import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'datamodel.dart';
import 'dart:async';
import 'package:geolocator/geolocator.dart';

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

  @override
  State<AddEvent> createState() => _AddEventPageState();
}

class _AddEventPageState extends State<AddEvent>  {
  bool disableGNSSEditing = true;
  final List<bool> _isGNSSSelected = [true];
  late LocationPermission permission;
  late Position position;
  late String long = "";
  late String lat = "";
  late String alt = "";
  late double accuracy = 0.0;
  late StreamSubscription<Position> positionStream;
  LocationSettings locationSettings = const LocationSettings(
    accuracy: LocationAccuracy.high,
    distanceFilter: 0,
  );

  getLocation() async {
    StreamSubscription<Position> positionStream = Geolocator.getPositionStream(
        locationSettings: locationSettings).listen((Position position) {
      debugPrint('Get Location: Lat:' + position.latitude.toString() +
          ' Long:' + position.longitude.toString() +
          ' Alt:' + position.altitude.toString());

      long = position.longitude.toString();
      lat = position.latitude.toString();
      alt = position.altitude.toString();
      accuracy = position.accuracy;


      if (disableGNSSEditing == true) {
        if(mounted){
        setState(() {
          //refresh UI on update
        });}
      };
    });
  }

  startGNSS() async {
    debugPrint("Check Location Permission");
    bool serviceStatus = false;
    bool hasPermission = false;
    serviceStatus = await Geolocator.isLocationServiceEnabled();
    if(serviceStatus){
      permission = await Geolocator.checkPermission();

      if (permission == LocationPermission.denied) {
        permission = await Geolocator.requestPermission();
        if (permission == LocationPermission.denied) {
          debugPrint('Location permissions are denied');
        }else if(permission == LocationPermission.deniedForever){
          debugPrint('Location permissions are permanently denied');
        }else{
          hasPermission = true;
        }
      }else{
        hasPermission = true;
      }

      if(hasPermission){
        debugPrint('Location permissions granted');
        if(mounted){
        setState(() {
          //refresh the UI
        });};

        getLocation();
      }
    }else{
      debugPrint("GPS Service is not enabled, turn on GPS location");
    }
    if(mounted){
    setState(() {
      //refresh the UI
    });}
  }

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

  void _storeCurrentEvent() {
    final EventStoreInstance storedEvents = EventStoreInstance();
    final EventCurrentInstance currentEvent = EventCurrentInstance();
    storedEvents.store.add(
        Event(
          currentEvent.store.id,
          currentEvent.store.urn,
          currentEvent.store.label,
          currentEvent.store.type,
          currentEvent.store.description,
          currentEvent.store.status,
        ));
  }

  //TODO: add field validators for freetext fields. Check allowed characters in sensor.awi.de

  @override
  Widget build(BuildContext context) {
    /* Get singletons to access relevant data here.*/
    final EventTypeStoreInstance eventTypes = EventTypeStoreInstance();
    final DeviceStoreInstance availableDevice = DeviceStoreInstance();
    final EventStoreInstance storedEvents = EventStoreInstance();
    final EventCurrentInstance currentEvent = EventCurrentInstance();
    String gnssStatusText = "";

    if (true == disableGNSSEditing){
      // Update current event coordinates from GNSS stream
      currentEvent.store.latitude = lat;
      currentEvent.store.longitude = long;
      currentEvent.store.elevation = alt;

      if(accuracy == 0.0){
        gnssStatusText = "No-Fix";
        }
      else{
        gnssStatusText = "Precision: "+ accuracy.toStringAsFixed(2) +"m";
      }
    }
    else{
      gnssStatusText = "GNSS Disabled"; // Just display existing event coordinates
    }

    return Scaffold(
      appBar: AppBar(title: const Text("Add Event")),
      body:
      Column(
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: <Widget>[
            TextFormField(
              initialValue: currentEvent.store.label,
              decoration: const InputDecoration(
                  labelText: 'Label'
              ),
              onChanged: (value) {
                currentEvent.store.label = value;
              },
            ),
            DropdownButtonFormField(
                value: currentEvent.store.type,
                decoration: const InputDecoration(
                  labelText: 'Event Type',
                ),
                items:
                eventTypes.store.map((EventType event) {
                  return DropdownMenuItem(
                    value: event.name,
                    child: Text(event.name),
                  );
                }).toList(),
                onChanged: (value) {
                  currentEvent.store.type = value.toString();
                }
            ),
            DropdownButtonFormField(
                value: currentEvent.store.urn,
                decoration: const InputDecoration(
                  labelText: 'URN',
                ),
                items:
                availableDevice.store.map((Device device) {
                  return DropdownMenuItem(
                    value: device.urn,
                    child: Text(device.urn),
                  );
                }).toList(),
                onChanged: (value) {
                  currentEvent.store.urn = value.toString();
                  currentEvent.store.id = availableDevice.getDeviceIdFromUrn(value.toString());
                }
            ),
            TextFormField(
              initialValue: currentEvent.store.description,
              decoration: const InputDecoration(
                  labelText: 'Description'
              ),
              onChanged: (value) {
                currentEvent.store.description = value;
              },
            ),
            TextField(
              readOnly: false,
              enabled: !disableGNSSEditing,
              //controller: _controllerLat,
              controller: TextEditingController(text: currentEvent.store.latitude.toString()),
              decoration: const InputDecoration(
                labelText: 'Latitude',
                border: OutlineInputBorder(),
              ),
            ),
            TextField(
              readOnly: false,
              enabled: !disableGNSSEditing,
              controller: TextEditingController(text: currentEvent.store.longitude.toString()),
              decoration: const InputDecoration(
                labelText: 'Longitude',
                border: OutlineInputBorder(),
              ),
            ),
            TextField(
              readOnly: false,
              enabled: !disableGNSSEditing,
              controller: TextEditingController(text: currentEvent.store.elevation.toString()),
              decoration: const InputDecoration(
                labelText: 'Elevation',
                border: OutlineInputBorder(),
              ),
            ),
          ]),
      bottomNavigationBar: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: [
          Text(gnssStatusText),
          const SizedBox(width: 50),
          ToggleButtons(
            children: const <Widget>[
              Icon(Icons.my_location),
            ],
            isSelected: _isGNSSSelected,
            onPressed: (int index) {
              setState(() {
                _isGNSSSelected[index] = !_isGNSSSelected[index];
                disableGNSSEditing = _isGNSSSelected[index];
              });
            },
          ),
          const SizedBox(width: 50),
          FloatingActionButton(
            heroTag: null,
            onPressed: _storeCurrentEvent,
            tooltip: 'Add Event',
            child: const Icon(Icons.add),
          ),
          const SizedBox(width: 20),
        ],
      ),
    );
  }
}