/// Page de détail d'une conversation — Messages v4
library conversation_detail_page;

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

import '../../../../core/utils/logger.dart';
import '../../../../shared/design_system/unionflow_design_system.dart';
import '../../domain/entities/conversation.dart';
import '../../domain/entities/message.dart';
import '../bloc/messaging_bloc.dart';
import '../bloc/messaging_event.dart';
import '../bloc/messaging_state.dart';
import '../widgets/message_bubble.dart';

/// Page détail conversation : messages + champ d'envoi
class ConversationDetailPage extends StatefulWidget {
  final String conversationId;

  const ConversationDetailPage({
    super.key,
    required this.conversationId,
  });

  @override
  State<ConversationDetailPage> createState() => _ConversationDetailPageState();
}

class _ConversationDetailPageState extends State<ConversationDetailPage> {
  final TextEditingController _messageController = TextEditingController();
  final ScrollController _scrollController = ScrollController();
  final FocusNode _focusNode = FocusNode();

  Conversation? _conversation;
  String? _currentUserId;

  @override
  void initState() {
    super.initState();
    context.read<MessagingBloc>().add(OpenConversation(widget.conversationId));
  }

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

  void _sendMessage() {
    final content = _messageController.text.trim();
    if (content.isEmpty) return;

    context.read<MessagingBloc>().add(
          EnvoyerMessageTexte(
            conversationId: widget.conversationId,
            contenu: content,
          ),
        );
    _messageController.clear();
    _focusNode.requestFocus();
  }

  void _scrollToBottom() {
    if (_scrollController.hasClients) {
      _scrollController.animateTo(
        _scrollController.position.maxScrollExtent,
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeOut,
      );
    }
  }

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

    return Scaffold(
      backgroundColor: scheme.surface,
      appBar: _buildAppBar(),
      body: Column(
        children: [
          Expanded(
            child: BlocConsumer<MessagingBloc, MessagingState>(
              listener: (context, state) {
                if (state is ConversationOuverte) {
                  setState(() {
                    _conversation = state.conversation;
                    // Déterminer l'id de l'utilisateur courant via le premier participant non-expéditeur
                  });
                }
                if (state is MessagesLoaded) {
                  WidgetsBinding.instance.addPostFrameCallback((_) => _scrollToBottom());
                }
                if (state is MessageEnvoye) {
                  AppLogger.info('Message envoyé: ${state.message.id}');
                }
                if (state is MessagingError) {
                  ScaffoldMessenger.of(context).showSnackBar(
                    SnackBar(
                      content: Text(state.message),
                      backgroundColor: ColorTokens.error,
                    ),
                  );
                }
              },
              builder: (context, state) {
                if (state is MessagingLoading && _conversation == null) {
                  return const Center(child: CircularProgressIndicator());
                }

                if (state is ConversationOuverte) {
                  return _buildMessagesList(state.conversation.messages, scheme);
                }

                if (state is MessagesLoaded) {
                  return _buildMessagesList(state.messages, scheme);
                }

                if (_conversation != null) {
                  return _buildMessagesList(_conversation!.messages, scheme);
                }

                return const SizedBox.shrink();
              },
            ),
          ),
          _buildInputBar(scheme),
        ],
      ),
    );
  }

  UFAppBar _buildAppBar() {
    final title = _conversation?.titre ?? 'Conversation';

    return UFAppBar(
      title: title,
      moduleGradient: ModuleColors.communicationGradient,
      automaticallyImplyLeading: true,
      actions: [
        IconButton(
          icon: const Icon(Icons.delete_outline, color: ModuleColors.communicationOnColor),
          onPressed: _conversation != null ? _confirmArchive : null,
          tooltip: 'Archiver',
        ),
      ],
    );
  }

  void _confirmArchive() {
    showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Archiver la conversation ?'),
        content: const Text('La conversation sera archivée et n\'apparaîtra plus dans votre liste.'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: const Text('Annuler'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, true),
            style: TextButton.styleFrom(foregroundColor: ColorTokens.error),
            child: const Text('Archiver'),
          ),
        ],
      ),
    ).then((confirmed) {
      if (confirmed == true && mounted) {
        context.read<MessagingBloc>().add(ArchiverConversation(widget.conversationId));
        Navigator.of(context).pop();
      }
    });
  }

  Widget _buildMessagesList(List<Message> messages, ColorScheme scheme) {
    if (messages.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              Icons.chat_bubble_outline,
              size: 64,
              color: scheme.onSurfaceVariant.withOpacity(0.4),
            ),
            const SizedBox(height: SpacingTokens.md),
            Text('Aucun message', style: AppTypography.headerSmall),
            const SizedBox(height: SpacingTokens.sm),
            Text('Envoyez le premier message !', style: AppTypography.bodyTextSmall),
          ],
        ),
      );
    }

    return ListView.builder(
      controller: _scrollController,
      padding: const EdgeInsets.symmetric(
        horizontal: SpacingTokens.md,
        vertical: SpacingTokens.sm,
      ),
      itemCount: messages.length,
      itemBuilder: (context, index) {
        final message = messages[index];
        final isMine = _isMyMessage(message);

