#!/bin/bash
# I, Ian Kelling, follow the GNU license recommendations at
# https://www.gnu.org/licenses/license-recommendations.en.html. They
# recommend that small programs, < 300 lines, be licensed under the
# Apache License 2.0. This file contains or is part of one or more small
# programs. If a small program grows beyond 300 lines, I plan to switch
# its license to GPL.

# Copyright 2024 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Copyright (C) 2016 Ian Kelling

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


# ian: This section is the git upstream example hook, but it's actually useful.

# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "pre-commit".

if git rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

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

# Redirect output to stderr.
exec 1>&2

# 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.
if [[ $allownonascii != true ]] &&
       # Note that the use of brackets around a tr range is ok here, (it's
       # even required, for portability to Solaris 10's /usr/bin/tr), since
       # the square bracket bytes happen to fall in the designated range.
       test "$(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



# ian: inspired from:
# https://github.com/ntc2/conf/blob/master/dot.gitconfig
# last checked for any changes there on 7/2016
# duplicated at,
# http://stackoverflow.com/a/15398512/14456


set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?"' ERR

if [[ $(git config --bool hooks.allowwhitespace) == true ]] || \
       [[ $GIT_ALLOWWHITESPACE == true ]]; then
    exit 0
fi

# bail out when we call ourselves or there are no whitespace issues.
if [[ $GIT_ALLOWWHITESPACE == ignore ]] ||
       ws_issues=$(git diff-index --check --cached $against --); then
    echo "$ws_issues"
    exit 0
fi
if [[ -d "$(git rev-parse --git-dir)/rebase-merge" ]] ; then
    cat <<'EOF'
warning: whitespace issues, but rebase in progress, so I can't/won't fix them.
If you want to fix them, do for example:
git rebase --whitespace=fix HEAD~2
EOF
    echo "$ws_issues"
    exit 0
fi
# can't do it on the first commit
if ! git rev-list HEAD --count &>/dev/null; then
    cat <<'EOF'
Whitespace issues found. We can't fix in a pre-commit hook for the first commit.
Either fix on your own. I suggest https://github.com/dlenski/wtf, from git root:

git ls-files --exclude-standard -cmo --no-empty-directory | while read -r f; do if [[ -L $f ]] || ! grep -Iq . "$f"; then continue; fi;  wtf.py -i -E lf "$f"; done

or allow whitespace with:
git config hooks.allowwhitespace true, or export GIT_ALLOWWHITESPACE=true
EOF
    echo "$ws_issues"
    exit 1
fi
echo "Fixing whitespace lines. To avoid this, do:
git config hooks.allowwhitespace true, or export GIT_ALLOWWHITESPACE=true"
export GIT_ALLOWWHITESPACE=ignore
if ! git diff-files --quiet . && \
        ! git diff-index --quiet --cached HEAD; then
    # - dirty tree and dirty index
    git commit -m "temporary commit of index while fixing whitespace"
    git add -u :/
    git commit -m "temporary commit of non-index while fixing whitespace"
    git rebase --whitespace=fix HEAD~2
    git reset HEAD~ &&
        git reset --soft HEAD~
elif ! git diff-files --quiet .; then
    # - dirty tree and clean index
    git add -u :/
    git commit -m "temporary commit of non-index while fixing whitespace"
    git rebase --whitespace=fix HEAD~
    git reset HEAD~
elif ! git diff-index --quiet --cached HEAD; then
    # - clean tree and dirty index
    git commit -m "temporary commit of index while fixing whitespace"
    git rebase --whitespace=fix HEAD~
    git reset --soft HEAD~
fi