Trua nay an zi Slack - Run: brew install go && go run trua-nay-an-zi.go || go run trua-nay-an-zi.go

trua-nay-an-zi.go

package main

import (
	"bytes"
	"container/list"
	"encoding/json"
	"errors"
	"log"
	"math/rand"
	"net/http"
	"time"
)

// Set quan
var angi []string = []string{"Quan 1", "Quan 2", "Quan 3", "Quan 4", "Quan 5", "Quan 6", "Quan 7"}

// Set gio: 11:55:00 everyday
const hourToTick int = 11
const minuteToTick int = 55
const secondToTick int = 00
const intervalPeriod time.Duration = 24 * time.Hour

// Link Slack webhook
const webhookURL string = "https://hooks.slack.com/services/X1234"

func main() {
	queue := list.New()
	initQueue(queue)
	jt := newJobTicker()
	for {
		<-jt.t.C
		pingEveryone(queue)
		jt.updateJobTicker()
	}
}

func pingEveryone(queue *list.List) {
	quan := getFood(queue).Value.(string)
	msg := "Di an trua thoi moi nguoi oi, an o quan " + quan + " nha!"
	log.Println(msg)
	err := sendSlackNotification(webhookURL, msg)
	if err != nil {
		log.Println(err)
	}
}

type jobTicker struct {
	t *time.Timer
}

func getNextTickDuration() time.Duration {
	now := time.Now()
	nextTick := time.Date(now.Year(), now.Month(), now.Day(), hourToTick, minuteToTick, secondToTick, 0, time.Local)
	if nextTick.Before(now) {
		nextTick = nextTick.Add(intervalPeriod)
	}
	return nextTick.Sub(time.Now())
}

func newJobTicker() jobTicker {
	log.Println("Dang chay trong nen ahihi...")
	return jobTicker{time.NewTimer(getNextTickDuration())}
}

func (jt jobTicker) updateJobTicker() {
	jt.t.Reset(getNextTickDuration())
}

func initQueue(queue *list.List) {
	r := rand.New(rand.NewSource(time.Now().Unix()))
	for _, i := range r.Perm(len(angi)) {
		queue.PushBack(angi[i])
	}
}

func getFood(queue *list.List) *list.Element {
	if queue.Len() > 0 {
		e := queue.Front()
		queue.Remove(e)
		return e
	}
	initQueue(queue)
	return getFood(queue)
}

type slackRequestBody struct {
	Text string `json:"text"`
}

func sendSlackNotification(webhookURL string, msg string) error {
	slackBody, _ := json.Marshal(slackRequestBody{Text: msg})
	req, err := http.NewRequest(http.MethodPost, webhookURL, bytes.NewBuffer(slackBody))
	if err != nil {
		return err
	}
	req.Header.Add("Content-Type", "application/json")
	client := &http.Client{Timeout: 30 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	buf := new(bytes.Buffer)
	buf.ReadFrom(resp.Body)
	if buf.String() != "ok" {
		return errors.New("Slack khong cho gui")
	}
	return nil
}