/// Log of saved shopping trips, with a monthly heatmap and product search.
library;

import 'package:flutter/material.dart';

import 'models/shop.dart';
import 'models/supermarket.dart';
import 'services/app_settings.dart';
import 'services/product_repository.dart';
import 'shop_detail_screen.dart';
import 'utils/dates.dart';
import 'utils/money.dart';
import 'utils/shop_calendar.dart';
import 'utils/shop_log_filter.dart';
import 'widgets/confirm_dialog.dart';
import 'widgets/settings_button.dart';
import 'widgets/shop_heatmap.dart';
import 'widgets/store_tag.dart';
import 'widgets/tag_editor.dart';

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

  final ProductRepository repository;

  @override
  State<ShopLogScreen> createState() => _ShopLogScreenState();
}

class _ShopLogScreenState extends State<ShopLogScreen> {
  late Future<({List<Shop> shops, Map<int, List<String>> productNames})>
  _future;
  final _search = TextEditingController();
  bool _editing = false;
  bool _searching = false;
  DateTime _month = monthStart(DateTime.now());
  DateTime? _selectedDay;
  String? _tagFilter;

  @override
  void initState() {
    super.initState();
    _future = _load();
    _search.addListener(() => setState(() {}));
  }

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

  Future<({List<Shop> shops, Map<int, List<String>> productNames})>
  _load() async {
    final shops = await widget.repository.getShops();
    final productNames = await widget.repository.getShopItemNamesByShop();
    return (shops: shops, productNames: productNames);
  }

  void _reload() {
    setState(() => _future = _load());
  }

  Future<void> _openShop(Shop shop) async {
    await Navigator.of(context).push<void>(
      MaterialPageRoute(
        builder: (_) =>
            ShopDetailScreen(repository: widget.repository, shopId: shop.id),
      ),
    );
    if (mounted) _reload();
  }

  Future<void> _removeShop(Shop shop) async {
    final confirmed = await confirmAction(
      context,
      title: 'Remove shopping trip?',
      message: 'This trip will be removed from the shop log. Products from this trip stay in your catalog.',
    );
    if (!confirmed || !mounted) return;
    await widget.repository.deleteShop(shop.id);
    if (mounted) _reload();
  }

  void _selectDay(DateTime? day) {
    setState(() => _selectedDay = day);
  }

  void _goMonth(int delta) {
    final next = addMonths(_month, delta);
    final current = monthStart(DateTime.now());
    if (delta > 0 && !next.isBefore(current) && next != current) return;
    setState(() {
      _month = next.isAfter(current) ? current : next;
      _selectedDay = null;
    });
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final stores = SettingsScope.maybeOf(context)?.supermarkets ?? const [];
    final nowMonth = monthStart(DateTime.now());

    return Scaffold(
      appBar: AppBar(
        title: _searching
            ? TextField(
                controller: _search,
                autofocus: true,
                decoration: const InputDecoration(
                  hintText: 'Search products in trips',
                  border: InputBorder.none,
                  enabledBorder: InputBorder.none,
                  focusedBorder: InputBorder.none,
                  filled: false,
                ),
              )
            : const Text('Shop log'),
        actions: [
          IconButton(
            tooltip: _searching ? 'Close search' : 'Search products',
            onPressed: () {
              setState(() {
                _searching = !_searching;
                if (!_searching) _search.clear();
              });
            },
            icon: Icon(_searching ? Icons.close : Icons.search),
          ),
          IconButton(
            tooltip: _editing ? 'Done' : 'Edit',
            onPressed: () => setState(() => _editing = !_editing),
            icon: Icon(_editing ? Icons.check : Icons.edit_outlined),
          ),
          const SettingsButton(),
        ],
      ),
      body: FutureBuilder(
        future: _future,
        builder: (context, snapshot) {
          if (snapshot.hasError) {
            return Center(
              child: Text(
                'Could not load the shop log.',
                style: theme.textTheme.bodyLarge,
              ),
            );
          }
          if (!snapshot.hasData) {
            return const Center(child: CircularProgressIndicator());
          }

          final shops = snapshot.data!.shops;
          final productNames = snapshot.data!.productNames;
          final counts = tripCountsByDay([
            for (final shop in shops)
              if (isSameMonth(shop.shoppedAt, _month)) shop.shoppedAt,
          ]);
          final monthShops = [
            for (final shop in shops)
              if (isSameMonth(shop.shoppedAt, _month)) shop,
          ];
          final monthTotal = monthShops.fold<double>(
            0,
            (sum, shop) => sum + shop.total,
          );
          final visible = filterShops(
            shops: shops,
            productNames: productNames,
            selectedDay: _selectedDay,
            tag: _tagFilter,
            query: _search.text,
          );

