import 'package:flutter/material.dart';
import 'backend.dart';
import 'chat_screen.dart';

class AgentEntry {
  final int id;
  final String name;

  AgentEntry({required this.id, required this.name});
}

class CreateChatScreen extends StatefulWidget {
  @override
  _CreateChatScreenState createState() => _CreateChatScreenState();
}

class _CreateChatScreenState extends State<CreateChatScreen> {
  final TextEditingController nameController = TextEditingController();

  // Track selected participants
  final Set<int> selectedParticipants = {};

  void _submit() async {
    Backend.invalidateCache(chat: true);
    final response = await Backend.sendAction("create-chat", {
        'name': nameController.text,
        'members': selectedParticipants.toList(),
    });
    Navigator.push(
        context,
        MaterialPageRoute(
            builder: (context) => ChatScreen(chatId: response['chatId']),
        ),
    );
  }

  void _toggleParticipant(int id) {
    setState(() {
      if (selectedParticipants.contains(id)) {
        selectedParticipants.remove(id);
      } else {
        selectedParticipants.add(id);
      }
    });
  }

  // TODO: Agents should only be retrieved once, then the same future is reused in `build`
  static Future<List<AgentEntry>> getAgents() async {
    final response = await Backend.sendAction("get-agents", {});
    List<dynamic> chatObjects = response['agents'];
    List<AgentEntry> chats = chatObjects
        .map((msg) => AgentEntry(
              id: msg['id'],
              name: msg['name']?.isNotEmpty == true ? msg['name'] : '[Chat ${msg['id']}]',
            ))
        .toList();
    return chats;
  }

  Widget _buildParticipantTile(AgentEntry entry) {
    final isSelected = selectedParticipants.contains(entry.id);
    return GestureDetector(
      onTap: () => _toggleParticipant(entry.id),
      child: Container(
        padding: EdgeInsets.symmetric(vertical: 12, horizontal: 16),
        margin: EdgeInsets.symmetric(vertical: 4),
        decoration: BoxDecoration(
          color: isSelected ? Colors.blue.shade100 : Colors.grey.shade200,
          border: Border.all(
            color: isSelected ? Colors.blue : Colors.transparent,
            width: 2,
          ),
          borderRadius: BorderRadius.circular(8),
        ),
        child: Text(
          entry.name,
          style: TextStyle(
            fontWeight: FontWeight.w600,
            color: isSelected ? Colors.blue.shade900 : Colors.black87,
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Create Chat')),
      body: Center(
        child: Padding(
          padding: const EdgeInsets.all(16.0),
          child: Column(
            children: [
              TextField(
                controller: nameController,
                decoration: InputDecoration(labelText: 'Title'),
              ),
              SizedBox(height: 20),
              Align(
                alignment: Alignment.centerLeft,
                child: Text('Select Participants:',
                    style: TextStyle(
                        fontSize: 16, fontWeight: FontWeight.bold)),
              ),
              SizedBox(height: 8),
              Expanded(
                child: FutureBuilder<List<AgentEntry>>(
                    future: getAgents(),
                    builder: (context, snapshot) {
                        if (snapshot.hasData) {
                            final agents = snapshot.data!;
                            return ListView.builder(
                                itemCount: agents.length,
                                itemBuilder: (context, index) {
                                    return _buildParticipantTile(agents[index]);
                                },
                            );
                        } else {
                            return ListView.builder(
                                itemCount: 0,
                                itemBuilder: (context, index) {
                                    return ListTile();
                                },
                            );
                        }
                    },
                ),
              ),
              ElevatedButton(
                onPressed: _submit,
                child: Text('Create Chat'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}