gecko/lib/ui/historyScreen.dart

import 'package:gecko/parsingGVA.dart';
import 'package:gecko/query.dart';
import 'package:gecko/models/history.dart';
import 'package:flutter/material.dart';
import 'package:flutter/foundation.dart';
import 'dart:ui';
import 'package:graphql_flutter/graphql_flutter.dart';
import 'package:provider/provider.dart';
import 'package:truncate/truncate.dart';

//ignore: must_be_immutable
class HistoryScreen extends StatelessWidget with ChangeNotifier {
  final TextEditingController _outputPubkey = new TextEditingController();
  ScrollController scrollController = new ScrollController();
  final nRepositories = 20;
  HistoryProvider _historyProvider;

  FetchMore fetchMore;
  FetchMoreOptions opts;
  // scrollListener() {
  //   if (scrollController.offset >= scrollController.position.maxScrollExtent &&
  //       !scrollController.position.outOfRange) {
  //     print('On est en bas !!');
  //     print(opts.document);
  //     fetchMore(opts);
  //     notifyListeners();
  //   }
  // }

  @override
  Widget build(BuildContext context) {
    _historyProvider = Provider.of<HistoryProvider>(context);
    print('Build pubkey : ' + _historyProvider.pubkey);
    // scrollController.addListener(scrollListener);
    return Scaffold(
        floatingActionButton: Container(
          height: 80.0,
          width: 80.0,
          child: FittedBox(
            child: FloatingActionButton(
              heroTag: "buttonScan",
              onPressed: () async {
                await _historyProvider.scan();
              },
              child: Container(
                  height: 40.0,
                  width: 40.0,
                  child: Image.asset('images/scanner.png')),
              backgroundColor: Color(
                  0xffEFEFBF), //Color(0xffFFD68E), //Color.fromARGB(500, 204, 255, 255),
            ),
          ),
        ),
        body: Column(children: <Widget>[
          SizedBox(height: 8),
          TextField(
              // Entrée de la pubkey
              onChanged: (text) {
                print("Clé tappxé: $text");
                _historyProvider.isPubkey(text);
              },
              controller: this._outputPubkey,
              maxLines: 1,
              textAlign: TextAlign.center,
              decoration: InputDecoration(
                hintText: 'Tappez/Collez une clé publique, ou scannez',
                hintStyle: TextStyle(fontSize: 14),
                contentPadding:
                    EdgeInsets.symmetric(horizontal: 7, vertical: 15),
                border: InputBorder.none,
                focusedBorder: InputBorder.none,
                enabledBorder: InputBorder.none,
                errorBorder: InputBorder.none,
                disabledBorder: InputBorder.none,
              ),
              style: TextStyle(fontSize: 14.0, fontWeight: FontWeight.bold)),
          if (_historyProvider.pubkey != '') historyQuery(),
        ]));
  }

  historyQuery() {
    return Expanded(
        child: Column(
      mainAxisAlignment: MainAxisAlignment.start,
      mainAxisSize: MainAxisSize.max,
      children: <Widget>[
        Query(
          options: QueryOptions(
            document: gql(getHistory),
            variables: <String, dynamic>{
              'pubkey': _historyProvider.pubkey,
              'number': nRepositories,
              // set cursor to null so as to start at the beginning
              'cursor': null
            },
          ),
          builder: (QueryResult result, {refetch, fetchMore}) {
            if (result.isLoading && result.data == null) {
              return const Center(
                child: CircularProgressIndicator(),
              );
            }

            if (result.hasException) {
              print('Error GVA: ' + result.exception.toString());
              return Column(children: <Widget>[
                SizedBox(height: 50),
                Text(
                  "Aucun noeud GVA valide n'a pu être trouvé.\nVeuillez réessayer ultérieurement.",
                  style: TextStyle(fontSize: 17.0),
                )
              ]);
            }

