#!/usr/bin/env bash
# Conventional Commits, with the scope naming an epic in plan/.
#
# The scope is how a commit says which line of work it belongs to, and it is
# only useful if it means something: an id that matches no epic is a typo or an
# epic somebody forgot to write. Archived epics count - a follow-up fix to
# finished work is still that epic's commit.
#
#   scripts/check-commit-scope.sh .git/COMMIT_EDITMSG
set -euo pipefail

HERE="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
MSG_FILE="${1:?usage: check-commit-scope.sh <commit-msg-file>}"
SUBJECT="$(head -n 1 "$MSG_FILE")"

# Fixups and merges are not ours to judge.
case "$SUBJECT" in
  fixup!*|squash!*|Merge*|Revert*) exit 0 ;;
esac

CONVENTIONAL='^(feat|fix|docs|refactor|perf|test|build|ci|chore)(\([a-z0-9-]+\))?!?: .+'
if ! printf '%s' "$SUBJECT" | grep -Eq "$CONVENTIONAL"; then
  echo "commit subject is not Conventional Commits:" >&2
  echo "  $SUBJECT" >&2
  echo "want: type(scope): summary   e.g. feat(features): normalise the basis" >&2
  exit 1
fi

SCOPE="$(printf '%s' "$SUBJECT" | sed -n 's/^[a-z]*(\([a-z0-9-]*\)).*/\1/p')"
[ -n "$SCOPE" ] && [ "$SCOPE" != "plan" ] || exit 0

for dir in "$HERE/plan" "$HERE/plan/complete"; do
  [ -f "$dir/$SCOPE.md" ] && exit 0
done

echo "commit scope '$SCOPE' names no epic in plan/." >&2
echo "known:" >&2
for f in "$HERE"/plan/*.md "$HERE"/plan/complete/*.md; do
  [ -e "$f" ] || continue
  b="$(basename "$f" .md)"
  [ "$b" = "README" ] || echo "  $b" >&2
done
echo "  plan   (for the register itself)" >&2
exit 1