From 673d298633b61e7764ad28eaac93fa36041ac58f Mon Sep 17 00:00:00 2001
From: Alexis Couvreur <alexiscouvreur.pro@gmail.com>
Date: Tue, 17 Mar 2026 14:15:11 -0400
Subject: [PATCH] feat(windows): add error code from async operation

---
 adapter_windows.go | 48 ++++++++++++++++++++++++++++++++++++++++++++++
 go.mod             |  2 +-
 go.sum             |  2 ++
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/adapter_windows.go b/adapter_windows.go
index 726a45e0..e5df9952 100644
--- a/adapter_windows.go
+++ b/adapter_windows.go
@@ -3,6 +3,8 @@ package bluetooth
 import (
 	"errors"
 	"fmt"
+	"syscall"
+	"unsafe"
 
 	"github.com/go-ole/go-ole"
 	"github.com/saltosystems/winrt-go"
@@ -55,11 +57,57 @@ func awaitAsyncOperation(asyncOperation *foundation.IAsyncOperation, genericPara
 	<-waitChan
 
 	if status != foundation.AsyncStatusCompleted {
+		if err := getAsyncError(asyncOperation); err != nil {
+			return fmt.Errorf("async operation failed with status %d: %w", status, err)
+		}
 		return fmt.Errorf("async operation failed with status %d", status)
 	}
 	return nil
 }
 
+// getAsyncError queries IAsyncInfo from an IAsyncOperation to retrieve
+// the error code of a failed async operation. If the HRESULT corresponds
+// to a Bluetooth ATT error (facility 0x65), it returns an AttributeProtocolError.
+func getAsyncError(asyncOperation *foundation.IAsyncOperation) error {
+	iid := ole.NewGUID(foundation.GUIDIAsyncInfo)
+
+	var asyncInfo *foundation.IAsyncInfo
+	hr, _, _ := syscall.SyscallN(
+		asyncOperation.VTable().QueryInterface,
+		uintptr(unsafe.Pointer(asyncOperation)),
+		uintptr(unsafe.Pointer(iid)),
+		uintptr(unsafe.Pointer(&asyncInfo)),
+	)
+	if hr != 0 {
+		return nil
+	}
+	defer asyncInfo.Release()
+
+	result, err := asyncInfo.GetErrorCode()
+	if err != nil {
+		return err
+	}
+	if result.Value == 0 {
+		return nil
+	}
+
+	return hresultToError(uint32(result.Value))
+}
+
+// hresultToError converts an HRESULT to an appropriate error type.
+// For Bluetooth ATT errors (facility 0x65), it returns an error with the ATT error code.
+// For other errors, it returns a generic error with the HRESULT value.
+func hresultToError(hr uint32) error {
+	facility := (hr >> 16) & 0x1FFF
+	code := hr & 0xFFFF
+
+	if facility == 0x65 { // FACILITY_BLUETOOTH_ATT
+		return fmt.Errorf("Bluetooth ATT error (code 0x%04X)", code)
+	}
+
+	return fmt.Errorf("HRESULT 0x%08X", hr)
+}
+
 func (a *Adapter) Address() (MACAddress, error) {
 	// TODO: get mac address
 	return MACAddress{}, errors.New("not implemented")
diff --git a/go.mod b/go.mod
index 6b79071d..cffcd88c 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,7 @@ go 1.22.1
 require (
 	github.com/go-ole/go-ole v1.2.6
 	github.com/godbus/dbus/v5 v5.1.0
-	github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b
+	github.com/saltosystems/winrt-go v0.0.0-20260317170058-9c2fec580d96
 	github.com/soypat/cyw43439 v0.0.0-20250505012923-830110c8f4af
 	github.com/tinygo-org/cbgo v0.0.4
 	golang.org/x/crypto v0.12.0
diff --git a/go.sum b/go.sum
index b7eeec2d..84dd9ab3 100644
--- a/go.sum
+++ b/go.sum
@@ -12,6 +12,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b h1:du3zG5fd8snsFN6RBoLA7fpaYV9ZQIsyH9snlk2Zvik=
 github.com/saltosystems/winrt-go v0.0.0-20240509164145-4f7860a3bd2b/go.mod h1:CIltaIm7qaANUIvzr0Vmz71lmQMAIbGJ7cvgzX7FMfA=
+github.com/saltosystems/winrt-go v0.0.0-20260317170058-9c2fec580d96 h1:IXxzj3yjfDNXZJ35foY+RpFShqPsZZ81hhCckgfh5PI=
+github.com/saltosystems/winrt-go v0.0.0-20260317170058-9c2fec580d96/go.mod h1:CIltaIm7qaANUIvzr0Vmz71lmQMAIbGJ7cvgzX7FMfA=
 github.com/sirupsen/logrus v1.5.0/go.mod h1:+F7Ogzej0PZc/94MaYx/nvG9jOFMD2osvC3s+Squfpo=
 github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
 github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=