# -*- coding: utf-8 -*-
# !/usr/bin/env python

import logging
import os

from django.http import StreamingHttpResponse
from typing import TYPE_CHECKING

from apilib.utils_json import JsonResponse
from apps.web.api.models import DeviceVersionConfig
from apps.web.device.models import Device

logger = logging.getLogger(__name__)

if TYPE_CHECKING:
    pass

DEVICE_VERSION_BASE_PATH = '/var/www/uploaded/version'
DEVICE_VERSION_BUFFER = dict()


def get_firmware_upgrade_file(request):
    def file_iterator(file_name, chunk_size = 512):
        with open(file_name) as f:
            while True:
                c = f.read(chunk_size)
                if c:
                    yield c
                else:
                    break

    project_key = request.GET.get('project_key')
    dev_no = request.GET.get('imei')
    version = str(request.GET.get('version'))

    logger.debug('project key = {}; imei = {}; version = {}'.format(project_key, dev_no, version))

    dev = Device.get_dev(dev_no)
    if not dev:
        logger.debug('{} is not exists.'.format(dev_no))
        return JsonResponse({"payload": {}}, status = 404)

    if project_key not in ['vivostone', 'viveston']:
        logger.debug('project key {} is not mine.'.format(project_key))
        return JsonResponse({"payload": {}}, status = 404)

    tokens = version.split('.')
    match_version = '{}.{}.'.format(tokens[0], tokens[1])

    config = DeviceVersionConfig.objects(matchVersions = match_version,
                                         allowable = True).first()  # type: DeviceVersionConfig
    if not config:
        logger.debug('config is not exits.')
        return JsonResponse({"payload": {}}, status = 404)

    version_path = '{}/{}'.format(DEVICE_VERSION_BASE_PATH, config.filePath).format(dev['driverCode'])
    if version_path not in DEVICE_VERSION_BUFFER:
        if not os.path.isfile(version_path):
            return JsonResponse({"payload": {}}, status = 404)

        content = file_iterator(version_path)
        DEVICE_VERSION_BUFFER[version_path] = content
    else:
        content = DEVICE_VERSION_BUFFER[version_path]

    response = StreamingHttpResponse(content)
    response['Content-Type'] = 'application/octet-stream'
    response['Content-Disposition'] = 'attachment;filename=%s' % version_path
    response['Content-Length'] = os.path.getsize(version_path)

    return response