import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'dart:io';
import 'package:file_selector/file_selector.dart';

import '../services/chat_service.dart';
import '../services/reverb_socket_service.dart';
import '../services/dio_client.dart';
import '../providers/chat_unread_provider.dart';
import '../widgets/chat_file_preview.dart';
import 'chat_file_viewer.dart';

class ChatScreen extends StatefulWidget {
  const ChatScreen({super.key});

  @override
  State<ChatScreen> createState() => _ChatScreenState();
}

class _ChatScreenState extends State<ChatScreen> {
  final TextEditingController _messageCtrl = TextEditingController();
  final ScrollController _scrollCtrl = ScrollController();

  Map<String, dynamic>? uploadingMessage;

  late ChatService _chatService;
  final ReverbSocketService _socket = ReverbSocketService();

  int? ticketId;
  List<Map<String, dynamic>> messages = [];
  bool isLoading = true;

  @override
  void initState() {
    super.initState();
    _chatService = ChatService(DioClient.getInstance(context));

    WidgetsBinding.instance.addPostFrameCallback((_) {
      context.read<ChatUnreadProvider>().setChatOpen(true);
    });

    _initChat();
  }

  String _guessMimeType(String path) {
    final lower = path.toLowerCase();
    if (lower.endsWith('.jpg') || lower.endsWith('.png')) return 'image/*';
    if (lower.endsWith('.mp4')) return 'video/*';
    if (lower.endsWith('.pdf')) return 'application/pdf';
    return 'application/octet-stream';
  }

  Future<void> _pickAndSendFile() async {
    final XFile? picked = await openFile();
    if (picked == null || ticketId == null) return;

    final file = File(picked.path);

    setState(() {
      uploadingMessage = {
        'local_file': file,
        'file_type': _guessMimeType(file.path),
        'progress': 0.0,
      };
    });

    await _chatService.sendFile(
      ticketId!,
      file,
      onProgress: (progress) {
        if (!mounted) return;
        setState(() => uploadingMessage!['progress'] = progress);
      },
    );

    if (!mounted) return;
    setState(() => uploadingMessage = null);
  }

  Future<void> _initChat() async {
    final ticketRes = await _chatService.startChat();
    ticketId = ticketRes['ticket']['id'];

    final msgs = await _chatService.getMessages(ticketId!);
    messages = List<Map<String, dynamic>>.from(msgs);

    await _socket.connect(
      context: context,
      ticketId: ticketId!,
      onMessage: (msg) {
        final incomingClientId = msg['client_id'];

        setState(() {
          messages.removeWhere((m) => m['client_id'] == incomingClientId);
          messages.add(msg);
        });

        _scrollToBottom();
      },
      onAdminMessage: () {
        if (!mounted) {
          context.read<ChatUnreadProvider>().increment();
        }
      },
    );

    if (!mounted) return;
    setState(() => isLoading = false);
    _scrollToBottom();
  }

  void _scrollToBottom() {
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (_scrollCtrl.hasClients) {
        _scrollCtrl.animateTo(
          _scrollCtrl.position.maxScrollExtent,
          duration: const Duration(milliseconds: 250),
          curve: Curves.easeOut,
        );
      }
    });
  }

  Future<void> _sendMessage() async {
    final text = _messageCtrl.text.trim();
    if (text.isEmpty || ticketId == null) return;

    _messageCtrl.clear();
    final clientId = DateTime.now().millisecondsSinceEpoch.toString();

    setState(() {
      messages.add({
        'client_id': clientId,
        'sender_type': 'App\\Models\\User',
        'message': text,
        'file_path': null,
        'file_type': null,
        'sending': true,
      });
    });

    _scrollToBottom();

    await _chatService.sendMessage(
      ticketId!,
      message: text,
      clientId: clientId,
    );
  }