          return ListView(
            padding: const EdgeInsets.only(bottom: 16),
            children: [
              ShopHeatmap(
                month: _month,
                counts: counts,
                monthTotal: monthTotal,
                monthTripCount: monthShops.length,
                canGoForward: _month.isBefore(nowMonth),
                selectedDay: _selectedDay,
                onPreviousMonth: () => _goMonth(-1),
                onNextMonth: () => _goMonth(1),
                onSelectDay: _selectDay,
              ),
              if (_selectedDay != null || _tagFilter != null)
                Padding(
                  padding: const EdgeInsets.fromLTRB(16, 0, 16, 8),
                  child: Wrap(
                    spacing: 8,
                    runSpacing: 8,
                    children: [
                      if (_selectedDay != null)
                        InputChip(
                          label: Text(formatDate(_selectedDay!)),
                          onDeleted: () => _selectDay(null),
                        ),
                      if (_tagFilter != null)
                        InputChip(
                          label: Text(_tagFilter!),
                          onDeleted: () => setState(() => _tagFilter = null),
                        ),
                    ],
                  ),
                ),
              if (shops.isEmpty)
                Padding(
                  padding: const EdgeInsets.fromLTRB(24, 24, 24, 8),
                  child: Text(
                    'Scan a receipt or enter a trip to log it.',
                    textAlign: TextAlign.center,
                    style: theme.textTheme.bodyLarge,
                  ),
                )
              else if (visible.isEmpty)
                Padding(
                  padding: const EdgeInsets.fromLTRB(24, 16, 24, 8),
                  child: Text(
                    _search.text.trim().isNotEmpty
                        ? 'No trips contain that product.'
                        : 'No trips match this filter.',
                    textAlign: TextAlign.center,
                    style: theme.textTheme.bodyLarge,
                  ),
                )
              else
                for (final shop in visible)
                  Padding(
                    padding: const EdgeInsets.fromLTRB(8, 0, 8, 4),
                    child: _ShopLogTile(
                      shop: shop,
                      stores: stores,
                      editing: _editing,
                      selectedTag: _tagFilter,
                      onOpen: () => _openShop(shop),
                      onRemove: () => _removeShop(shop),
                      onTagTap: (tag) {
                        setState(() {
                          _tagFilter =
                              _tagFilter?.toLowerCase() == tag.toLowerCase()
                              ? null
                              : tag;
                        });
                      },
                    ),
                  ),
            ],
          );
        },
      ),
    );
  }
}

class _ShopLogTile extends StatelessWidget {
  const _ShopLogTile({
    required this.shop,
    required this.stores,
    required this.editing,
    required this.onOpen,
    required this.onRemove,
    required this.onTagTap,
    this.selectedTag,
  });

  final Shop shop;
  final List<Supermarket> stores;
  final bool editing;
  final VoidCallback onOpen;
  final VoidCallback onRemove;
  final ValueChanged<String> onTagTap;
  final String? selectedTag;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final count = shop.itemCount;
    final hasName = shop.name != null && shop.name!.isNotEmpty;
    final meta = [
      formatDate(shop.shoppedAt),
      count == 1 ? '1 product' : '$count products',
    ].join(' · ');

    return Material(
      color: Colors.transparent,
      child: InkWell(
        onTap: editing ? null : onOpen,
        borderRadius: BorderRadius.circular(12),
        child: Padding(
          padding: const EdgeInsets.fromLTRB(16, 10, 8, 10),
          child: Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    if (hasName)
                      Text(shop.name!, style: theme.textTheme.titleMedium)
                    else
                      StoreTag(name: shop.supermarket, stores: stores),
                    const SizedBox(height: 4),
                    if (hasName) ...[
                      StoreTag(
                        name: shop.supermarket,
                        stores: stores,
                        compact: true,
                      ),
                      const SizedBox(height: 4),
                    ],
                    Text(meta, style: theme.textTheme.bodyMedium),
                    if (shop.tags.isNotEmpty) ...[
                      const SizedBox(height: 8),
                      TagChips(
                        tags: shop.tags,
                        compact: true,
                        selected: selectedTag,
                        onTap: onTagTap,
                      ),
                    ],
                  ],
                ),
              ),
              const SizedBox(width: 8),
              editing
                  ? IconButton(
                      tooltip: 'Remove',
                      onPressed: onRemove,
                      icon: const Icon(Icons.delete_outline),
                    )
                  : Padding(
                      padding: const EdgeInsets.only(top: 8, right: 8),
                      child: Text(
                        formatEuro(shop.total),
                        style: theme.textTheme.titleMedium,
                      ),
                    ),
            ],
          ),
        ),
      ),
    );
  }
}