#pragma once

#include <condition_variable>
#include <glibmm/dispatcher.h>
#include <memory>
#include <mutex>
#include <sigc++/sigc++.h>
#include <string>
#include <thread>

#include "services/hidppBattery.hpp"

/// Polls the mouse battery once for the whole application.
///
/// The bar builds one window per monitor, so the widget cannot own the polling
/// itself without every monitor opening its own HID++ session against the same
/// receiver and competing for it. This service keeps a single worker thread and
/// fans the result out to every widget through updated().
class MouseBatteryService {
  public:
    static constexpr const char *kDeviceName = "MX Ergo S";

    static std::shared_ptr<MouseBatteryService> getInstance();

    ~MouseBatteryService();

    MouseBatteryService(const MouseBatteryService &)            = delete;
    MouseBatteryService &operator=(const MouseBatteryService &) = delete;

    /// Last reading. Safe to call from the main thread.
    hidpp::BatteryStatus getStatus() const;

    /// Emitted on the main thread whenever a new reading lands.
    sigc::signal<void()> &updated() { return updatedSignal; }

    /// Stops the worker thread; called from the application's shutdown handler
    /// so it cannot outlive the main loop the dispatcher posts to.
    void stop();

  private:
    explicit MouseBatteryService(std::string deviceName);

    void poll();

    hidpp::BatteryReader reader;

    Glib::Dispatcher dispatcher;
    sigc::signal<void()> updatedSignal;

    std::thread worker;
    mutable std::mutex mutex;
    std::condition_variable wakeup;
    bool running = true;
    hidpp::BatteryStatus status{};

    inline static std::shared_ptr<MouseBatteryService> instance = nullptr;
};