  @override
  void dispose() {
    context.read<ChatUnreadProvider>().setChatOpen(false);
    _socket.disconnect();
    _messageCtrl.dispose();
    _scrollCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: PreferredSize(
        preferredSize: const Size.fromHeight(56),
        child: AnimatedContainer(
          duration: const Duration(milliseconds: 300),
          curve: Curves.easeInOut,
          decoration: const BoxDecoration(
            gradient: LinearGradient(
              colors: [
                Color(0xFF2196F3),
                Color(0xFF1565C0),
              ],
              begin: Alignment.topLeft,
              end: Alignment.bottomRight,
            ),
            boxShadow: [
              BoxShadow(
                color: Colors.black26,
                blurRadius: 10,
                offset: Offset(0, 3),
              ),
            ],
          ),
          child: AppBar(
            backgroundColor: Colors.transparent,
            elevation: 0,
            leading: Padding(
              padding: const EdgeInsets.only(left: 12),
              child: CircleAvatar(
                radius: 18,
                backgroundColor: Colors.white,
                child: Icon(
                  Icons.support_agent,
                  color: Colors.blue,
                  size: 20,
                ),
              ),
            ),
            title: const Text(
              "Support Chat",
              style: TextStyle(
                color: Colors.white,
                fontWeight: FontWeight.w600,
                fontSize: 18,
              ),
            ),
            centerTitle: false,
            iconTheme: const IconThemeData(color: Colors.white),
          ),
        ),
      ),
      body: isLoading
          ? const Center(child: CircularProgressIndicator())
          : Column(
        children: [
          Expanded(child: _buildMessages()),
          _buildInput(),
        ],
      ),
    );
  }

  Widget _buildMessages() {
    return ListView(
      controller: _scrollCtrl,
      padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 8),
      children: [
        ...messages.map((msg) {
          final isUser = msg['sender_type'] == 'App\\Models\\User';

          return Align(
            alignment:
            isUser ? Alignment.centerRight : Alignment.centerLeft,
            child: Container(
              constraints: const BoxConstraints(maxWidth: 280),
              margin: const EdgeInsets.symmetric(vertical: 6),
              padding: const EdgeInsets.all(12),
              decoration: BoxDecoration(
                color: isUser ? null : Colors.white,
                gradient: isUser
                    ? LinearGradient(
                  colors: [
                    Colors.lightBlueAccent,
                    Colors.blue.shade700,
                  ],
                  begin: Alignment.topLeft,
                  end: Alignment.bottomRight,
                )
                    : null,
                borderRadius: BorderRadius.only(
                  topLeft: const Radius.circular(16),
                  topRight: const Radius.circular(16),
                  bottomLeft:
                  isUser ? const Radius.circular(16) : Radius.zero,
                  bottomRight:
                  isUser ? Radius.zero : const Radius.circular(16),
                ),
                boxShadow: [
                  BoxShadow(
                    color: Colors.black.withOpacity(0.05),
                    blurRadius: 6,
                  ),
                ],
              ),
              child: msg['file_path'] == null
                  ? Text(
                msg['message'] ?? '',
                style: TextStyle(
                  color: isUser ? Colors.white : Colors.blue,
                  fontSize: 15,
                ),
              )
                  : ChatFilePreview(
                filePath: msg['file_path'],
                fileType: msg['file_type'] ?? '',
                isUser: isUser,
              ),
            ),
          );
        }),
      ],
    );
  }

  Widget _buildInput() {
    return SafeArea(
      child: Padding(
        padding: const EdgeInsets.all(8),
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 12),
          decoration: BoxDecoration(
            color: Colors.white,
            borderRadius: BorderRadius.circular(24),
            boxShadow: [
              BoxShadow(
                color: Colors.black.withOpacity(0.05),
                blurRadius: 6,
              ),
            ],
          ),
          child: Row(
            children: [
              IconButton(
                icon: const Icon(Icons.attach_file),
                onPressed: _pickAndSendFile,
              ),
              Expanded(
                child: TextField(
                  controller: _messageCtrl,
                  decoration: const InputDecoration(
                    hintText: "Type a message…",
                    border: InputBorder.none,
                  ),
                ),
              ),
              IconButton(
                icon: const Icon(Icons.send, color: Colors.blue),
                onPressed: _sendMessage,
              ),
            ],
          ),
        ),
      ),
    );
  }
}