yokutango-mobile-reader/lib/service/tangocard_files.dart

import 'dart:convert';
import 'dart:io';

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:yokutango_mobile_reader/models/data_entry.dart';

// TODO: merge

Future<Map<File, List<YokutangoEntry>>> get tangocardFilePaths => rootBundle
    .loadString('AssetManifest.json')
    .then(
      (json) => jsonDecode(json)
          .keys
          .where((String key) =>
              key.contains('yokutango/json/') && key.contains('.json'))
          .toList(),
    )
    .then(
      (l) async => Map.fromIterables(
        l.map<File>((f) => File(f)),
        await Future.wait<List<YokutangoEntry>>(
            l.map<Future<List<YokutangoEntry>>>(
          (String t) => rootBundle.loadString(t).then<List<YokutangoEntry>>(
              (s) => jsonDecode(s)
                  .map<YokutangoEntry>((e) => YokutangoEntry.fromJson(e))
                  .toList()),
        )),
      ),
    );

Future<Map<File, List<KanjiEntry>>> get kanjicardFilePaths =>
    rootBundle.loadString('AssetManifest.json').then(
      (json) {
        final jsonKeys = jsonDecode(json).keys;

        final kanjiPaths = jsonKeys
            .where((String key) =>
                RegExp(r'assets/yokutango/kanji/kanji_\d+.json')
                    .matchAsPrefix(key) !=
                null)
            .toList();

        final kanaPaths = jsonKeys
            .where((String key) =>
                RegExp(r'assets/yokutango/kanji/(?:hiragana|katakana).json')
                    .matchAsPrefix(key) !=
                null)
            .toList();

        return kanaPaths + kanjiPaths;
      },
    ).then(
      (l) async => Map.fromIterables(
        l.map<File>((f) => File(f)),
        await Future.wait<List<KanjiEntry>>(l.map<Future<List<KanjiEntry>>>(
          (String t) => rootBundle.loadString(t).then<List<KanjiEntry>>((s) =>
              jsonDecode(s)
                  .map<KanjiEntry>((e) => KanjiEntry.fromJson(e))
                  .toList()),
        )),
      ),
    );