Adds initial implementation of the Telegram bot

notification/service_telegram.go

@@ -1,22 +1,52 @@
 package notification
 
 import (
+	"fmt"
+	"strconv"
+
 	"git.ctrlz.es/mgdelacroix/birthdaybot/model"
 	"github.com/charmbracelet/log"
+	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
 )
 
 type TelegramNotificationService struct {
 	logger *log.Logger
 	config *model.TelegramNotificationsConfig
+	bot    *tgbotapi.BotAPI
 }
 
-func NewTelegramNotificationService(logger *log.Logger, config *model.TelegramNotificationsConfig) *TelegramNotificationService {
+func NewTelegramNotificationService(logger *log.Logger, config *model.TelegramNotificationsConfig) (*TelegramNotificationService, error) {
+	bot, err := tgbotapi.NewBotAPI(config.BotToken)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create bot: %w", err)
+	}
+
+	botUser, err := bot.GetMe()
+	if err != nil {
+		return nil, fmt.Errorf("cannot get bot information: %w", err)
+	}
+
+	logger.Info("telegram bot initialized", "id", botUser.ID, "username", botUser.UserName)
+
 	return &TelegramNotificationService{
 		logger: logger,
 		config: config,
-	}
+		bot:    bot,
+	}, nil
 }
 
 func (tns *TelegramNotificationService) Notify(birthday *model.Birthday) error {
+	// ToDo: introduce templates here
+	msgText := fmt.Sprintf("It's %s's birthday! You can reach them out at %s or %s", birthday.Name, birthday.Email, birthday.Phone)
+	chatID, err := strconv.Atoi(tns.config.ChannelID)
+	if err != nil {
+		return fmt.Errorf("cannot parse ChannelID: %w", err)
+	}
+
+	msg := tgbotapi.NewMessage(int64(chatID), msgText)
+	if _, err := tns.bot.Send(msg); err != nil {
+		return fmt.Errorf("error sending message: %w", err)
+	}
+
 	return nil
 }