didvan-app/lib/views/home/radar/radar_details/radar_details_state.dart

import 'dart:async';
import 'dart:math';

import 'package:didvan/models/enums.dart';
import 'package:didvan/models/overview_data.dart';
import 'package:didvan/models/radar_details_data.dart';
import 'package:didvan/models/requests/radar.dart';
import 'package:didvan/providers/core.dart';
import 'package:didvan/services/network/request.dart';
import 'package:didvan/services/network/request_helper.dart';

class RadarDetailsState extends CoreProvier {
  final List<RadarDetailsData?> radars = [];
  late Timer _trackingTimer;
  int _trackingTimerCounter = 0;
  late final int initialIndex;
  late final RadarRequestArgs args;
  bool isFetchingNewItem = false;
  final List<int> relatedQueue = [];

  int _currentIndex = 0;
  int get currentIndex => _currentIndex;

  RadarDetailsData get currentRadar {
    try {
      return radars[_currentIndex]!;
    } catch (e) {
      return radars[_currentIndex + 1]!;
    }
  }

  Future<void> getRadarDetails(int id, {bool? isForward}) async {
    if (isForward == null) {
      appState = AppState.busy;
    } else {
      isFetchingNewItem = true;
      notifyListeners();
    }
    final service = RequestService(RequestHelper.radarDetails(id, args));
    await service.httpGet();
    _handleTracking(sendRequest: isForward != null);
    if (service.isSuccess) {
      final result = service.result;
      final radar = RadarDetailsData.fromJson(result['radar']);
      if (args.page == 0) {
        radars.add(radar);
        initialIndex = 0;
        appState = AppState.idle;
        return;
      }

      RadarDetailsData? prevRadar;
      if (result['prevRadar'].isNotEmpty) {
        prevRadar = RadarDetailsData.fromJson(result['prevRadar']);
      }

      RadarDetailsData? nextRadar;
      if (result['nextRadar'].isNotEmpty) {
        nextRadar = RadarDetailsData.fromJson(result['nextRadar']);
      }

      if (isForward == null) {
        radars.addAll(List.generate(max(radar.order - 2, 0), (index) => null));
        if (prevRadar != null) {
          radars.add(prevRadar);
        }
        radars.add(radar);
        if (nextRadar != null) {
          radars.add(nextRadar);
        }
        _currentIndex = initialIndex = radar.order - 1;
      } else if (isForward) {
        if (!exists(nextRadar) && nextRadar != null) {
          radars.add(nextRadar);
        }
        _currentIndex++;
      } else if (!isForward) {
        if (!exists(prevRadar) && prevRadar != null) {
          radars[_currentIndex - 2] = prevRadar;
        }
        _currentIndex--;
      }
      isFetchingNewItem = false;
      appState = AppState.idle;
      return;
    }
    //why? total page state shouldn't die!
    if (isForward == null) {
      appState = AppState.failed;
    }
  }

  Future<void> getRelatedContents() async {
    if (currentRadar.relatedContents.isNotEmpty) return;
    relatedQueue.add(currentRadar.id);
    final service = RequestService(RequestHelper.tag(
      ids: currentRadar.tags.map((tag) => tag.id).toList(),
      itemId: currentRadar.id,
      type: 'radar',
    ));
    await service.httpGet();
    if (service.isSuccess) {
      final relateds = service.result['contents'];
      for (var i = 0; i < relateds.length; i++) {
        radars
            .where((element) => element != null)
            .firstWhere((element) => element!.id == currentRadar.id)!
            .relatedContents
            .add(OverviewData.fromJson(relateds[i]));
      }
      notifyListeners();
    }
  }

  bool exists(RadarDetailsData? radar) =>
      radars.any((r) => radar != null && r != null && r.id == radar.id);

  void onCommentsChanged(int count) {
    radars.firstWhere((radar) => radar?.id == currentRadar.id)!.comments =
        count;
    notifyListeners();
  }

  Future<void> _handleTracking({bool sendRequest = true}) async {
    if (!sendRequest) {
      _trackingTimerCounter = 0;
      _trackingTimer = Timer.periodic(const Duration(seconds: 1), (timer) {
        _trackingTimerCounter++;
      });
      return;
    }
    final service = RequestService(
      RequestHelper.tracking(currentRadar.id, 'radar'),
      body: {
        'sec': _trackingTimerCounter,
      },
    );
    service.put();
    _trackingTimerCounter = 0;
    _trackingTimer.cancel();
  }

  @override
  void dispose() {
    _handleTracking(sendRequest: true);
    _trackingTimer.cancel();
    super.dispose();
  }
}