#!/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="${DB_PASSWORD:-jsjj8888}"
UPLOADS_PATH="${UPLOADS_PATH:-/app/uploads}"
TIMESTAMP="$(date +%Y%m%d_%H%M%S)"
BACKUP_DIR="${BACKUP_ROOT}/${TIMESTAMP}"

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

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 "${BACKUP_ROOT}" -mindepth 1 -maxdepth 1 -type d | sort)
  local total="${#existing_backups[@]}"

  if [ "${total}" -le "${KEEP_BACKUPS}" ]; then
    echo ">>> 当前备份数量 ${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

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

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

echo ">>> 备份数据库 ${DB_NAME}"
docker exec "${DB_CONTAINER}" \
  sh -lc "exec mysqldump -u${DB_USER} -p'${DB_PASSWORD}' --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"

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 "${BACKUP_DIR}"
  sha256sum db/${DB_NAME}.sql.gz uploads/uploads.tar.gz config/docker-compose.yml config/deploy.sh config/Dockerfile > SHA256SUMS
)

prune_old_backups
trap - ERR

echo "备份完成: ${BACKUP_DIR}"