const { WebSocketServer } = require('ws');
const config = require('./config');
const { authenticate } = require('./auth');
const { createJsonSender, createClientHandlers, validateFile, broadcast } = require('./clients');

const server = new WebSocketServer({ port: config.port });
console.log(`WebSocket server running on ws://0.0.0.0:${config.port}`);

let pinnedMessage = null;

server.on('connection', (ws, req) => {
  const clientIp = req.socket.remoteAddress;
  console.log(`Connection from ${clientIp}`);

  const send = createJsonSender(ws);
  const client = createClientHandlers(ws, send);
  const handle = client.wrapHandler((parsed) => {
    switch (parsed.type) {
      case 'auth': {
        const user = authenticate(parsed.login, parsed.password);
        if (user) {
          const sysMsg = client.handleAuth(user.login);
          if (pinnedMessage) {
            send({ type: 'pinned', message: pinnedMessage.message, pinnedBy: pinnedMessage.from });
          }
          return sysMsg;
        }
        client.handleAuthFail('Invalid login or password');
        return null;
      }
      case 'pin': {
        pinnedMessage = {
          type: 'pinned', from: client.getLogin(), timestamp: Date.now(),
          message: parsed.message,
        };
        console.log(`${client.getLogin()} pinned a message`);
        return pinnedMessage;
      }
      case 'unpin': {
        pinnedMessage = null;
        console.log(`${client.getLogin()} unpinned the message`);
        return { type: 'unpinned', from: client.getLogin(), timestamp: Date.now() };
      }
      case 'text': {
        if (!parsed.text || typeof parsed.text !== 'string') {
          send({ type: 'error', message: 'Invalid text message' });
          return null;
        }
        console.log(`Text from ${client.getLogin()}: ${parsed.text.substring(0, 50)}`);
        return { type: 'text', from: client.getLogin(), timestamp: Date.now(), text: parsed.text };
      }
      case 'file': {
        const error = validateFile(parsed);
        if (error) {
          send({ type: 'error', message: error });
          return null;
        }
        console.log(`File from ${client.getLogin()}: ${parsed.filename} (${parsed.mime})`);
        return {
          type: 'file', from: client.getLogin(), timestamp: Date.now(),
          filename: parsed.filename, mime: parsed.mime, data: parsed.data,
        };
      }
      default:
        send({ type: 'error', message: 'Unknown message type' });
        return null;
    }
  });

  ws.on('message', (raw) => {
    const msg = handle(raw);
    if (msg) {
      broadcast(server, msg, null);
    }
  });

  ws.on('close', (code) => {
    console.log(`Disconnected: ${client.getLogin() || 'unauthenticated'} (code: ${code})`);
    if (client.getLogin()) {
      broadcast(server, { type: 'system', text: `${client.getLogin()} left the chat` }, null);
    }
  });

  ws.on('error', (err) => {
    console.error(`Socket error (${client.getLogin() || 'unknown'}):`, err.message);
  });
});