import 'dart:convert';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'datamodel.dart';
import 'sensorconnector.dart';
import 'databaseconnector.dart';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';

class Configuration extends StatefulWidget {
  const Configuration({Key? key}) : super(key: key);

  @override
  State<Configuration> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<Configuration> {
  late Future<Collection> futureCollection;
  late Future<List<Collection>> futureCollections;
  late Future<List<EventType>> futureEventTypes;
  late Future<List<Device>> futureDevices;
  late Future<String> futureAuthToken;
  var database = DatabaseInstance();
  SensorConnector connector = SensorConnector();
  final ConfigurationStoreInstance configuration = ConfigurationStoreInstance();
  String _status = '';
  TextStyle _statusStyle = const TextStyle(color: Colors.black);

  Future<void> dumpToFile() async{
    var date = DateTime.now().toUtc();
    var isoDate = date.toIso8601String();

    String filename =
        date.year.toString().padLeft(4, '0') +
            date.month.toString().padLeft(2, '0') +
            date.day.toString().padLeft(2, '0') +
            date.hour.toString().padLeft(2, '0') +
            date.minute.toString().padLeft(2, '0') +
            date.second.toString().padLeft(2, '0') +
            '_events.json';

    String eventsJson = await database.eventDump();

    final Directory? directory = await getExternalStorageDirectory();
    if(directory != null) {
      String filepath = join(directory.path, filename);

      final File file = File(filepath);
      await file.writeAsString(eventsJson);
      debugPrint('Stored file at: ' + filepath);

      _status = 'Event database dump created: ' + filepath;
      _statusStyle = const TextStyle(color: Colors.green);
      setState(() {});
      HapticFeedback.vibrate();
    }
  }


  Future<void> updateConfiguration() async {
    final EventStoreInstance event = EventStoreInstance();
    String token = '';

    try{
      token = await connector.getAuthToken(configuration.loginInformation.mail, configuration.loginInformation.password);
      configuration.devices = await connector.fetchCollectionDevices(configuration.currentCollection.id); //await futureDevices; //already fetched just use the data.
      configuration.eventTypes = await connector.fetchEventTypes();

      event.currentEvent.id = 0;
      event.currentEvent.urnId = configuration.devices[0].id; //TODO: fix if devices are an empty list.
      event.currentEvent.urn = configuration.devices[0].urn;
      event.currentEvent.description = '';
      event.currentEvent.label = '';
      event.currentEvent.type = configuration.eventTypes[0].name;

      var date = DateTime.now().toUtc();
      var isoDate = date.toIso8601String();
      event.currentEvent.startDate = isoDate;
      event.currentEvent.endDate = isoDate;
      configuration.initialized = true;

      HapticFeedback.vibrate();
      //TODO: display success user feedback
      //TODO: store complete "configuration"

      await event.storeToSharedPrefs();
      await configuration.storeToSharedPrefs();
      debugPrint('Configuration stored!');

      _status = 'Login success, got all EventTypes, loaded Collection Devices & stored configuration for offline usage.';
      _statusStyle = const TextStyle(color: Colors.green);
      setState(() {});

    } catch (e) {
      String errorText = e.toString();
      errorText = errorText.substring(10, errorText.length);  //Remove 'Exception' from string.
      _status = errorText;
      _statusStyle = const TextStyle(color: Colors.red);
      setState(() {});
    }
  }

  Future<void> fetchInitData() async {
    try {
      futureCollections = connector.fetchCollections();
      await futureCollections;  //wait and catch error here!
    }catch(e){
      String errorText = e.toString();
      errorText = errorText.substring(10, errorText.length);  //Remove 'Exception' from string.
      _status = errorText;
      _statusStyle = const TextStyle(color: Colors.red);
      setState(() {});
    }
  }

