/// Gear that opens the settings sheet.
library;

import 'package:flutter/material.dart';

import '../models/supermarket.dart';
import '../services/app_settings.dart';
import '../services/backup_service.dart';

class SettingsButton extends StatelessWidget {
  const SettingsButton({super.key});

  @override
  Widget build(BuildContext context) {
    return IconButton(
      tooltip: 'Settings',
      onPressed: () => showSettingsSheet(context),
      icon: const Icon(Icons.settings_outlined),
    );
  }
}

Future<void> showSettingsSheet(BuildContext context) {
  return showModalBottomSheet<void>(
    context: context,
    isScrollControlled: true,
    showDragHandle: true,
    builder: (context) {
      return const _SettingsSheet();
    },
  );
}

class _SettingsSheet extends StatefulWidget {
  const _SettingsSheet();

  @override
  State<_SettingsSheet> createState() => _SettingsSheetState();
}

class _SettingsSheetState extends State<_SettingsSheet> {
  bool _busy = false;

  Future<void> _export(AppSettings settings) async {
    setState(() => _busy = true);
    try {
      final shared = await BackupService(settings.repository).exportBackup();
      if (!mounted) return;
      if (shared) {
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Backup ready.')),
        );
      }
    } catch (_) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Could not export the backup.')),
      );
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  Future<void> _import(AppSettings settings) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: const Text('Import backup?'),
          content: const Text(
            'This replaces all products, shopping trips, photos, and settings on this device.',
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context, false),
              child: const Text('Cancel'),
            ),
            FilledButton(
              onPressed: () => Navigator.pop(context, true),
              child: const Text('Import'),
            ),
          ],
        );
      },
    );
    if (confirmed != true || !mounted) return;

    setState(() => _busy = true);
    try {
      final imported = await BackupService(settings.repository).importBackup();
      if (!mounted) return;
      if (imported) {
        await settings.reload();
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Backup imported.')),
        );
      }
    } catch (_) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('Could not import this backup.')),
      );
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

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

    return ListenableBuilder(
      listenable: settings,
      builder: (context, _) {
        return Padding(
          padding: EdgeInsets.fromLTRB(16, 0, 16, 16 + bottom),
          child: SizedBox(
            height: MediaQuery.sizeOf(context).height * 0.75,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Text('Settings', style: Theme.of(context).textTheme.titleLarge),
                const SizedBox(height: 8),
                SwitchListTile(
                  contentPadding: EdgeInsets.zero,
                  title: const Text('Dark mode'),
                  value: settings.darkMode,
                  onChanged: _busy ? null : settings.setDarkMode,
                ),
                Text('Backup', style: Theme.of(context).textTheme.titleMedium),
                Text(
                  'Save everything to a JSON file, or replace this device from a backup.',
                  style: Theme.of(context).textTheme.bodyMedium,
                ),
                const SizedBox(height: 8),
                Row(
                  children: [
                    Expanded(
                      child: OutlinedButton.icon(
                        onPressed: _busy ? null : () => _export(settings),
                        icon: const Icon(Icons.file_upload_outlined),
                        label: const Text('Export'),
                      ),
                    ),
                    const SizedBox(width: 8),
                    Expanded(
                      child: OutlinedButton.icon(
                        onPressed: _busy ? null : () => _import(settings),
                        icon: const Icon(Icons.file_download_outlined),
                        label: const Text('Import'),
                      ),
                    ),
                  ],
                ),
                if (_busy) ...[
                  const SizedBox(height: 8),
                  const LinearProgressIndicator(),
                ],
                const SizedBox(height: 16),
                Text(
                  'Supermarkets',
                  style: Theme.of(context).textTheme.titleMedium,
                ),
                Text(
                  'Name and color used as tags on products.',
                  style: Theme.of(context).textTheme.bodyMedium,
                ),
                const SizedBox(height: 8),
                Expanded(
                  child: ListView(
                    children: [
                      for (final store in settings.supermarkets)
                        _StoreRow(
                          store: store,
                          onEdit: _busy
                              ? () {}
                              : () => _editStore(context, settings, store),
                          onDelete: _busy || store.id == null
                              ? null
                              : () => settings.deleteSupermarket(store.id!),
                        ),
                    ],
                  ),
                ),
                const SizedBox(height: 8),
                OutlinedButton.icon(
                  onPressed: _busy
                      ? null
                      : () => _editStore(context, settings, null),
                  icon: const Icon(Icons.add),
                  label: const Text('Add supermarket'),
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  Future<void> _editStore(
    BuildContext context,
    AppSettings settings,
    Supermarket? existing,
  ) async {
    final result = await showDialog<Supermarket>(
      context: context,
      builder: (context) => _StoreEditDialog(store: existing),
    );
    if (result == null) return;
    if (existing == null) {
      try {
        await settings.addSupermarket(result.name, result.colorValue);
      } catch (_) {
        if (context.mounted) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text('That supermarket already exists.')),
          );
        }
      }
    } else {
      await settings.updateSupermarket(
        existing.copyWith(name: result.name, colorValue: result.colorValue),
      );
    }
  }
}

