/// Dialogs to nest or create labels.
library;

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

import '../models/transaction_meta.dart';
import '../providers/tx_meta_provider.dart';

Future<void> showMoveLabelDialog(
  BuildContext context, {
  required TxLabel label,
}) async {
  final meta = context.read<TxMetaController>();
  final parents = meta.validParentsFor(label.id);
  final currentParent = meta.parentIdOf(label.id);

  final chosen = await showDialog<String?>(
    context: context,
    builder: (dialogContext) {
      final theme = Theme.of(dialogContext);
      final maxHeight = MediaQuery.sizeOf(dialogContext).height * 0.45;
      return AlertDialog(
        title: Text('Move “${label.name}”'),
        titleTextStyle: theme.textTheme.titleMedium?.copyWith(
          color: theme.colorScheme.onSurface,
        ),
        contentPadding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
        content: SizedBox(
          width: double.maxFinite,
          child: ConstrainedBox(
            constraints: BoxConstraints(maxHeight: maxHeight),
            child: ListView(
              shrinkWrap: true,
              padding: EdgeInsets.zero,
              children: [
                ListTile(
                  dense: true,
                  visualDensity: const VisualDensity(
                    horizontal: -4,
                    vertical: -3,
                  ),
                  contentPadding: const EdgeInsets.symmetric(horizontal: 4),
                  minLeadingWidth: 28,
                  leading: Icon(
                    currentParent == null
                        ? Icons.check_circle
                        : Icons.circle_outlined,
                    size: 18,
                  ),
                  title: Text(
                    'Top level',
                    style: theme.textTheme.bodyMedium,
                  ),
                  onTap: () => Navigator.pop(dialogContext, ''),
                ),
                Divider(
                  height: 1,
                  color: theme.colorScheme.outlineVariant.withValues(
                    alpha: 0.5,
                  ),
                ),
                for (final parent in parents)
                  ListTile(
                    dense: true,
                    visualDensity: const VisualDensity(
                      horizontal: -4,
                      vertical: -3,
                    ),
                    contentPadding: const EdgeInsets.symmetric(horizontal: 4),
                    minLeadingWidth: 28,
                    leading: Icon(
                      parent.id == currentParent
                          ? Icons.check_circle
                          : parent.icon,
                      size: 18,
                      color: parent.color,
                    ),
                    title: Text(
                      parent.name,
                      style: theme.textTheme.bodyMedium,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    onTap: () => Navigator.pop(dialogContext, parent.id),
                  ),
              ],
            ),
          ),
        ),
        actionsPadding: const EdgeInsets.fromLTRB(12, 4, 12, 8),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(dialogContext),
            child: const Text('Cancel'),
          ),
        ],
      );
    },
  );

  if (chosen == null || !context.mounted) return;
  await meta.setLabelParent(label.id, chosen.isEmpty ? null : chosen);
}

/// Returns name + optional parent, or null if cancelled.
Future<({String name, String? parentId})?> showCreateLabelDialog(
  BuildContext context, {
  required List<TxLabel> parents,
  String? initialParentId,
}) {
  return showDialog<({String name, String? parentId})>(
    context: context,
    builder: (context) => _CreateLabelDialog(
      parents: parents,
      initialParentId: initialParentId,
    ),
  );
}

class _CreateLabelDialog extends StatefulWidget {
  const _CreateLabelDialog({
    required this.parents,
    this.initialParentId,
  });

  final List<TxLabel> parents;
  final String? initialParentId;

  @override
  State<_CreateLabelDialog> createState() => _CreateLabelDialogState();
}

class _CreateLabelDialogState extends State<_CreateLabelDialog> {
  late final TextEditingController _controller;
  String? _parentId;

  @override
  void initState() {
    super.initState();
    _controller = TextEditingController();
    _parentId = widget.initialParentId;
  }

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

  void _submit() {
    final name = _controller.text.trim();
    if (name.isEmpty) return;
    Navigator.pop(context, (name: name, parentId: _parentId));
  }

  @override
  Widget build(BuildContext context) {
    final parentChoices = List<TxLabel>.of(widget.parents)
      ..sort((a, b) => a.name.toLowerCase().compareTo(b.name.toLowerCase()));

    return AlertDialog(
      title: const Text('New label'),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          TextField(
            controller: _controller,
            autofocus: true,
            textCapitalization: TextCapitalization.sentences,
            decoration: const InputDecoration(hintText: 'e.g. Supermarket'),
            onSubmitted: (_) => _submit(),
          ),
          const SizedBox(height: 12),
          DropdownButtonFormField<String?>(
            initialValue: _parentId,
            decoration: const InputDecoration(
              labelText: 'Under label (optional)',
            ),
            items: [
              const DropdownMenuItem<String?>(
                value: null,
                child: Text('Top level'),
              ),
              for (final parent in parentChoices)
                DropdownMenuItem<String?>(
                  value: parent.id,
                  child: Text(parent.name),
                ),
            ],
            onChanged: (value) => setState(() => _parentId = value),
          ),
        ],
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: _submit,
          child: const Text('Create'),
        ),
      ],
    );
  }
}