/// Drag a crop box over the receipt photo before OCR runs.
library;

import 'dart:io';
import 'dart:typed_data';

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

class CropReceiptScreen extends StatefulWidget {
  const CropReceiptScreen({super.key, required this.imagePath});

  final String imagePath;

  @override
  State<CropReceiptScreen> createState() => _CropReceiptScreenState();
}

class _CropReceiptScreenState extends State<CropReceiptScreen> {
  final CropController _controller = CropController();

  Uint8List? _image;
  String? _error;
  bool _ready = false;
  bool _cropping = false;

  @override
  void initState() {
    super.initState();
    _load();
  }

  Future<void> _load() async {
    try {
      final bytes = await File(widget.imagePath).readAsBytes();
      if (!mounted) return;
      setState(() => _image = bytes);
    } catch (_) {
      if (!mounted) return;
      setState(() => _error = 'Could not open this photo.');
    }
  }

  void _onCropped(CropResult result) {
    switch (result) {
      case CropSuccess(:final croppedImage):
        _saveAndPop(croppedImage);
      case CropFailure():
        if (!mounted) return;
        setState(() => _cropping = false);
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Could not crop this photo.')),
        );
    }
  }

  Future<void> _saveAndPop(Uint8List bytes) async {
    try {
      final file = File(
        '${Directory.systemTemp.path}/receipity_crop_${DateTime.now().millisecondsSinceEpoch}.jpg',
      );
      await file.writeAsBytes(bytes, flush: true);
      if (!mounted) return;
      Navigator.of(context).pop(file.path);
    } catch (_) {
      if (!mounted) return;
      setState(() => _cropping = false);
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Could not save the cropped photo.')),
      );
    }
  }

  void _confirm() {
    if (!_ready || _cropping) return;
    setState(() => _cropping = true);
    _controller.crop();
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);

    return PopScope(
      canPop: !_cropping,
      child: Scaffold(
        appBar: AppBar(title: const Text('Crop receipt')),
        body: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: [
            Expanded(child: _editor(theme)),
            SafeArea(
              top: false,
              child: Padding(
                padding: const EdgeInsets.fromLTRB(16, 8, 16, 16),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Text(
                      'Drag the corners over the text you want to read. Pinch to zoom.',
                      style: theme.textTheme.bodyMedium,
                      textAlign: TextAlign.center,
                    ),
                    const SizedBox(height: 12),
                    FilledButton.icon(
                      onPressed: _ready && !_cropping ? _confirm : null,
                      icon: const Icon(Icons.check),
                      label: Text(_cropping ? 'Cropping…' : 'Use this area'),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _editor(ThemeData theme) {
    if (_error != null) {
      return Center(
        child: Padding(
          padding: const EdgeInsets.all(24),
          child: Text(
            _error!,
            textAlign: TextAlign.center,
            style: theme.textTheme.bodyLarge,
          ),
        ),
      );
    }

    final image = _image;
    if (image == null) {
      return const Center(child: CircularProgressIndicator());
    }

    return Stack(
      fit: StackFit.expand,
      children: [
        Crop(
          image: image,
          controller: _controller,
          onCropped: _onCropped,
          interactive: true,
          filterQuality: FilterQuality.medium,
          baseColor: theme.colorScheme.surface,
          maskColor: Colors.black.withValues(alpha: 0.55),
          radius: 8,
          progressIndicator: const Center(child: CircularProgressIndicator()),
          initialRectBuilder: InitialRectBuilder.withBuilder((
            viewportRect,
            imageRect,
          ) {
            final dx = imageRect.width * 0.06;
            final dy = imageRect.height * 0.06;
            return Rect.fromLTRB(
              imageRect.left + dx,
              imageRect.top + dy,
              imageRect.right - dx,
              imageRect.bottom - dy,
            );
          }),
          cornerDotBuilder: (size, _) =>
              DotControl(color: theme.colorScheme.primary),
          onStatusChanged: (status) {
            final ready = status == CropStatus.ready;
            if (ready == _ready) return;
            setState(() => _ready = ready);
          },
        ),
        if (_cropping)
          const ColoredBox(
            color: Color(0x66000000),
            child: Center(child: CircularProgressIndicator()),
          ),
      ],
    );
  }
}