"""
StorageView 文件下载模块
提供文件下载功能（导出日志、导出配置等场景使用）。
"""
from app.views.ViewsBase import *
from app.utils.LanguageUtils import LANG_VIEWS_T
from django.core import signing
from django.utils.encoding import escape_uri_path
import os


DOWNLOAD_ID_SALT = "monitor.temp-download.v1"
DOWNLOAD_ID_MAX_AGE_SECONDS = 300
ALLOWED_DOWNLOAD_SUFFIXES = frozenset((
    ".mp4", ".wav", ".jpg", ".png", ".tar", ".xclogs", ".xcsettings", ".xcupdate", ".xcflow",
))


def _safe_temp_download_path(filename, require_exists=True):
    if not filename or filename != os.path.basename(filename):
        raise ValueError("invalid download file")
    if os.path.splitext(filename)[1].lower() not in ALLOWED_DOWNLOAD_SUFFIXES:
        raise ValueError("unsupported download file type")
    base = os.path.realpath(g_config.storageTempDir)
    path = os.path.realpath(os.path.join(base, filename))
    if os.path.dirname(path) != base:
        raise ValueError("invalid download path")
    if require_exists and not os.path.isfile(path):
        raise FileNotFoundError("download file not found")
    return path


def issue_download_file_id(filename):
    """Return an opaque, short-lived identifier for a server-created temp file."""
    _safe_temp_download_path(filename, require_exists=True)
    return signing.dumps({"name": filename}, salt=DOWNLOAD_ID_SALT, compress=True)


def resolve_download_file_id(file_id):
    data = signing.loads(file_id, salt=DOWNLOAD_ID_SALT, max_age=DOWNLOAD_ID_MAX_AGE_SECONDS)
    if not isinstance(data, dict):
        raise signing.BadSignature("invalid download id")
    filename = str(data.get("name") or "")
    return filename, _safe_temp_download_path(filename, require_exists=True)


def api_openInfo(request):
    """查询存储空间信息（原 Storage 模块，已移除）"""
    if request.method != 'GET':
        return f_responseJson({"code": 0, "msg": LANG_VIEWS_T(request, "msg_method_not_supported")})

    __check_ret, __check_msg = f_checkRequestSafe(request)
    if not __check_ret:
        return f_responseJson({"code": 0, "msg": __check_msg})

    g_logger.info("StorageView.api_openInfo() ip:%s" % f_parseRequestIp(request))
    return f_responseJson({
        "code": 1000,
        "msg": "ok",
        "info": {
            "alarmFolderSize": 0,
            "recordFolderSize": 0
        }
    })


def api_openDownload(request):
    """Download a server-created temp file by a short-lived signed identifier."""
    __check_ret, __check_msg = f_checkRequestSafe(request)
    if not __check_ret:
        return f_responseJson({"code": 0, "msg": __check_msg})
    params = f_parseGetParams(request)
    file_id = params.get("file_id", "").strip()
    try:
        if not file_id:
            raise signing.BadSignature("missing download id")
        filename, filepath = resolve_download_file_id(file_id)
        from django.http import FileResponse
        response = FileResponse(open(filepath, mode="rb"), content_type="application/octet-stream")
        response['Content-Disposition'] = "attachment; filename={};".format(escape_uri_path(filename))
        response['Cache-Control'] = "no-store"
        return response
    except (signing.BadSignature, signing.SignatureExpired, ValueError, FileNotFoundError) as e:
        g_logger.warning("StorageView.openDownload() rejected: %s" % str(e))
        return f_responseJson({"code": 0, "msg": "invalid or expired download id"})