#!/usr/bin/env bash
# review-note: manage code-review notes under refs/notes/review.
# The protocol lives in REVIEW.md.
set -euo pipefail

NOTES_REF=refs/notes/review
REMOTE=origin

die() { echo "review-note: $*" >&2; exit 1; }

usage() {
  cat >&2 <<'EOF'
usage:
  review-note show [commit]
  review-note write <file> [--force]
  review-note latest [branch]
  review-note push
EOF
  exit 1
}

validate() {
  local file="$1"
  grep -q '^branch: .\+' "$file" || die "missing or empty 'branch:' header"
  grep -Eq '^round: [0-9]+$' "$file" || die "missing or invalid 'round:' header"
  grep -Eq '^verdict: (approve|request-changes)$' "$file" \
    || die "verdict must be 'approve' or 'request-changes'"
}

cmd_show() {
  local commit="${1:-HEAD}"
  git notes --ref="$NOTES_REF" show "$commit" 2>/dev/null \
    || die "no review note for $commit"
}

cmd_write() {
  local force="" file=""
  local arg
  for arg in "$@"; do
    case "$arg" in
      --force) force=1 ;;
      *) file="$arg" ;;
    esac
  done
  [ -n "$file" ] || usage
  [ -f "$file" ] || die "no such file: $file"
  local tip
  tip=$(git rev-parse HEAD)
  if [ -z "$force" ] && git notes --ref="$NOTES_REF" show "$tip" >/dev/null 2>&1; then
    die "tip $tip already has a review note; pass --force to replace"
  fi
  validate "$file"
  if [ -n "$force" ]; then
    git notes --ref="$NOTES_REF" add -f -F "$file" "$tip"
  else
    git notes --ref="$NOTES_REF" add -F "$file" "$tip"
  fi
}

cmd_latest() {
  local branch="${1:-$(git branch --show-current)}"
  local blob obj note br rnd best="" best_round=-1
  while read -r blob obj; do
    note=$(git notes --ref="$NOTES_REF" show "$obj") || continue
    br=$(sed -n '/^$/q; s/^branch: //p' <<<"$note")
    [ "$br" = "$branch" ] || continue
    rnd=$(sed -n '/^$/q; s/^round: //p' <<<"$note")
    [[ "$rnd" =~ ^[0-9]+$ ]] || continue
    if [ "$rnd" -gt "$best_round" ]; then
      best_round=$rnd
      best=$note
    fi
  done < <(git notes --ref="$NOTES_REF" list)
  [ -n "$best" ] || die "no review notes for branch: $branch"
  printf '%s\n' "$best"
}

cmd_push() {
  git rev-parse -q --verify "$NOTES_REF" >/dev/null || die "no review notes to push"
  git push "$REMOTE" "$NOTES_REF"
}

main() {
  local cmd="${1:-}"
  if [ $# -gt 0 ]; then shift; fi
  case "$cmd" in
    show) cmd_show "$@" ;;
    write) cmd_write "$@" ;;
    latest) cmd_latest "$@" ;;
    push) cmd_push "$@" ;;
    *) usage ;;
  esac
}

main "$@"