library;

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:wolf_3d_flutter/wolf_3d_flutter.dart';

import 'game_data_picker_manager.dart';
import 'no_game_data_screen.dart';

/// GUI-host application shell that owns setup/import UX.
class Wolf3dGuiApp extends StatefulWidget {
  /// Creates the GUI host shell for a prepared engine facade.
  const Wolf3dGuiApp({
    super.key,
    required this.engine,
    this.pickerManager,
  });

  /// Shared initialized facade that owns game data, input, and audio services.
  final Wolf3dFlutterEngine engine;

  /// Optional injected picker manager used by tests.
  final GameDataPickerManager? pickerManager;

  @override
  State<Wolf3dGuiApp> createState() => _Wolf3dGuiAppState();
}

class _Wolf3dGuiAppState extends State<Wolf3dGuiApp>
    with WidgetsBindingObserver {
  late final GameDataPickerManager _pickerManager;
  Future<void>? _shutdownFuture;

  @override
  void initState() {
    super.initState();
    _pickerManager =
        widget.pickerManager ?? GameDataPickerManager(engine: widget.engine);
    WidgetsBinding.instance.addObserver(this);
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    unawaited(_ensureAudioShutdown());
    super.dispose();
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.detached) {
      unawaited(_ensureAudioShutdown());
    }
  }

  Future<void> _ensureAudioShutdown() {
    final Future<void>? existing = _shutdownFuture;
    if (existing != null) {
      return existing;
    }

    final Future<void> shutdown = widget.engine.shutdownAudio();
    _shutdownFuture = shutdown;
    return shutdown;
  }

  Future<void> _pickGameDataDirectory() {
    return _runPickerAction(
      () => _pickerManager.pickGameDataDirectory(
        notifyChanged: () {
          if (mounted) {
            setState(() {});
          }
        },
      ),
    );
  }

  Future<void> _pickGameDataFiles() {
    return _runPickerAction(
      () => _pickerManager.pickGameDataFiles(
        notifyChanged: () {
          if (mounted) {
            setState(() {});
          }
        },
      ),
    );
  }

  Future<void> _runPickerAction(Future<void> Function() action) async {
    await action();

    final GameDataVersionAnalysis? soleReadyVersion =
        _pickerManager.scanResult?.soleReadyVersion;
    if (soleReadyVersion == null ||
        !mounted ||
        widget.engine.availableGames.isNotEmpty) {
      return;
    }

    if (_pickerManager.selectedReadyVersion != soleReadyVersion.version) {
      setState(() {
        _pickerManager.selectReadyVersion(soleReadyVersion.version);
      });
    }

    await _useSelectedData();
  }

  Future<void> _useSelectedData() {
    return _pickerManager.useSelectedData(
      notifyChanged: () {
        if (mounted) {
          setState(() {});
        }
      },
    );
  }

  Future<void> _importSelectedData() {
    return _pickerManager.importSelectedData(
      notifyChanged: () {
        if (mounted) {
          setState(() {});
        }
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return widget.engine.availableGames.isEmpty
        ? NoGameDataScreen(
            configuredDataDirectory: widget.engine.configuredDataDirectory,
            onPickGameDataDirectory: _pickGameDataDirectory,
            onPickGameDataFiles: _pickGameDataFiles,
            onUseSelectedData: _useSelectedData,
            onImportSelectedData: _importSelectedData,
            onSelectReadyVersion: (version) {
              if (version == null) {
                return;
              }
              setState(() {
                _pickerManager.selectReadyVersion(version);
              });
            },
            isLoadingGameData: _pickerManager.isLoadingGameData,
            pickerError: _pickerManager.pickerError,
            scanResult: _pickerManager.scanResult,
            selectedReadyVersion: _pickerManager.selectedReadyVersion,
          )
        : GameScreen(wolf3d: widget.engine);
  }
}