viewevents.dart

import 'package:flutter/material.dart';
import 'datamodel.dart';
import 'sensorconnector.dart';
import 'databaseconnector.dart';
import 'package:getwidget/getwidget.dart';

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

  @override
  _ViewEvents createState() => _ViewEvents();
}

class _ViewEvents extends State<ViewEvents> {
  // Get singleton to access locally stored events:
  final EventStoreInstance _events = EventStoreInstance();
  String _status = '';
  TextStyle _statusStyle = const TextStyle(color: Colors.black);
  String _appBarText = '';
  int _selectedRow = -1;
  String _pendingEventCnt = '';
  String _syncedEventCnt = '';
  bool _cancelSync = false;  //Flag to cancel sync process
  bool _currentlySyncing = false; // State flag to indicate if sync is ongoing
  var database = DatabaseInstance();

  List<Event> _localEvents = [];
  Widget _buildSyncDialog(BuildContext context) {
    SensorConnector sensorConnector = SensorConnector();

    String startButtonText = '';
    String closeButtonText = '';

    if (_currentlySyncing == true){
      startButtonText = 'Syncing';
      closeButtonText = 'Cancel';
    }else{
      startButtonText = 'Start';
      closeButtonText = 'Close';
    }

    return WillPopScope(
        onWillPop: () async => false,
        child: AlertDialog(
          content: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              const Text('Syncing Events...'),
              const SizedBox(height: 15.0),
              GFProgressBar(
                percentage: 0.7,  //Get percentage from global variable here
                backgroundColor : Colors.black12,
                progressBarColor: Colors.blue,
              ),
              const SizedBox(height: 5.0),
              Text(_syncedEventCnt + ' / ' + _pendingEventCnt),
              //TODO: show text XX pending events. count down
            ],
          ),
          actions: <Widget>[
            TextButton(
              onPressed: () {
                if(_currentlySyncing == false){
                  syncEvents(); //Initiate sync
                }
              },
              child: Text(startButtonText),  //Change text to Syncing... during Sync process.
            ),
            TextButton(
              onPressed: () {
                // Depending on state. Cancel or close. TODO: implement statemachine.
                if(_currentlySyncing){
                  _cancelSync = true; // Set flag so that async tasks stops syncing
                }else{
                  Navigator.of(context).pop();  // Close widget only if sync has stopped.
                }
              },
              child: Text(closeButtonText),  // Change to Cancel during Sync process.
            ),
          ],
        )
    );
  }

  Future<void> fetchEventsFromDb() async{
    final EventStoreInstance event = EventStoreInstance();
    int pendingEvents = 0;

    if (event.showAllEvents == false) {
      _appBarText = 'Pending Events';
      //Get only pending events
      _localEvents = await database.getPendingEvents();
      pendingEvents = _localEvents.length;

    }else {
      _appBarText = 'All Events';
      _localEvents = await database.getEvents();
      pendingEvents = await database.getPendingEventCnt();
    }

    _status = pendingEvents.toString() + ' event(s) pending';
    _statusStyle = const TextStyle(color: Colors.black);
    setState(() {}); //Got events from database, so update UI
  }

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

  @override
  void dispose() async {

    /*Async update current configuration to shared preferences*/
    final EventStoreInstance event = EventStoreInstance();
    event.storeToSharedPrefs();
    super.dispose();
  }

  Future<void> syncEvents() async {

    _cancelSync = false;
    final ConfigurationStoreInstance configuration = ConfigurationStoreInstance();
    SensorConnector connection = SensorConnector();

    List<Event> events = await database.getPendingEvents();
    int syncCounter = events.length;
    _pendingEventCnt = syncCounter.toString();
    debugPrint('Pending Events');
    for (var event in events){
      debugPrint(event.toString());
    }

    if(syncCounter > 0) {
      try {
        String? token = await connection.getAuthToken(
            configuration.loginInformation.mail,
            configuration.loginInformation.password);
        var index = 0;
        for (var event in events) {
          if(_cancelSync == true){
              _currentlySyncing = false;
              debugPrint('Sync process canceled');
              return;
            }
          _currentlySyncing = true;

          debugPrint('Idx: ' + index.toString() + ' ' +
              event.toSensorJson().toString());
          index++;
          if (await connection.putEvent(event, token) == true) {
            //Event has been posted to Sensor.
            syncCounter--;
            debugPrint(
                'put success, remaining events: ' + syncCounter.toString());
            event.status = 'EXPORTED'; //Update event to export only once
            database.updateEvent(event); //Update Event as exported in SQL Database
            await fetchEventsFromDb(); //update view list   //TODO: this is bad for the sync performance!
            setState(() {});
          } else {
            throw Exception('Sync for ' + event.urn + 'failed');
          }
        }
        _status = 'export success';
        _statusStyle = const TextStyle(color: Colors.green);
        _syncedEventCnt = index.toString();
      } 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(() {});
      }
    }else{
      debugPrint('No PENDING event(s)');
    }
    _currentlySyncing = false;
  }

