#!/bin/sh
#
# A hook script to check the commit log message.
# Called by "git commit" with one argument, the name of the file that has the
# commit message.
# The hook should exit with non-zero status after issuing an appropriate message
# if it wants to stop the commit.
# The hook is allowed to edit the commit message file.
#
# To enable this hook, save this file in ".git/hooks/commit-msg".

die() {
	printf "$1" >&2
	exit ${2:-1}
}

subject="$(head -1 "$1")"
body="$(tail +2 "$1" | grep -v "^#")"

[ ${#subject} -le 50 ] || die "Subject too long. (<= 50)\n"

if ! echo "$subject" | grep -qE "^([-_,*(){}a-zA-Z0-9]+:)+ "; then
	die "Specify which program was modified. (e.g. \"zsh:p10k: <subject>\")\n"
fi
if ! echo "$subject" | grep -qE "^([-_,*(){}a-zA-Z0-9]+:)+ [A-Z]"; then
	die "Start subject with a capital letter.\n"
fi
if ! echo "$subject" | grep -qE "^([-_,*(){}a-zA-Z0-9]+:)+ [A-Z].*[^.]$"; then
	die "Remove punctuation mark from end.\n"
fi

BKP_IFS="$IFS"
IFS='
'
for line in $body; do
	[ ${#line} -le 72 ] || die "Body lines too long. (<= 72)\n"
done
IFS="$BKP_IFS"