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

archive_path="${1:-}"
passphrase_file="${DATA_BACKUP_PASSPHRASE_FILE:-}"

if [[ -z "${archive_path}" || ! -f "${archive_path}" ]]; then
  echo "用法：DATA_BACKUP_PASSPHRASE_FILE=/安全路径/密钥 $0 /备份/mysql-all-*.enc" >&2
  exit 2
fi
if [[ -z "${passphrase_file}" || ! -r "${passphrase_file}" ]]; then
  echo "缺少可读的 DATA_BACKUP_PASSPHRASE_FILE" >&2
  exit 2
fi

checksum_file="${archive_path}.sha256"
if [[ ! -f "${checksum_file}" ]]; then
  echo "缺少校验文件：${checksum_file}" >&2
  exit 2
fi
expected="$(awk 'NR==1 {print $1}' "${checksum_file}")"
if command -v sha256sum >/dev/null 2>&1; then
  actual="$(sha256sum "${archive_path}" | awk '{print $1}')"
else
  actual="$(shasum -a 256 "${archive_path}" | awk '{print $1}')"
fi
if [[ -z "${expected}" || "${actual}" != "${expected}" ]]; then
  echo "备份 SHA-256 校验失败" >&2
  exit 1
fi

openssl enc -d -aes-256-cbc -pbkdf2 -iter 200000 \
  -pass "file:${passphrase_file}" -in "${archive_path}" | gzip -t

echo "备份加密、校验和与压缩结构验证通过。"
echo "生产环境仍应定期恢复到隔离 MySQL 实例进行完整恢复演练。"