/// Visual browser for decoded VGA pictures and UI art.
library;

import 'dart:async';
import 'dart:typed_data';
import 'dart:ui' as ui;

import 'package:flutter/material.dart';
import 'package:super_clipboard/super_clipboard.dart';
import 'package:wolf_3d_dart/wolf_3d_data_types.dart';
import 'package:wolf_3d_renderer/wolf_3d_asset_painter.dart';

/// Shows each VGA image extracted from the currently selected game data set.
class VgaGallery extends StatelessWidget {
  /// Raw VGA images decoded from the active asset pack.
  final List<VgaImage> images;

  /// Creates the gallery for [images].
  const VgaGallery({super.key, required this.images});

  Future<ui.Image> _buildVgaUiImage(VgaImage image) {
    final completer = Completer<ui.Image>();
    final Uint8List pixels = Uint8List(image.width * image.height * 4);

    for (int y = 0; y < image.height; y++) {
      for (int x = 0; x < image.width; x++) {
        final int colorByte = image.decodePixel(x, y);
        final int abgr = ColorPalette.vga32Bit[colorByte];
        final int offset = (y * image.width + x) * 4;
        pixels[offset] = abgr & 0xFF; // R
        pixels[offset + 1] = (abgr >> 8) & 0xFF; // G
        pixels[offset + 2] = (abgr >> 16) & 0xFF; // B
        pixels[offset + 3] = (abgr >> 24) & 0xFF; // A
      }
    }

    ui.decodeImageFromPixels(
      pixels,
      image.width,
      image.height,
      ui.PixelFormat.rgba8888,
      (ui.Image decoded) => completer.complete(decoded),
    );
    return completer.future;
  }

  Future<void> _copyImageToClipboard(BuildContext context, int index) async {
    final clipboard = SystemClipboard.instance;
    if (clipboard == null) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Clipboard API is unavailable here.')),
        );
      }
      return;
    }

    final VgaImage image = images[index];
    ui.Image? uiImage;
    try {
      uiImage = await _buildVgaUiImage(image);
      final ByteData? pngData = await uiImage.toByteData(
        format: ui.ImageByteFormat.png,
      );
      if (pngData == null) {
        throw StateError('Failed to encode image as PNG.');
      }

      final item = DataWriterItem();
      item.add(Formats.png(pngData.buffer.asUint8List()));
      await clipboard.write([item]);

      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Copied VGA image #$index to clipboard.')),
        );
      }
    } catch (error) {
      if (context.mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text('Copy failed: $error')),
        );
      }
    } finally {
      uiImage?.dispose();
    }
  }

  void _showImagePreviewDialog(BuildContext context, int index) {
    final VgaImage image = images[index];

    showDialog<void>(
      context: context,
      builder: (dialogContext) {
        return AlertDialog(
          title: Text(
            'Index: $index  ${image.width} x ${image.height}',
            style: const TextStyle(
              fontSize: 14,
              fontWeight: FontWeight.w600,
            ),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.of(dialogContext).pop(),
              child: const Text('Close'),
            ),
            ElevatedButton.icon(
              onPressed: () => _copyImageToClipboard(dialogContext, index),
              icon: const Icon(Icons.copy),
              label: const Text('Copy'),
            ),
          ],
          content: Center(
            child: AspectRatio(
              aspectRatio: image.width / image.height,
              child: WolfAssetPainter.vga(image),
            ),
          ),
        );
      },
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: const Text("VGA Image Gallery")),
      backgroundColor: Colors.black,
      body: GridView.builder(
        gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
          maxCrossAxisExtent: 150,
          crossAxisSpacing: 8,
          mainAxisSpacing: 8,
        ),
        itemCount: images.length,
        itemBuilder: (context, index) {
          return Card(
            color: Colors.blueGrey,
            child: InkWell(
              onTap: () => _showImagePreviewDialog(context, index),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                spacing: 8,
                children: [
                  Text(
                    "Index: $index\n${images[index].width} x ${images[index].height}",
                    style: const TextStyle(color: Colors.white, fontSize: 12),
                    textAlign: TextAlign.center,
                  ),
                  Expanded(
                    child: Center(
                      child: AspectRatio(
                        aspectRatio: images[index].width / images[index].height,
                        child: WolfAssetPainter.vga(images[index]),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          );
        },
      ),
    );
  }
}