#!/bin/sh
set -eu

SCRIPT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
INFRA_DIR=$(CDPATH= cd -- "$SCRIPT_DIR/.." && pwd)
PROJECT_DIR=$(CDPATH= cd -- "$INFRA_DIR/.." && pwd)
BACKUP_ROOT=${BACKUP_ROOT:-"$PROJECT_DIR/backups"}
RETENTION_DAYS=${BACKUP_RETENTION_DAYS:-30}

case "$RETENTION_DAYS" in
  *[!0-9]*|"") echo "BACKUP_RETENTION_DAYS 必须是正整数" >&2; exit 2 ;;
esac
if [ "$RETENTION_DAYS" -lt 1 ]; then
  echo "BACKUP_RETENTION_DAYS 必须至少为 1" >&2
  exit 2
fi

mkdir -p "$BACKUP_ROOT"
BACKUP_ROOT=$(CDPATH= cd -- "$BACKUP_ROOT" && pwd)
case "$BACKUP_ROOT" in
  "$PROJECT_DIR/backups"|"$PROJECT_DIR/backups/"*) ;;
  *) echo "拒绝清理项目 backups 目录之外的路径：$BACKUP_ROOT" >&2; exit 2 ;;
esac

find "$BACKUP_ROOT" -mindepth 1 -maxdepth 1 -type d -mtime "+$RETENTION_DAYS" -print |
while IFS= read -r candidate; do
  name=$(basename "$candidate")
  if ! printf '%s\n' "$name" | grep -Eq '^20[0-9]{6}T[0-9]{6}Z$'; then
    echo "跳过非标准备份目录：$candidate"
    continue
  fi
  if [ ! -f "$candidate/manifest.txt" ] || [ ! -f "$candidate/SHA256SUMS" ]; then
    echo "跳过缺少清单的目录：$candidate"
    continue
  fi
  rm -rf -- "$candidate"
  echo "已按保留策略删除：$candidate"
done