const cds = require("@sap/cds");

const getDurationInMilliseconds = (start) => {
  const NS_PER_SEC = 1e9; //  convert to nanoseconds
  const NS_TO_MS = 1e6; // convert to milliseconds
  const diff = process.hrtime(start);
  return (diff[0] * NS_PER_SEC + diff[1]) / NS_TO_MS;
};

const getFormattedDateTime = () => {
  let currentDateTime = new Date();
  let formattedDateTime =
    currentDateTime.getFullYear() +
    "-" +
    (currentDateTime.getMonth() + 1) +
    "-" +
    currentDateTime.getDate() +
    " " +
    currentDateTime.getHours() +
    ":" +
    currentDateTime.getMinutes() +
    ":" +
    currentDateTime.getSeconds();
  return formattedDateTime;
};

const corsMiddleware = (req, res, next) => {
  res.header("Access-Control-Allow-Origin", "*");
  res.header(
    "Access-Control-Allow-Methods",
    "GET, PUT, PATCH, POST, DELETE, OPTIONS"
  );
  res.header(
    "Access-Control-Allow-Headers",
    "Origin, X-Requested-With, Content-Type, Accept, Authorization, Accept-Language"
  );

  //intercepts OPTIONS method
  if ("OPTIONS" === req.method) {
    //respond with 200
    res.sendStatus(200);
  } else {
    //move on
    next();
  }
};

// handle bootstrapping events...
cds.on("bootstrap", (app) => {
  if (cds.env.env === "development") {
    app.use(corsMiddleware);
  }
});
cds.on("served", async ({ db, messaging, ...servedServices }) => {
  // add logging current user before any request
  for (let i in servedServices) {
    servedServices[i].prepend((srv) => {
      srv.on("*", async (req, next) => {
        const method = req._.req.method;
        const url = req._.req.url;
        const start = process.hrtime();

        if (req.user) {
          console.log("[USER]:", req.user.id, req.user.attr, req.user._roles);
        }
        const result = await next();

        const status = req._.res.statusCode;
        const currentDateTime = getFormattedDateTime();
        const durationInMilliseconds = getDurationInMilliseconds(start);
        const log = `[${currentDateTime}] ${durationInMilliseconds.toLocaleString()} ms ${method}:${url} status: ${status} `;
        console.log(log);

        return result;
      });
    });
  }
});

module.exports = cds.server;