import 'dart:async';
import 'package:flutter/material.dart';
import 'package:window_manager/window_manager.dart';
import 'package:desktop_drop/desktop_drop.dart';
import '../services/image_manager.dart';
import '../services/file_handler.dart';
import '../widgets/custom_title_bar.dart';
import '../widgets/image_canvas.dart';
import '../widgets/window_resize_zones.dart';
import '../shortcuts/app_shortcuts.dart';
import '../services/window_persistence.dart';

class ViewerScreen extends StatefulWidget {
  final List<String> initialFiles;
  const ViewerScreen({super.key, this.initialFiles = const []});
  @override
  State<ViewerScreen> createState() => _ViewerScreenState();
}

class _ViewerScreenState extends State<ViewerScreen> with WindowListener {
  bool _hasImages = false;
  bool _isDragging = false;
  Timer? _saveDebounce;
  Timer? _pollTimer;
  Rect _lastBounds = Rect.zero;

  @override
  void initState() {
    super.initState();
    windowManager.addListener(this);
    ImageManager.instance.addListener(_onImageManagerChanged);

    if (widget.initialFiles.isNotEmpty) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        FileHandler.loadImagesFromPaths(widget.initialFiles);
      });
    }

    // İlk kayıt + periyodik polling başlat
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      await Future.delayed(const Duration(milliseconds: 200));
      await _doSave();
      _startPolling();
    });
  }

  void _startPolling() {
    _pollTimer?.cancel();
    _pollTimer = Timer.periodic(const Duration(seconds: 2), (_) async {
      try {
        final bounds = await windowManager.getBounds();
        if (bounds != _lastBounds) {
          _lastBounds = bounds;
          WindowPersistence.saveSync(
            position: bounds.topLeft,
            size: bounds.size,
          );
        }
      } catch (_) {}
    });
  }

  @override
  void dispose() {
    windowManager.removeListener(this);
    ImageManager.instance.removeListener(_onImageManagerChanged);
    _saveDebounce?.cancel();
    _pollTimer?.cancel();
    super.dispose();
  }

  /// Universal event handler
  @override
  void onWindowEvent(String eventName) {
    switch (eventName) {
      case 'close':
        _doSave();
        break;
      case 'resize':
      case 'move':
        _saveDebounce?.cancel();
        _saveDebounce = Timer(const Duration(milliseconds: 300), () {
          _doSave();
        });
        break;
    }
  }

  void _onImageManagerChanged() {
    setState(() => _hasImages = ImageManager.instance.images.isNotEmpty);
  }

  Future<void> _doSave() async {
    try {
      final pos = await windowManager.getPosition();
      final size = await windowManager.getSize();
      _lastBounds = Rect.fromLTWH(pos.dx, pos.dy, size.width, size.height);
      WindowPersistence.saveSync(position: pos, size: size);
    } catch (_) {
      // Silently ignore save errors
    }
  }

  @override
  Widget build(BuildContext context) {
    ImageManager.instance.buildContext = context;
    return AppShortcuts(
      child: Scaffold(
        backgroundColor: Colors.transparent,
        body: WindowResizeZones(
          child: DropTarget(
            onDragEntered: (_) => setState(() => _isDragging = true),
            onDragExited: (_) => setState(() => _isDragging = false),
            onDragDone: (details) {
              setState(() => _isDragging = false);
              FileHandler.loadImagesFromPaths(
                  details.files.map((f) => f.path).toList());
            },
            child: Stack(
              children: [
                Positioned(
                  top: 28,
                  left: 0,
                  right: 0,
                  bottom: 0,
                  child: Container(color: const Color(0xFF1a1a1a)),
                ),
                Container(
                  color: Colors.transparent,
                  child: _hasImages
                      ? ImageCanvas(filePath: ImageManager.instance.currentImagePath)
                      : const Center(
                          child: Column(
                            mainAxisSize: MainAxisSize.min,
                            children: [
                              Icon(Icons.image, size: 64, color: Colors.white24),
                              SizedBox(height: 16),
                              Text('Resimleri buraya sürükleyin\nveya Ctrl+O ile açın',
                                  textAlign: TextAlign.center,
                                  style: TextStyle(color: Colors.white38, fontSize: 16)),
                            ],
                          ),
                        ),
                ),
                const CustomTitleBar(),
                if (_isDragging)
                  Positioned.fill(
                    child: Container(
                      color: Colors.blue.withValues(alpha: 0.1),
                      child: Center(
                        child: Container(
                          padding: const EdgeInsets.all(32),
                          decoration: BoxDecoration(
                            color: Colors.black87,
                            borderRadius: BorderRadius.circular(16),
                            border: Border.all(color: Colors.blueAccent, width: 2),
                          ),
                          child: const Text('Bırakın',
                              style: TextStyle(color: Colors.white, fontSize: 24)),
                        ),
                      ),
                    ),
                  ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}