/// Transaction detail: label, recurring, notes, apply-to-similar.
library;

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

import '../models/bank.dart';
import '../models/transaction_meta.dart';
import '../providers/bank_provider.dart';
import '../providers/tx_meta_provider.dart';
import '../utils/helpers.dart';
import '../widgets/responsive_body.dart';

class TransactionDetailScreen extends StatefulWidget {
  const TransactionDetailScreen({super.key, required this.tx});

  final BankTransaction tx;

  @override
  State<TransactionDetailScreen> createState() =>
      _TransactionDetailScreenState();
}

class _TransactionDetailScreenState extends State<TransactionDetailScreen> {
  late final TextEditingController _notesController;
  var _dirty = false;
  late bool _applyToSimilar;

  @override
  void initState() {
    super.initState();
    final meta = context.read<TxMetaController>();
    final notes = meta.metaFor(widget.tx).notes;
    _notesController = TextEditingController(text: notes);
    final all = context.read<BankController>().transactions;
    final similarCount = meta.countSimilar(widget.tx, all);
    // Default on when there are peers — otherwise users never notice the toggle.
    _applyToSimilar = similarCount > 1;
  }

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

  List<BankTransaction> _similarScope(TxMetaController meta) {
    final all = context.read<BankController>().transactions;
    if (!_applyToSimilar) return const [];
    return meta.similarTo(widget.tx, all);
  }

  Future<void> _saveNotes() async {
    final meta = context.read<TxMetaController>();
    final similar = _similarScope(meta);
    await meta.setNotes(
      widget.tx,
      _notesController.text,
      applyToSimilar: similar,
    );
    if (!mounted) return;
    setState(() => _dirty = false);
    final count = similar.isEmpty ? 1 : similar.length;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(
          count == 1
              ? 'Notes saved'
              : 'Notes saved on $count similar transactions',
        ),
      ),
    );
  }

  Future<void> _toggleLabel(String labelId) async {
    final meta = context.read<TxMetaController>();
    final similar = _similarScope(meta);
    await meta.toggleLabel(
      widget.tx,
      labelId,
      applyToSimilar: similar,
    );
    if (!mounted) return;
    final count = similar.isEmpty ? 1 : similar.length;
    if (count > 1) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text('Labels updated on $count similar transactions'),
        ),
      );
    }
  }

  Future<void> _clearLabels() async {
    final meta = context.read<TxMetaController>();
    final similar = _similarScope(meta);
    await meta.clearLabels(
      widget.tx,
      applyToSimilar: similar,
    );
  }

  Future<void> _createLabel() async {
    final name = await showDialog<String>(
      context: context,
      builder: (context) => const _NewLabelDialog(),
    );
    if (name == null || name.isEmpty || !mounted) return;
    final meta = context.read<TxMetaController>();
    final label = await meta.createLabel(name);
    if (!mounted) return;
    await _toggleLabel(label.id);
  }

  Future<void> _confirmRemoveLabel(TxLabel label) async {
    final ok = await showDialog<bool>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: Text('Remove “${label.name}”?'),
          content: const Text(
            'This deletes the label. Transactions keep any other labels.',
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context, false),
              child: const Text('Cancel'),
            ),
            FilledButton(
              onPressed: () => Navigator.pop(context, true),
              child: const Text('Remove'),
            ),
          ],
        );
      },
    );
    if (ok != true || !mounted) return;
    await context.read<TxMetaController>().removeLabel(label.id);
  }

  @override
  Widget build(BuildContext context) {
    final tx = widget.tx;
    final metaController = context.watch<TxMetaController>();
    final meta = metaController.metaFor(tx);
    final all = context.watch<BankController>().transactions;
    final similarCount = metaController.countSimilar(tx, all);
    final theme = Theme.of(context);
    final colors = theme.colorScheme;
    final amountColor = tx.amount >= 0 ? colors.primary : colors.error;
    final selectedIds = meta.labelIds.toSet();
    final merchantPreview = tx.merchantKey.isEmpty
        ? tx.description
        : (tx.merchantKey.length > 48
            ? '${tx.merchantKey.substring(0, 47)}…'
            : tx.merchantKey);

