package mxgateway

import (
	"errors"
	"testing"
)

// TestMxAccessErrorUnwrapHResultPathNoTypedNilCommandError reproduces
// Client.Go-001: an MxAccessError built via the HRESULT / MxStatusProxy path
// leaves Command nil. Unwrap must not hand back a typed-nil *CommandError,
// because errors.As would then succeed while binding a nil pointer and a
// caller dereferencing it would panic.
func TestMxAccessErrorUnwrapHResultPathNoTypedNilCommandError(t *testing.T) {
	hresult := int32(-2147467259) // 0x80004005, a failing HRESULT.
	reply := &MxCommandReply{Hresult: &hresult}

	err := EnsureMxAccessSuccess("invoke", reply)
	if err == nil {
		t.Fatal("expected MxAccessError for a failing HRESULT, got nil")
	}

	var ce *CommandError
	if errors.As(err, &ce) {
		t.Fatalf("errors.As bound *CommandError from an HRESULT-only MxAccessError (ce=%v); "+
			"a caller dereferencing ce.Status would panic", ce)
	}
}

// TestMxAccessErrorUnwrapPopulatedCommand confirms the non-nil Command path
// still unwraps to the wrapped *CommandError.
func TestMxAccessErrorUnwrapPopulatedCommand(t *testing.T) {
	command := &CommandError{Op: "invoke"}
	err := &MxAccessError{Command: command}

	var ce *CommandError
	if !errors.As(err, &ce) {
		t.Fatal("errors.As failed to bind the populated *CommandError")
	}
	if ce != command {
		t.Fatalf("errors.As bound an unexpected *CommandError: got %v want %v", ce, command)
	}
}