telegram-bot-send-message/main.go

package main

import (
	"fmt"
	"log"
	"os"
	"strconv"
	"time"

	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
)

type Config struct {
	Token  string `json:"token"`
	ChatId int64  `json:"chat_id"`
}

func readConfig() (Config, error) {
	config := Config{}

	config.Token = os.Getenv("TELEGRAM_BOT_TOKEN")

	var err error
	config.ChatId, err = strconv.ParseInt(os.Getenv("TELEGRAM_CHAT_ID"), 10, 64)
	if err != nil {
		return config, err
	}

	return config, nil
}

const DEADLINE = 6000

func main() {
	config, err := readConfig()
	if err != nil {
		panic(err)
	}

	text := "No se especificó un mensaje."
	if len(os.Args) > 1 {
		text = os.Args[1]
	}

	delay := 1
	original_time := time.Now()

	for true {
		bot, err := tgbotapi.NewBotAPI(config.Token)
		if err != nil {
			log.Println(err)
			delay = delay * 2
			if delay > DEADLINE {
				break
			}
			time.Sleep(time.Second * time.Duration(delay))
			continue
		}

		timestamp := ""
		if delay > 1 {
			timestamp = fmt.Sprintf("[%s] ", original_time)
		}

		msg := tgbotapi.NewMessage(config.ChatId, timestamp+text)

		if _, err := bot.Send(msg); err != nil {
			log.Println(err)
			delay = delay * 2
			if delay > DEADLINE {
				break
			}
			time.Sleep(time.Second * time.Duration(delay))
			continue
		} else {
			break
		}
	}
}