main.go

package main

import (
	"fmt"
	"strings"
	"sync"
	"time"
)

const conferenceTickets int = 50

var webinarName = "Parul University Webinar"
var remainingSeats uint = 50
var reserved = make([]UserData, 0)

type UserData struct {
	firstName       string
	lastName        string
	email           string
	numberOfTickets uint
}

var wg = sync.WaitGroup{}

func main() {

	greetUsers()

	// for {
	firstName, lastName, email, userTickets := getUserInput()
	isValidName, isValidEmail, isValidTicketNumber := validateUserInput(firstName, lastName, email, userTickets)

	if isValidName && isValidEmail && isValidTicketNumber {

		bookTicket(userTickets, firstName, lastName, email)

		wg.Add(1)
		go sendTicket(userTickets, firstName, lastName, email)

		firstNames := getFirstNames()
		fmt.Printf("The first names of bookings are: %v\n", firstNames)

		if remainingSeats == 0 {
			// end program
			fmt.Println("Our conference is booked out. Come back next year.")
			// break
		}
	} else {
		if !isValidName {
			fmt.Println("first name or last name you entered is too short")
		}
		if !isValidEmail {
			fmt.Println("email address you entered doesn't contain @ sign")
		}
		if !isValidTicketNumber {
			fmt.Println("number of tickets you entered is invalid")
		}
	}
	//}
	wg.Wait()
}

func greetUsers() {
	fmt.Printf("Welcome to %v booking application\n", webinarName)
	fmt.Printf("We have total of %v seats and %v are still available.\n", conferenceTickets, remainingSeats)
	fmt.Println("Reserve your seats Now!!!")
}

func getFirstNames() []string {
	firstNames := []string{}
	for _, booking := range reserved {
		firstNames = append(firstNames, booking.firstName)
	}
	return firstNames
}

func getUserInput() (string, string, string, uint) {
	var firstName string
	var lastName string
	var email string
	var userSeats uint

	fmt.Println("Enter your first name: ")
	fmt.Scan(&firstName)

	fmt.Println("Enter your last name: ")
	fmt.Scan(&lastName)

	fmt.Println("Enter your email address: ")
	fmt.Scan(&email)

	fmt.Println("Enter number of tickets: ")
	fmt.Scan(&userSeats)

	return firstName, lastName, email, userSeats
}

func bookTicket(userTickets uint, firstName string, lastName string, email string) {
	remainingSeats = remainingSeats - userTickets

	var userData = UserData{
		firstName:       firstName,
		lastName:        lastName,
		email:           email,
		numberOfTickets: userTickets,
	}

	reserved = append(reserved, userData)
	fmt.Printf("List of bookings is %v\n", reserved)

	fmt.Printf("Thank you %v %v for booking %v tickets. You will receive a confirmation email at %v\n", firstName, lastName, userTickets, email)
	fmt.Printf("%v tickets remaining for %v\n", remainingSeats, webinarName)
}

func sendTicket(userSeats uint, firstName string, lastName string, email string) {
	time.Sleep(15 * time.Second)
	var ticket = fmt.Sprintf("%v tickets for %v %v", userSeats, firstName, lastName)
	fmt.Println("##############")
	fmt.Printf("Sending ticket:\n %v \nto email address %v\n", ticket, email)
	fmt.Println("##############")
	wg.Done()
}

func validateUserInput(firstName string, lastName string, email string, userTickets uint) (bool, bool, bool) {
	isValidName := len(firstName) >= 2 && len(lastName) >= 2
	isValidEmail := strings.Contains(email, "@")
	isValidTicketNumber := userTickets > 0 && userTickets <= remainingSeats
	return isValidName, isValidEmail, isValidTicketNumber
}