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

import '../../../common/theme/theme.dart';
import '../../../sample/shop_sample_data.dart';
import '../../components/field/field.dart';
import '../../router/app_router.gr.dart';
import 'shop_ui.dart';
import 'widgets/shop_category_grid.dart';
import 'widgets/shop_product_card.dart';
import 'widgets/shop_promo_banner.dart';

@RoutePage()
class ShopPage extends StatefulWidget {
  const ShopPage({super.key});

  @override
  State<ShopPage> createState() => _ShopPageState();
}

class _ShopPageState extends State<ShopPage> {
  static const double _rowCardWidth = 150;

  final _searchController = TextEditingController();
  final _bannerController = PageController(viewportFraction: 0.9);
  int _bannerIndex = 0;

  final List<ShopPromo> _promos = shopPromoSamples;

  /// Terlaris di atas.
  final List<ShopProduct> _products = shopSamples
    ..sort((a, b) => b.soldCount.compareTo(a.soldCount));

  @override
  void initState() {
    super.initState();
    _searchController.addListener(() => setState(() {}));
  }

  @override
  void dispose() {
    _searchController.dispose();
    _bannerController.dispose();
    super.dispose();
  }

  void _openProduct(ShopProduct product) =>
      context.router.push(ShopProductDetailRoute(product: product));

  void _openCategory({ShopCategory? category, bool promoOnly = false}) =>
      context.router.push(
        ShopCategoryRoute(category: category, promoOnly: promoOnly),
      );

  @override
  Widget build(BuildContext context) {
    final query = _searchController.text.trim().toLowerCase();

    return Scaffold(
      backgroundColor: AppColor.background,
      appBar: AppBar(title: const Text('EnakShop')),
      body: CustomScrollView(
        slivers: [
          SliverToBoxAdapter(
            child: Padding(
              padding: const EdgeInsets.only(top: 12),
              child: SearchTextField(
                hintText: 'Cari di EnakShop',
                prefixIcon: Icons.search,
                controller: _searchController,
              ),
            ),
          ),
          if (query.isNotEmpty)
            ..._buildSearchResults(query)
          else ...[
            SliverToBoxAdapter(child: _buildBanners()),
            const SliverToBoxAdapter(child: _SectionTitle(title: 'Kategori')),
            SliverToBoxAdapter(
              child: ShopCategoryGrid(
                onTap: (category) => _openCategory(category: category),
              ),
            ),
            SliverToBoxAdapter(
              child: _SectionTitle(
                title: 'Lagi Promo',
                onSeeAll: () => _openCategory(promoOnly: true),
              ),
            ),
            SliverToBoxAdapter(
              child: _buildProductRow(
                _products.where((p) => p.isDiscounted).toList(),
              ),
            ),
            const SliverToBoxAdapter(
              child: _SectionTitle(title: 'Rekomendasi'),
            ),
            _buildGrid(_products),
          ],
          const SliverToBoxAdapter(child: SizedBox(height: 24)),
        ],
      ),
    );
  }

  List<Widget> _buildSearchResults(String query) {
    final results = _products
        .where(
          (p) =>
              p.name.toLowerCase().contains(query) ||
              p.category.label.toLowerCase().contains(query),
        )
        .toList();

    if (results.isEmpty) {
      return [
        SliverFillRemaining(
          hasScrollBody: false,
          child: Padding(
            padding: const EdgeInsets.fromLTRB(32, 32, 32, 64),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                const Text('🔍', style: TextStyle(fontSize: 44)),
                const SizedBox(height: 16),
                Text(
                  'Produk tidak ditemukan',
                  style: AppStyle.lg.copyWith(fontWeight: FontWeight.w700),
                ),
                const SizedBox(height: 6),
                Text(
                  'Coba kata kunci lain, mis. "sambal" atau "kopi".',
                  textAlign: TextAlign.center,
                  style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
                ),
              ],
            ),
          ),
        ),
      ];
    }

    return [
      SliverToBoxAdapter(
        child: Padding(
          padding: const EdgeInsets.fromLTRB(16, 0, 16, 12),
          child: Text(
            '${results.length} produk ditemukan',
            style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
          ),
        ),
      ),
      _buildGrid(results),
    ];
  }

  Widget _buildBanners() {
    return Column(
      children: [
        SizedBox(
          // Ikut skala font sistem supaya teks banner tidak terpotong.
          height: MediaQuery.textScalerOf(context).scale(150),
          child: PageView.builder(
            controller: _bannerController,
            itemCount: _promos.length,
            onPageChanged: (index) => setState(() => _bannerIndex = index),
            itemBuilder: (context, index) {
              final promo = _promos[index];
              return Padding(
                padding: const EdgeInsets.symmetric(horizontal: 6),
                child: ShopPromoBanner(
                  promo: promo,
                  onTap: () => _openCategory(category: promo.category),
                ),
              );
            },
          ),
        ),
        const SizedBox(height: 10),
        Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: List.generate(_promos.length, (index) {
            final isActive = index == _bannerIndex;
            return AnimatedContainer(
              duration: const Duration(milliseconds: 200),
              margin: const EdgeInsets.symmetric(horizontal: 3),
              width: isActive ? 18 : 6,
              height: 6,
              decoration: BoxDecoration(
                color: isActive ? AppColor.primary : AppColor.border,
                borderRadius: BorderRadius.circular(3),
              ),
            );
          }),
        ),
      ],
    );
  }

  Widget _buildProductRow(List<ShopProduct> products) {
    return SizedBox(
      height: _rowCardWidth + shopCardInfoHeight(context),
      child: ListView.separated(
        scrollDirection: Axis.horizontal,
        padding: const EdgeInsets.symmetric(horizontal: 16),
        itemCount: products.length,
        separatorBuilder: (_, _) => const SizedBox(width: 12),
        itemBuilder: (context, index) {
          final product = products[index];
          return SizedBox(
            width: _rowCardWidth,
            child: ShopProductCard(
              product: product,
              onTap: () => _openProduct(product),
            ),
          );
        },
      ),
    );
  }

  Widget _buildGrid(List<ShopProduct> products) {
    return SliverPadding(
      padding: const EdgeInsets.symmetric(horizontal: 16),
      sliver: SliverGrid.builder(
        gridDelegate: shopProductGridDelegate(context),
        itemCount: products.length,
        itemBuilder: (context, index) {
          final product = products[index];
          return ShopProductCard(
            product: product,
            onTap: () => _openProduct(product),
          );
        },
      ),
    );
  }
}

class _SectionTitle extends StatelessWidget {
  const _SectionTitle({required this.title, this.onSeeAll});

  final String title;
  final VoidCallback? onSeeAll;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.fromLTRB(16, 20, onSeeAll == null ? 16 : 4, 10),
      child: Row(
        children: [
          Expanded(
            child: Text(
              title,
              style: AppStyle.lg.copyWith(fontWeight: FontWeight.w700),
            ),
          ),
          if (onSeeAll != null)
            TextButton(
              onPressed: onSeeAll,
              child: Text(
                'Lihat semua',
                style: AppStyle.sm.copyWith(
                  color: AppColor.primary,
                  fontWeight: FontWeight.w700,
                ),
              ),
            ),
        ],
      ),
    );
  }
}