now if checksum fails client will be close, and now client handle con…

…firmation invalid packet from server

pkg/client/main.go

@@ -93,17 +93,26 @@ func (c *Client) verifyConfirmation(confirm *msg.Confirmation) {
 	case msg.Result_VALID_CHECKSUM:
 		if err := c.validateCheckSum(confirm.Token); err != nil {
 			fmt.Println(err)
-			//if err := c.File.DeleteFile(); err != nil {
-			//	fmt.Println(err)
-			//}
+			if err := c.File.DeleteFile(); err != nil {
+				fmt.Println(err)
+			}
 			return
 		}
+
 		c.Transfering = false // stop reading packets
 		fmt.Println("sha256 checksum", c.File.CheckSum)
 		fmt.Println("file transfering succeed")
 
 		break
 	case msg.Result_OK, msg.Result_INVALID_PACKET_FORMAT:
+		token := c.File.LastReceivedToken()
+		if token != nil {
+			c.sendConfirmationPacket(
+				msg.Result_OK,
+				f.TokenHash(token.Index),
+			)
+			fmt.Println("re-sending confirmation token")
+		}
 	default:
 		break
 	}
@@ -136,6 +145,7 @@ func (c *Client) KeepCheckingServer(miss bool, missed int) {
 			break
 		case packet := <-c.PacketChannel:
 
+			//fmt.Println("packet: ", packet)
 			timer.Reset(time.Duration(RESEND_MAX_TIME) * time.Second)
 
 			if miss {

pkg/file/file.go

@@ -82,6 +82,17 @@ func (tF *TokenizableFile) FindNotReceivedToken() *Token {
 	return nil
 }
 
+func (tF *TokenizableFile) LastReceivedToken() *Token {
+
+	for i := len(tF.Tokens) - 1; i >= 0; i-- {
+		if tF.Tokens[i].Received {
+			return tF.Tokens[i]
+		}
+	}
+
+	return nil
+}
+
 func (tF *TokenizableFile) PushToken(idx int, received bool) {
 	tF.Tokens = append(tF.Tokens, &Token{Index: idx, Received: received})
 }

pkg/worker/worker.go

@@ -188,7 +188,7 @@ func (w *Worker) Execute() {
 				if err := pb.Unmarshal(buffer[1:], &confirm); err != nil {
 					slog.Error("failed confirmation to decode buffer as protobuf message", "address", w.Addr.String(), "error", err)
 					w.sendConfirmationPacket(msg.Result_INVALID_PACKET_FORMAT, "")
-					return // exit worker
+					break
 				}
 				// reset timer to wait next confirmation messages
 				timer.Reset(time.Duration(TIMEOUT) * time.Second)
@@ -197,10 +197,11 @@ func (w *Worker) Execute() {
 				case msg.Result_OK:
 					w.Waiting = false // stop waiting confirmation packet
 					if err := w.confirmPacket(confirm.Token); err != nil {
-						slog.Error("cannot confirm packet, failed to find token hash", "address", w.Addr.String(), "token", confirm.Token, "error", err)
+						//slog.Error("cannot confirm packet, failed to find token hash", "address", w.Addr.String(), "token", confirm.Token, "error", err)
 						w.sendConfirmationPacket(msg.Result_INVALID_TOKEN, confirm.Token)
+						break
 					}
-					slog.Info("received packet", "address", w.Addr.String(), "token", confirm.Token)
+					//slog.Info("received packet", "address", w.Addr.String(), "token", confirm.Token)
 					break
 				case msg.Result_PACKET_MISS:
 					w.resendLastPacket(confirm.Token)