ files.
  if ! which clang-format > /dev/null; then
    cat <<\EOF
Warning: clang-format is not installed or is not in the PATH.

Please install and amend this commit.

Debian:
        sudo apt install clang-format
EOF
    return
  fi

  # Reformat the files in-place and re-add any that were changed.
  #
  # Note that this has the side effect of incorporating changes to staged files
  # that were not themselves staged. E.g., if you edit a file, `git add`, then
  # edit some more, then commit, all of the changes will be committed, not just
  # the staged ones. Depending on typical workflows it might be better to do
  # something more complicated here, or to just have the hook fail instead of
  # perform an in-place fix.
  files_to_format="$(echo "${changed_c_filenames}" | grep -v '3rdparty')"
  echo "${files_to_format}" | xargs clang-format -i
  echo "${files_to_format}" | xargs git add
}


# If you want to allow non-ASCII filenames set this variable to true.
allownonascii=$(git config --bool hooks.allownonascii)

if git rev-parse --verify HEAD >/dev/null 2>&1; then
  against=HEAD
else
  # Initial commit: diff against an empty tree object
  against=$(git hash-object -t tree /dev/null)
fi

# Redirect output to stderr.
exec 1>&2


added_and_modified_filenames="$(git diff --cached --name-only --diff-filter=d)"
changed_c_filenames="$(echo "${added_and_modified_filenames}" | \
                            grep -E '.*\.(c|cpp|h|hpp)$')"


# Allow blank line at EOF.
git config --local core.whitespace -blank-at-eof

check_no_nonascii_characters
check_no_diffmarkers_or_whitespace_errors
run_clang_format