Feat(Initial): Initial Go codebase

backend/internal/telegrampackage/telegram.go

@@ -0,0 +1,173 @@
+package telegrampackage
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"math/rand"
+	"strings"
+	"time"
+
+	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
+
+type ChatIDMap struct {
+	ID          uuid.UUID `gorm:"primaryKey;type:uuid;default:uuid_generate_v4()"`
+	CreatedAt   time.Time
+	UpdatedAt   time.Time
+	DeletedAt   gorm.DeletedAt `gorm:"index"`
+	ChatID      int64
+	ChatIDShort string
+}
+
+func (env *Env) TelegramSend(chatIDShort string, msg string) error {
+	if chatIDShort == "" {
+		return errors.New("no chat ID provided")
+	}
+	bot, err := tgbotapi.NewBotAPI(env.TelegramAPIKey)
+	if err != nil {
+		log.Println(err)
+		return err
+	}
+	var chatIDMap ChatIDMap
+	err = env.DB.Where(&ChatIDMap{ChatIDShort: chatIDShort}).Last(&chatIDMap).Error
+	if err != nil {
+		log.Println(err)
+		log.Println("No such telegram chat ID")
+		return err
+	}
+	chatMsg := tgbotapi.NewMessage(chatIDMap.ChatID, msg)
+	_, err = bot.Send(chatMsg)
+	if err != nil {
+		log.Println(err)
+	}
+	return nil
+}
+
+func (env *Env) TelegramListenAndGen() error {
+	for {
+		bot, err := tgbotapi.NewBotAPI(env.TelegramAPIKey)
+		if err != nil {
+			log.Println(err)
+			log.Println("Error occured on Telegram listen. Waiting 1 minute")
+			time.Sleep(60 * time.Second)
+		}
+		u := tgbotapi.NewUpdate(0)
+		u.Timeout = 60
+
+		updates := bot.GetUpdatesChan(u)
+
+		for update := range updates {
+			if update.Message == nil { // ignore any non-Message Updates
+				continue
+			}
+
+			log.Printf("New message: [%s] %s", update.Message.From.UserName, update.Message.Text)
+
+			// check if contains registration
+			if strings.Compare(update.Message.Text, "/register") == 0 {
+				var chatIDMap ChatIDMap
+				err := env.DB.Where(&ChatIDMap{ChatID: update.Message.Chat.ID}).Last(&chatIDMap).Error
+				// chatID already exists
+				if err == nil {
+					msg := tgbotapi.NewMessage(update.Message.Chat.ID, "You already have a chat ID")
+					_, err := bot.Send(msg)
+					if err != nil {
+						log.Println(err)
+					}
+					msg = tgbotapi.NewMessage(update.Message.Chat.ID, fmt.Sprintf("Your chat ID is: %s", chatIDMap.ChatIDShort))
+					_, err = bot.Send(msg)
+					if err != nil {
+						log.Println(err)
+					}
+				} else {
+					currChatCode := genShortCode(5)
+					chatIDMap.ChatIDShort = currChatCode
+					chatIDMap.ChatID = update.Message.Chat.ID
+					err := env.DB.Create(&chatIDMap).Error
+					if err != nil {
+						fmt.Println(err)
+					}
+					msg := tgbotapi.NewMessage(update.Message.Chat.ID, fmt.Sprintf("Your chat ID is: %s", chatIDMap.ChatIDShort))
+					_, err = bot.Send(msg)
+					if err != nil {
+						log.Println(err)
+					}
+				}
+			} else {
+				// Get his current chat ID
+				var chatIDMap ChatIDMap
+				err := env.DB.Where(&ChatIDMap{ChatID: update.Message.Chat.ID}).Last(&chatIDMap).Error
+				if err != nil {
+					fmt.Println(err)
+				}
+
+				var handled = false
+				for _, currFunc := range env.HandlerFunctions {
+					currHandled, responseText := currFunc(chatIDMap.ChatIDShort, update.Message.Text)
+					handled = handled || currHandled
+					if responseText != nil {
+						splitSendMessage(bot, update.Message.Chat.ID, *responseText)
+					}
+				}
+				if !handled {
+					msg := tgbotapi.NewMessage(update.Message.Chat.ID, "Please send /register to register for a chat ID")
+					_, err := bot.Send(msg)
+					if err != nil {
+						log.Println(err)
+					}
+				}
+			}
+
+		}
+	}
+}
+
+func genShortCode(n int) string {
+	var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	runeCode := make([]rune, n)
+	for i := range runeCode {
+		runeCode[i] = letters[rand.Intn(len(letters))]
+	}
+	return string(runeCode)
+}
+
+func splitSendMessage(bot *tgbotapi.BotAPI, chatID int64, message string) {
+	MAXMESSAGELENGTH := 2000
+
+	leftoverMessage := []rune(tgbotapi.EscapeText("HTML", message))
+	if len(leftoverMessage) > MAXMESSAGELENGTH {
+		for len(leftoverMessage) > 0 {
+			var currMessage []rune
+			if len(leftoverMessage) <= MAXMESSAGELENGTH {
+				currMessage = leftoverMessage[:]
+				leftoverMessage = []rune("")
+			} else {
+				currMessage = leftoverMessage[:MAXMESSAGELENGTH]
+				leftoverMessage = leftoverMessage[MAXMESSAGELENGTH:]
+			}
+
+			msg := tgbotapi.NewMessage(chatID, string(currMessage))
+			msg.ParseMode = "HTML"
+			msg.DisableWebPagePreview = true
+			_, err := bot.Send(msg)
+			if err != nil {
+				msg := tgbotapi.NewMessage(chatID, err.Error())
+				bot.Send(msg)
+				log.Println(err)
+			}
+		}
+	} else {
+		msg := tgbotapi.NewMessage(chatID, string(message))
+		msg.ParseMode = "HTML"
+		msg.DisableWebPagePreview = true
+		_, err := bot.Send(msg)
+		if err != nil {
+			msg := tgbotapi.NewMessage(chatID, err.Error())
+			bot.Send(msg)
+			log.Println(err)
+		}
+	}
+}