chat: create ChatID Recipient type

bot_test.go

@@ -324,7 +324,7 @@ func TestBot(t *testing.T) {
 		assert.True(t, fwd.IsForwarded())
 
 		fwd.ID += 1 // nonexistent message
-		fwd, err = b.Forward(to, fwd)
+		_, err = b.Forward(to, fwd)
 		assert.Equal(t, ErrToForwardNotFound, err)
 	})
 

chat.go

@@ -86,3 +86,25 @@ type ChatMember struct {
 	//
 	RestrictedUntil int64 `json:"until_date,omitempty"`
 }
+
+// ChatID represents a chat or an user integer ID, which can be used
+// as recipient in bot methods. It is very useful in cases where
+// you have special group IDs, for example in your config, and don't
+// want to wrap it into *tb.Chat every time you send messages.
+//
+// Example:
+//
+//		group := tb.ChatID(-100756389456)
+//		b.Send(group, "Hello!")
+//
+//		type Config struct {
+//			AdminGroup tb.ChatID `json:"admin_group"`
+//		}
+//		b.Send(conf.AdminGroup, "Hello!")
+//
+type ChatID int64
+
+// Recipient returns chat ID (see Recipient interface).
+func (i ChatID) Recipient() string {
+	return strconv.FormatInt(int64(i), 10)
+}

chat_test.go

@@ -0,0 +1,21 @@
+package telebot
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestChat(t *testing.T) {
+	user := &User{ID: 1}
+	chat := &Chat{ID: 1}
+	chatID := ChatID(1)
+
+	assert.Implements(t, (*Recipient)(nil), user)
+	assert.Implements(t, (*Recipient)(nil), chat)
+	assert.Implements(t, (*Recipient)(nil), chatID)
+
+	assert.Equal(t, "1", user.Recipient())
+	assert.Equal(t, "1", chat.Recipient())
+	assert.Equal(t, "1", chatID.Recipient())
+}