From d8d20e35e5af09c7304435d95a89a7c6ccc5dac4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Rudowicz?= <michal.rudowicz@fl9.eu>
Date: Mon, 4 Mar 2024 20:24:13 +0100
Subject: [PATCH] Device name from SATEL with error checking

---
 get_name.go      | 45 +++++++++++++++++++++++++++++++++++++++++----
 get_name_test.go | 11 ++++++++++-
 satel.go         | 39 ---------------------------------------
 3 files changed, 51 insertions(+), 44 deletions(-)

diff --git a/get_name.go b/get_name.go
index ad13e94..361a890 100644
--- a/get_name.go
+++ b/get_name.go
@@ -1,6 +1,7 @@
 package satel
 
 import (
+	"errors"
 	"strings"
 
 	"golang.org/x/text/encoding/charmap"
@@ -30,16 +31,52 @@ type NameEvent struct {
 	DevName         string
 }
 
-func makeNameEvent(bytes []byte) NameEvent {
+func makeNameEvent(bytes []byte) (*NameEvent, error) {
+	if len(bytes) < 19 {
+		return nil, errors.New("Received data too short")
+	}
 	cp1250dec := charmap.Windows1250.NewDecoder()
 	name, err := cp1250dec.String(string(bytes[3:19]))
 	if err != nil {
-		name = "CP1250 DECODE ERROR"
+		return nil, err
 	}
-	return NameEvent{
+	return &NameEvent{
 		DevType:         DeviceType(bytes[0]),
 		DevNumber:       bytes[1],
 		DevTypeFunction: bytes[2],
 		DevName:         strings.TrimSpace(name),
-	}
+	}, nil
+}
+
+type getNameResult struct {
+	ev *NameEvent
+	err error
+}
+
+func (s *Satel) GetName(devType DeviceType, devIndex byte) (*NameEvent, error) {
+	resultChan := make(chan getNameResult)
+
+	s.commandQueue <- func() {
+		err := s.sendCmd(0xEE, byte(devType), devIndex)
+		if err != nil {
+			resultChan <- getNameResult{nil, errors.New("Could not send Satel read device name")}
+		}
+
+		var bytes = <-s.rawEvents
+		if len(bytes) < (1 + 19 + 2) {
+			resultChan <- getNameResult{nil, errors.New("Received data too short")}
+		}
+		cmd := bytes[0]
+		bytes = bytes[1 : len(bytes)-2]
+		if cmd == 0xEF {
+			resultChan <- getNameResult{nil, errors.New("Did not receive a name")}
+		} else if cmd == 0xEE {
+			name, err := makeNameEvent(bytes)
+			resultChan <- getNameResult{name, err}
+		} else {
+			resultChan <- getNameResult{nil, errors.New("Received unexpected result instead of a name")}
+		}
+	}
+	nameResult := <-resultChan
+	return nameResult.ev, nameResult.err
 }
diff --git a/get_name_test.go b/get_name_test.go
index f961f07..ef32e66 100644
--- a/get_name_test.go
+++ b/get_name_test.go
@@ -7,10 +7,19 @@ import (
 
 func TestMakeNameEvent(t *testing.T) {
 	assert := assert.New(t)
+	name, err := makeNameEvent([]byte{01, 02, 03, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 0xFF})
 	assert.Equal(NameEvent{
 		DevType:         DeviceType(1),
 		DevNumber:       2,
 		DevTypeFunction: 3,
 		DevName:         "0123456789ABCDEF",
-	}, makeNameEvent([]byte{01, 02, 03, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 0xFF}))
+	}, *name)
+	assert.NoError(err)
+}
+
+func TestMakeNameEvent_tooShort(t *testing.T) {
+	assert := assert.New(t)
+	name, err := makeNameEvent([]byte{01, 02, 03, '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'})
+	assert.Nil(name)
+	assert.Error(err)
 }
diff --git a/satel.go b/satel.go
index da9f7e3..eadc443 100644
--- a/satel.go
+++ b/satel.go
@@ -3,7 +3,6 @@ package satel
 import (
 	"bufio"
 	"errors"
-	"fmt"
 	"net"
 	"sync"
 	"time"
@@ -105,44 +104,6 @@ func (s *Satel) SetOutput(code string, index int, value bool) error {
 	return s.sendCmd(bytes...)
 }
 
-func (s *Satel) GetName(devType DeviceType, devIndex byte) NameEvent {
-	resultChan := make(chan NameEvent)
-
-	s.commandQueue <- func() {
-		err := s.sendCmd(0xEE, byte(devType), devIndex)
-		if err != nil {
-			resultChan <- NameEvent{
-				DevType:         DeviceType(devType),
-				DevNumber:       devIndex,
-				DevTypeFunction: 0,
-				DevName:         fmt.Sprint("ERROR RETRIEVING NAME ", devType, devIndex),
-			}
-		}
-
-		var bytes = <-s.rawEvents
-		cmd := bytes[0]
-		bytes = bytes[1 : len(bytes)-2]
-		if cmd == 0xEF {
-			resultChan <- NameEvent{
-				DevType:         DeviceType(devType),
-				DevNumber:       devIndex,
-				DevTypeFunction: 0,
-				DevName:         fmt.Sprint("NO NAME ", devType, devIndex),
-			}
-		} else if cmd == 0xEE {
-			resultChan <- makeNameEvent(bytes)
-		} else {
-			resultChan <- NameEvent{
-				DevType:         DeviceType(devType),
-				DevNumber:       devIndex,
-				DevTypeFunction: 0,
-				DevName:         fmt.Sprint("ERROR GETTING NAME ", devType, devIndex),
-			}
-		}
-	}
-	return <-resultChan
-}
-
 func prepareCommand(code string, cmd byte, data ...byte) []byte {
 	bytes := append([]byte{cmd}, transformCode(code)...)
 	return append(bytes, data...)