app.js

const express = require("express");
const app = express();
const port = 3000;

let golfCoursesData = {
  timeslots: {
    "08:00": { capacity: 4, booked: [], waitingList: [] },
    "10:00": { capacity: 4, booked: [], waitingList: [] },
  },
};

const addBooking = (user) => {
  if (!golfCoursesData.timeslots[user.slot]) {
    console.log("Invalid time slot");
    return;
  }

  if (
    golfCoursesData.timeslots[user.slot].booked.length <
    golfCoursesData.timeslots[user.slot].capacity
  ) {
    console.log("Booking successful!");
    golfCoursesData.timeslots[user.slot].booked.push(user);
  } else {
    console.log("Sorry, the time slot is full. Adding to waitlist.");

    if (golfCoursesData.timeslots[user.slot].waitingList.length < 2) {
      console.log("You have been added to the waiting list");
      golfCoursesData.timeslots[user.slot].waitingList.push(user);
    } else {
      console.log(
        "Sorry, the waiting list is full. Please try another time slot."
      );
    }
  }
};

const cancelBooking = (user) => {
  if (!golfCoursesData.timeslots[user.slot]) {
    console.log("Invalid time slot. No booking found for user");
    return;
  }

  if (golfCoursesData.timeslots[user.slot].booked.length > 0) {
    const index = golfCoursesData.timeslots[user.slot].booked.findIndex(
      (booking) => booking.user === user.user
    );
    if (index === -1) {
      console.log("No booking found for user");
      return;
    }
    golfCoursesData.timeslots[user.slot].booked.splice(index, 1);
    console.log("Booking cancelled");

    // Checking for waiting list
    if (golfCoursesData.timeslots[user.slot].waitingList.length > 0) {
      const nextUser = golfCoursesData.timeslots[user.slot].waitingList.shift();
      console.log("Next user in waiting list: ", nextUser);
      addBooking(nextUser);
    }
  }
};

const viewBookings = () => {
  for (const [key, value] of Object.entries(golfCoursesData.timeslots)) {
    console.log(
      `${key}: ${value.booked.length} booked. waiting list: ${
        value.waitingList.length
      }. Booked users: ${value.booked.map((user) => user.user)}`
    );
  }
};

// Step 1
addBooking({ slot: "08:00", user: "user1" });
addBooking({ slot: "08:00", user: "user2" });
addBooking({ slot: "08:00", user: "user3" });
addBooking({ slot: "08:00", user: "user4" });
addBooking({ slot: "08:00", user: "user5" });
addBooking({ slot: "08:00", user: "user6" });
addBooking({ slot: "08:00", user: "user7" });
console.log("\n\n\n");

// Step 2
cancelBooking({ slot: "08:00", user: "user4" });
console.log("\n\n\n");
cancelBooking({ slot: "08:00", user: "user5" });
console.log("\n\n\n");
addBooking({ slot: "08:00", user: "user8" });
console.log("\n\n\n");

// Step 3
viewBookings();

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});