import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:share_plus/share_plus.dart';
import 'package:url_launcher/url_launcher.dart';

import '../widgets/shared/mini_header_bar.dart';
import '../../shared/widgets/core_card.dart';
import '../../shared/widgets/mini_avatar.dart';
import '../../shared/widgets/action_row.dart';
import '../../shared/widgets/dynamic_fab.dart';
import '../../shared/widgets/core_shimmer.dart';
import '../../shared/widgets/info_badge.dart';
import '../../shared/design_system/tokens/app_typography.dart';
import '../../shared/design_system/tokens/app_colors.dart';

import '../../core/di/injection.dart';
import '../../features/feed/presentation/bloc/unified_feed_bloc.dart';
import '../../features/feed/presentation/bloc/unified_feed_event.dart';
import '../../features/feed/presentation/bloc/unified_feed_state.dart';
import '../../features/feed/domain/entities/feed_item.dart';
import '../../features/solidarity/presentation/pages/demandes_aide_page_wrapper.dart';

/// UnionFlow Mobile - Flux d'Actualité Unifié (Mode DRY)
/// N'affiche que des CoreCard dynamiques en écoutant UnifiedFeedBloc.
class UnifiedFeedPage extends StatelessWidget {
  const UnifiedFeedPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (_) => getIt<UnifiedFeedBloc>()..add(const LoadFeedRequested()),
      child: const _UnifiedFeedView(),
    );
  }
}

class _UnifiedFeedView extends StatefulWidget {
  const _UnifiedFeedView();

  @override
  State<_UnifiedFeedView> createState() => _UnifiedFeedViewState();
}

class _UnifiedFeedViewState extends State<_UnifiedFeedView> {
  final ScrollController _scrollController = ScrollController();

  @override
  void initState() {
    super.initState();
    _scrollController.addListener(_onScroll);
  }

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

  void _onScroll() {
    if (_isBottom) {
      context.read<UnifiedFeedBloc>().add(FeedLoadMoreRequested());
    }
  }

  bool get _isBottom {
    if (!_scrollController.hasClients) return false;
    final maxScroll = _scrollController.position.maxScrollExtent;
    final currentScroll = _scrollController.offset;
    return currentScroll >= (maxScroll * 0.9);
  }

  @override
  Widget build(BuildContext context) {
    return BlocListener<UnifiedFeedBloc, UnifiedFeedState>(
      listenWhen: (previous, current) =>
          current is UnifiedFeedLoaded && (current as UnifiedFeedLoaded).loadMoreErrorMessage != null,
      listener: (context, state) {
        final loadedState = state as UnifiedFeedLoaded;
        final msg = loadedState.loadMoreErrorMessage;
        if (msg != null) {
          ScaffoldMessenger.of(context).showSnackBar(
            SnackBar(content: Text(msg), behavior: SnackBarBehavior.floating),
          );
          context.read<UnifiedFeedBloc>().add(ClearLoadMoreError());
        }
      },
      child: Scaffold(
        appBar: MiniHeaderBar(
          title: 'Accueil',
          trailing: Builder(
            builder: (ctx) => IconButton(
              icon: const Icon(Icons.refresh),
              onPressed: () => ctx.read<UnifiedFeedBloc>().add(const LoadFeedRequested(isRefresh: true)),
              tooltip: 'Actualiser',
            ),
          ),
        ),
        body: RefreshIndicator(
        color: AppColors.primaryGreen,
        backgroundColor: Theme.of(context).scaffoldBackgroundColor,
        onRefresh: () async {
          context.read<UnifiedFeedBloc>().add(const LoadFeedRequested(isRefresh: true));
        },
        child: BlocBuilder<UnifiedFeedBloc, UnifiedFeedState>(
          builder: (context, state) {
            if (state is UnifiedFeedInitial || state is UnifiedFeedLoading) {
              return const Padding(
                padding: EdgeInsets.all(8.0),
                child: CoreShimmer(itemCount: 4),
              );
            }

            if (state is UnifiedFeedError) {
              return Center(
                child: Text(
                  state.message,
                  style: AppTypography.bodyTextSmall.copyWith(color: AppColors.error),
                ),
              );
            }

            if (state is UnifiedFeedLoaded) {
              if (state.items.isEmpty) {
                return const Center(
                  child: Text('Aucune activité récente.', style: AppTypography.subtitleSmall),
                );
              }

              return ListView.builder(
                controller: _scrollController,
                itemCount: state.hasReachedMax ? state.items.length : state.items.length + 1,
                itemBuilder: (context, index) {
                  if (index >= state.items.length) {
                    return const Center(
                      child: Padding(
                        padding: EdgeInsets.symmetric(vertical: 16),
                        child: CircularProgressIndicator(strokeWidth: 2),
                      ),
                    );
                  }

                  final item = state.items[index];
                  return _buildFeedCard(context, item);
                },
              );
            }

            return const SizedBox.shrink();
          },
        ),
      ),
        floatingActionButton: DynamicFAB(
          icon: Icons.add,
          onPressed: () => _showCreateBottomSheet(context),
        ),
      ),
    );
  }

