import 'package:flutter/material.dart';
import 'package:mymuseum_visitapp/Models/AssistantResponse.dart';
import 'package:mymuseum_visitapp/Models/visitContext.dart';
import 'package:mymuseum_visitapp/Services/assistantService.dart';
import 'package:mymuseum_visitapp/constants.dart';

class AssistantChatSheet extends StatefulWidget {
  final VisitAppContext visitAppContext;
  final String? configurationId; // null = scope instance, fourni = scope configuration
  final void Function(String sectionId, String sectionTitle)? onNavigateToSection;

  const AssistantChatSheet({
    Key? key,
    required this.visitAppContext,
    this.configurationId,
    this.onNavigateToSection,
  }) : super(key: key);

  @override
  State<AssistantChatSheet> createState() => _AssistantChatSheetState();
}

class _AssistantChatSheetState extends State<AssistantChatSheet> {
  late AssistantService _assistantService;
  final TextEditingController _controller = TextEditingController();
  final ScrollController _scrollController = ScrollController();
  final List<Widget> _bubbles = [];
  bool _isLoading = false;

  @override
  void initState() {
    super.initState();
    _assistantService = AssistantService(visitAppContext: widget.visitAppContext);
  }

  Future<void> _send() async {
    final text = _controller.text.trim();
    if (text.isEmpty || _isLoading) return;

    _controller.clear();
    setState(() {
      _bubbles.add(_ChatBubble(text: text, isUser: true));
      _isLoading = true;
    });
    _scrollToBottom();

    try {
      final response = await _assistantService.chat(
        message: text,
        configurationId: widget.configurationId,
      );
      setState(() {
        _bubbles.add(_AssistantMessage(
          response: response,
          onNavigate: widget.onNavigateToSection,
        ));
      });
    } catch (_) {
      setState(() {
        _bubbles.add(_ChatBubble(text: "Une erreur est survenue, réessayez.", isUser: false));
      });
    } finally {
      setState(() => _isLoading = false);
      _scrollToBottom();
    }
  }

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

  @override
  Widget build(BuildContext context) {
    return DraggableScrollableSheet(
      initialChildSize: 0.6,
      minChildSize: 0.4,
      maxChildSize: 0.92,
      expand: false,
      builder: (context, scrollController) {
        return Container(
          decoration: const BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.vertical(top: Radius.circular(20)),
          ),
          child: Column(
            children: [
              // Handle
              Container(
                margin: const EdgeInsets.symmetric(vertical: 10),
                width: 40,
                height: 4,
                decoration: BoxDecoration(
                  color: Colors.grey[300],
                  borderRadius: BorderRadius.circular(2),
                ),
              ),
              // Header
              Padding(
                padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                child: Row(
                  children: [
                    Icon(Icons.chat_bubble_outline, color: kMainColor1),
                    const SizedBox(width: 8),
                    Text("Assistant",
                        style: TextStyle(fontSize: 18, fontWeight: FontWeight.w600, color: kSecondGrey)),
                  ],
                ),
              ),
              const Divider(height: 1),
              // Messages
              Expanded(
                child: _bubbles.isEmpty
                    ? Center(
                        child: Padding(
                          padding: const EdgeInsets.all(24),
                          child: Text(
                            "Bonjour ! Posez-moi vos questions sur cette visite.",
                            textAlign: TextAlign.center,
                            style: TextStyle(color: Colors.grey[500], fontSize: 15),
                          ),
                        ),
                      )
                    : ListView.builder(
                        controller: _scrollController,
                        padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
                        itemCount: _bubbles.length,
                        itemBuilder: (_, i) => _bubbles[i],
                      ),
              ),
              // Loading indicator
              if (_isLoading)
                Padding(
                  padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
                  child: Row(
                    children: [
                      SizedBox(
                        width: 20, height: 20,
                        child: CircularProgressIndicator(strokeWidth: 2, color: kMainColor1),
                      ),
                      const SizedBox(width: 8),
                      Text("...", style: TextStyle(color: Colors.grey[400])),
                    ],
                  ),
                ),
              // Input
              SafeArea(
                child: Padding(
                  padding: EdgeInsets.only(
                    left: 12, right: 12, bottom: MediaQuery.of(context).viewInsets.bottom + 8, top: 8),
                  child: Row(
                    children: [
                      Expanded(
                        child: TextField(
                          controller: _controller,
                          textCapitalization: TextCapitalization.sentences,
                          decoration: InputDecoration(
                            hintText: "Votre question...",
                            filled: true,
                            fillColor: Colors.grey[100],
                            border: OutlineInputBorder(
                              borderRadius: BorderRadius.circular(24),
                              borderSide: BorderSide.none,
                            ),
                            contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                          ),
                          onSubmitted: (_) => _send(),
                        ),
                      ),
                      const SizedBox(width: 8),
                      CircleAvatar(
                        backgroundColor: kMainColor1,
                        child: IconButton(
                          icon: const Icon(Icons.send, color: Colors.white, size: 18),
                          onPressed: _send,
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ],
          ),
        );
      },
    );
  }
}

