bootdotdev-fcc-learn-golang-assets/course/13-channels/exercises/7-select/complete.go

package main

import (
	"fmt"
	"math/rand"
	"time"
)

func logMessages(chEmails, chSms chan string) {
	for {
		select {
		case email, ok := <-chEmails:
			if !ok {
				return
			}
			logEmail(email)
		case sms, ok := <-chSms:
			if !ok {
				return
			}
			logSms(sms)
		}
	}
}

// TEST SUITE - Don't touch below this line

func logSms(sms string) {
	fmt.Println("SMS:", sms)
}

func logEmail(email string) {
	fmt.Println("Email:", email)
}

func test(sms []string, emails []string) {
	fmt.Println("Starting...")

	chSms, chEmails := sendToLogger(sms, emails)

	logMessages(chEmails, chSms)
	fmt.Println("===============================")
}

func main() {
	rand.Seed(0)
	test(
		[]string{
			"hi friend",
			"What's going on?",
			"Welcome to the business",
			"I'll pay you to be my friend",
		},
		[]string{
			"Will you make your appointment?",
			"Let's be friends",
			"What are you doing?",
			"I can't believe you've done this.",
		},
	)
	test(
		[]string{
			"this song slaps hard",
			"yooo hoooo",
			"i'm a big fan",
		},
		[]string{
			"What do you think of this song?",
			"I hate this band",
			"Can you believe this song?",
		},
	)
}

func sendToLogger(sms, emails []string) (chSms, chEmails chan string) {
	chSms = make(chan string)
	chEmails = make(chan string)
	go func() {
		for i := 0; i < len(sms) && i < len(emails); i++ {
			done := make(chan struct{})
			s := sms[i]
			e := emails[i]
			t1 := time.Millisecond * time.Duration(rand.Intn(1000))
			t2 := time.Millisecond * time.Duration(rand.Intn(1000))
			go func() {
				time.Sleep(t1)
				chSms <- s
				done <- struct{}{}
			}()
			go func() {
				time.Sleep(t2)
				chEmails <- e
				done <- struct{}{}
			}()
			<-done
			<-done
			time.Sleep(10 * time.Millisecond)
		}
		close(chSms)
		close(chEmails)
	}()
	return chSms, chEmails
}