package main

import (
	"log"
	"os"
	"time"

	"gitea.nulo.in/Nulo/zulip-checkin-cyborg/zulip"
	"golang.org/x/exp/slices"
)

var bot zulip.Bot
var stream string
var message string

func main() {
	bot.Url = os.Getenv("ZULIP_URL")
	if len(bot.Url) == 0 {
		log.Fatalln("Falta ZULIP_URL")
	}
	bot.Email = os.Getenv("ZULIP_BOT_EMAIL")
	if len(bot.Email) == 0 {
		log.Fatalln("Falta ZULIP_BOT_EMAIL")
	}
	bot.Key = os.Getenv("ZULIP_BOT_KEY")
	if len(bot.Key) == 0 {
		log.Fatalln("Falta ZULIP_BOT_KEY")
	}
	stream = os.Getenv("ZULIP_STREAM")
	if len(stream) == 0 {
		stream = "check-in bot test"
	}
	message = os.Getenv("ZULIP_MESSAGE")
	if len(message) == 0 {
		message = "prueba de mensaje"
	}

	cycle()
}

const timezoneOffset = -3

func cycle() {
	date := getDate()
	if time.Now().After(date) {
		err := createIfNotExists(date.Format("semana 2006-01-02"))
		if err != nil {
			log.Fatalln(err)
		}
	}

	time.Sleep(time.Minute * 10)
	cycle()
}

func getDate() time.Time {
	year, month, day := time.Now().Date()
	currentZeroDay := time.Date(year, month, day, 0, 0, 0, 0, time.UTC)
	now := time.Now()
	zeroMonday := currentZeroDay.Add(time.Duration(-time.Hour * 24 * time.Duration(now.Weekday()-time.Monday)))
	return zeroMonday.Add(time.Hour * (8 - timezoneOffset))
}

func createIfNotExists(topicName string) (err error) {
	streamId, err := bot.GetStreamId(stream)
	if err != nil {
		log.Fatalln(err)
	}
	topics, err := bot.GetStreamTopics(streamId)
	if err != nil {
		log.Fatalln(err)
	}
	names := mapSlice(topics, func(t zulip.GetStreamTopicsResStream) string {
		return t.Name
	})

	if slices.Contains(names, topicName) {
		return
	}

	err = bot.SendMessage(stream, topicName, message)
	if err != nil {
		return
	}
	return
}

// https://gosamples.dev/generics-map-function/
func mapSlice[T any, M any](a []T, f func(T) M) []M {
	n := make([]M, len(a))
	for i, e := range a {
		n[i] = f(e)
	}
	return n
}