import 'package:flutter/material.dart';
import '../../../../app/theme/app_colors.dart';
import '../../../../app/theme/app_typography.dart';
import '../../../../app/theme/app_spacing.dart';
import '../../../../shared/widgets/coupon_card.dart';
import '../../../ai_agent/presentation/widgets/ai_fab.dart';
import '../widgets/receive_coupon_sheet.dart';
import '../../../../app/i18n/app_localizations.dart';
import '../../../../core/services/coupon_service.dart';
import '../../data/models/coupon_model.dart';
import '../../data/models/holdings_summary_model.dart';

/// 首页 - 轻量持仓卡 + 分类网格 + AI推荐 + 精选券
///
/// Tab导航：首页/交易/消息/我的
class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  final CouponApiService _couponService = CouponApiService();

  List<CouponModel> _featuredCoupons = [];
  HoldingsSummaryModel? _holdingsSummary;
  bool _isLoading = true;
  String? _error;

  @override
  void initState() {
    super.initState();
    _loadData();
  }

  Future<void> _loadData() async {
    setState(() {
      _isLoading = true;
      _error = null;
    });

    try {
      final results = await Future.wait([
        _couponService.getFeaturedCoupons(limit: 10),
        _couponService.getHoldingsSummary(),
      ]);

      if (mounted) {
        setState(() {
          _featuredCoupons = results[0] as List<CouponModel>;
          _holdingsSummary = results[1] as HoldingsSummaryModel;
          _isLoading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _error = e.toString();
          _isLoading = false;
        });
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: [
          RefreshIndicator(
            onRefresh: _loadData,
            child: CustomScrollView(
              slivers: [
                // Floating App Bar
                SliverAppBar(
                  floating: true,
                  pinned: false,
                  automaticallyImplyLeading: false,
                  backgroundColor: AppColors.background,
                  elevation: 0,
                  toolbarHeight: 60,
                  title: _buildSearchBar(context),
                  actions: [
                    IconButton(
                      icon: const Icon(Icons.qr_code_scanner_rounded, size: 24),
                      onPressed: () {},
                      color: AppColors.textPrimary,
                    ),
                  ],
                ),

                // Lightweight Position Card (持仓)
                SliverToBoxAdapter(child: _buildWalletCard(context)),

                // Category Grid (8 items, 4x2)
                SliverToBoxAdapter(child: _buildCategoryGrid(context)),

                // AI Smart Suggestions
                SliverToBoxAdapter(child: _buildAiSuggestions(context)),

                // Section: Featured Coupons
                SliverToBoxAdapter(
                  child: Padding(
                    padding: const EdgeInsets.fromLTRB(20, 24, 20, 12),
                    child: Row(
                      mainAxisAlignment: MainAxisAlignment.spaceBetween,
                      children: [
                        Text(context.t('home.featuredCoupons'), style: AppTypography.h2),
                        GestureDetector(
                          onTap: () {},
                          child: Text(context.t('home.viewAllCoupons'), style: AppTypography.labelSmall.copyWith(
                            color: AppColors.primary,
                          )),
                        ),
                      ],
                    ),
                  ),
                ),

                // Coupon List
                if (_isLoading)
                  SliverPadding(
                    padding: AppSpacing.pagePadding,
                    sliver: SliverList(
                      delegate: SliverChildBuilderDelegate(
                        (context, index) => Padding(
                          padding: const EdgeInsets.only(bottom: 12),
                          child: _buildSkeletonCard(),
                        ),
                        childCount: 3,
                      ),
                    ),
                  )
                else if (_error != null)
                  SliverToBoxAdapter(
                    child: Padding(
                      padding: const EdgeInsets.all(20),
                      child: Column(
                        children: [
                          Icon(Icons.cloud_off_rounded, size: 48, color: AppColors.textTertiary),
                          const SizedBox(height: 12),
                          Text(
                            context.t('home.loadFailed'),
                            style: AppTypography.bodyMedium.copyWith(color: AppColors.textSecondary),
                          ),
                          const SizedBox(height: 12),
                          TextButton(
                            onPressed: _loadData,
                            child: Text(context.t('home.retry')),
                          ),
                        ],
                      ),
                    ),
                  )
                else if (_featuredCoupons.isEmpty)
                  SliverToBoxAdapter(
                    child: Padding(
                      padding: const EdgeInsets.all(40),
                      child: Center(
                        child: Text(
                          context.t('home.noCoupons'),
                          style: AppTypography.bodyMedium.copyWith(color: AppColors.textTertiary),
                        ),
                      ),
                    ),
                  )
                else
                  SliverPadding(
                    padding: AppSpacing.pagePadding,
                    sliver: SliverList(
                      delegate: SliverChildBuilderDelegate(
                        (context, index) {
                          final coupon = _featuredCoupons[index];
                          return Padding(
                            padding: const EdgeInsets.only(bottom: 12),
                            child: CouponCard(
                              brandName: coupon.brandName ?? '',
                              couponName: coupon.name,
                              faceValue: coupon.faceValue,
                              currentPrice: coupon.currentPrice,
                              creditRating: coupon.creditRating ?? '',
                              expiryDate: coupon.expiryDate,
                              onTap: () {
                                Navigator.pushNamed(context, '/coupon/detail', arguments: coupon.id);
                              },
                            ),
                          );
                        },
                        childCount: _featuredCoupons.length,
                      ),
                    ),
                  ),

