/// Dashboard of catalog, trips, lists, and this month's spend.
library;

import 'dart:io';

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

import 'models/app_overview.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 'widgets/profile_button.dart';
import 'widgets/settings_button.dart';
import 'widgets/store_tag.dart';

class HomeScreen extends StatefulWidget {
  const HomeScreen({
    super.key,
    required this.repository,
    required this.onOpenProducts,
    required this.onOpenLists,
    required this.onOpenShopLog,
    required this.onOpenAdd,
  });

  final ProductRepository repository;
  final VoidCallback onOpenProducts;
  final VoidCallback onOpenLists;
  final VoidCallback onOpenShopLog;
  final VoidCallback onOpenAdd;

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  AppOverview? _overview;
  List<Supermarket> _stores = const [];
  Object? _error;
  int _loadToken = 0;
  final ImagePicker _picker = ImagePicker();

  @override
  void initState() {
    super.initState();
    widget.repository.addListener(_load);
    _load();
  }

  @override
  void dispose() {
    widget.repository.removeListener(_load);
    super.dispose();
  }

  Future<void> _load() async {
    final token = ++_loadToken;
    try {
      final overview = await widget.repository.getOverview();
      final stores = await widget.repository.getSupermarkets();
      final lastTripStores = await widget.repository.getLastTripSupermarkets();
      if (!mounted || token != _loadToken) return;
      setState(() {
        _overview = overview;
        _stores = sortStoresByLastTrip(stores, lastTripStores);
        _error = null;
      });
    } catch (error) {
      if (!mounted || token != _loadToken) return;
      setState(() => _error = error);
    }
  }

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

  Future<void> _openBonusCard(Supermarket store) async {
    final path = store.bonusImagePath;
    if (path != null && path.isNotEmpty && File(path).existsSync()) {
      await _viewBonusCard(path);
      return;
    }
    await _pickBonusCard(store);
  }

  Future<void> _viewBonusCard(String path) async {
    await showDialog<void>(
      context: context,
      builder: (context) {
        return Dialog(
          insetPadding: const EdgeInsets.all(16),
          child: InteractiveViewer(
            child: Image.file(File(path), fit: BoxFit.contain),
          ),
        );
      },
    );
  }

  Future<void> _pickBonusCard(Supermarket store) async {
    final source = await showModalBottomSheet<ImageSource>(
      context: context,
      showDragHandle: true,
      builder: (context) {
        return SafeArea(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              ListTile(
                leading: const Icon(Icons.photo_camera_outlined),
                title: const Text('Take photo'),
                onTap: () => Navigator.pop(context, ImageSource.camera),
              ),
              ListTile(
                leading: const Icon(Icons.photo_library_outlined),
                title: const Text('Pick from gallery'),
                onTap: () => Navigator.pop(context, ImageSource.gallery),
              ),
            ],
          ),
        );
      },
    );
    if (source == null || store.id == null) return;
    final file = await _picker.pickImage(source: source, imageQuality: 85);
    if (file == null) return;
    await widget.repository.setSupermarketBonusCard(store.id!, file.path);
    if (mounted) _load();
  }

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

    return Scaffold(
      appBar: AppBar(
        title: const Text('Home'),
        actions: const [ProfileButton(), SettingsButton()],
      ),
      body: _error != null && _overview == null
          ? Center(
              child: Text(
                'Could not load an overview.',
                style: theme.textTheme.bodyLarge,
              ),
            )
          : _overview == null
          ? const Center(child: CircularProgressIndicator())
          : _HomeBody(
              overview: _overview!,
              stores: _stores,
              onOpenProducts: widget.onOpenProducts,
              onOpenLists: widget.onOpenLists,
              onOpenShopLog: widget.onOpenShopLog,
              onOpenAdd: widget.onOpenAdd,
              onOpenShop: _openShop,
              onOpenBonusCard: _openBonusCard,
            ),
    );
  }
}

class _HomeBody extends StatelessWidget {
  const _HomeBody({
    required this.overview,
    required this.stores,
    required this.onOpenProducts,
    required this.onOpenLists,
    required this.onOpenShopLog,
    required this.onOpenAdd,
    required this.onOpenShop,
    required this.onOpenBonusCard,
  });

  final AppOverview overview;
  final List<Supermarket> stores;
  final VoidCallback onOpenProducts;
  final VoidCallback onOpenLists;
  final VoidCallback onOpenShopLog;
  final VoidCallback onOpenAdd;
  final ValueChanged<Shop> onOpenShop;
  final ValueChanged<Supermarket> onOpenBonusCard;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final settingsStores =
        SettingsScope.maybeOf(context)?.supermarkets ?? stores;
    final empty =
        overview.productCount == 0 &&
        overview.tripCount == 0 &&
        overview.listCount == 0;

