fnotes/lib/theme_bloc.dart

import 'package:drift/drift.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:fnotes/database.dart';
import 'package:fnotes/persisted_brightness.dart';
import 'package:google_fonts/google_fonts.dart';

class PersistedThemeBloc extends Bloc<ThemeEvent, ThemeState> {
  PersistedThemeBloc(Brightness brightness)
      : super(ThemeState.withBrightness(brightness)) {
    on<ThemeChangedEvent>(switchTheme);
    on<LoadThemeEvent>(loadTheme);
  }

  void switchTheme(ThemeChangedEvent event, Emitter<ThemeState> emit) async {
    await database.delete(database.persistentTheme).go();

    var newBrightness =
        PersistedBrightness.fromFlutterBrightness(state.theme.brightness)
            .toOpposite();

    await database
        .into(database.persistentTheme)
        .insert(PersistentThemeCompanion.insert(
          brightness: Value(newBrightness.toString()),
        ));

    emit(ThemeState.withBrightness(newBrightness.toFlutterBrightness()));
  }

  void loadTheme(LoadThemeEvent event, Emitter<ThemeState> emit) async {
    PersistedBrightness persistedBrightness = await getPersistedBrightness();
    emit(ThemeState.withBrightness(persistedBrightness.toFlutterBrightness()));
  }

  static Future<PersistedBrightness> getPersistedBrightness() async {
    PersistedBrightness persistedBrightness = PersistedBrightness("light");

    await database.select(database.persistentTheme).get().then(
      (value) {
        var brightnessIter = value.map((row) {
          return row.brightness;
        });

        if (brightnessIter.isNotEmpty) {
          persistedBrightness = PersistedBrightness(brightnessIter.first);
        }
      },
    );
    return persistedBrightness;
  }
}

class ThemeEvent {}

class LoadThemeEvent extends ThemeEvent {}

class ThemeChangedEvent extends ThemeEvent {}

class ThemeState {
  final ThemeData theme;

  ThemeState({required this.theme});

  static Future<ThemeState> fetchAndConstructInitState() async {
    PersistedBrightness persistedBrightness = PersistedBrightness('light');
    await database.select(database.persistentTheme).get().then(
      (value) {
        var brightnessIter = value.map((row) {
          return row.brightness;
        });
        persistedBrightness = PersistedBrightness(brightnessIter.first);
      },
    );

    return ThemeState.withBrightness(persistedBrightness.toFlutterBrightness());
  }

  factory ThemeState.withBrightness(Brightness brightness) {
    return ThemeState(
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
            seedColor: Colors.deepPurpleAccent, brightness: brightness),
      ),
    );
  }
}