/// Editable list of parsed receipt lines before they are saved as products.
library;

import 'package:flutter/material.dart';

import 'models/line_item.dart';
import 'products_screen.dart';
import 'services/product_repository.dart';
import 'utils/money.dart';

class ReviewScreen extends StatefulWidget {
  const ReviewScreen({
    super.key,
    required this.items,
    required this.rawText,
    required this.repository,
  });

  final List<LineItem> items;
  final String rawText;
  final ProductRepository repository;

  @override
  State<ReviewScreen> createState() => _ReviewScreenState();
}

class _ReviewScreenState extends State<ReviewScreen> {
  late List<LineItem> _items;
  bool _saving = false;

  @override
  void initState() {
    super.initState();
    _items = List<LineItem>.from(widget.items);
  }

  Future<void> _edit({LineItem? existing}) async {
    final result = await showModalBottomSheet<LineItem>(
      context: context,
      isScrollControlled: true,
      showDragHandle: true,
      builder: (context) => _ItemEditSheet(item: existing),
    );
    if (result == null || !mounted) return;

    setState(() {
      if (existing == null) {
        _items.add(result);
      } else {
        final index = _items.indexWhere((item) => item.id == existing.id);
        if (index >= 0) {
          _items[index] = result;
        }
      }
    });
  }

  Future<void> _confirm() async {
    setState(() => _saving = true);
    try {
      await widget.repository.upsertItems(_items);
      if (!mounted) return;
      Navigator.of(context).pushAndRemoveUntil(
        MaterialPageRoute<void>(
          builder: (_) => ProductsScreen(
            repository: widget.repository,
            savedCount: _items.length,
          ),
        ),
        (route) => route.isFirst,
      );
    } catch (_) {
      if (!mounted) return;
      setState(() => _saving = false);
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Could not save products.')),
      );
    }
  }

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

    return Scaffold(
      appBar: AppBar(title: const Text('Review items')),
      body: Column(
        children: [
          Expanded(
            child: _items.isEmpty
                ? Center(
                    child: Text(
                      'No line items found.\nAdd anything the parser missed.',
                      textAlign: TextAlign.center,
                      style: theme.textTheme.bodyLarge,
                    ),
                  )
                : ListView.separated(
                    padding: const EdgeInsets.fromLTRB(8, 8, 8, 8),
                    itemCount: _items.length,
                    separatorBuilder: (_, _) => const SizedBox(height: 4),
                    itemBuilder: (context, index) {
                      final item = _items[index];
                      return Dismissible(
                        key: ValueKey(item.id),
                        direction: DismissDirection.endToStart,
                        background: Container(
                          alignment: Alignment.centerRight,
                          padding: const EdgeInsets.only(right: 20),
                          decoration: BoxDecoration(
                            color: theme.colorScheme.errorContainer,
                            borderRadius: BorderRadius.circular(12),
                          ),
                          child: Icon(
                            Icons.delete_outline,
                            color: theme.colorScheme.onErrorContainer,
                          ),
                        ),
                        onDismissed: (_) {
                          setState(() {
                            _items.removeWhere((row) => row.id == item.id);
                          });
                        },
                        child: ListTile(
                          title: Text(item.name),
                          subtitle: item.quantity == null
                              ? null
                              : Text(
                                  '${item.quantity} × ${formatEuro(item.unitPrice ?? 0)}',
                                ),
                          trailing: Text(
                            formatEuro(item.price),
                            style: theme.textTheme.titleMedium,
                          ),
                          onTap: _saving ? null : () => _edit(existing: item),
                        ),
                      );
                    },
                  ),
          ),
          if (widget.rawText.isNotEmpty)
            ExpansionTile(
              title: const Text('Raw OCR text'),
              children: [
                ConstrainedBox(
                  constraints: const BoxConstraints(maxHeight: 180),
                  child: SingleChildScrollView(
                    padding: const EdgeInsets.fromLTRB(16, 0, 16, 16),
                    child: SelectableText(widget.rawText),
                  ),
                ),
              ],
            ),
          SafeArea(
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 8, 16, 16),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: [
                  OutlinedButton.icon(
                    onPressed: _saving ? null : () => _edit(),
                    icon: const Icon(Icons.add),
                    label: const Text('Add item'),
                  ),
                  const SizedBox(height: 8),
                  FilledButton(
                    onPressed: _saving ? null : _confirm,
                    child: Text(
                      _saving ? 'Saving…' : 'Confirm',
                    ),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}

class _ItemEditSheet extends StatefulWidget {
  const _ItemEditSheet({this.item});

  final LineItem? item;

  @override
  State<_ItemEditSheet> createState() => _ItemEditSheetState();
}

class _ItemEditSheetState extends State<_ItemEditSheet> {
  late final TextEditingController _nameController;
  late final TextEditingController _priceController;
  String? _error;

  @override
  void initState() {
    super.initState();
    final item = widget.item;
    _nameController = TextEditingController(text: item?.name ?? '');
    _priceController = TextEditingController(
      text: item == null ? '' : item.price.toStringAsFixed(2),
    );
  }

  @override
  void dispose() {
    _nameController.dispose();
    _priceController.dispose();
    super.dispose();
  }

  void _save() {
    final name = _nameController.text.trim();
    final price = tryParsePrice(_priceController.text);
    if (name.isEmpty || price == null) {
      setState(() => _error = 'Enter a product name and a price.');
      return;
    }
    Navigator.of(context).pop(
      LineItem(
        id: widget.item?.id ?? 'manual-${DateTime.now().microsecondsSinceEpoch}',
        name: name,
        price: roundMoney(price),
        quantity: widget.item?.quantity,
        unitPrice: widget.item?.unitPrice,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final bottom = MediaQuery.viewInsetsOf(context).bottom;

    return Padding(
      padding: EdgeInsets.fromLTRB(16, 0, 16, 16 + bottom),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: [
          Text(
            widget.item == null ? 'Add item' : 'Edit item',
            style: Theme.of(context).textTheme.titleLarge,
          ),
          const SizedBox(height: 16),
          TextField(
            controller: _nameController,
            textCapitalization: TextCapitalization.sentences,
            decoration: const InputDecoration(labelText: 'Product name'),
            autofocus: widget.item == null,
          ),
          const SizedBox(height: 12),
          TextField(
            controller: _priceController,
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            decoration: const InputDecoration(labelText: 'Price'),
          ),
          if (_error != null) ...[
            const SizedBox(height: 8),
            Text(
              _error!,
              style: TextStyle(color: Theme.of(context).colorScheme.error),
            ),
          ],
          const SizedBox(height: 16),
          FilledButton(
            onPressed: _save,
            child: const Text('Save'),
          ),
        ],
      ),
    );
  }
}