const os = require("os");
const fs = require("fs");
const path = require("path");
const http = require("http");
const { io } = require("socket.io-client");
const HttpsProxyAgent = require("https-proxy-agent");
const { program, InvalidArgumentError, Argument } = require("commander");
const { TunnelRequest, TunnelResponse } = require("./lib");
const { generateUUID, addPrefixOnHttpSchema } = require("./util");

// constants
const PROFILE_DEFAULT = "default";

// create socket instance
let socket = null;

function keepAlive() {
  setTimeout(() => {
    if (socket && socket.connected) {
      socket.send("ping");
    }
    keepAlive();
  }, 5000);
}

function initClient(options) {
  // Please change this if your domain goes wrong here
  // Current style using sub-domain: https://{{clientId}}-tunnel.myhostingdomain.com
  // (Original server: https://tunnel.myhostingdomain.com)
  const profile = options.profile || PROFILE_DEFAULT;
  const clientId = `${options.clientId || generateUUID()}`;
  const clientIdSub = `${clientId}-${profile}-`;
  const serverUrl = addPrefixOnHttpSchema(options.server, clientIdSub);

  const initParams = {
    path: "/$cubetiq_http_tunnel",
    transports: ["websocket"],
    auth: {
      token: options.token,
      apiKey: options.apiKey,
      clientId: options.clientId,
      profile: options.profile,
      clientIdSub: clientIdSub,
      serverUrl: serverUrl,
    },
  };

  const http_proxy = process.env.https_proxy || process.env.http_proxy;
  if (http_proxy) {
    initParams.agent = new HttpsProxyAgent(http_proxy);
  }

  // Connecting to socket server and agent here...
  console.log(`client connecting to server: ${serverUrl}`);
  socket = io(serverUrl, initParams);

  const clientLogPrefix = `client: ${clientId} on profile: ${profile}`;
  socket.on("connect", () => {
    if (socket.connected) {
      console.log(`${clientLogPrefix} is connected to server successfully!`);
    }
  });

  socket.on("connect_error", (e) => {
    console.log(`${clientLogPrefix} connect error!`, e && e.message);
  });

  socket.on("disconnect", () => {
    console.log(`${clientLogPrefix} disconnected!`);
  });

  socket.on("request", (requestId, request) => {
    const isWebSocket = request.headers.upgrade === "websocket";
    console.log(`${isWebSocket ? "WS" : request.method}: `, request.path);
    request.port = options.port;
    request.hostname = options.host;

    if (options.origin) {
      request.headers.host = options.origin;
    }

    const tunnelRequest = new TunnelRequest({
      requestId,
      socket: socket,
    });

    const localReq = http.request(request);
    tunnelRequest.pipe(localReq);

    const onTunnelRequestError = (e) => {
      tunnelRequest.off("end", onTunnelRequestEnd);
      localReq.destroy(e);
    };

    const onTunnelRequestEnd = () => {
      tunnelRequest.off("error", onTunnelRequestError);
    };

    tunnelRequest.once("error", onTunnelRequestError);
    tunnelRequest.once("end", onTunnelRequestEnd);

    const onLocalResponse = (localRes) => {
      localReq.off("error", onLocalError);

      if (isWebSocket && localRes.upgrade) {
        return;
      }

      const tunnelResponse = new TunnelResponse({
        responseId: requestId,
        socket: socket,
      });

      tunnelResponse.writeHead(
        localRes.statusCode,
        localRes.statusMessage,
        localRes.headers,
        localRes.httpVersion
      );

      localRes.pipe(tunnelResponse);
    };

    const onLocalError = (error) => {
      console.log(error);
      localReq.off("response", onLocalResponse);
      socket.emit("request-error", requestId, error && error.message);
      tunnelRequest.destroy(error);
    };

    const onUpgrade = (localRes, localSocket, localHead) => {
      // localSocket.once('error', onTunnelRequestError);
      if (localHead && localHead.length) localSocket.unshift(localHead);

      const tunnelResponse = new TunnelResponse({
        responseId: requestId,
        socket: socket,
        duplex: true,
      });

      tunnelResponse.writeHead(null, null, localRes.headers);
      localSocket.pipe(tunnelResponse).pipe(localSocket);
    };

    localReq.once("error", onLocalError);
    localReq.once("response", onLocalResponse);

    if (isWebSocket) {
      localReq.on("upgrade", onUpgrade);
    }
  });

  keepAlive();
}

program.name("http-tunnel").description("CUBETIQ HTTP tunnel client");

program
  .command("start")
  .argument("<port>", "local server port number", (value) => {
    const port = parseInt(value, 10);
    if (isNaN(port)) {
      throw new InvalidArgumentError("Not a number.");
    }
    return port;
  })
  .option("-p, --profile <string>", "setting profile name", PROFILE_DEFAULT)
  .option("-h, --host <string>", "local host value", "localhost")
  .option("-o, --origin <string>", "change request origin")
  .action((port, options) => {
    const configDir = path.resolve(os.homedir(), ".http-tunnel");

    if (!fs.existsSync(configDir)) {
      fs.mkdirSync(configDir);
    }

    let config = {};
    const configFilename = `${options.profile}.json`;
    const configFilePath = path.resolve(configDir, configFilename);

    if (fs.existsSync(configFilePath)) {
      config = JSON.parse(fs.readFileSync(configFilePath, "utf8"));
    }

    if (!config.server) {
      console.error("Please set remote tunnel server firstly!");
      return;
    }

    if (!config.token) {
      console.error(`Please set jwt token for ${config.server} firstly!`);
      return;
    }

    if (!config.clientId) {
      console.error(`Please create client for ${config.server} firstly!`);
      return;
    }

    options.port = port;
    options.token = config.token;
    options.server = config.server;
    options.clientId = config.clientId;
    options.apiKey = config.apiKey;

    initClient(options);
  });

program
  .command("config")
  .addArgument(
    new Argument("<type>", "config type").choices([
      "token",
      "server",
      "client",
      "key",
    ])
  )
  .argument("<value>", "config value")
  .option("-p --profile <string>", "setting profile name", PROFILE_DEFAULT)
  .action((type, value, options) => {
    if (!type) {
      console.error("type config is required!");
      return;
    }

    const configDir = path.resolve(os.homedir(), ".http-tunnel");

    if (!fs.existsSync(configDir)) {
      fs.mkdirSync(configDir);
      console.log(`config file ${configDir} was created!`);
    }

    let config = {};
    const configFilename = `${options.profile}.json`;
    const configFilePath = path.resolve(configDir, configFilename);

    if (fs.existsSync(configFilePath)) {
      config = JSON.parse(fs.readFileSync(configFilePath, "utf8"));
    }

    if (type === "token" || type === "jwt") {
      config.token = value;
    } else if (type === "server") {
      config.server = value;
    } else if (type === "clientId" || type === "client") {
      if (!value || value === "" || value === "new") {
        config.clientId = generateUUID();
      } else {
        config.clientId = value;
      }
      console.log(`client: ${config.clientId} was set to config!`);
    } else if (type === "apiKey" || type === "key") {
      config.apiKey = value;
    } else {
      config[key] = value;
    }

    fs.writeFileSync(configFilePath, JSON.stringify(config, null, 2));
    console.log(`${type} config saved successfully to: ${configFilePath}!`);
  });

program.parse();