const readline = require('readline');
const WebSocket = require('ws');

// Configure readline for user input
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

/**
 * Prompt the user for the WebSocket server host.
 * @param {string} question - The question to display.
 * @returns {Promise<string>} - The user input.
 */
function askQuestion(question) {
  return new Promise((resolve) => {
    rl.question(question, resolve);
  });
}

/**
 * Connect to the WebSocket server and handle communication.
 * @param {string} host - The WebSocket server host.
 */
async function connectToWebSocket(host) {
  const ws = new WebSocket(`ws://${host}:64999`);

  ws.on('open', () => {
    console.log('Connected to the WebSocket server.');
    showMenu(ws);
  });

  ws.on('message', (data) => {
    console.log('Server response:', data.toString());
  });

  ws.on('error', (err) => {
    console.error('WebSocket error:', err.message);
    rl.close();
  });

  ws.on('close', () => {
    console.log('Connection closed.');
    rl.close();
  });
}

/**
 * Display a menu of actions for the user.
 * @param {WebSocket} ws - The WebSocket connection.
 */
function showMenu(ws) {
  console.log(`
Available commands:
1. prevconf - Get the previous configuration.
2. currconf - Get the current configuration.
3. Update - Send a new configuration.
4. Exit - Close the client.
  `);

  rl.question('Enter your choice: ', async (choice) => {
    switch (choice.trim()) {
      case '1':
        ws.send(JSON.stringify({ command: 'prevconf' }));
        break;
      case '2':
        ws.send(JSON.stringify({ command: 'currconf' }));
        break;
      case '3':
        const newConfig = await askForNewConfig();
        ws.send(JSON.stringify(newConfig));
        break;
      case '4':
        console.log('Closing the client...');
        ws.close();
        rl.close();
        return;
      default:
        console.log('Invalid choice.');
    }
    showMenu(ws); // Show the menu again after the action
  });
}

/**
 * Prompt the user for a new configuration.
 * @returns {Promise<object>} - The new configuration object.
 */
async function askForNewConfig() {
  const numMappings = await askQuestion('How many mappings do you want to add? ');
  const mappings = [];

  for (let i = 0; i < parseInt(numMappings, 10); i++) {
    const host = await askQuestion(`Enter host for mapping ${i + 1}: `);
    const port = await askQuestion(`Enter port for mapping ${i + 1}: `);
    mappings.push({ host, port: parseInt(port, 10) });
  }

  return { mappings };
}

/**
 * Entry point for the client.
 */
(async function main() {
  const host = await askQuestion('Enter the WebSocket server host (e.g., localhost): ');
  connectToWebSocket(host);
})();