class _StoreRow extends StatelessWidget {
  const _StoreRow({
    required this.store,
    required this.onEdit,
    this.onDelete,
  });

  final Supermarket store;
  final VoidCallback onEdit;
  final VoidCallback? onDelete;

  @override
  Widget build(BuildContext context) {
    final onColor = store.color.computeLuminance() > 0.55
        ? Colors.black87
        : Colors.white;

    return ListTile(
      contentPadding: EdgeInsets.zero,
      leading: CircleAvatar(
        backgroundColor: store.color,
        child: Text(
          store.name.isEmpty ? '?' : store.name.substring(0, 1),
          style: TextStyle(color: onColor, fontWeight: FontWeight.w700),
        ),
      ),
      title: Text(store.name),
      trailing: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          IconButton(
            tooltip: 'Edit',
            onPressed: onEdit,
            icon: const Icon(Icons.edit_outlined),
          ),
          IconButton(
            tooltip: 'Delete',
            onPressed: onDelete,
            icon: const Icon(Icons.delete_outline),
          ),
        ],
      ),
    );
  }
}

class _StoreEditDialog extends StatefulWidget {
  const _StoreEditDialog({this.store});

  final Supermarket? store;

  @override
  State<_StoreEditDialog> createState() => _StoreEditDialogState();
}

class _StoreEditDialogState extends State<_StoreEditDialog> {
  late final TextEditingController _name;
  late int _color;

  @override
  void initState() {
    super.initState();
    _name = TextEditingController(text: widget.store?.name ?? '');
    _color = widget.store?.colorValue ?? kStoreColorPalette.first;
  }

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

  @override
  Widget build(BuildContext context) {
    return AlertDialog(
      title: Text(widget.store == null ? 'Add supermarket' : 'Edit supermarket'),
      content: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          TextField(
            controller: _name,
            textCapitalization: TextCapitalization.words,
            decoration: const InputDecoration(labelText: 'Name'),
            autofocus: widget.store == null,
          ),
          const SizedBox(height: 16),
          Align(
            alignment: Alignment.centerLeft,
            child: Text('Color', style: Theme.of(context).textTheme.titleMedium),
          ),
          const SizedBox(height: 8),
          Wrap(
            spacing: 8,
            runSpacing: 8,
            children: [
              for (final value in kStoreColorPalette)
                GestureDetector(
                  onTap: () => setState(() => _color = value),
                  child: Container(
                    width: 32,
                    height: 32,
                    decoration: BoxDecoration(
                      color: Color(value),
                      shape: BoxShape.circle,
                      border: Border.all(
                        color: _color == value
                            ? Theme.of(context).colorScheme.onSurface
                            : Colors.transparent,
                        width: 2,
                      ),
                    ),
                  ),
                ),
            ],
          ),
        ],
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('Cancel'),
        ),
        FilledButton(
          onPressed: () {
            final name = _name.text.trim();
            if (name.isEmpty) return;
            Navigator.pop(
              context,
              Supermarket(
                id: widget.store?.id,
                name: name,
                colorValue: _color,
                sortOrder: widget.store?.sortOrder ?? 0,
              ),
            );
          },
          child: const Text('Save'),
        ),
      ],
    );
  }
}