#!/usr/bin/env sh
#
# Copyright 2016-present the IoT DC3 original author or authors.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#

# Conventional-commit lint per the repository guidelines: enforces the
# <type>(<scope>): <lowercase imperative description> subject line.
# Auto-generated commits (merges, reverts, fixup) pass through untouched.

commit_msg_file="$1"
[ -f "$commit_msg_file" ] || exit 1

subject=$(grep -m1 -v '^#' "$commit_msg_file" | grep -v '^$')
[ -z "$subject" ] && exit 0

# passthrough for git-generated messages
printf '%s' "$subject" | grep -qE '^(Merge |Revert |fixup!|squash! )' && exit 0

fail() {
  echo "commit-msg: $1" >&2
  echo "  subject: $subject" >&2
  echo "  expected: <type>(<scope>): <lowercase imperative description>" >&2
  exit 1
}

type='feat|fix|perf|refactor|docs|build|ci|test|chore|style|security|revert'
breaking='!'

# <type>(<scope>)!??: <description>, scope optional, '!' marks breaking
pattern="^(${type})(\\([a-z0-9-]+\\))?${breaking}?: .+$"
printf '%s' "$subject" | grep -qE "$pattern" || fail "type or format not allowed"

[ "${#subject}" -le 100 ] || fail "subject exceeds 100 chars (${#subject})"

description=$(printf '%s' "$subject" | sed -E "s/^(${type})(\\([a-z0-9-]+\\))?${breaking}?: //")
[ "${#description}" -ge 10 ] || fail "description shorter than 10 chars"

printf '%s' "$description" | grep -qE '[[:upper:]]' && fail "description must be lowercase"

printf '%s' "$description" | grep -qE '[^ -~]' && fail "description must be ascii/english"

exit 0