#!/bin/sh
#
# A 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, save this file in ".git/hooks/pre-commit".

# Source die()
. "$HOME"/.local/bin/helpers.sh

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

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

# Redirect output to stderr.
exec 1>&2

# Check that all filenames include only ASCII characters.
if [ "$allownonascii" != "true" ]; then
	# We exploit the fact that the printable range starts at the space
	# character and ends with tilde.
	# Note that the use of brackets around a tr range is ok here, (it's
	# even required, for portability to Solaris 10's /usr/bin/tr), since
	# the square bracket bytes happen to fall in the designated range.
	num_nonascii=$(
		git diff-index --cached --name-only --diff-filter=A -z $against \
		| LC_ALL=C tr -d '[ -~]\0' \
		| wc -c
	)
	if [ $num_nonascii != 0 ]; then
		die "Rename files with ASCII characters only, or enable hooks.allownonascii"
	fi
fi

# Check for whitespace errors.
if ! git diff-index --check --cached $against --; then
	die
fi

# Check that added symlinks are neither absolute nor broken
git diff --staged --name-only --diff-filter=AT $against \
| {
	abort=0
	while read -r line; do
		[ -h "$line" ] || continue

		target="$(readlink "$line")"
		if [ -z "${target##/*}" ]; then
			abort=1
			printf "%s\n" "$line: Absolute symlink" >&2
		fi
		if [ ! -e "$line" ]; then
			abort=1
			printf "%s\n" "$line: Broken symlink" >&2
		fi
	done
	[ "$abort" -eq 0 ] || die
}