  Widget _buildFeedCard(BuildContext context, FeedItem item) {
    return CoreCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              MiniAvatar(
                imageUrl: item.authorAvatarUrl,
                fallbackText: item.authorName.isNotEmpty ? item.authorName[0] : 'U',
              ),
              const SizedBox(width: 8),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      item.authorName,
                      style: AppTypography.actionText,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                    ),
                    Row(
                      children: [
                        Text(
                          _formatDate(item.createdAt),
                          style: AppTypography.subtitleSmall,
                        ),
                        if (item.type != FeedItemType.post) ...[
                          const SizedBox(width: 6),
                          InfoBadge(
                            text: item.type.name.toUpperCase(),
                            backgroundColor: AppColors.primaryGreen.withOpacity(0.1),
                            textColor: AppColors.primaryGreen,
                          ),
                        ]
                      ],
                    ),
                  ],
                ),
              ),
              IconButton(
                padding: EdgeInsets.zero,
                constraints: const BoxConstraints(),
                icon: Icon(
                  Icons.more_vert,
                  size: 16,
                  color: Theme.of(context).brightness == Brightness.dark 
                      ? AppColors.textSecondaryDark 
                      : AppColors.textSecondaryLight,
                ),
                onPressed: () => _showPostOptionsMenu(context, item),
              )
            ],
          ),
          const SizedBox(height: 8),
          Text(
            item.content,
            style: AppTypography.bodyTextSmall,
          ),
          const SizedBox(height: 8),
          ActionRow(
            likesCount: item.likesCount,
            commentsCount: item.commentsCount,
            isLiked: item.isLikedByMe,
            onLike: () {
              context.read<UnifiedFeedBloc>().add(FeedItemLiked(item.id));
            },
            onComment: () => _onComment(context, item),
            onShare: () => Share.share('${item.content}\n— ${item.authorName}', subject: item.type.name),
            customActionLabel: item.customActionLabel,
            customActionIcon: item.customActionLabel != null ? Icons.arrow_forward : null,
            onCustomAction: item.customActionLabel != null ? () => _onCustomAction(context, item) : null,
          ),
        ],
      ),
    );
  }

  void _showCreateBottomSheet(BuildContext context) {
    showModalBottomSheet<void>(
      context: context,
      builder: (ctx) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.post_add_outlined),
              title: const Text('Nouveau post'),
              onTap: () {
                Navigator.pop(ctx);
                ScaffoldMessenger.of(context).showSnackBar(
                  const SnackBar(content: Text('Création de post — à brancher sur l\'API.')),
                );
              },
            ),
            ListTile(
              leading: const Icon(Icons.volunteer_activism_outlined),
              title: const Text('Demande d\'aide'),
              onTap: () {
                Navigator.pop(ctx);
                Navigator.of(context).push(
                  MaterialPageRoute<void>(builder: (_) => const DemandesAidePageWrapper()),
                );
              },
            ),
          ],
        ),
      ),
    );
  }

  void _onComment(BuildContext context, FeedItem item) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text('Commentaires pour "${item.content.length > 30 ? "${item.content.substring(0, 30)}..." : item.content}" — à venir.'),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  void _onCustomAction(BuildContext context, FeedItem item) {
    if (item.actionUrlTarget != null && item.actionUrlTarget!.isNotEmpty) {
      final uri = Uri.tryParse(item.actionUrlTarget!);
      if (uri != null) {
        launchUrl(uri, mode: LaunchMode.externalApplication).catchError((_) {
          ScaffoldMessenger.of(context).showSnackBar(
            const SnackBar(content: Text('Impossible d\'ouvrir le lien.')),
          );
          return false;
        });
        return;
      }
    }
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text('Action: ${item.customActionLabel ?? "—"}'), behavior: SnackBarBehavior.floating),
    );
  }

  void _showPostOptionsMenu(BuildContext context, FeedItem item) {
    showModalBottomSheet<void>(
      context: context,
      builder: (ctx) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.edit_outlined),
              title: const Text('Modifier'),
              onTap: () => Navigator.pop(ctx),
            ),
            ListTile(
              leading: const Icon(Icons.delete_outline),
              title: const Text('Supprimer'),
              onTap: () => Navigator.pop(ctx),
            ),
            ListTile(
              leading: const Icon(Icons.flag_outlined),
              title: const Text('Signaler'),
              onTap: () => Navigator.pop(ctx),
            ),
          ],
        ),
      ),
    );
  }

  String _formatDate(DateTime date) {
    // Dans un vrai projet, utiliser intl pour "Il y a 2h"
    return '${date.day}/${date.month}/${date.year} ${date.hour}:${date.minute.toString().padLeft(2, '0')}';
  }
}