  @override
  void initState() {
    super.initState();
    fetchInitData();
  }

  @override
  Widget build(BuildContext context) {
    final ConfigurationStoreInstance configuration = ConfigurationStoreInstance();
    final EventStoreInstance events = EventStoreInstance();

    return Scaffold(
        appBar: AppBar(
          title: const Text('Configuration'),
        ),
        body: Container(
          //constraints: const BoxConstraints.expand(),
          margin: const EdgeInsets.symmetric(horizontal: 5.0),
          child: SingleChildScrollView(
            scrollDirection: Axis.vertical,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              mainAxisSize: MainAxisSize.max,
              children: <Widget>[
                const SizedBox(height: 50),
                const Text(
                    'You must be online to do something here!',
                    style: TextStyle(fontSize: 14)
                ),
                const SizedBox(height: 50),
                TextFormField(
                  keyboardType: TextInputType.emailAddress,
                  autofocus: false,
                  initialValue: configuration.loginInformation.mail,
                  decoration: const InputDecoration(
                    border: OutlineInputBorder(),
                    labelText: 'E-Mail',
                    hintText: '',
                  ),
                  onChanged: (value) {
                    configuration.loginInformation.mail = value;
                  },
                ),
                const SizedBox(height: 15.0),
                TextFormField(
                  obscureText: true,
                  autofocus: false,
                  initialValue: configuration.loginInformation.password,
                  decoration: const InputDecoration(
                    border: OutlineInputBorder(),
                    labelText: 'Password',
                    hintText: '',
                  ),
                  onChanged: (value){
                    configuration.loginInformation.password = value;
                  },
                ),
                const SizedBox(height: 50),
                FutureBuilder<List<Collection>>(
                    future: futureCollections,
                    builder: (context, snapshot){
                      if (snapshot.hasData)
                      {
                        configuration.collections = [];
                        snapshot.data?.forEach((element) {
                          configuration.collections.add(element);
                        });

                        /*Initialize active collection with first received collection if not initialized yet*/
                        if(configuration.currentCollection.id == -1){
                          configuration.currentCollection = configuration.collections[0];
                        }

                        return DropdownButtonFormField(
                            value: configuration.currentCollection.collectionName,
                            decoration: const InputDecoration(
                              labelText: 'Chose Collection',
                              border: OutlineInputBorder(),
                            ),
                            items:
                            configuration.collections.map((Collection collection) {
                              return DropdownMenuItem(
                                value: collection.collectionName,
                                child: Text(collection.collectionName),
                              );
                            }).toList(),
                            onChanged: (value) {
                              configuration.currentCollection = configuration.getCollectionFromName(value.toString());
                              //Fetch new selected collection devices
                              futureDevices = connector.fetchCollectionDevices(configuration.currentCollection.id);
                            }
                        );
                      }
                      if (snapshot.hasError) {
                        debugPrint('Some error happened');
                        return const CircularProgressIndicator();
                      }
                      else{
                        return const CircularProgressIndicator();
                      }
                    }
                ),
                const SizedBox(height: 50.0),
                TextFormField(
                  minLines: 1,
                  maxLines: 5,
                  readOnly: true,
                  autofocus: false,
                  enabled: false,
                  style: _statusStyle,
                  controller: TextEditingController(
                    text: _status,
                  ),
                ),
              ],
            ),
          ),
        ),
        bottomNavigationBar: Container(
          margin: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 5.0),
          child:Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            mainAxisSize: MainAxisSize.max,
            children: [
              FloatingActionButton.extended(
                heroTag: null,
                tooltip: 'Export events to local .json file',
                icon: const Icon(Icons.download),
                label: const Text('Dump Events'),
                onPressed: () {
                  dumpToFile();
                },
              ),
              FloatingActionButton.extended(
                heroTag: null,
                tooltip: 'Download corresponding devices and store locally',
                icon: const Icon(Icons.save),
                label: const Text('Set'),
                onPressed: () {
                  updateConfiguration();
                  //TODO: display failed as user feedback somehow
                },
              ),
            ],
          ),
        )
    );
  }
}

//TODO: write configuration on app dispose!
//TODO: align bottom buttons nicely!
//TODO: add label prefix with appended upcounting number.
//TODO: grey out update button if nothing has changed. ?