                const SliverPadding(padding: EdgeInsets.only(bottom: 100)),
              ],
            ),
          ),

          // AI FAB
          Positioned(
            right: 20,
            bottom: 100,
            child: AiFab(
              unreadCount: 3,
              onTap: () {
                Navigator.pushNamed(context, '/ai-chat');
              },
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildSkeletonCard() {
    return Container(
      height: 100,
      decoration: BoxDecoration(
        color: AppColors.gray50,
        borderRadius: AppSpacing.borderRadiusMd,
      ),
      child: const Center(
        child: SizedBox(
          width: 24,
          height: 24,
          child: CircularProgressIndicator(strokeWidth: 2),
        ),
      ),
    );
  }

  Widget _buildSearchBar(BuildContext context) {
    return GestureDetector(
      onTap: () {
        Navigator.pushNamed(context, '/search');
      },
      child: Container(
        height: 40,
        decoration: BoxDecoration(
          color: AppColors.gray50,
          borderRadius: AppSpacing.borderRadiusFull,
          border: Border.all(color: AppColors.borderLight),
        ),
        child: Row(
          children: [
            const SizedBox(width: 14),
            const Icon(Icons.search_rounded, size: 20, color: AppColors.textTertiary),
            const SizedBox(width: 8),
            Expanded(
              child: Text(
                context.t('home.searchHint'),
                style: AppTypography.bodyMedium.copyWith(color: AppColors.textTertiary),
                overflow: TextOverflow.ellipsis,
              ),
            ),
          ],
        ),
      ),
    );
  }

  // ============================================================
  // Lightweight Position Card (持仓卡片)
  // 点击非快捷入口区域打开完整持仓页面
  // ============================================================
  Widget _buildWalletCard(BuildContext context) {
    final count = _holdingsSummary?.count ?? 0;
    final totalValue = _holdingsSummary?.totalFaceValue ?? 0;

    return GestureDetector(
      onTap: () => Navigator.pushNamed(context, '/wallet/coupons'),
      child: Container(
        margin: const EdgeInsets.fromLTRB(20, 8, 20, 0),
        padding: const EdgeInsets.all(16),
        decoration: BoxDecoration(
          gradient: AppColors.cardGradient,
          borderRadius: AppSpacing.borderRadiusLg,
          boxShadow: AppSpacing.shadowPrimary,
        ),
        child: Column(
          children: [
            // Top row: wallet info + receive button
            Row(
              children: [
                const Icon(Icons.inventory_2_rounded,
                    size: 20, color: Colors.white),
                const SizedBox(width: 8),
                Text(context.t('home.position'),
                    style: AppTypography.labelMedium.copyWith(color: Colors.white)),
                const Spacer(),
                // Summary
                Text('${context.t('home.hold')} ',
                    style: AppTypography.bodySmall.copyWith(
                      color: Colors.white.withValues(alpha: 0.7),
                    )),
                Text('$count',
                    style: AppTypography.h3.copyWith(
                      color: Colors.white,
                      fontWeight: FontWeight.w700,
                    )),
                Text(' ${context.t('home.couponUnit')}  ${context.t('home.totalValue')} ',
                    style: AppTypography.bodySmall.copyWith(
                      color: Colors.white.withValues(alpha: 0.7),
                    )),
                Text('\$${totalValue.toStringAsFixed(0)}',
                    style: AppTypography.h3.copyWith(
                      color: Colors.white,
                      fontWeight: FontWeight.w700,
                    )),
                const SizedBox(width: 4),
                Icon(Icons.chevron_right_rounded,
                    size: 18, color: Colors.white.withValues(alpha: 0.7)),
              ],
            ),

