PowerToys/src/modules/shortcut_guide/target_state.h

#pragma once
#include <deque>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <chrono>
#include "shortcut_guide.h"

struct KeyEvent
{
    bool key_down;
    unsigned vk_code;
};

class TargetState
{
public:
    TargetState(int ms_delay);
    bool signal_event(unsigned vk_code, bool key_down);
    void was_hiden();
    void exit();
    void set_delay(int ms_delay);

private:
    KeyEvent next();
    void handle_hidden();
    void handle_timeout();
    void handle_shown();
    void thread_proc();
    std::mutex mutex;
    std::condition_variable cv;
    std::chrono::system_clock::time_point winkey_timestamp, singnal_timestamp;
    std::chrono::milliseconds delay;
    std::deque<KeyEvent> events;
    enum
    {
        Hidden,
        Timeout,
        Shown,
        Exiting
    } state = Hidden;
    bool key_was_pressed = false;
    std::thread thread;
};