// SPDX-FileCopyrightText: 2019-Present Christian Kußowski
// SPDX-FileCopyrightText: 2019-Present Contributors to FluffyChat
//
// SPDX-License-Identifier: AGPL-3.0-or-later

import 'dart:async';

import 'package:collection/collection.dart';
import 'package:dynamic_color/dynamic_color.dart';
import 'package:tatchat/utils/account_config.dart';
import 'package:tatchat/utils/color_value.dart';
import 'package:material_ui/material_ui.dart';
import 'package:matrix/matrix.dart';
import 'package:provider/provider.dart';
import 'package:shared_preferences/shared_preferences.dart';

class ThemeBuilder extends StatefulWidget {
  final Widget Function(
    BuildContext context,
    ThemeMode themeMode,
    Color? primaryColor,
    ThemeController controller,
  )
  builder;

  final String themeModeSettingsKey;
  final String primaryColorSettingsKey;

  const ThemeBuilder({
    required this.builder,
    this.themeModeSettingsKey = 'theme_mode',
    this.primaryColorSettingsKey = 'primary_color',
    super.key,
  });

  @override
  State<ThemeBuilder> createState() => ThemeController();
}

class ThemeController extends State<ThemeBuilder> {
  SharedPreferences? _sharedPreferences;
  ThemeMode? _themeMode;
  Color? _primaryColor;
  Color? _localPrimaryColor;
  Color? _accountPrimaryColor;
  Client? _accountClient;
  StreamSubscription<SyncUpdate>? _accountClientSubscription;
  int _accountClientGeneration = 0;

  ThemeMode get themeMode => _themeMode ?? ThemeMode.system;

  Color? get primaryColor => _primaryColor;

  static ThemeController of(BuildContext context) =>
      Provider.of<ThemeController>(context, listen: false);

  void _updatePrimaryColor() {
    if (!mounted) return;
    final newColor = _accountPrimaryColor ?? _localPrimaryColor;
    if (newColor == _primaryColor) return;
    setState(() {
      _primaryColor = newColor;
    });
  }

  Future<void> _loadData(_) async {
    final preferences = _sharedPreferences ??=
        await SharedPreferences.getInstance();

    final rawThemeMode = preferences.getString(widget.themeModeSettingsKey);
    final rawColor = preferences.getInt(widget.primaryColorSettingsKey);

    if (!mounted) return;
    setState(() {
      _themeMode = ThemeMode.values.singleWhereOrNull(
        (value) => value.name == rawThemeMode,
      );
      _localPrimaryColor = rawColor == null ? null : Color(rawColor);
    });
    _updatePrimaryColor();
  }

  Future<void> setThemeMode(ThemeMode newThemeMode) async {
    final preferences = _sharedPreferences ??=
        await SharedPreferences.getInstance();
    await preferences.setString(widget.themeModeSettingsKey, newThemeMode.name);
    setState(() {
      _themeMode = newThemeMode;
    });
  }

  Future<void> setPrimaryColor(Color? newPrimaryColor) async {
    if (!mounted) return;
    setState(() {
      _localPrimaryColor = newPrimaryColor;
      _accountPrimaryColor = newPrimaryColor;
      _primaryColor = newPrimaryColor;
    });
    final preferences = _sharedPreferences ??=
        await SharedPreferences.getInstance();
    if (newPrimaryColor == null) {
      await preferences.remove(widget.primaryColorSettingsKey);
    } else {
      await preferences.setInt(
        widget.primaryColorSettingsKey,
        newPrimaryColor.hexValue,
      );
    }
  }

  void setAccountClient(Client? client) {
    if (!mounted) return;
    final generation = ++_accountClientGeneration;
    _accountClientSubscription?.cancel();
    _accountClientSubscription = null;
    _accountClient = client;
    _accountPrimaryColor = null;
    _updatePrimaryColor();
    if (client == null) return;

    unawaited(_loadAccountClientColor(client, generation));
    _accountClientSubscription = client.onSync.stream
        .where(
          (sync) =>
              sync.accountData?.any(
                (accountData) =>
                    accountData.type ==
                    ApplicationAccountConfigExtension.accountDataKey,
              ) ??
              false,
        )
        .listen((_) => _applyAccountClientColor(client, generation));
  }

  Future<void> _loadAccountClientColor(Client client, int generation) async {
    final accountDataLoading = client.accountDataLoading;
    if (accountDataLoading != null) {
      try {
        await accountDataLoading;
      } catch (_) {}
    }
    if (!mounted ||
        generation != _accountClientGeneration ||
        !identical(_accountClient, client)) {
      return;
    }
    _applyAccountClientColor(client, generation);
  }

  void _applyAccountClientColor(Client client, int generation) {
    if (!mounted ||
        generation != _accountClientGeneration ||
        !identical(_accountClient, client)) {
      return;
    }
    final primaryColor = client.applicationAccountConfig.primaryColor;
    _accountPrimaryColor = primaryColor == null ? null : Color(primaryColor);
    _updatePrimaryColor();
  }

  @override
  void initState() {
    WidgetsBinding.instance.addPostFrameCallback(_loadData);
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Provider(
      create: (_) => this,
      child: DynamicColorBuilder(
        builder: (light, _) => widget.builder(
          context,
          themeMode,
          primaryColor ?? light?.primary,
          this,
        ),
      ),
    );
  }

  @override
  void dispose() {
    _accountClientSubscription?.cancel();
    super.dispose();
  }
}