info_tren/lib/components/select_train_suggestions/select_train_suggestions.dart

import 'dart:convert';

import 'package:flutter/widgets.dart';
import 'package:info_tren/components/select_train_suggestions/select_train_suggestions_cupertino.dart';
import 'package:info_tren/components/select_train_suggestions/select_train_suggestions_material.dart';
import 'package:info_tren/models/train_operator_lines.dart';
import 'package:info_tren/models/ui_design.dart';
import 'package:info_tren/utils/default_ui_design.dart';
import 'package:tuple/tuple.dart';

class SelectTrainSuggestions extends StatefulWidget {
  final UiDesign? uiDesign;
  final String userInput;
  final void Function(int trainNumber) onTrainSelected;

  const SelectTrainSuggestions({ Key? key, required this.uiDesign, required this.userInput, required this.onTrainSelected }) : super(key: key);

  @override
  SelectTrainSuggestionsState createState() {
    final uiDesign = this.uiDesign ?? defaultUiDesign;
    switch(uiDesign) {
      case UiDesign.MATERIAL:
        return SelectTrainSuggestionsStateMaterial();
      case UiDesign.CUPERTINO:
        return SelectTrainSuggestionsStateCupertino();
      default:
        throw UnmatchedUiDesignException(uiDesign);
    }
  }
}

abstract class SelectTrainSuggestionsState extends State<SelectTrainSuggestions> {
  late String userInput;

  List<TrainOperatorLines> operators = [];

  Future loadOperators(BuildContext context) async {
    operators = [];

    final operatorsString = await DefaultAssetBundle.of(context).loadString("assets/lines/files.txt");
    final operatorsFilesList = operatorsString.split("\n");

    final decoder = JsonDecoder();

    for (final operatorFile in operatorsFilesList) {
      final operatorString = await DefaultAssetBundle.of(context).loadString("assets/lines/$operatorFile");
      final operatorData = decoder.convert(operatorString);
      final _operator = TrainOperatorLines.fromJson(operatorData);
      operators.add(_operator);
    }
  }

  @override
  void initState() {
    super.initState();
    userInput = widget.userInput;

    loadOperators(context).then((_) {
      setState(() {});
    });
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    if (userInput != widget.userInput) {
      setState(() {
        userInput = widget.userInput;
      });
    }
  }

  String getUseCurrentInputWidgetText(int currentInput) => 'Caută trenul cu numărul $currentInput';
  Widget getUseCurrentInputWidget(int currentInput, void Function(int) onTrainSelected);

  @override
  Widget build(BuildContext context) {
    var sliversTuple = operators.map(
      (op) => Tuple2(
        getFilteredLines(op, userInput), 
        op.operator, 
      )
    ).where((tuple) => tuple.item1.isNotEmpty).toList();
    if (userInput.isNotEmpty) sliversTuple.sort((a, b) {
      final aTrain = a.item1.first;
      final bTrain = b.item1.first;

      final inputAsRegExp = RegExp(userInput);

      final matchOnA = inputAsRegExp.firstMatch(aTrain.number)!;
      final matchOnB = inputAsRegExp.firstMatch(bTrain.number)!;

      if (matchOnA.start != matchOnB.start) return matchOnA.start - matchOnB.start;

      if (aTrain.number.length != bTrain.number.length) return aTrain.number.length - bTrain.number.length;

      return aTrain.number.compareTo(bTrain.number);
    });
    var slivers = sliversTuple.map((tuple) => OperatorAutocompleteSliver(
      uiDesign: widget.uiDesign,
      operatorName: tuple.item2, 
      trains: tuple.item1, 
      onTrainSelected: widget.onTrainSelected,
    )).toList();

    return CustomScrollView(
      slivers: <Widget>[
        ...slivers,
        SliverToBoxAdapter(
          child: int.tryParse(userInput) != null ? getUseCurrentInputWidget(int.parse(userInput), widget.onTrainSelected) : Container(),
        ),
        SliverToBoxAdapter(
          child: Container(
            height: MediaQuery.of(context).viewPadding.bottom,
          ),
        ),
      ],
    );
  }

  List<TrainOperatorTrainDescription> getFilteredLines(TrainOperatorLines _operator, String currentInput) {
    if (currentInput.isNotEmpty) {
      final filteredLines = _operator.trains
        .where((elem) => elem.number.contains(currentInput))
        .toList();

      filteredLines.sort((a, b) {
        final inputAsRegExp = RegExp(currentInput);

        final matchOnA = inputAsRegExp.firstMatch(a.number)!;
        final matchOnB = inputAsRegExp.firstMatch(b.number)!;

        if (matchOnA.start != matchOnB.start) return matchOnA.start - matchOnB.start;

        if (a.number.length != b.number.length) return a.number.length - b.number.length;

        return a.number.compareTo(b.number);
      });

      return filteredLines;
    }
    else {
      return _operator.trains;
    }
  }
}

class OperatorAutocompleteSliver extends StatelessWidget {
  final UiDesign? uiDesign;
  final String operatorName;
  final List<TrainOperatorTrainDescription> trains;
  final void Function(int) onTrainSelected;

  const OperatorAutocompleteSliver({ Key? key, required this.uiDesign, required this.operatorName, required this.trains, required this.onTrainSelected }) : super(key: key);

  Widget mapTrainToItem(TrainOperatorTrainDescription train) {
    final uiDesign = this.uiDesign ?? defaultUiDesign;
    switch (uiDesign) {
      case UiDesign.MATERIAL:
        return OperatorAutocompleteTileMaterial(
          onTrainSelected: onTrainSelected,
          operatorName: operatorName,
          train: train,
        );
      case UiDesign.CUPERTINO:
        return OperatorAutocompleteTileCupertino(
          onTrainSelected: onTrainSelected,
          operatorName: operatorName,
          train: train,
        );
      default:
        throw UnmatchedUiDesignException(uiDesign);
    }
  }

  @override
  Widget build(BuildContext context) {
    if (trains.isEmpty) {
      return SliverToBoxAdapter(child: Container(),);
    }

    return SliverPrototypeExtentList(
      prototypeItem: Column(
        children: <Widget>[
          mapTrainToItem(TrainOperatorTrainDescription()),
        ],
      ),
      delegate: SliverChildBuilderDelegate(
        (context, index) {
          return Column(
            children: <Widget>[
              mapTrainToItem(trains[index]),
            ],
          );
        },
        childCount: trains.length,
        addSemanticIndexes: true,
      ),
    );
  }
}

abstract class OperatorAutocompleteTile extends StatelessWidget {
  final String operatorName;
  final TrainOperatorTrainDescription train;
  final void Function(int) onTrainSelected;

  const OperatorAutocompleteTile({ Key? key, required this.onTrainSelected, required this.operatorName, required this.train }) : super(key: key);
}