            const SizedBox(height: 14),

            // Quick action entries
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceAround,
              children: [
                _buildQuickAction(context, Icons.qr_code_rounded, context.t('home.receive'), () {
                  showModalBottomSheet(
                    context: context,
                    isScrollControlled: true,
                    backgroundColor: Colors.transparent,
                    builder: (_) => const ReceiveCouponSheet(),
                  );
                }),
                _buildQuickAction(context, Icons.card_giftcard_rounded, context.t('home.transfer'), () {
                  Navigator.pushNamed(context, '/transfer');
                }),
                _buildQuickAction(context, Icons.sell_rounded, context.t('home.sell'), () {
                  Navigator.pushNamed(context, '/sell');
                }),
                _buildQuickAction(context, Icons.check_circle_outline_rounded, context.t('home.redeem'), () {
                  Navigator.pushNamed(context, '/redeem');
                }),
              ],
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildQuickAction(
      BuildContext context, IconData icon, String label, VoidCallback onTap) {
    return GestureDetector(
      onTap: onTap,
      behavior: HitTestBehavior.opaque,
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          Container(
            width: 40,
            height: 40,
            decoration: BoxDecoration(
              color: Colors.white.withValues(alpha: 0.15),
              borderRadius: AppSpacing.borderRadiusMd,
            ),
            child: Icon(icon, size: 20, color: Colors.white),
          ),
          const SizedBox(height: 6),
          Text(
            label,
            style: AppTypography.caption.copyWith(
              color: Colors.white.withValues(alpha: 0.9),
              fontWeight: FontWeight.w500,
            ),
          ),
        ],
      ),
    );
  }

  // ============================================================
  // Category Grid (8 items, 4x2, A+C savings-focused)
  // ============================================================
  Widget _buildCategoryGrid(BuildContext context) {
    final categories = [
      (context.t('home.flashSale'), Icons.flash_on_rounded, AppColors.error),
      (context.t('home.newRelease'), Icons.fiber_new_rounded, AppColors.primary),
      (context.t('home.discountRank'), Icons.trending_up_rounded, AppColors.couponEntertainment),
      (context.t('home.expiringSoon'), Icons.timer_rounded, AppColors.warning),
      (context.t('home.priceCompare'), Icons.compare_arrows_rounded, AppColors.couponShopping),
      (context.t('home.resaleMarket'), Icons.swap_horiz_rounded, AppColors.info),
      (context.t('home.hotTrades'), Icons.local_fire_department_rounded, AppColors.couponDining),
      (context.t('home.viewAll'), Icons.grid_view_rounded, AppColors.textSecondary),
    ];

    return Padding(
      padding: const EdgeInsets.fromLTRB(20, 20, 20, 0),
      child: GridView.builder(
        shrinkWrap: true,
        physics: const NeverScrollableScrollPhysics(),
        gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 4,
          mainAxisSpacing: 4,
          crossAxisSpacing: 4,
          childAspectRatio: 0.9,
        ),
        itemCount: categories.length,
        itemBuilder: (context, index) {
          final (name, icon, color) = categories[index];
          return GestureDetector(
            onTap: () {},
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                Container(
                  width: 44,
                  height: 44,
                  decoration: BoxDecoration(
                    color: color.withValues(alpha: 0.1),
                    borderRadius: AppSpacing.borderRadiusMd,
                  ),
                  child: Icon(icon, color: color, size: 22),
                ),
                const SizedBox(height: 6),
                Text(name, style: AppTypography.caption.copyWith(
                  color: AppColors.textPrimary,
                  fontWeight: FontWeight.w500,
                )),
              ],
            ),
          );
        },
      ),
    );
  }

  Widget _buildAiSuggestions(BuildContext context) {
    return Container(
      margin: const EdgeInsets.fromLTRB(20, 16, 20, 0),
      padding: const EdgeInsets.all(14),
      decoration: BoxDecoration(
        color: AppColors.primarySurface,
        borderRadius: AppSpacing.borderRadiusMd,
        border: Border.all(color: AppColors.primary.withValues(alpha: 0.15)),
      ),
      child: Row(
        children: [
          Container(
            width: 32,
            height: 32,
            decoration: BoxDecoration(
              gradient: AppColors.primaryGradient,
              borderRadius: AppSpacing.borderRadiusSm,
            ),
            child: const Icon(Icons.auto_awesome_rounded, color: Colors.white, size: 16),
          ),
          const SizedBox(width: 10),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(context.t('home.aiRecommend'), style: AppTypography.labelSmall.copyWith(
                  color: AppColors.primary,
                )),
                const SizedBox(height: 2),
                Text(
                  context.t('home.aiRecommendDesc'),
                  style: AppTypography.bodySmall,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                ),
              ],
            ),
          ),
          const Icon(Icons.chevron_right_rounded, color: AppColors.primary, size: 20),
        ],
      ),
    );
  }
}