// Idle tracking for the auto-lock: pure, header-only, main-thread only.
#pragma once
#include <chrono>

namespace dragonx {
namespace util {

class IdleTracker {
public:
    using Clock = std::chrono::steady_clock;
    explicit IdleTracker(Clock::time_point start = Clock::now()) : last_(start) {}
    // Never moves backwards (an event stamped before the last one must not shorten the idle time).
    void noteActivity(Clock::time_point t = Clock::now()) { if (t > last_) last_ = t; }
    double idleSeconds(Clock::time_point now = Clock::now()) const {
        return now <= last_ ? 0.0 : std::chrono::duration<double>(now - last_).count();
    }
private:
    Clock::time_point last_;
};

}  // namespace util
}  // namespace dragonx