  @override
  Widget build(BuildContext context) {
    final EventStoreInstance event = EventStoreInstance();
    return Scaffold(
      appBar: AppBar(
        title: const Text("View & Sync"),
        actions: <Widget>[
          Text(_appBarText, style: const TextStyle(fontStyle: FontStyle.italic),),
          Switch(  //Enable showing all or only pending events. Default is to show only pending events
              value: event.showAllEvents,
              onChanged: (value) {
                event.showAllEvents = value;
                fetchEventsFromDb();
                setState(() {});
              }),
        ],
      ),
      body: Container(
        margin: const EdgeInsets.symmetric(horizontal: 5.0),
        child:
        SingleChildScrollView(
          scrollDirection: Axis.horizontal,
          child: SingleChildScrollView(
            scrollDirection: Axis.vertical,
            child: DataTable(

              columns: const <DataColumn>[
                DataColumn(
                  label: Text(
                    '(ID)  URN',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Label',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Type',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Description',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'StartDate',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'EndDate',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Latitude',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Longitude',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Elevation',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
                DataColumn(
                  label: Text(
                    'Status',
                    style: TextStyle(fontStyle: FontStyle.italic),
                  ),
                ),
              ],
              rows: <DataRow>[
                //for (var event in _localEvents)
                for (var i = 0; i < _localEvents.length; i++)
                  DataRow(
                    selected: i == _selectedRow,
                    onLongPress: () {
                      debugPrint("Selected Row: " + i.toString());
                      //TODO: open widget to edit the rows event values.   Provide "cancel" and "update" functionality
                      //TODO: display "Exported Events are read only, Edit via Sensor.awi.de" when trying to edit.
                      debugPrint(_localEvents[i].toString());

                      //Navigator.pushNamed(context, '/second', arguments: {'event': _localEvents[i]},);
                      // TODO: create an edit widget. As Add Event, GNSS editing always enabled, No GNSS switch,  Now Button?

                      /*   //How to get the argument.
                      @override
                      Widget build(BuildContext context) {
                        final arguments = (ModalRoute.of(context)?.settings.arguments ?? <String, dynamic>{}) as Map;

                        print(arguments['exampleArgument']);

                        return Scaffold(...);
                      }
                      */


                    },
                    cells: <DataCell>[
                      //DataCell(Text(_localEvents[i].urnId.toString())),
                      DataCell(Text('('+_localEvents[i].urnId.toString()+')  ' + _localEvents[i].urn)),
                      DataCell(
                        Text(_localEvents[i].label),
                      ),
                      DataCell(Text(_localEvents[i].type)),
                      DataCell(Text(_localEvents[i].description)),

                      //Do not show microseconds
                      DataCell(Text(_localEvents[i].startDate.substring(0, 19) + 'Z')),
                      DataCell(Text(_localEvents[i].endDate.substring(0, 19) + 'Z')),
                      DataCell(Text(_localEvents[i].latitude)),
                      DataCell(Text(_localEvents[i].longitude)),
                      DataCell(Text(_localEvents[i].elevation == '' ? '' : double.parse(_localEvents[i].elevation).toStringAsFixed(2))),
                      DataCell(Text(_localEvents[i].status)),
                    ],
                  ),
              ],
            ),
          ),
        ),
      ),
      bottomNavigationBar: Container(
        margin: const EdgeInsets.symmetric(vertical: 10.0, horizontal: 5.0),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            const SizedBox(width: 1),
            Text(_status, style: _statusStyle),
            FloatingActionButton.extended(
              heroTag: null,
              tooltip: 'Upload Events',
              icon: null,
              label: const Text('Sync'),
              onPressed: () {
                syncEvents();

                //showDialog(
                //  barrierDismissible: false,
                //  context: context,
                //  builder: (BuildContext context) => _buildSyncDialog(context),
                //);


              },
            ),
          ],
        ),
      ),
    );
  }
}
//TODO: allow editing fields here.