#!/usr/bin/env bash
# prune-branches.sh — Delete merged remote branches older than N days.
# Usage: ./prune-branches.sh [--days 14] [--remote forgejo] [--execute]
# Default: dry-run (shows what would be deleted). Pass --execute to actually delete.
set -euo pipefail

DAYS=14
REMOTE="forgejo"
EXECUTE=false

while [ $# -gt 0 ]; do
  case "$1" in
    --days) DAYS="$2"; shift 2 ;;
    --remote) REMOTE="$2"; shift 2 ;;
    --execute) EXECUTE=true; shift ;;
    --help|-h) echo "Usage: $0 [--days N] [--remote name] [--execute]"; exit 0 ;;
    *) echo "Unknown arg: $1"; exit 1 ;;
  esac
done

CUTOFF=$(date -v-${DAYS}d +%Y-%m-%d 2>/dev/null || date -d "-${DAYS} days" +%Y-%m-%d)
PROTECTED="main|HEAD"

echo "Scanning $REMOTE for merged branches older than $CUTOFF..."
echo ""

git fetch "$REMOTE" --prune --quiet

COUNT=0
DELETE_COUNT=0

while IFS= read -r branch; do
  branch=$(echo "$branch" | sed 's/^[[:space:]]*//')
  [ -z "$branch" ] && continue

  short="${branch#$REMOTE/}"
  echo "$short" | grep -qE "^($PROTECTED)$" && continue

  last_date=$(git log -1 --format='%ai' "$branch" 2>/dev/null | cut -d' ' -f1)
  [ -z "$last_date" ] && continue
  COUNT=$((COUNT + 1))

  if [[ "$last_date" < "$CUTOFF" ]]; then
    if ! git merge-base --is-ancestor "$branch" "$REMOTE/main" 2>/dev/null; then
      echo "  SKIP (unmerged): $short ($last_date)"
      continue
    fi
    if $EXECUTE; then
      echo "  DELETE: $short ($last_date)"
      git push "$REMOTE" --delete "$short" 2>&1 && DELETE_COUNT=$((DELETE_COUNT + 1)) || echo "    FAILED: $short"
    else
      echo "  WOULD DELETE: $short ($last_date)"
      DELETE_COUNT=$((DELETE_COUNT + 1))
    fi
  fi
done < <(git branch -r | grep "^  $REMOTE/")

echo ""
if $EXECUTE; then
  echo "Deleted $DELETE_COUNT of $COUNT branches."
else
  echo "Would delete $DELETE_COUNT of $COUNT branches. Run with --execute to proceed."
fi