package rand

import (
	"internal/syscall/windows"
)

func init() { Reader = &rngReader{} }

type rngReader struct{}

func (r *rngReader) Read(b []byte) (int, error) {
	if err := windows.ProcessPrng(b); err != nil {
		return 0, err
	}
	return len(b), nil

//   - On macOS and iOS, Reader uses arc4random_buf(3).
//   - On OpenBSD and NetBSD, Reader uses getentropy(2).
//   - On other Unix-like systems, Reader reads from /dev/urandom.
//   - On Windows, Reader uses the ProcessPrng API.
//   - On js/wasm, Reader uses the Web Crypto API.
//   - On wasip1/wasm, Reader uses random_get from wasi_snapshot_preview1.
var Reader io.Reader

// Read is a helper function that calls Reader.Read using io.ReadFull.

//sys	CreateEvent(eventAttrs *SecurityAttributes, manualReset uint32, initialState uint32, name *uint16) (handle syscall.Handle, err error) = kernel32.CreateEventW

//sys	ProcessPrng(buf []byte) (err error) = bcryptprimitives.ProcessPrng

type FILE_ID_BOTH_DIR_INFO struct {
	NextEntryOffset uint32
	FileIndex       uint32
	CreationTime    syscall.Filetime
	LastAccessTime  syscall.Filetime

	procRevertToSelf                      = modadvapi32.NewProc("RevertToSelf")
	procSetTokenInformation               = modadvapi32.NewProc("SetTokenInformation")
	procProcessPrng                       = modbcryptprimitives.NewProc("ProcessPrng")
	procGetAdaptersAddresses              = modiphlpapi.NewProc("GetAdaptersAddresses")
	procCreateEventW                      = modkernel32.NewProc("CreateEventW")

	_VirtualAlloc,
	_VirtualFree,
	_VirtualQuery,
	_WaitForSingleObject,
	_WaitForMultipleObjects,
	_WerGetFlags,
	_WerSetFlags,
	_WriteConsoleW,
	_WriteFile,
	_ stdFunction

	// Use ProcessPrng to generate cryptographically random data.
	_ProcessPrng stdFunction

	// Load ntdll.dll manually during startup, otherwise Mingw
	// links wrong printf function to cgo executable (see issue
	// 12030 for details).