"""系统管理 API（数据备份导出/导入）。仅管理员。

导出：POST /api/system/backup/export  → 返回 zip 附件下载
预览：POST /api/system/backup/preview → multipart 上传 zip/db，返回暂存 token + 表清单
应用：POST /api/system/backup/apply    → 校验后落「重启生效」恢复任务

导入涉及整库替换，只允许管理员操作（web/auth.admin_required）。
"""
from io import BytesIO

from flask import Blueprint, jsonify, request, send_file
from flask_login import current_user

from web.auth import admin_required
from core import system_backup as sb
from core.logger import get_logger

_log = get_logger("web.system")

bp = Blueprint("system", __name__)


@bp.route("/api/system/backup/export", methods=["POST"])
@admin_required
def api_system_backup_export():
    """生成导出 zip 并作为附件返回（含 users.db 快照 + manifest.json + 可选 apks）。"""
    data = request.json or {}
    include_apk = bool(data.get("include_apk", True))
    try:
        zip_path, fname, manifest = sb.create_export(include_apk=include_apk)
    except sb.BackupError as e:
        return jsonify({"ok": False, "error": str(e)}), 400
    except Exception as e:
        _log.error(f"导出备份失败: {e}")
        return jsonify({"ok": False, "error": f"导出失败: {e}"}), 500

    # 读入内存后立即删除磁盘文件再发送——Windows 上 send_file 流式发送时文件
    # 句柄可能到 close 仍未释放，call_on_close 删不掉会残留；改 BytesIO 发送
    # 则可确定性清理（导出为一次性下载，无需保留服务端副本）。
    with open(zip_path, "rb") as f:
        data = f.read()
    sb.remove_quiet(zip_path)
    try:
        from core import notifier
        notifier.notify("system.backup.exported", filename=fname, size=len(data),
                        tables=len(manifest.get("tables") or []),
                        include_apk=include_apk,
                        user=getattr(current_user, "username", ""))
    except Exception:
        pass          # 通知失败不影响导出
    resp = send_file(BytesIO(data), as_attachment=True, download_name=fname,
                     mimetype="application/zip")
    return resp


@bp.route("/api/system/backup/preview", methods=["POST"])
@admin_required
def api_system_backup_preview():
    """上传备份文件（zip/db）→ 暂存并校验 → 返回预览（表行数/schema/告警）。"""
    f = request.files.get("file")
    if not f or not f.filename:
        return jsonify({"ok": False, "error": "未选择文件"}), 400
    try:
        token, info = sb.stage_upload(f)
    except sb.BackupError as e:
        return jsonify({"ok": False, "error": str(e)}), 400
    except Exception as e:
        _log.error(f"备份预览失败: {e}")
        return jsonify({"ok": False, "error": f"解析文件失败: {e}"}), 500
    _log.info(f"备份预览: {info.get('file_name')} "
              f"(schema v{info.get('schema_version')}) token={token}")
    return jsonify({"ok": True, "token": token, "preview": info})


@bp.route("/api/system/backup/apply", methods=["POST"])
@admin_required
def api_system_backup_apply():
    """确认应用导入：自动备份当前库 → 落待生效恢复任务（重启后生效）。

    force_env_mismatch 默认 False：备份来源环境与当前库环境不符时拒绝导入，
    要跨环境（如把生产数据导进 dev 库）必须显式传 true。
    """
    body = request.json or {}
    token = body.get("token", "")
    force = bool(body.get("force_env_mismatch", False))
    try:
        res = sb.apply_restore(str(token).strip(), force_env_mismatch=force)
    except sb.BackupError as e:
        return jsonify({"ok": False, "error": str(e)}), 400
    except Exception as e:
        _log.error(f"应用导入失败: {e}")
        return jsonify({"ok": False, "error": f"应用导入失败: {e}"}), 500
    return jsonify({"ok": True, **res})