doc: added example of how to use command suggestion

docs/examples/suggestions_with_custom_commands.md

@@ -0,0 +1,143 @@
+# Suggestions with custom commands
+
+Suggestions with personalized commands, so that when the user types "/", they will receive suggestions for possible commands. Also, add a menu to view all the available commands.
+
+```go
+package main
+
+import (
+	"bufio"
+	"context"
+	"log"
+	"os"
+
+	tgbotapi "github.com/go-telegram-bot-api/telegram-bot-api/v5"
+)
+
+var (
+	bot *tgbotapi.BotAPI
+)
+
+func main() {
+	var err error
+	bot, err = tgbotapi.NewBotAPI("<TELEGRAM_APITOKEN>")
+	if err != nil {
+		log.Panic(err)
+	}
+
+	bot.Debug = true
+
+	u := tgbotapi.NewUpdate(0)
+	u.Timeout = 60
+
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	updates := bot.GetUpdatesChan(u)
+
+	commands := []tgbotapi.BotCommand{
+		{
+			Command:     "repo",
+			Description: "repository",
+		},
+		{
+			Command:     "issues",
+			Description: "contribute reviews to issues",
+		},
+		{
+			Command:     "pr",
+			Description: "pull requests",
+		},
+		{
+			Command:     "doc",
+			Description: "documentation",
+		},
+	}
+
+	// Defines the ReplyKeyboardMarkup object with custom commands as suggestions
+	replyKeyboard := tgbotapi.NewReplyKeyboard(
+		tgbotapi.NewKeyboardButtonRow(
+			tgbotapi.NewKeyboardButton("/repo"),
+			tgbotapi.NewKeyboardButton("/issues"),
+			tgbotapi.NewKeyboardButton("/pr"),
+			tgbotapi.NewKeyboardButton("/doc"),
+		),
+	)
+	replyKeyboard.ResizeKeyboard = true
+
+	config := tgbotapi.NewSetMyCommands(commands...)
+	bot.Send(config)
+
+	go receiveUpdates(ctx, updates)
+
+	log.Println("INFO: Start listening for updates. Press enter to stop")
+
+	_, err = bufio.NewReader(os.Stdin).ReadBytes('\n')
+	if err != nil {
+		log.Printf("ERROR: %s", err.Error())
+	}
+}
+
+func receiveUpdates(ctx context.Context, updates tgbotapi.UpdatesChannel) {
+	<-updates
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case update := <-updates:
+			handleUpdate(update)
+		}
+	}
+}
+
+func Commands(message *tgbotapi.Message, command string) error {
+	chatID := message.Chat.ID
+
+	switch message.Command() {
+	case "repo":
+		return SendMessage(chatID, "Repository: https://github.com/go-telegram-bot-api/telegram-bot-api")
+
+	case "issues":
+		return SendMessage(chatID, "Issues: https://github.com/go-telegram-bot-api/telegram-bot-api/issues")
+
+	case "pr":
+		return SendMessage(chatID, "Pull requests: https://github.com/go-telegram-bot-api/telegram-bot-api/pulls")
+
+	case "doc":
+		return SendMessage(chatID, "Documentation: https://go-telegram-bot-api.dev/")
+	default:
+		return SendMessage(chatID, "Not Found Command")
+	}
+}
+
+func handleUpdate(update tgbotapi.Update) {
+	switch {
+	case update.Message != nil:
+		handleMessage(update.Message)
+	}
+}
+
+func handleMessage(message *tgbotapi.Message) {
+	user := message.From
+	text := message.Text
+
+	if user == nil {
+		return
+	}
+
+	if message.IsCommand() {
+		err := Commands(message, text)
+		if err != nil {
+			log.Printf("ERROR: %s", err.Error())
+			return
+		}
+	}
+}
+
+func SendMessage(chatID int64, msg string) error {
+	_, err := bot.Send(tgbotapi.NewMessage(chatID, msg))
+	return err
+}
+```