import 'dart:async';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../../../core/chat/mitra_chat_notifier.dart';
import '../../../core/chat/extension_notifier.dart';
import '../../../core/constants.dart';

class MitraChatScreen extends ConsumerStatefulWidget {
  final String sessionId;
  final String customerName;

  const MitraChatScreen({super.key, required this.sessionId, required this.customerName});

  @override
  ConsumerState<MitraChatScreen> createState() => _MitraChatScreenState();
}

class _MitraChatScreenState extends ConsumerState<MitraChatScreen> {
  final _messageController = TextEditingController();
  final _scrollController = ScrollController();
  Timer? _typingThrottle;

  @override
  void initState() {
    super.initState();
    ref.read(mitraChatProvider.notifier).connect(widget.sessionId);
  }

  @override
  void dispose() {
    ref.read(mitraChatProvider.notifier).disconnect();
    _messageController.dispose();
    _scrollController.dispose();
    _typingThrottle?.cancel();
    super.dispose();
  }

  void _scrollToBottom() {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (_scrollController.hasClients) {
        _scrollController.animateTo(
          _scrollController.position.maxScrollExtent,
          duration: const Duration(milliseconds: 200),
          curve: Curves.easeOut,
        );
      }
    });
  }

  void _onTextChanged(String text) {
    if (_typingThrottle?.isActive ?? false) return;
    ref.read(mitraChatProvider.notifier).sendTyping();
    _typingThrottle = Timer(const Duration(seconds: 2), () {});
  }

  void _sendMessage() {
    final text = _messageController.text.trim();
    if (text.isEmpty) return;
    ref.read(mitraChatProvider.notifier).sendMessage(text);
    _messageController.clear();
    _scrollToBottom();
  }

  @override
  Widget build(BuildContext context) {
    final chatState = ref.watch(mitraChatProvider);
    final extState = ref.watch(mitraExtensionProvider);

    // Listen for extension complete → navigate home
    ref.listen(mitraExtensionProvider, (prev, next) {
      if (next is ExtensionCompleteData) {
        context.go('/home');
      }
    });

    // Listen for chat state changes
    ref.listen(mitraChatProvider, (prev, next) {
      if (next is MitraChatConnectedData) {
        _scrollToBottom();
        final unread = next.messages
            .where((m) => m.senderType == UserType.customer && m.status != MessageStatus.read)
            .map((m) => m.id)
            .toList();
        if (unread.isNotEmpty) {
          ref.read(mitraChatProvider.notifier).markRead(unread);
        }
      }
    });

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.customerName),
        actions: [
          if (chatState is MitraChatConnectedData && chatState.remainingSeconds != null)
            Padding(
              padding: const EdgeInsets.only(right: 16),
              child: Center(
                child: Text(
                  '${chatState.remainingSeconds}s',
                  style: TextStyle(
                    color: chatState.remainingSeconds! < 30 ? Colors.red : null,
                    fontWeight: FontWeight.bold,
                  ),
                ),
              ),
            ),
        ],
      ),
      body: _buildBody(chatState, extState),
    );
  }

  Widget _buildBody(MitraChatData chatState, ExtensionData extState) {
    if (chatState is MitraChatConnectingData) {
      return const Center(child: CircularProgressIndicator());
    }
    if (chatState is MitraChatErrorData) {
      return Center(child: Text(chatState.message));
    }
    if (chatState is MitraChatConnectedData) {
      return _buildChatBody(chatState, extState);
    }
    return const SizedBox.shrink();
  }

  Widget _buildChatBody(MitraChatConnectedData state, ExtensionData extState) {
    // Extension request from customer
    if (state.extensionRequest != null) {
      return _buildExtensionView(state.extensionRequest!, extState);
    }

    // Goodbye view
    if (state.sessionClosing || extState is ExtensionShowGoodbyeData || extState is ExtensionSubmittingData) {
      return _buildGoodbyeView(extState);
    }

    return Column(
      children: [
        Expanded(
          child: ListView.builder(
            controller: _scrollController,
            padding: const EdgeInsets.all(16),
            itemCount: state.messages.length,
            itemBuilder: (context, index) {
              final msg = state.messages[index];
              final isMe = msg.senderType == UserType.mitra;
              return _buildMessageBubble(msg, isMe);
            },
          ),
        ),
        if (state.isOtherTyping)
          const Padding(
            padding: EdgeInsets.symmetric(horizontal: 16, vertical: 4),
            child: Align(
              alignment: Alignment.centerLeft,
              child: Text('Customer sedang mengetik...', style: TextStyle(color: Colors.grey, fontSize: 12)),
            ),
          ),
        _buildInputBar(),
      ],
    );
  }

