import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:window_manager/window_manager.dart';
import 'package:desktop_drop/desktop_drop.dart';
import 'package:pdf/pdf.dart';
import 'package:pdf/widgets.dart' as pw;
import 'package:printing/printing.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;
  bool _controlsVisible = false;
  Timer? _saveDebounce;
  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);
      });
    }
  }

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

  /// Universal event handler
  @override
  void onWindowEvent(String eventName) {
    switch (eventName) {
      case 'close':
        // Senkron kayıt — async çağrı kapanışta tamamlanmayabilir
        if (_lastBounds != Rect.zero) {
          WindowPersistence.saveSync(
            position: _lastBounds.topLeft,
            size: _lastBounds.size,
          );
        }
        break;
      case 'resize':
      case 'move':
        // Son bilinen konumu hemen güncelle (kapanış senkron kaydı için)
        windowManager.getBounds().then((b) => _lastBounds = b).catchError((_) => _lastBounds);
        _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
    }
  }

  void _showSettings() {
    showDialog(
      context: context,
      builder: (context) => StatefulBuilder(
        builder: (context, setDialogState) => AlertDialog(
          backgroundColor: const Color(0xFF2a2a2a),
          title: const Text('Ayarlar',
              style: TextStyle(color: Colors.white, fontSize: 18)),
          content: SingleChildScrollView(
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                const Text('Sıralama',
                    style: TextStyle(color: Colors.white70, fontSize: 13)),
                RadioListTile<bool>(
                  value: false,
                  groupValue: ImageManager.instance.sortByName,
                  dense: true,
                  activeColor: Colors.blueAccent,
                  title: const Text('Zamana göre',
                      style: TextStyle(color: Colors.white, fontSize: 14)),
                  onChanged: (v) {
                    ImageManager.instance.setSortByName(v!);
                    setDialogState(() {});
                  },
                ),
                RadioListTile<bool>(
                  value: true,
                  groupValue: ImageManager.instance.sortByName,
                  dense: true,
                  activeColor: Colors.blueAccent,
                  title: const Text('İsme göre',
                      style: TextStyle(color: Colors.white, fontSize: 14)),
                  onChanged: (v) {
                    ImageManager.instance.setSortByName(v!);
                    setDialogState(() {});
                  },
                ),
                const Divider(color: Colors.white24, height: 24),
                const Text('imajViewer', style: TextStyle(color: Colors.white, fontSize: 15)),
                const SizedBox(height: 4),
                const Text(
                  'Ultra hafif ve hızlı resim görüntüleyici. '
                  'Görselleri açın, gezinti için okları veya klavye tuşlarını kullanın.',
                  style: TextStyle(color: Colors.white70, fontSize: 13, height: 1.5),
                ),
                const SizedBox(height: 12),
                const Text('Kısayollar',
                    style: TextStyle(color: Colors.white70, fontSize: 13)),
                const SizedBox(height: 4),
                const Text(
                  '• Sol/Sağ ok — önceki/sonraki resim\n'
                  '• Ctrl+Q — pencereyi kapat\n'
                  '• Ctrl+Shift+Q — tüm pencereleri kapat\n'
                  '• Çift tık — doldur/sığdır geçişi\n'
                  '• Sağ tık sürükle — kontrast\n'
                  '• Shift+sağ tık — döndür\n'
                  '• Ctrl+sağ tık — doygunluk\n'
                  '• Ctrl+Shift+sağ tık — parlaklık',
                  style: TextStyle(color: Colors.white70, fontSize: 13, height: 1.6),
                ),
              ],
            ),
          ),
          actions: [
            TextButton.icon(
              onPressed: () {
                Navigator.pop(context);
                _printImage();
              },
              icon: const Icon(Icons.print, color: Colors.white70, size: 18),
              label: const Text('Yazdır',
                  style: TextStyle(color: Colors.white70)),
            ),
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text('Kapat', style: TextStyle(color: Colors.white70)),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _printImage() async {
    final path = ImageManager.instance.currentImagePath;
    if (path.isEmpty) return;
    final bytes = await File(path).readAsBytes();
    final image = pw.MemoryImage(bytes);
    await Printing.layoutPdf(
      onLayout: (format) async {
        final doc = pw.Document();
        doc.addPage(
          pw.Page(
            pageFormat: PdfPageFormat.a4,
            build: (context) => pw.Center(
              child: pw.Image(image, fit: pw.BoxFit.contain),
            ),
          ),
        );
        return doc.save();
      },
    );
  }

  @override
  Widget build(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: MouseRegion(
              onEnter: (_) => setState(() => _controlsVisible = true),
              onExit: (_) => setState(() => _controlsVisible = false),
              child: Stack(
                children: [
                  Positioned(
                    top: 0,
                    left: 0,
                    right: 0,
                    bottom: 0,
                    child: Container(color: const Color(0xFF1a1a1a)),
                  ),
                  Positioned(
                    top: 0,
                    left: 0,
                    right: 0,
                    bottom: 0,
                    child: 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)),
                                ],
                              ),
                            ),
                    ),
                  ),
                  CustomTitleBar(
                    onSettings: _showSettings,
                    visible: _controlsVisible,
                  ),
                  if (_hasImages && _controlsVisible) ...[
                  Positioned(
                    left: 8,
                    bottom: 8,
                    child: _NavButton(
                      icon: Icons.chevron_left,
                      onTap: () => ImageManager.instance.previousImage(),
                    ),
                  ),
                  Positioned(
                    right: 8,
                    bottom: 8,
                    child: _NavButton(
                      icon: Icons.chevron_right,
                      onTap: () => ImageManager.instance.nextImage(),
                    ),
                  ),
                ],
                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)),
                        ),
                      ),
                    ),
                  ),
              ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

class _NavButton extends StatefulWidget {
  final IconData icon;
  final VoidCallback onTap;

  const _NavButton({required this.icon, required this.onTap});

  @override
  State<_NavButton> createState() => _NavButtonState();
}

class _NavButtonState extends State<_NavButton> {
  bool _hovered = false;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: widget.onTap,
      child: MouseRegion(
        cursor: SystemMouseCursors.click,
        onEnter: (_) => setState(() => _hovered = true),
        onExit: (_) => setState(() => _hovered = false),
        child: Container(
          width: 36,
          height: 36,
          decoration: BoxDecoration(
            color: _hovered
                ? Colors.red.withValues(alpha: 0.8)
                : Colors.black.withValues(alpha: 0.35),
            shape: BoxShape.circle,
          ),
          child: Icon(widget.icon, color: Colors.white, size: 22),
        ),
      ),
    );
  }
}