    return ListView(
      padding: const EdgeInsets.fromLTRB(16, 8, 16, 24),
      children: [
        Text('Overview', style: theme.textTheme.titleMedium),
        const SizedBox(height: 8),
        if (empty)
          Card(
            child: Padding(
              padding: const EdgeInsets.all(20),
              child: Column(
                children: [
                  Text(
                    'Nothing logged yet.',
                    style: theme.textTheme.titleMedium,
                  ),
                  const SizedBox(height: 8),
                  Text(
                    'Scan a receipt or add a trip to see products, lists, and spending here.',
                    textAlign: TextAlign.center,
                    style: theme.textTheme.bodyMedium,
                  ),
                  const SizedBox(height: 16),
                  FilledButton.icon(
                    onPressed: onOpenAdd,
                    icon: const Icon(Icons.add),
                    label: const Text('Add a trip'),
                  ),
                ],
              ),
            ),
          )
        else ...[
          Row(
            children: [
              Expanded(
                child: _StatCard(
                  icon: Icons.receipt_long_outlined,
                  label: formatMonthYear(DateTime.now()),
                  value: formatEuro(overview.monthTotal),
                  detail: overview.monthTripCount == 0
                      ? 'No trips yet'
                      : overview.monthTripCount == 1
                      ? '1 trip'
                      : '${overview.monthTripCount} trips',
                  onTap: onOpenShopLog,
                ),
              ),
              const SizedBox(width: 8),
              Expanded(
                child: _StatCard(
                  icon: Icons.inventory_2_outlined,
                  label: 'Products',
                  value: '${overview.productCount}',
                  detail: overview.favouriteCount == 0
                      ? 'No favourites'
                      : overview.favouriteCount == 1
                      ? '1 favourite'
                      : '${overview.favouriteCount} favourites',
                  onTap: onOpenProducts,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),
          _StatCard(
            icon: Icons.checklist_outlined,
            label: 'Shopping lists',
            value: '${overview.listCount}',
            detail: overview.listCount == 1 ? '1 list' : 'Open your lists',
            onTap: onOpenLists,
          ),
        ],
        if (stores.isNotEmpty) ...[
          const SizedBox(height: 24),
          Text('Bonus cards', style: theme.textTheme.titleMedium),
          const SizedBox(height: 8),
          SizedBox(
            height: 148,
            child: ListView.separated(
              key: ValueKey(
                stores.isEmpty ? 'bonus-empty' : 'bonus-${stores.first.name}',
              ),
              scrollDirection: Axis.horizontal,
              itemCount: stores.length,
              separatorBuilder: (_, _) => const SizedBox(width: 12),
              itemBuilder: (context, index) {
                final store = stores[index];
                return _BonusCardTile(
                  store: store,
                  stores: settingsStores,
                  onTap: () => onOpenBonusCard(store),
                );
              },
            ),
          ),
        ],
        if (overview.recentShops.isNotEmpty) ...[
          const SizedBox(height: 24),
          Text('Recent trips', style: theme.textTheme.titleMedium),
          const SizedBox(height: 8),
          for (final shop in overview.recentShops)
            Padding(
              padding: const EdgeInsets.only(bottom: 4),
              child: ListTile(
                contentPadding: const EdgeInsets.symmetric(horizontal: 8),
                title: shop.name == null || shop.name!.isEmpty
                    ? StoreTag(name: shop.supermarket, stores: settingsStores)
                    : Text(shop.name!),
                subtitle: Text(
                  [
                    formatDate(shop.shoppedAt),
                    formatEuro(shop.total),
                  ].join(' · '),
                ),
                trailing: const Icon(Icons.chevron_right),
                onTap: () => onOpenShop(shop),
              ),
            ),
        ],
      ],
    );
  }
}

class _BonusCardTile extends StatelessWidget {
  const _BonusCardTile({
    required this.store,
    required this.stores,
    required this.onTap,
  });

  final Supermarket store;
  final List<Supermarket> stores;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final scheme = theme.colorScheme;
    final path = store.bonusImagePath;
    final hasCard =
        path != null && path.isNotEmpty && File(path).existsSync();

    return SizedBox(
      width: 220,
      child: Card(
        clipBehavior: Clip.antiAlias,
        child: InkWell(
          onTap: onTap,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Expanded(
                child: !hasCard
                    ? ColoredBox(
                        color: store.color.withValues(alpha: 0.18),
                        child: Center(
                          child: Column(
                            mainAxisSize: MainAxisSize.min,
                            children: [
                              Icon(
                                Icons.card_membership_outlined,
                                color: store.color,
                                size: 32,
                              ),
                              const SizedBox(height: 8),
                              Text(
                                'Add bonus card',
                                style: theme.textTheme.bodySmall,
                              ),
                            ],
                          ),
                        ),
                      )
                    : Image.file(
                        File(path),
                        fit: BoxFit.cover,
                        width: double.infinity,
                      ),
              ),
              Padding(
                padding: const EdgeInsets.fromLTRB(12, 8, 12, 10),
                child: Row(
                  children: [
                    StoreTag(name: store.name, stores: stores, compact: true),
                    const Spacer(),
                    Icon(
                      hasCard
                          ? Icons.zoom_in
                          : Icons.camera_alt_outlined,
                      size: 16,
                      color: scheme.onSurfaceVariant,
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _StatCard extends StatelessWidget {
  const _StatCard({
    required this.icon,
    required this.label,
    required this.value,
    required this.detail,
    required this.onTap,
  });

  final IconData icon;
  final String label;
  final String value;
  final String detail;
  final VoidCallback onTap;

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

    return Card(
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(16),
        child: Padding(
          padding: const EdgeInsets.fromLTRB(16, 16, 16, 14),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Icon(icon, color: scheme.primary),
              const SizedBox(height: 12),
              Text(label, style: theme.textTheme.bodyMedium),
              const SizedBox(height: 4),
              Text(value, style: theme.textTheme.titleLarge),
              const SizedBox(height: 2),
              Text(detail, style: theme.textTheme.bodyMedium),
            ],
          ),
        ),
      ),
    );
  }
}