#!/usr/bin/env bash
set -euo pipefail

readonly HEADER_PATTERN='^(feat|fix|perf|refactor|test|docs|build|ci|chore|revert)(\([[:alnum:]./_-]+\))?!?: .+$'

is_conventional_header() {
  [[ "$1" =~ ${HEADER_PATTERN} ]]
}

run_self_test() {
  local subject

  for subject in \
    'feat(rpc): add request timeout' \
    'fix!: preserve legacy config behavior' \
    'docs(release): document versioning'; do
    is_conventional_header "${subject}" || {
      echo "expected valid Conventional Commit: ${subject}" >&2
      exit 1
    }
  done

  for subject in 'update dependency' 'feature: invalid type' 'fix missing separator'; do
    if is_conventional_header "${subject}"; then
      echo "expected invalid Conventional Commit: ${subject}" >&2
      exit 1
    fi
  done
}

if [ "${1:-}" = "--self-test" ]; then
  run_self_test
  echo "Conventional Commit validator self-test passed"
  exit 0
fi

baseline="${1:-v1.0.0}"
git rev-parse --verify "${baseline}^{commit}" >/dev/null

invalid=0
while IFS=$'\t' read -r commit subject; do
  if ! is_conventional_header "${subject}"; then
    echo "${commit}: ${subject}" >&2
    invalid=1
  fi
done < <(git log --format='%H%x09%s' --no-merges "${baseline}..HEAD")

if [ "${invalid}" -ne 0 ]; then
  echo "Conventional Commit validation failed after ${baseline}" >&2
  exit 1
fi

echo "Conventional Commit validation passed after ${baseline}"