main.go

package main

import (
	"booking-app/helper"
	"fmt"
	"time"
)

const conferenceTickets = 50 //We cannot use := for constants
var conferenceName = "Go Conference"
var remainingTickets = 50 //we cannot use := when we declare variables on package level
var bookings = make([]UserData, 0)

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

func main() {

	greetUsers()

	for {
		firstName, lastName, email, userTickets := getUserInput()

		isValidName, isValidEmail, isValidTickets := helper.ValidateUserInput(firstName, lastName, email, userTickets, remainingTickets)

		if isValidName && isValidEmail && isValidTickets {
			bookTickets(userTickets, firstName, lastName, email)
			go sendTicket(userTickets, firstName, lastName, email)

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

			if remainingTickets == 0 {
				//end of program
				fmt.Println("Our conference tickets are sold out.")
				break
			}
		} else {
			if !isValidName {
				fmt.Println("Firstname or last name you entered is too short")
			}
			if !isValidEmail {
				fmt.Println("Email address is incorrect")
			}
			if !isValidTickets {
				fmt.Println("No of tickets is invalid")
			}
		}

	}

}

func greetUsers() {
	fmt.Printf("Welcome to %v booking application\n", conferenceName)
	fmt.Printf("We have total of %v tickets and %v are still available\n", conferenceTickets, remainingTickets)
	fmt.Println("get your tickets from here to attend")
}

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

func getUserInput() (string, string, string, int) {
	var firstName string
	var lastName string
	var email string
	var userTickets int
	// ask user for their name
	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 the number of tickets:")
	fmt.Scan(&userTickets)

	return firstName, lastName, email, userTickets
}

func bookTickets(userTickets int, firstName string, lastName string, email string) {

	remainingTickets = remainingTickets - userTickets

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

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

	fmt.Printf("Thank you %v %v for booking %v tickets. you will receive confirmation email at %v \n", firstName, lastName, userTickets, email)
	fmt.Printf("%v tickets remaining are available now\n", remainingTickets)
}

func sendTicket(userTickets int, firstName string, lastName string, email string) {
	time.Sleep(10 * time.Second)
	ticket := fmt.Sprintf("%v tickets for %v %v", userTickets, firstName, lastName)
	fmt.Println("#################")
	fmt.Printf("sending %v to email address %v\n", ticket, email)
	fmt.Println("#################")
}