            if (result.data == null && result.exception.toString() == null) {
              return const Text('Aucune donnée à afficher.');
            }

            final List<dynamic> blockchainTX =
                (result.data['txsHistoryBc']['both']['edges'] as List<dynamic>);

            final Map pageInfo =
                result.data['txsHistoryBc']['both']['pageInfo'];

            final String fetchMoreCursor = pageInfo['endCursor'];

            final num balance =
                removeDecimalZero(result.data['balance']['amount'] / 100);

            opts = FetchMoreOptions(
              variables: {'cursor': fetchMoreCursor},
              updateQuery: (previousResultData, fetchMoreResultData) {
                final List<dynamic> repos = [
                  ...previousResultData['txsHistoryBc']['both']['edges']
                      as List<dynamic>,
                  ...fetchMoreResultData['txsHistoryBc']['both']['edges']
                      as List<dynamic>
                ];

                fetchMoreResultData['txsHistoryBc']['both']['edges'] = repos;
                return fetchMoreResultData;
              },
            );

            // _scrollController
            //   ..addListener(() {
            //     if (_scrollController.position.pixels ==
            //         _scrollController.position.maxScrollExtent) {
            //       if (!result.isLoading) {
            //         print(
            //             "DEBUG H fetchMoreCursor in scrollController: $fetchMoreCursor");
            //         fetchMore(opts);
            //       }
            //     }
            //   });

            // s/o : https://stackoverflow.com/questions/54065354/how-to-detect-scroll-position-of-listview-in-flutter/54188385#54188385
            // new NotificationListener(
            //   child: new ListView(
            //     controller: _scrollController,
            //   ),
            //   onNotification: (t) {
            //     if (t is ScrollEndNotification) {
            //       fetchMore(opts);
            //     }
            //   },
            // );

            // fetchMore(opts);

            print(
                "###### DEBUG H Parse blockchainTX list. Cursor: $fetchMoreCursor ######");
            List _transBC = parseHistory(blockchainTX);

            // Build history list
            return NotificationListener(
                child: Expanded(
                    child: ListView(
                  controller: scrollController,
                  children: <Widget>[
                    SizedBox(height: 7),
                    if (_historyProvider.pubkey != '')
                      Text(balance.toString() + ' Ğ1',
                          textAlign: TextAlign.center,
                          style: TextStyle(fontSize: 30.0)),
                    SizedBox(height: 12),
                    for (var repository in _transBC)
                      ListTile(
                          contentPadding: const EdgeInsets.all(5.0),
                          leading: Text(repository[3],
                              style: TextStyle(fontSize: 14.0)),
                          title: Text(
                              repository[1].toString() +
                                  '\n' +
                                  truncate(repository[2], 17,
                                      omission: "...",
                                      position: TruncatePosition.end),
                              style: TextStyle(fontSize: 14.0)),
                          subtitle: Text(repository[5],
                              style: TextStyle(fontSize: 14.0)),
                          dense: true,
                          onTap: () {
                            this._outputPubkey.text = repository[2];
                            _historyProvider.isPubkey(repository[2]);
                            // notifyListeners();
                          }),
                    if (result.isLoading)
                      Row(
                        mainAxisAlignment: MainAxisAlignment.center,
                        children: <Widget>[
                          CircularProgressIndicator(),
                        ],
                      ),
                  ],
                )),
                onNotification: (t) {
                  // print(scrollController.position.pixels);
                  // print(scrollController.position.maxScrollExtent);
                  if (t is ScrollEndNotification &&
                      scrollController.position.pixels >=
                          scrollController.position.maxScrollExtent * 0.8) {
                    fetchMore(opts);
                    // notifyListeners();
                  }
                  return true;
                });
          },
        ),
      ],
    ));
  }

  num removeDecimalZero(double n) {
    String result = n.toStringAsFixed(n.truncateToDouble() == n ? 0 : 1);
    return num.parse(result);
  }
}