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");

let socket = null;

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

function initClient(options) {
  const initParams = {
    path: "/$web_tunnel",
    transports: ["websocket"],
    auth: {
      token: options.token,
    },
  };

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

  socket = io(options.server, initParams);

  socket.on("connect", () => {
    if (socket.connected) {
      console.log("client connect to server successfully");
    }
  });

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

  socket.on("disconnect", () => {
    console.log("client 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("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", "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.log("Please set remote tunnel server firstly");
      return;
    }

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

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

    initClient(options);
  });

program
  .command("config")
  .addArgument(new Argument("<type>", "config type").choices(["jwt", "server"]))
  .argument("<value>", "config value")
  .option("-p --profile <string>", "setting profile name", "default")
  .action((type, value, 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 (type === "jwt") {
      config.token = value;
    }

    if (type === "server") {
      config.server = value;
    }

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

program.parse();