// 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 'package:flutter/material.dart';
import 'package:meincantor/background_fetch.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:meincantor/dashboard.dart';
import 'package:meincantor/login.dart';
import 'dart:math';
import 'package:background_fetch/background_fetch.dart';

void backgroundFetchHeadlessTask(HeadlessTask task) async {
  String taskId = task.taskId;
  bool isTimeout = task.timeout;
  if (isTimeout) {
    // This task has exceeded its allowed running-time.
    // You must stop what you're doing and immediately .finish(taskId)
    print("[BackgroundFetch] Headless task timed-out: $taskId");
    BackgroundFetch.finish(taskId);
    return;
  }
  print('[BackgroundFetch] Headless event received.');

  await backgroundFetchTimetable();
  await backgroundFetchArticles();

  BackgroundFetch.finish(taskId);
}

void main() async {
  runApp(const App());

  BackgroundFetch.registerHeadlessTask(backgroundFetchHeadlessTask);
}

class App extends StatefulWidget {
  const App({Key? key}) : super(key: key);
  @override
  _AppState createState() => _AppState();
}

class _AppState extends State<App> {
  MaterialColor generateMaterialColor(Color color) {
    return MaterialColor(color.value, {
      50: tintColor(color, 0.5),
      100: tintColor(color, 0.4),
      200: tintColor(color, 0.3),
      300: tintColor(color, 0.2),
      400: tintColor(color, 0.1),
      500: tintColor(color, 0),
      600: tintColor(color, -0.1),
      700: tintColor(color, -0.2),
      800: tintColor(color, -0.3),
      900: tintColor(color, -0.4),
    });
  }

  int tintValue(int value, double factor) =>
      max(0, min((value + ((255 - value) * factor)).round(), 255));

  Color tintColor(Color color, double factor) => Color.fromRGBO(
      tintValue(color.red, factor),
      tintValue(color.green, factor),
      tintValue(color.blue, factor),
      1);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      theme: ThemeData(
        primaryColor: Palette.primary,
        colorScheme: ColorScheme.fromSwatch(
          primarySwatch: generateMaterialColor(Palette.primary),
        ).copyWith(
          secondary: generateMaterialColor(Palette.accent),
        ),
      ),
      darkTheme: ThemeData.from(
          colorScheme: const ColorScheme.dark(
              primary: Palette.accent, secondary: Palette.accent)),
      title: "GCG.MeinCantor",
      home: buildHomePage(),
    );
  }
}

Future<bool> apiKeyEmpty() async {
  SharedPreferences prefs = await SharedPreferences.getInstance();
  String? apiKey = prefs.getString("api_key");
  return apiKey == null || apiKey.isEmpty;
}

Widget buildHomePage() {
  return FutureBuilder(
      future: apiKeyEmpty(),
      builder: (context, snapshot) {
        if (snapshot.data == true) {
          return Login();
        } else if (snapshot.data == false) {
          return const Dashboard();
        } else {
          return const Center(child: CircularProgressIndicator());
        }
      });
}

class Palette {
  static const Color primary = Color(0xFF1A1A37);
  static const Color accent = Color(0xFFFFBC3B);
}