const path = require("path");
const fs = require("fs");
const swaggerUi = require("swagger-ui-express");

const express = require("express");
const helmet = require("helmet");
const cors = require("cors");
const logger = require("./utils/logger");
const { verifyJWT } = require("./middleware/verifyJWT");
const { handleErrors } = require("./middleware/handleErrors");
const { errorMessages } = require("./utils/messages");
const authRouter = require("./routes/authRoute");
const inviteRouter = require("./routes/inviteRoute");
const monitorRouter = require("./routes/monitorRoute");
const checkRouter = require("./routes/checkRoute");
const maintenanceWindowRouter = require("./routes/maintenanceWindowRoute");
const settingsRouter = require("./routes/settingsRoute");

const { connectDbAndRunServer } = require("./configs/db");
const queueRouter = require("./routes/queueRoute");
const JobQueue = require("./service/jobQueue");
const NetworkService = require("./service/networkService");
const EmailService = require("./service/emailService");
const SettingsService = require("./service/settingsService");
const SERVICE_NAME = "Server";

let cleaningUp = false;
const openApiSpec = JSON.parse(
  fs.readFileSync(path.join(__dirname, "openapi.json"), "utf8")
);
// Need to wrap server setup in a function to handle async nature of JobQueue
const startApp = async () => {
  // **************************
  // Here is where we can swap out DBs easily.  Spin up a mongoDB instance and try it out.
  // Simply comment out the FakeDB and uncomment the MongoDB or vice versa.
  // We can easily swap between any type of data source as long as the methods are implemented
  //
  // FakeDB
  // const db = require("./db/FakeDb");
  //
  // MongoDB
  // const db = require("./db/MongoDB");
  //
  // **************************
  const DB_TYPE = {
    MongoDB: () => require("./db/mongo/MongoDB"),
    FakedDB: () => require("./db/FakeDb"),
  };

  // const db = DB_TYPE[process.env.DB_TYPE]
  //   ? DB_TYPE[process.env.DB_TYPE]()
  //   : require("./db/FakeDb");

  const db = DB_TYPE.MongoDB();

  const app = express();

  // middlewares
  app.use(
    cors()
    //We will add configuration later
  );
  app.use(express.json());
  app.use(helmet());
  // **************************
  // Make DB accessible anywhere we have a Request object
  // By adding the DB to the request object, we can access it in any route
  // Thus we do not need to import it in every route file, and we can easily swap out DBs as there is only one place to change it
  // Same applies for JobQueue and emailService
  // **************************
  app.use((req, res, next) => {
    req.db = db;
    req.jobQueue = jobQueue;
    req.emailService = emailService;
    req.settingsService = settingsService;
    next();
  });

  // Swagger UI
  app.use("/api-docs", swaggerUi.serve, swaggerUi.setup(openApiSpec));

  //routes
  app.use("/api/v1/auth", authRouter);
  app.use("/api/v1/settings", verifyJWT, settingsRouter);
  app.use("/api/v1/invite", inviteRouter);
  app.use("/api/v1/monitors", verifyJWT, monitorRouter);
  app.use("/api/v1/checks", verifyJWT, checkRouter);
  app.use("/api/v1/maintenance-window", verifyJWT, maintenanceWindowRouter);
  app.use("/api/v1/queue", verifyJWT, queueRouter);

  //health check
  app.use("/api/v1/healthy", (req, res) => {
    try {
      logger.info("Checking Health of the server.");
      return res.status(200).json({ message: "Healthy" });
    } catch (error) {
      logger.error(error.message);
      return res.status(500).json({ message: error.message });
    }
  });

  app.use("/api/v1/mail", async (req, res) => {
    try {
      const id = await req.emailService.buildAndSendEmail(
        "welcomeEmailTemplate",
        {
          name: "Alex",
        },
        "ajhollid@gmail.com",
        "Welcome"
      );
      res.status(200).json({ success: true, msg: "Email sent", data: id });
    } catch (error) {
      logger.error(error.message);
      return res.status(500).json({ message: error.message });
    }
  });

  /**
   * Error handler middleware
   * Should be called last
   */
  app.use(handleErrors);

  // Create services
  await connectDbAndRunServer(app, db);
  const settingsService = new SettingsService();

  await settingsService.loadSettings();
  const emailService = new EmailService(settingsService);
  const networkService = new NetworkService(db, emailService);
  const jobQueue = await JobQueue.createJobQueue(
    db,
    networkService,
    settingsService
  );

  const cleanup = async () => {
    if (cleaningUp) {
      console.log("Already cleaning up");
      return;
    }
    cleaningUp = true;
    try {
      console.log("Shutting down gracefully");
      await jobQueue.obliterate();
      console.log("Finished cleanup");
    } catch (error) {
      logger.error(errorMessages.JOB_QUEUE_DELETE_JOB, {
        service: SERVICE_NAME,
        errorMsg: error.message,
      });
    }
    process.exit(0);
  };
  process.on("SIGUSR2", cleanup);
  process.on("SIGINT", cleanup);
  process.on("SIGTERM", cleanup);
};

startApp().catch((error) => {
  console.log(error);
});