import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:flutter_spinkit/flutter_spinkit.dart';
import 'package:shimmer/shimmer.dart';

import '../../../../application/wallet/wallet_history_loader/wallet_history_loader_bloc.dart';
import '../../../../common/theme/theme.dart';
import '../../../../domain/wallet/wallet.dart';
import '../wallet_ui.dart';
import 'wallet_transaction_tile.dart';

/// Riwayat dari [WalletHistoryLoaderBloc] terdekat, sebagai sliver di dalam
/// [CustomScrollView]. Filter tipe/mata uang diatur oleh halaman pemakainya.
class WalletHistorySection extends StatefulWidget {
  const WalletHistorySection({
    super.key,
    required this.title,
    required this.emptyIcon,
    required this.emptyTitle,
    required this.emptySubtitle,
  });

  final String title;
  final IconData emptyIcon;
  final String emptyTitle;
  final String Function(WalletCurrency currency) emptySubtitle;

  @override
  State<WalletHistorySection> createState() => _WalletHistorySectionState();
}

class _WalletHistorySectionState extends State<WalletHistorySection> {
  static const _radius = Radius.circular(AppValue.borderRadius);

  /// Item yang sudah pernah dianimasikan, supaya tidak berkedip ulang saat
  /// di-scroll keluar lalu masuk lagi.
  final Set<String> _animatedIds = {};

  /// Sebelum request pertama selesai, tampilkan skeleton, bukan "kosong".
  bool _hasFetched = false;

  @override
  Widget build(BuildContext context) {
    return BlocConsumer<WalletHistoryLoaderBloc, WalletHistoryLoaderState>(
      // Awal fetch halaman pertama (ganti tab / refresh) mengosongkan list,
      // jadi item yang datang berikutnya boleh dianimasikan lagi.
      listenWhen: (p, c) => p.isFetching != c.isFetching,
      listener: (context, state) {
        if (state.isFetching) {
          _animatedIds.clear();
        } else {
          _hasFetched = true;
        }
      },
      builder: (context, state) {
        final showList = state.items.isNotEmpty;

        return SliverMainAxisGroup(
          slivers: [
            SliverToBoxAdapter(child: _buildHeader(state)),
            if (showList)
              SliverList.builder(
                itemCount: state.items.length + (state.hasMore ? 1 : 0),
                itemBuilder: (context, index) {
                  if (index >= state.items.length) return _buildLoadingMore();
                  return _buildItem(state, index);
                },
              )
            else
              SliverToBoxAdapter(
                child: AnimatedSwitcher(
                  duration: const Duration(milliseconds: 250),
                  child: _buildPlaceholder(state),
                ),
              ),
          ],
        );
      },
    );
  }

  Widget _buildHeader(WalletHistoryLoaderState state) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(4, 0, 4, 12),
      child: Row(
        children: [
          Expanded(
            child: Text(
              widget.title,
              style: AppStyle.lg.copyWith(fontWeight: FontWeight.w700),
            ),
          ),
          AnimatedSwitcher(
            duration: const Duration(milliseconds: 200),
            child: Text(
              state.currency.label,
              key: ValueKey(state.currency),
              style: AppStyle.sm.copyWith(
                color: AppColor.textSecondary,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildItem(WalletHistoryLoaderState state, int index) {
    final tx = state.items[index];
    final isFirst = index == 0;
    final isLast = index == state.items.length - 1 && !state.hasMore;
    final animate = _animatedIds.add(tx.id);

    final tile = Container(
      decoration: BoxDecoration(
        color: AppColor.white,
        borderRadius: BorderRadius.vertical(
          top: isFirst ? _radius : Radius.zero,
          bottom: isLast ? _radius : Radius.zero,
        ),
      ),
      child: Column(
        children: [
          if (!isFirst)
            const Divider(
              height: 1,
              indent: 68,
              endIndent: 16,
              color: AppColor.borderLight,
            ),
          WalletTransactionTile(transaction: tx),
        ],
      ),
    );

    if (!animate) return tile;
    return _FadeSlideIn(
      key: ValueKey(tx.id),
      // Hanya item awal yang bertahap; item hasil scroll langsung muncul.
      delay: Duration(milliseconds: index < 8 ? index * 50 : 0),
      child: tile,
    );
  }

  Widget _buildLoadingMore() {
    return Container(
      padding: const EdgeInsets.symmetric(vertical: 16),
      decoration: const BoxDecoration(
        color: AppColor.white,
        borderRadius: BorderRadius.vertical(bottom: _radius),
      ),
      child: const Center(
        child: SpinKitFadingCircle(color: AppColor.primary, size: 24),
      ),
    );
  }

