//go:build windows

package win

import (
	"reflect"
	"syscall"
	"unsafe"

	"golang.org/x/sys/windows"
)

const (
	COINIT_MULTITHREADED     = windows.COINIT_MULTITHREADED
	COINIT_APARTMENTTHREADED = windows.COINIT_APARTMENTTHREADED
	COINIT_DISABLE_OLE1DDE   = windows.COINIT_DISABLE_OLE1DDE
	COINIT_SPEED_OVER_MEMORY = windows.COINIT_SPEED_OVER_MEMORY

	CLSCTX_INPROC_SERVER  = windows.CLSCTX_INPROC_SERVER
	CLSCTX_INPROC_HANDLER = windows.CLSCTX_INPROC_HANDLER
	CLSCTX_LOCAL_SERVER   = windows.CLSCTX_LOCAL_SERVER
	CLSCTX_REMOTE_SERVER  = windows.CLSCTX_REMOTE_SERVER
	CLSCTX_ALL            = windows.CLSCTX_INPROC_SERVER | windows.CLSCTX_INPROC_HANDLER | windows.CLSCTX_LOCAL_SERVER | windows.CLSCTX_REMOTE_SERVER

	E_CANCELED         = windows.ERROR_CANCELLED | windows.FACILITY_WIN32<<16 | 0x80000000
	RPC_E_CHANGED_MODE = syscall.Errno(windows.RPC_E_CHANGED_MODE)
)

func CoInitializeEx(reserved uintptr, coInit uint32) error {
	return windows.CoInitializeEx(reserved, coInit)
}

func CoUninitialize() { windows.CoUninitialize() }

// https://github.com/wine-mirror/wine/blob/master/include/unknwn.idl

type _IUnknownBase struct{ COMObject }
type _IUnknownVtbl struct {
	QueryInterface uintptr
	AddRef         uintptr
	Release        uintptr
}

func (c *_IUnknownBase) Release() {
	vtbl := (*(**_IUnknownVtbl)(unsafe.Pointer(c)))
	c.Call(vtbl.Release)
}

type COMObject struct{}

//go:uintptrescapes
func (o *COMObject) Call(trap uintptr, a ...uintptr) (r1, r2 uintptr, lastErr error) {
	switch nargs := uintptr(len(a)); nargs {
	case 0:
		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), 0, 0)
	case 1:
		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), a[0], 0)
	case 2:
		return syscall.Syscall(trap, nargs+1, uintptr(unsafe.Pointer(o)), a[0], a[1])
	default:
		panic("COM call with too many arguments.")
	}
}

//sys CoCreateInstance(clsid uintptr, unkOuter *COMObject, clsContext int32, iid uintptr, address unsafe.Pointer) (res error) = ole32.CoCreateInstance
//sys CoTaskMemFree(address Pointer) = ole32.CoTaskMemFree

func uuid(s string) uintptr {
	return (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
}