meincantor-app/lib/cache_manager.dart

// GCG.MeinCantor - Die Schulplattform für Cantorianer.
// Copyright (C) 2021-2022 Georg-Cantor-Gymnasium Halle (Saale)

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.

// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

import 'dart:convert';

import 'package:flutter_cache_manager/flutter_cache_manager.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:http/http.dart' as http;

Future<String> getCachedTimetable(String ext, String? presetClassNum) async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String classNum;
  if (presetClassNum != null) {
    classNum = presetClassNum.replaceAll("/", "_");
  } else if (prefs.getString('class_num') != null) {
    classNum = prefs.getString('class_num')!.replaceAll("/", "_");
  } else {
    classNum = '05_1';
  }
  var apiKey = prefs.getString('api_key');
  var headers = {"x-api-key": "$apiKey"};

  var uri =
      Uri.https("mein.cantorgymnasium.de", "/api/timetable/$ext/$classNum");
  final response =
      await http.get(uri, headers: headers).onError((error, stackTrace) {
    return http.Response("", 404);
  });

  if (response.statusCode == 404) {
    var file = await DefaultCacheManager().getSingleFile(
        "https://mein.cantorgymnasium.de/api/timetable/$ext/$classNum",
        headers: headers);
    return (utf8.decode(await file.readAsBytes()));
  } else {
    DefaultCacheManager().putFile(
        "https://mein.cantorgymnasium.de/api/timetable/$ext/$classNum",
        response.bodyBytes);
    return (utf8.decode(response.bodyBytes));
  }
}