f64 GetUnixTimestamp ();
s64 GetUnixTimestampNanoseconds ();

struct Condition_Variable;
struct Semaphore;
struct Mutex;
struct OS_Thread;

enum class Wait_For_Result : s32 {
  SUCCESS = 0,
  TIMEOUT = 1,
  ERROR = 2 // can't use ERROR because of Windows.h *sigh*
};

internal void mutex_init (Mutex* mutex);
internal void mutex_destroy (Mutex* mutex);
internal void lock (Mutex* mutex);
internal void unlock (Mutex* mutex);

internal void semaphore_init (Semaphore* sem, s32 initial_value = 0);
internal void semaphore_destroy (Semaphore* sem);
internal void signal (Semaphore* sem);
internal Wait_For_Result wait_for (Semaphore* sem, s32 milliseconds = -1);

internal void condition_variable_init (Condition_Variable* cv);
internal void condition_variable_destroy (Condition_Variable* cv);
internal void wait (Condition_Variable* cv, Mutex* mutex, s32 wait_time_ms = -1);
internal void wake (Condition_Variable* cv);
internal void wake_all (Condition_Variable* cv);

// #window_creation
typedef HWND Window_Type;