    return Scaffold(
      appBar: AppBar(
        title: const Text('Transaction'),
        actions: [
          if (_dirty)
            TextButton(
              onPressed: _saveNotes,
              child: const Text('Save'),
            ),
        ],
      ),
      body: ResponsiveBody(
        child: ListView(
          padding: const EdgeInsets.only(top: 8, bottom: 32),
          children: [
            Text(
              formatMoney(tx.amount, tx.currency),
              style: theme.textTheme.headlineMedium?.copyWith(color: amountColor),
            ),
            const SizedBox(height: 8),
            Text(tx.description, style: theme.textTheme.titleMedium),
            const SizedBox(height: 4),
            Text(
              [
                formatIsoDate(tx.date),
                if (tx.pending) 'Pending',
              ].join(' · '),
              style: theme.textTheme.bodyMedium,
            ),
            if (similarCount > 1) ...[
              const SizedBox(height: 16),
              SwitchListTile(
                contentPadding: EdgeInsets.zero,
                secondary: const Icon(Icons.copy_all_outlined),
                title: const Text('Apply to all similar'),
                subtitle: Text(
                  '$similarCount matches · $merchantPreview',
                ),
                value: _applyToSimilar,
                onChanged: (value) => setState(() => _applyToSimilar = value),
              ),
            ],
            const SizedBox(height: 8),
            SwitchListTile(
              contentPadding: EdgeInsets.zero,
              secondary: const Icon(Icons.autorenew),
              title: const Text('Recurring'),
              subtitle: const Text('Salary, mortgage, subscriptions…'),
              value: meta.recurring,
              onChanged: (value) {
                context.read<TxMetaController>().setRecurring(tx, value);
              },
            ),
            const SizedBox(height: 16),
            Row(
              children: [
                Text('Labels', style: theme.textTheme.titleSmall),
                const Spacer(),
                if (meta.hasLabel)
                  TextButton(
                    onPressed: _clearLabels,
                    child: const Text('Clear'),
                  ),
              ],
            ),
            const SizedBox(height: 8),
            Wrap(
              spacing: 8,
              runSpacing: 8,
              children: [
                for (final label in metaController.allLabels)
                  GestureDetector(
                    onLongPress: label.custom
                        ? () => _confirmRemoveLabel(label)
                        : null,
                    child: FilterChip(
                      avatar: Icon(label.icon, size: 16, color: label.color),
                      label: Text(label.name),
                      selected: selectedIds.contains(label.id),
                      onSelected: (_) => _toggleLabel(label.id),
                    ),
                  ),
                ActionChip(
                  avatar: const Icon(Icons.add, size: 16),
                  label: const Text('New label'),
                  onPressed: _createLabel,
                ),
              ],
            ),
            const SizedBox(height: 24),
            Text('Notes', style: theme.textTheme.titleSmall),
            const SizedBox(height: 8),
            TextField(
              controller: _notesController,
              minLines: 3,
              maxLines: 6,
              textInputAction: TextInputAction.newline,
              decoration: const InputDecoration(
                hintText: 'Add a private note…',
              ),
              onChanged: (_) {
                if (!_dirty) setState(() => _dirty = true);
              },
            ),
            const SizedBox(height: 12),
            FilledButton(
              onPressed: _dirty ? _saveNotes : null,
              child: Text(
                _applyToSimilar && similarCount > 1
                    ? 'Save notes for $similarCount'
                    : 'Save notes',
              ),
            ),
            const SizedBox(height: 16),
            Text(
              'Tap labels to add or remove several. Long-press a custom label '
              'to delete it. Similar matches strip dates and ids so supermarket '
              'purchases group together.',
              style: theme.textTheme.labelMedium,
            ),
          ],
        ),
      ),
    );
  }
}

class _NewLabelDialog extends StatefulWidget {
  const _NewLabelDialog();

  @override
  State<_NewLabelDialog> createState() => _NewLabelDialogState();
}

class _NewLabelDialogState extends State<_NewLabelDialog> {
  late final TextEditingController _controller;

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

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

  void _submit() {
    Navigator.pop(context, _controller.text.trim());
  }

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: const Text('New label'),
      content: TextField(
        controller: _controller,
        autofocus: true,
        textCapitalization: TextCapitalization.sentences,
        decoration: const InputDecoration(hintText: 'e.g. Supermarket'),
        onSubmitted: (_) => _submit(),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: _submit,
          child: const Text('Create'),
        ),
      ],
    );
  }
}