  Widget _buildPlaceholder(WalletHistoryLoaderState state) {
    if (state.isFetching || !_hasFetched) {
      return const _HistorySkeleton(key: ValueKey('skeleton'));
    }

    final failure = state.failureOption.toNullable();
    if (failure != null) {
      return _MessageCard(
        key: const ValueKey('error'),
        icon: Icons.wifi_off_rounded,
        title: walletFailureMessage(failure),
        action: TextButton(
          onPressed: () => context.read<WalletHistoryLoaderBloc>().add(
            const WalletHistoryLoaderEvent.refreshed(),
          ),
          child: Text(
            'Coba lagi',
            style: AppStyle.md.copyWith(
              color: AppColor.primary,
              fontWeight: FontWeight.w700,
            ),
          ),
        ),
      );
    }

    return _MessageCard(
      key: ValueKey('empty-${state.currency}'),
      icon: widget.emptyIcon,
      title: widget.emptyTitle,
      subtitle: widget.emptySubtitle(state.currency),
    );
  }
}

class _MessageCard extends StatelessWidget {
  const _MessageCard({
    super.key,
    required this.icon,
    required this.title,
    this.subtitle,
    this.action,
  });

  final IconData icon;
  final String title;
  final String? subtitle;
  final Widget? action;

  @override
  Widget build(BuildContext context) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.symmetric(horizontal: 24, vertical: 28),
      decoration: BoxDecoration(
        color: AppColor.white,
        borderRadius: BorderRadius.circular(AppValue.borderRadius),
      ),
      child: Column(
        children: [
          Container(
            width: 52,
            height: 52,
            decoration: BoxDecoration(
              color: AppColor.primaryWithOpacity(0.08),
              shape: BoxShape.circle,
            ),
            child: Icon(icon, color: AppColor.primary, size: 26),
          ),
          const SizedBox(height: 12),
          Text(
            title,
            textAlign: TextAlign.center,
            style: AppStyle.md.copyWith(fontWeight: FontWeight.w700),
          ),
          if (subtitle != null) ...[
            const SizedBox(height: 4),
            Text(
              subtitle!,
              textAlign: TextAlign.center,
              style: AppStyle.sm.copyWith(color: AppColor.textSecondary),
            ),
          ],
          if (action != null) ...[const SizedBox(height: 4), action!],
        ],
      ),
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    Widget bar(double width, double height) => Container(
      width: width,
      height: height,
      decoration: BoxDecoration(
        color: AppColor.white,
        borderRadius: BorderRadius.circular(4),
      ),
    );

    return Container(
      decoration: BoxDecoration(
        color: AppColor.white,
        borderRadius: BorderRadius.circular(AppValue.borderRadius),
      ),
      child: Shimmer.fromColors(
        baseColor: AppColor.borderLight,
        highlightColor: AppColor.white,
        child: Column(
          children: List.generate(
            3,
            (_) => Padding(
              padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
              child: Row(
                children: [
                  Container(
                    width: 40,
                    height: 40,
                    decoration: const BoxDecoration(
                      color: AppColor.white,
                      shape: BoxShape.circle,
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        bar(120, 12),
                        const SizedBox(height: 8),
                        bar(80, 10),
                      ],
                    ),
                  ),
                  bar(56, 14),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }
}

/// Fade + geser naik sekali saat pertama kali muncul.
class _FadeSlideIn extends StatefulWidget {
  const _FadeSlideIn({
    super.key,
    required this.child,
    this.delay = Duration.zero,
  });

  final Widget child;
  final Duration delay;

  @override
  State<_FadeSlideIn> createState() => _FadeSlideInState();
}

class _FadeSlideInState extends State<_FadeSlideIn>
    with SingleTickerProviderStateMixin {
  late final AnimationController _controller = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 350),
  );
  late final Animation<double> _curve = CurvedAnimation(
    parent: _controller,
    curve: Curves.easeOutCubic,
  );

  @override
  void initState() {
    super.initState();
    Future.delayed(widget.delay, () {
      if (mounted) _controller.forward();
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return FadeTransition(
      opacity: _curve,
      child: SlideTransition(
        position: Tween(
          begin: const Offset(0, 0.15),
          end: Offset.zero,
        ).animate(_curve),
        child: widget.child,
      ),
    );
  }
}