FacePlant/src/sensors/BatterySensor.h

#pragma once
#include <Arduino.h>
#include <Adafruit_MAX1704X.h>

class BatterySensor {
public:
  void begin();
  void loop();

  // Battery status
  int percent() const { return _percent; }
  float voltage() const { return _voltage; }
  bool isLow() const { return _isLow; }
  bool isCharging() const { return _isCharging; }
  bool shouldBlink() const;

  // For display
  int iconFillWidth(int maxWidth) const;

private:
  static constexpr unsigned long CHECK_INTERVAL_MS = 2000;

  static constexpr float VOLTAGE_LOW = 3.2;   // Low battery threshold
  static constexpr float CHARGE_RATE_MIN_PCT_PER_HR = 0.2f;  // heuristic

  int _percent = 100;
  float _voltage = 3.7;
  bool _isLow = false;
  bool _isCharging = false;
  unsigned long _lastCheckMs = 0;
  bool _ok = false;
  Adafruit_MAX17048 _maxlipo;

  void refresh();
};