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

import 'package:flutter/material.dart';
import 'package:flutter/rendering.dart';
import 'package:pyramid/core/theme.dart';

class BannerCropDialog extends StatefulWidget {
  final Uint8List imageBytes;
  // Width-to-height ratio for the crop frame (e.g. 2.4 = 2.4× wider than tall)
  final double aspectRatio;

  const BannerCropDialog({
    super.key,
    required this.imageBytes,
    this.aspectRatio = 2.4,
  });

  @override
  State<BannerCropDialog> createState() => _BannerCropDialogState();
}

class _BannerCropDialogState extends State<BannerCropDialog> {
  final _transformController = TransformationController();
  final _repaintKey = GlobalKey();
  bool _exporting = false;

  @override
  void dispose() {
    _transformController.dispose();
    super.dispose();
  }

  Future<void> _confirm() async {
    setState(() => _exporting = true);
    try {
      final boundary = _repaintKey.currentContext!.findRenderObject()
          as RenderRepaintBoundary;
      // pixelRatio 2 gives enough resolution for a banner
      final image = await boundary.toImage(pixelRatio: 2.0);
      final byteData =
          await image.toByteData(format: ui.ImageByteFormat.png);
      if (byteData == null || !mounted) return;
      Navigator.of(context).pop(byteData.buffer.asUint8List());
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text('Fehler beim Zuschneiden: $e')));
        setState(() => _exporting = false);
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    final pt = PyramidTheme.of(context);

    return Dialog(
      backgroundColor: pt.bg1,
      shape: RoundedRectangleBorder(
          borderRadius: BorderRadius.circular(pt.rLg)),
      insetPadding: const EdgeInsets.symmetric(horizontal: 24, vertical: 40),
      child: ConstrainedBox(
        constraints: const BoxConstraints(maxWidth: 520),
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            // ── Header ────────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(20, 20, 12, 12),
              child: Row(
                children: [
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text('Banner zuschneiden',
                            style: TextStyle(
                                color: pt.fg,
                                fontSize: 16,
                                fontWeight: FontWeight.w700)),
                        Text(
                            'Ziehe und zoome das Bild zum gewünschten Ausschnitt',
                            style: TextStyle(color: pt.fgDim, fontSize: 12)),
                      ],
                    ),
                  ),
                  IconButton(
                    icon: Icon(Icons.close, color: pt.fgDim, size: 20),
                    onPressed: () => Navigator.of(context).pop(),
                  ),
                ],
              ),
            ),
            // ── Crop frame ────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.symmetric(horizontal: 20),
              child: AspectRatio(
                aspectRatio: widget.aspectRatio,
                child: ClipRRect(
                  borderRadius: BorderRadius.circular(pt.rBase),
                  child: RepaintBoundary(
                    key: _repaintKey,
                    child: Container(
                      color: Colors.black,
                      child: InteractiveViewer(
                        transformationController: _transformController,
                        minScale: 0.25,
                        maxScale: 8.0,
                        child: Image.memory(
                          widget.imageBytes,
                          fit: BoxFit.cover,
                          width: double.infinity,
                          height: double.infinity,
                        ),
                      ),
                    ),
                  ),
                ),
              ),
            ),
            // ── Hint ──────────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(20, 10, 20, 0),
              child: Row(
                children: [
                  Icon(Icons.info_outline, size: 13, color: pt.fgDim),
                  const SizedBox(width: 6),
                  Expanded(
                    child: Text(
                      'Pinch/Scroll zum Zoomen, Drag zum Positionieren',
                      style: TextStyle(color: pt.fgDim, fontSize: 11),
                    ),
                  ),
                  TextButton(
                    onPressed: () {
                      _transformController.value = Matrix4.identity();
                    },
                    child:
                        Text('Zurücksetzen', style: TextStyle(color: pt.fgDim, fontSize: 11)),
                  ),
                ],
              ),
            ),
            // ── Actions ───────────────────────────────────────────────────
            Padding(
              padding: const EdgeInsets.fromLTRB(20, 12, 20, 20),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  TextButton(
                    onPressed: _exporting
                        ? null
                        : () => Navigator.of(context).pop(),
                    child: const Text('Abbrechen'),
                  ),
                  const SizedBox(width: 8),
                  FilledButton(
                    onPressed: _exporting ? null : _confirm,
                    style: FilledButton.styleFrom(
                      backgroundColor: pt.accent,
                      shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(pt.rBase)),
                    ),
                    child: _exporting
                        ? SizedBox(
                            width: 16,
                            height: 16,
                            child: CircularProgressIndicator(
                                strokeWidth: 2, color: pt.bg0))
                        : const Text('Übernehmen',
                            style: TextStyle(
                                color: Colors.white,
                                fontWeight: FontWeight.w600)),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}