// server/InputWS.js
const fs = require('fs');
const WebSocket = require('ws');

const LOG_DIR = './logs';

/**
 * Ensures the log directory exists so the first appendFileSync() call cannot
 * crash on a fresh container/checkout. Idempotent thanks to { recursive: true }.
 */
function ensureLogDir(dir = LOG_DIR) {
  fs.mkdirSync(dir, { recursive: true });
}

function initInputWS(server, robot, GCode, sharedState) {
  ensureLogDir();

  const wss = new WebSocket.Server({ server });

  wss.on('connection', (ws) => {
    console.log("WebSocket Input connected");

    const clientIP = ws._socket.remoteAddress || 'unknown';
    sharedState.connectedClients.push(clientIP);

    ws.on('close', () => {
      sharedState.connectedClients =
        sharedState.connectedClients.filter(ip => ip !== clientIP);
    });

    ws.on('message', (msg) => {
      const message = msg.toString();

      /* ---------- Ping (heartbeat) → targeted reply to requester ---------- */
      if (message === "Ping") {
        logPing(sharedState, clientIP);
        reply(ws, "Ping");
        return;
      }

      /* ---------- M114 (status query) → targeted reply to requester ---------- */
      if (message === "M114") {
        logCommand(sharedState, clientIP, message);
        reply(ws, GCode.getM114(robot));
        return;
      }

      /* ---------- G-code (motion command) → broadcast new state to all ----------
       * A move changes the robot position, which is a status update every client
       * (e.g. the simulation) should see → broadcast. Parsing/execution failures
       * are reported back to the sender as a machine-readable error. */
      if (GCode.containsCommand(message)) {
        console.log("🔵 GCode.receiveGCode: Incoming command: " + message);
        logCommand(sharedState, clientIP, message);
        try {
          GCode.receiveGCode(robot, message);
        } catch (err) {
          return sendError(ws, 'GCODE_ERROR', err.message, message);
        }
        broadcast(wss, GCode.getM114(robot));
        return;
      }

      /* ---------- File commands → broadcast result ----------
       * Behaviour kept as-is on purpose: file/log management (and finer-grained
       * targeting, e.g. FShow as a requester-only reply) is owned by ToDo 4. */
      if (GCode.ContainsFilesCommand(message)) {
        logCommand(sharedState, clientIP, message);
        let result;
        try {
          result = GCode.receiveFC(robot, message);
        } catch (err) {
          return sendError(ws, 'FILE_ERROR', err.message, message);
        }
        if (result !== undefined) broadcast(wss, result);
        return;
      }

      /* ---------- Unknown input → targeted machine-readable error ---------- */
      sendError(ws, 'UNKNOWN_COMMAND', 'Unrecognized input', message);
    });
  });

  return wss;
}

/* ---------- Helpers ---------- */

/** Targeted reply to a single client (status updates use broadcast instead). */
function reply(ws, payload) {
  if (ws.readyState === WebSocket.OPEN) {
    ws.send(payload);
  }
}

/**
 * Machine-readable error response, sent only to the requesting client.
 * Shape: { type: "error", code, message, input }
 */
function sendError(ws, code, message, input) {
  reply(ws, JSON.stringify({ type: 'error', code, message, input }));
}

function broadcast(wss, payload) {
  wss.clients.forEach(client => {
    if (client.readyState === WebSocket.OPEN) {
      client.send(payload);
    }
  });
}

function logCommand(state, ip, message) {
  fs.appendFileSync(
    `${LOG_DIR}/gcode_commands.log`,
    `${new Date().toISOString()} ${ip}: ${message}\n`
  );
  state.lastCommands.push(`${new Date().toISOString()}: ${message}`);
  if (state.lastCommands.length > 10) state.lastCommands.shift();
}

function logPing(state, ip) {
  fs.appendFileSync(
    `${LOG_DIR}/pings.log`,
    `${new Date().toISOString()} ${ip} : Ping\n`
  );
  state.lastPings.push(`${new Date().toISOString()}  ${ip} : Ping`);
  if (state.lastPings.length > 10) state.lastPings.shift();
}

module.exports = initInputWS;
module.exports.ensureLogDir = ensureLogDir;