import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../widgets/flood_station_list_view.dart';
import '../services/flood_station_provider.dart';
import '../widgets/loading_notifier.dart';
import '../widgets/station_filter.dart';
import 'flood_station_page.dart';

class LandingPage extends StatefulWidget {
  const LandingPage({super.key});

  @override
  State<LandingPage> createState() => _LandingPageState();
}

class _LandingPageState extends State<LandingPage> {
  late FloodStationProvider floodStationProvider;
  OverlayEntry? _overlayEntry;
  int loadingTimes = 0;

  @override
  Widget build(BuildContext context) {
    floodStationProvider = context.watch<FloodStationProvider>();
    return Column(
      children: [
        StationFilter(
          onChanged: (filterText) {
            if (filterText.isEmpty) {
              floodStationProvider.filtered = false;
              setState(() {});
              return;
            }
            showLoadingNotifier(context: context, message: 'Loading');
            floodStationProvider.loadFilteredStations(filterText);
            floodStationProvider.filteredStationsFuture
                ?.then((_) => removeLoadingNotifier());
            floodStationProvider.filtered = true;
          },
        ),
        _shouldShowList()
            ? Expanded(
                child: FloodStationListView(
                  stations: floodStationProvider.filtered
                      ? floodStationProvider.filteredStations
                      : floodStationProvider.allStations,
                  onItemTapped: (station) {
                    floodStationProvider.selectedStation = station;
                    Navigator.of(context).pushNamed(FloodStationPage.routeName);
                  },
                ),
              )
            : Expanded(
                child: Center(
                  child: ElevatedButton(
                    onPressed: () {
                      showLoadingNotifier(context: context, message: 'Loading');
                      floodStationProvider
                          .loadAllStations()
                          .whenComplete(() => removeLoadingNotifier());
                    },
                    child: Text('Load all Stations'),
                  ),
                ),
              ),
      ],
    );
  }

  bool _shouldShowList() {
    if (!floodStationProvider.filtered &&
        floodStationProvider.allStations.isNotEmpty) {
      return true;
    }
    if (floodStationProvider.filtered) {
      return true;
    }
    return false;
  }

  Future<void> showLoadingNotifier({
    required BuildContext context,
    required String message,
  }) async {
    if (_overlayEntry != null) return;
    OverlayState? overlayState = Overlay.of(context);
    _overlayEntry = OverlayEntry(
      builder: (c) {
        return Positioned(
          bottom: 16,
          left: 0,
          right: 0,
          child: Center(
            child: LoadingNotifier(
              message: 'Loading',
              onDismissed: () {
                floodStationProvider.cancelFilterLoading();
                removeLoadingNotifier();
              },
            ),
          ),
        );
      },
    );
    overlayState.insert(_overlayEntry!);
    overlayState.setState(() {});
  }

  void removeLoadingNotifier() {
    if (_overlayEntry != null) {
      _overlayEntry?.remove();
      _overlayEntry = null;
    }
  }
}