class _ChatBubble extends StatelessWidget {
  final String text;
  final bool isUser;

  const _ChatBubble({required this.text, required this.isUser});

  @override
  Widget build(BuildContext context) {
    return Align(
      alignment: isUser ? Alignment.centerRight : Alignment.centerLeft,
      child: Container(
        margin: const EdgeInsets.symmetric(vertical: 4),
        padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
        constraints: BoxConstraints(maxWidth: MediaQuery.of(context).size.width * 0.78),
        decoration: BoxDecoration(
          color: isUser ? kMainColor1 : Colors.grey[100],
          borderRadius: BorderRadius.only(
            topLeft: const Radius.circular(16),
            topRight: const Radius.circular(16),
            bottomLeft: isUser ? const Radius.circular(16) : const Radius.circular(4),
            bottomRight: isUser ? const Radius.circular(4) : const Radius.circular(16),
          ),
        ),
        child: Text(
          text,
          style: TextStyle(
            color: isUser ? Colors.white : kSecondGrey,
            fontSize: 14,
          ),
        ),
      ),
    );
  }
}

class _AssistantMessage extends StatelessWidget {
  final AssistantResponse response;
  final void Function(String sectionId, String sectionTitle)? onNavigate;

  const _AssistantMessage({required this.response, this.onNavigate});

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          // Text bubble
          _ChatBubble(text: response.reply, isUser: false),

          // Cards
          if (response.cards != null && response.cards!.isNotEmpty)
            Padding(
              padding: const EdgeInsets.only(top: 6, left: 4, right: 24),
              child: Column(
                children: response.cards!
                    .map((card) => _AiCardWidget(card: card))
                    .toList(),
              ),
            ),

          // Navigation button
          if (response.navigation != null && onNavigate != null)
            Padding(
              padding: const EdgeInsets.only(top: 8, left: 4),
              child: ElevatedButton.icon(
                onPressed: () {
                  Navigator.pop(context);
                  onNavigate!(
                    response.navigation!.sectionId,
                    response.navigation!.sectionTitle,
                  );
                },
                icon: const Icon(Icons.arrow_forward, size: 16),
                label: Text(response.navigation!.sectionTitle),
                style: ElevatedButton.styleFrom(
                  backgroundColor: kMainColor1,
                  foregroundColor: Colors.white,
                  shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(20)),
                  padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 8),
                  textStyle: const TextStyle(fontSize: 13),
                ),
              ),
            ),
        ],
      ),
    );
  }
}

class _AiCardWidget extends StatelessWidget {
  final AiCard card;

  const _AiCardWidget({required this.card});

  @override
  Widget build(BuildContext context) {
    return Container(
      margin: const EdgeInsets.only(bottom: 6),
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      decoration: BoxDecoration(
        color: Colors.white,
        borderRadius: BorderRadius.circular(10),
        border: Border.all(color: Colors.grey[200]!),
        boxShadow: [
          BoxShadow(color: Colors.black.withValues(alpha: 0.05), blurRadius: 3, offset: const Offset(0, 1)),
        ],
      ),
      child: Row(
        children: [
          if (card.icon != null) ...[
            Text(card.icon!, style: const TextStyle(fontSize: 18)),
            const SizedBox(width: 8),
          ],
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  card.title,
                  style: TextStyle(fontWeight: FontWeight.w600, fontSize: 13, color: kSecondGrey),
                ),
                if (card.subtitle.isNotEmpty)
                  Text(
                    card.subtitle,
                    style: const TextStyle(fontSize: 12, color: Colors.grey),
                  ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}