package win32api

import (
	"errors"
	"syscall"
	"unsafe"
)

func WTSGetActiveConsoleSessionId() (DWORD, error) {
	kernel32, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		return 0, errors.New("Can't Load Kernel32 API")
	}
	defer syscall.FreeLibrary(kernel32)
	WTGet, err := syscall.GetProcAddress(syscall.Handle(kernel32), "WTSGetActiveConsoleSessionId")
	if err != nil {
		return 0, errors.New("Can't Load WTSGetActiveConsoleSessionId API")
	}
	res, _, _ := syscall.Syscall(uintptr(WTGet), 0, 0, 0, 0)
	return DWORD(res), nil
}

func CloseHandle(hObject HANDLE) error {
	kernel32, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		return errors.New("Can't Load Kernel32 API")
	}
	defer syscall.FreeLibrary(kernel32)
	CH, err := syscall.GetProcAddress(syscall.Handle(kernel32), "CloseHandle")
	if err != nil {
		return errors.New("Can't Load CloseHandle API")
	}
	if r, _, err := syscall.Syscall(uintptr(CH), 1, uintptr(hObject), 0, 0); r == 0 {
		return err
	}
	return nil
}

func CreateToolhelp32Snapshot(dwFlags, th32ProcessID DWORD) (HANDLE, error) {
	kernel32, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		return 0, errors.New("Can't Load Kernel32 API")
	}
	defer syscall.FreeLibrary(kernel32)
	CTS, err := syscall.GetProcAddress(syscall.Handle(kernel32), "CreateToolhelp32Snapshot")
	if err != nil {
		return 0, errors.New("Can't Load CreateToolhelp32Snapshot API")
	}
	r, _, err := syscall.Syscall(uintptr(CTS), 2, uintptr(dwFlags), uintptr(th32ProcessID), 0)
	if int(r) == -1 {
		return 0, err
	}
	return HANDLE(r), nil
}

func Process32Next(hSnapshot HANDLE, lppe *PROCESSENTRY32) error {
	kernel32, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		return errors.New("Can't Load Kernel32 API")
	}
	defer syscall.FreeLibrary(kernel32)
	PN, err := syscall.GetProcAddress(syscall.Handle(kernel32), "Process32Next")
	if err != nil {
		return errors.New("Can't Load Process32Next API")
	}
	r, _, err := syscall.Syscall(uintptr(PN), 2, uintptr(hSnapshot), uintptr(unsafe.Pointer(lppe)), 0)
	if int(r) != 1 {
		return err
	}
	return nil
}

func GetProcessId(Process HANDLE) uint32 {
	kernel32, err := syscall.LoadLibrary("kernel32.dll")
	if err != nil {
		return 0
	}
	defer syscall.FreeLibrary(kernel32)
	GPI, err := syscall.GetProcAddress(syscall.Handle(kernel32), "GetProcessId")
	if err != nil {
		return 0
	}
	r, _, _ := syscall.Syscall(uintptr(GPI), 1, uintptr(Process), 0, 0)
	return uint32(r)
}