  Widget _buildMessageBubble(MitraChatMessage msg, bool isMe) {
    return Align(
      alignment: isMe ? 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 * 0.75),
        decoration: BoxDecoration(
          color: isMe ? Colors.green.shade100 : Colors.grey.shade200,
          borderRadius: BorderRadius.circular(16),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.end,
          children: [
            Text(msg.content, style: const TextStyle(fontSize: 15)),
            const SizedBox(height: 4),
            Row(
              mainAxisSize: MainAxisSize.min,
              children: [
                Text(
                  '${msg.createdAt.hour.toString().padLeft(2, '0')}:${msg.createdAt.minute.toString().padLeft(2, '0')}',
                  style: const TextStyle(fontSize: 10, color: Colors.grey),
                ),
                if (isMe) ...[
                  const SizedBox(width: 4),
                  _buildStatusIcon(msg.status),
                ],
              ],
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildStatusIcon(String status) {
    switch (status) {
      case 'sending':
        return const Icon(Icons.access_time, size: 14, color: Colors.grey);
      case MessageStatus.sent:
        return const Icon(Icons.check, size: 14, color: Colors.grey);
      case MessageStatus.delivered:
        return const Icon(Icons.done_all, size: 14, color: Colors.grey);
      case MessageStatus.read:
        return const Icon(Icons.done_all, size: 14, color: Colors.blue);
      default:
        return const SizedBox.shrink();
    }
  }

  Widget _buildInputBar() {
    return SafeArea(
      child: Padding(
        padding: const EdgeInsets.all(8),
        child: Row(
          children: [
            Expanded(
              child: TextField(
                controller: _messageController,
                onChanged: _onTextChanged,
                textInputAction: TextInputAction.send,
                onSubmitted: (_) => _sendMessage(),
                decoration: InputDecoration(
                  hintText: 'Ketik pesan...',
                  border: OutlineInputBorder(borderRadius: BorderRadius.circular(24)),
                  contentPadding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
                ),
              ),
            ),
            const SizedBox(width: 8),
            IconButton(
              icon: const Icon(Icons.send, color: Colors.green),
              onPressed: _sendMessage,
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildExtensionView(Map<String, dynamic> request, ExtensionData extState) {
    final duration = request['duration_minutes'] as int?;
    final extensionId = request['extension_id'] as String?;
    final isResponding = extState is ExtensionRespondingData;

    return Center(
      child: Padding(
        padding: const EdgeInsets.all(32),
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            const Icon(Icons.timer, size: 64, color: Colors.orange),
            const SizedBox(height: 16),
            const Text('Permintaan Perpanjangan', style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
            const SizedBox(height: 8),
            Text('Customer ingin perpanjang $duration menit', textAlign: TextAlign.center),
            const SizedBox(height: 24),
            if (isResponding)
              const CircularProgressIndicator()
            else
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  ElevatedButton(
                    style: ElevatedButton.styleFrom(backgroundColor: Colors.green),
                    onPressed: extensionId == null ? null : () => ref.read(mitraExtensionProvider.notifier).respond(
                      widget.sessionId,
                      extensionId: extensionId,
                      accepted: true,
                    ),
                    child: const Text('Terima', style: TextStyle(color: Colors.white)),
                  ),
                  const SizedBox(width: 16),
                  ElevatedButton(
                    style: ElevatedButton.styleFrom(backgroundColor: Colors.red),
                    onPressed: extensionId == null ? null : () => ref.read(mitraExtensionProvider.notifier).respond(
                      widget.sessionId,
                      extensionId: extensionId,
                      accepted: false,
                    ),
                    child: const Text('Tolak', style: TextStyle(color: Colors.white)),
                  ),
                ],
              ),
          ],
        ),
      ),
    );
  }

  Widget _buildGoodbyeView(ExtensionData extState) {
    final controller = TextEditingController();
    return SingleChildScrollView(
      padding: const EdgeInsets.all(32),
      child: Column(
        children: [
          const SizedBox(height: 48),
            const Icon(Icons.waving_hand, size: 64, color: Colors.amber),
            const SizedBox(height: 16),
            const Text('Pesan Penutup', style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
            const SizedBox(height: 8),
            const Text('Tuliskan pesan terakhirmu untuk Customer', textAlign: TextAlign.center),
            const SizedBox(height: 24),
            TextField(
              controller: controller,
              maxLines: 3,
              decoration: InputDecoration(
                hintText: 'Terima kasih sudah curhat...',
                border: OutlineInputBorder(borderRadius: BorderRadius.circular(12)),
              ),
            ),
            const SizedBox(height: 16),
            ElevatedButton(
              onPressed: extState is ExtensionSubmittingData
                  ? null
                  : () {
                      final text = controller.text.trim();
                      if (text.isNotEmpty) {
                        ref.read(mitraExtensionProvider.notifier).submitGoodbye(
                          widget.sessionId, text,
                        );
                      }
                    },
              child: extState is ExtensionSubmittingData
                  ? const SizedBox(width: 20, height: 20, child: CircularProgressIndicator(strokeWidth: 2))
                  : const Text('Kirim & Selesai'),
            ),
          ],
        ),
    );
  }
}