#pragma once

#include <cstddef>
#include <cstdint>
#include <deque>

namespace roro {

// Follows one access point's signal over repeated scans, for finding where it is.
class SignalTracker {
   public:
    static constexpr int kNoSignal = -127;
    static constexpr uint32_t kLostAfterMs = 5000;
    static constexpr uint32_t kFastestClickMs = 60;
    static constexpr uint32_t kSlowestClickMs = 1200;

    explicit SignalTracker(size_t historySize) : size_(historySize) {}

    void seen(int rssi, uint32_t nowMs) {
        push(rssi);
        latest_ = rssi;
        lastSeenMs_ = nowMs;
        everSeen_ = true;
    }
    void missed() { push(kNoSignal); }  // a scan that didn't see it

    bool lost(uint32_t nowMs) const { return !everSeen_ || nowMs - lastSeenMs_ >= kLostAfterMs; }
    int latest() const { return latest_; }
    const std::deque<int>& history() const { return history_; }

    // Time between clicks: fast when the signal is strong (close), slow when faint.
    static uint32_t clickIntervalMs(int rssi) {
        if (rssi >= -35) return kFastestClickMs;
        if (rssi <= -95) return kSlowestClickMs;
        float t = (rssi + 95) / 60.0f;  // 0 at -95 dBm, 1 at -35 dBm
        return static_cast<uint32_t>(kSlowestClickMs - t * (kSlowestClickMs - kFastestClickMs));
    }

   private:
    void push(int v) {
        history_.push_back(v);
        if (history_.size() > size_) history_.pop_front();
    }

    size_t size_;
    std::deque<int> history_;
    int latest_ = kNoSignal;
    uint32_t lastSeenMs_ = 0;
    bool everSeen_ = false;
};

}  // namespace roro