/**
 * @file battery.h
 * @author Alexander Klein (alex@kleiax.de)
 * @brief Contains a class for battery monitoring
 * @version 0.1
 * @date 2022-02-05
 * 
 * @copyright Copyright (c) 2022
 * 
 */

#ifndef AKKU_H
#define AKKU_H

#include <stdint.h>
#include <iostream>
#include <math.h>
#include <Arduino.h>

/**
 * @brief A class for battery monitoring
 * 
 * This class reads the voltage from an analog pin to calculate the
 * charge level of a 3 Cell Li-Poly battery pack. The battery pack have
 * to be after a voltage diveder, so that maximum voltage for the
 * microcontroller is 3.3 Volt.
 */
class Battery {
    public:
        /**
         * @brief Construct a new Battery object
         * 
         * The voltage devider have to be calculated, so that the input
         * voltage from 3.3 Volt is never exceeded. It is assumed that
         * the microcontroller is connected to the second resistor.
         * 
         * @param pin The analog to read from.
         * @param r1 First resistor of the voltage devider.
         * @param r2 Second resistor of the voltage devider.
         */
        Battery(uint8_t pin, uint32_t r1, uint32_t r2);

        /**
         * @brief Read new values if the delay is reached. 
         */
        void loop();

        /**
         * @brief Set the delay to wait befor new values are read
         * 
         * @param delay in milliseconds
         */
        void setDelay(uint16_t delay) {this->delay = delay;        }

        /**
         * @brief Get the delay to wait befor new values are read
         * 
         * @return uint16_t delay in milliseconds
         */
        uint16_t getDelay()           {return this->delay;         }

        /**
         * @brief Get the battery voltage
         * 
         * @return double in Volt
         */
        double getBatteryVoltage()    {return this->batteryVoltage;}

        /**
         * @brief Get the charge level of the battery
         * 
         * @return uint8_t charge level in percent
         */
        uint8_t getBatteryPercent()   {return this->batteryPercent;}

    private:
        double readInputVoltage();
        void calculateBatteryVoltage();
        void calculateBatteryPercent();

        uint8_t pin;
        uint8_t batteryPercent;
        uint16_t delay = 20000;
        uint32_t r1;
        uint32_t r2;
        uint64_t lastMillis = 0;
        double batteryVoltage;

        const float capacityVoltages[21] = {9.82, 10.83, 11.06, 11.12,
                                            11.18, 11.24, 11.3, 11.36,
                                            11.39, 11.45, 11.51, 11.56,
                                            11.62, 11.74, 11.86, 11.95, // 60 65 70 75
                                            12.07, 12.25, 12.33, 12.45, // 80 85 90 95
                                            12.6 };
};

#endif // AKKU_H