#!/bin/bash

# 固定资产系统备份脚本
set -euo pipefail

PROJECT_DIR="${PROJECT_DIR:-/opt/equipment-management}"
PROJECT_NAME="${PROJECT_NAME:-equipment-management}"
BACKUP_ROOT="${BACKUP_ROOT:-/opt/backups/equipment-management}"
KEEP_BACKUPS="${KEEP_BACKUPS:-3}"
DB_CONTAINER="${DB_CONTAINER:-equipment-mysql}"
BACKEND_CONTAINER="${BACKEND_CONTAINER:-equipment-backend}"
DB_NAME="${DB_NAME:-equipment_management}"
DB_USER="${DB_USER:-root}"
DB_PASSWORD="${DB_PASSWORD:-${MYSQL_ROOT_PASSWORD:-}}"
UPLOADS_PATH="${UPLOADS_PATH:-/app/uploads}"
TIMESTAMP="$(date +%Y%m%d_%H%M%S)"
BACKUP_DIR="${BACKUP_ROOT}/${TIMESTAMP}"

cleanup_on_error() {
  echo "备份失败，清理不完整目录: ${BACKUP_DIR}"
  rm -rf "${BACKUP_DIR}"
}

prune_old_backups() {
  if ! [[ "${KEEP_BACKUPS}" =~ ^[0-9]+$ ]]; then
    echo "KEEP_BACKUPS 不是有效数字: ${KEEP_BACKUPS}"
    exit 1
  fi

  mapfile -t existing_backups < <(
    find "${BACKUP_ROOT}" -mindepth 1 -maxdepth 1 -type d -exec basename {} \; \
      | awk '/^[0-9]{8}_[0-9]{6}$/' \
      | sort \
      | while IFS= read -r dir_name; do
          printf '%s/%s\n' "${BACKUP_ROOT}" "${dir_name}"
        done
  )
  local total="${#existing_backups[@]}"

  if [ "${total}" -le "${KEEP_BACKUPS}" ]; then
    echo ">>> 当前标准备份数量 ${total}，无需清理"
    return
  fi

  local delete_count=$((total - KEEP_BACKUPS))
  echo ">>> 仅保留最近 ${KEEP_BACKUPS} 份备份，清理 ${delete_count} 份旧备份"
  for backup_dir in "${existing_backups[@]:0:${delete_count}}"; do
    echo "    删除: ${backup_dir}"
    rm -rf "${backup_dir}"
  done
}

trap cleanup_on_error ERR

if ! docker inspect "${DB_CONTAINER}" >/dev/null 2>&1; then
  echo "数据库容器不存在: ${DB_CONTAINER}"
  exit 1
fi

if ! docker inspect "${BACKEND_CONTAINER}" >/dev/null 2>&1; then
  echo "后端容器不存在: ${BACKEND_CONTAINER}"
  exit 1
fi

if [ -z "${DB_PASSWORD}" ]; then
  echo ">>> 未从 DB_PASSWORD / MYSQL_ROOT_PASSWORD 读取到数据库密码，尝试读取 ${DB_CONTAINER} 容器环境"
  if ! container_env="$(docker inspect -f '{{range .Config.Env}}{{println .}}{{end}}' "${DB_CONTAINER}")"; then
    echo "无法读取数据库容器环境: ${DB_CONTAINER}" >&2
    exit 1
  fi

  while IFS= read -r env_line; do
    case "${env_line}" in
      MYSQL_ROOT_PASSWORD=*)
        DB_PASSWORD="${env_line#MYSQL_ROOT_PASSWORD=}"
        break
        ;;
    esac
  done <<< "${container_env}"
  unset container_env env_line
fi

if [ -z "${DB_PASSWORD}" ]; then
  echo "数据库密码缺失：请设置 DB_PASSWORD 或 MYSQL_ROOT_PASSWORD；容器 ${DB_CONTAINER} 中也未找到 MYSQL_ROOT_PASSWORD。" >&2
  exit 1
fi

mkdir -p "${BACKUP_DIR}/db" "${BACKUP_DIR}/uploads" "${BACKUP_DIR}/config"

echo "备份目录: ${BACKUP_DIR}"
echo "保留策略: 最近 ${KEEP_BACKUPS} 份"

echo ">>> 备份数据库 ${DB_NAME}"
docker exec -e "MYSQL_PWD=${DB_PASSWORD}" "${DB_CONTAINER}" \
  mysqldump -u"${DB_USER}" --single-transaction --routines --triggers "${DB_NAME}" \
  | gzip > "${BACKUP_DIR}/db/${DB_NAME}.sql.gz"

echo ">>> 备份上传目录 ${UPLOADS_PATH}"
docker exec "${BACKEND_CONTAINER}" \
  sh -lc "if [ -d '${UPLOADS_PATH}' ]; then tar -C '${UPLOADS_PATH}' -czf - .; else printf '' | gzip; fi" \
  > "${BACKUP_DIR}/uploads/uploads.tar.gz"

echo ">>> 备份部署配置"
cp "${PROJECT_DIR}/docker-compose.yml" "${BACKUP_DIR}/config/docker-compose.yml"
cp "${PROJECT_DIR}/deploy.sh" "${BACKUP_DIR}/config/deploy.sh"
cp "${PROJECT_DIR}/Dockerfile" "${BACKUP_DIR}/config/Dockerfile"
if [ -d "${PROJECT_DIR}/frontend/public/branding" ]; then
  cp -R "${PROJECT_DIR}/frontend/public/branding" "${BACKUP_DIR}/config/branding"
fi

cat > "${BACKUP_DIR}/backup-info.txt" <<EOF
timestamp=${TIMESTAMP}
project_name=${PROJECT_NAME}
project_dir=${PROJECT_DIR}
db_container=${DB_CONTAINER}
backend_container=${BACKEND_CONTAINER}
db_name=${DB_NAME}
uploads_path=${UPLOADS_PATH}
hostname=$(hostname)
EOF

echo ">>> 生成校验信息"
(
  cd "${BACKUP_DIR}"
  if [ -d config/branding ]; then
    find config/branding -type f -print0 | xargs -0 sha256sum > branding-sha256.tmp
  else
    : > branding-sha256.tmp
  fi
  cat <(sha256sum db/${DB_NAME}.sql.gz uploads/uploads.tar.gz config/docker-compose.yml config/deploy.sh config/Dockerfile) branding-sha256.tmp > SHA256SUMS
  rm -f branding-sha256.tmp
)

prune_old_backups
trap - ERR

echo "备份完成: ${BACKUP_DIR}"