        final showDateSeparator = index == 0 ||
            !_isSameDay(
              messages[index - 1].dateEnvoi ?? DateTime.now(),
              message.dateEnvoi ?? DateTime.now(),
            );

        return Column(
          children: [
            if (showDateSeparator)
              Padding(
                padding: const EdgeInsets.symmetric(vertical: SpacingTokens.sm),
                child: Center(
                  child: Container(
                    padding: const EdgeInsets.symmetric(horizontal: SpacingTokens.md, vertical: 4),
                    decoration: BoxDecoration(
                      color: scheme.surfaceContainerHighest,
                      borderRadius: BorderRadius.circular(SpacingTokens.radiusCircular),
                    ),
                    child: Text(
                      _formatDateSeparator(message.dateEnvoi ?? DateTime.now()),
                      style: AppTypography.badgeText.copyWith(
                        color: scheme.onSurfaceVariant,
                        fontSize: 11,
                      ),
                    ),
                  ),
                ),
              ),
            MessageBubble(
              message: message,
              isMine: isMine,
              onLongPress: isMine && !message.supprime
                  ? () => _showMessageOptions(message)
                  : null,
            ),
          ],
        );
      },
    );
  }

  void _showMessageOptions(Message message) {
    showModalBottomSheet<void>(
      context: context,
      builder: (ctx) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            ListTile(
              leading: const Icon(Icons.delete_outline, color: AppColors.error),
              title: const Text('Supprimer le message'),
              onTap: () {
                Navigator.pop(ctx);
                context.read<MessagingBloc>().add(
                      SupprimerMessage(
                        conversationId: widget.conversationId,
                        messageId: message.id,
                      ),
                    );
              },
            ),
            ListTile(
              leading: const Icon(Icons.close),
              title: const Text('Annuler'),
              onTap: () => Navigator.pop(ctx),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildInputBar(ColorScheme scheme) {
    return Container(
      padding: const EdgeInsets.symmetric(
        horizontal: SpacingTokens.sm,
        vertical: SpacingTokens.sm,
      ),
      decoration: BoxDecoration(
        color: scheme.surface,
        border: Border(
          top: BorderSide(color: scheme.outlineVariant.withOpacity(0.3)),
        ),
        boxShadow: [
          BoxShadow(
            color: scheme.shadow.withOpacity(0.05),
            blurRadius: 8,
            offset: const Offset(0, -2),
          ),
        ],
      ),
      child: SafeArea(
        child: Row(
          children: [
            Expanded(
              child: Container(
                decoration: BoxDecoration(
                  color: scheme.surfaceContainerHighest.withOpacity(0.5),
                  borderRadius: BorderRadius.circular(SpacingTokens.radiusCircular),
                ),
                child: TextField(
                  controller: _messageController,
                  focusNode: _focusNode,
                  textInputAction: TextInputAction.send,
                  maxLines: 4,
                  minLines: 1,
                  onSubmitted: (_) => _sendMessage(),
                  decoration: InputDecoration(
                    hintText: 'Écrire un message...',
                    hintStyle: AppTypography.bodyTextSmall.copyWith(
                      color: scheme.onSurfaceVariant,
                    ),
                    contentPadding: const EdgeInsets.symmetric(
                      horizontal: SpacingTokens.md,
                      vertical: SpacingTokens.sm,
                    ),
                    border: InputBorder.none,
                  ),
                  style: AppTypography.bodyTextSmall,
                ),
              ),
            ),
            const SizedBox(width: SpacingTokens.sm),
            Material(
              color: ModuleColors.communication,
              borderRadius: BorderRadius.circular(SpacingTokens.radiusCircular),
              child: InkWell(
                onTap: _sendMessage,
                borderRadius: BorderRadius.circular(SpacingTokens.radiusCircular),
                child: Container(
                  width: 44,
                  height: 44,
                  alignment: Alignment.center,
                  child: const Icon(
                    Icons.send_rounded,
                    color: ModuleColors.communicationOnColor,
                    size: 22,
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  // ── Helpers ────────────────────────────────────────────────────────────────

  bool _isMyMessage(Message message) {
    // On ne peut pas connaître l'ID du membre courant sans le BLoC d'auth,
    // mais l'expéditeur d'un message récent qu'on a envoyé sera déterminé
    // via la liste des participants. En attendant le token JWT, on utilise
    // le premier participant de type INITIATEUR s'il n'y en a pas d'autre.
    // TODO: Injecter AuthBloc pour comparer expediteurId avec l'id du user connecté.
    return false; // Tous les messages affichés comme reçus pour l'instant
  }

  bool _isSameDay(DateTime a, DateTime b) {
    return a.year == b.year && a.month == b.month && a.day == b.day;
  }

  String _formatDateSeparator(DateTime date) {
    final now = DateTime.now();
    if (_isSameDay(date, now)) return "Aujourd'hui";
    if (_isSameDay(date, now.subtract(const Duration(days: 1)))) return 'Hier';
    return '${date.day.toString().padLeft(2, '0')}/${date.month.toString().padLeft(2, '0')}/${date.year}';
  }
}