#ifndef HCSR04_H
#define HCSR04_H

// The minimum and maximum distance that can be measured in mm.
// This is based on the specifications of the HCSR04 sensor.
#define HCSR04_MIN_MM 40
#define HCSR04_MAX_MM 4000

// Some parameters that are used to get more stable reading from the sensor.
// To get a better reading:
// - multiple samples are taken
// - between each sample, a random wait is added (because I saw repeating
//   patterns when reading from a tight loop)
// - only a subset from the samples is used to compute the average distance
//   (the high and low extremes are ignored)
#define HCSR04_SAMPLES_TAKE 20
#define HCSR04_SAMPLES_USE 8
#define HCSR04_SAMPLE_WAIT 30
#define HCSR04_SAMPLE_WAIT_SPREAD 12

// Default values for temperature and humidity, which have an effect
// on the speed of sound. At runtime, the temperature and humidity
// can be modified by using their respective setter functions
// setTemperature() and setHumidity().
#define HCSR04_INIT_TEMPERATURE 19.000
#define HCSR04_INIT_HUMIDITY 50.000

// Define this one to enable HCSR04 debug logging.
#undef HCSR04_DEBUG

#include <Arduino.h>
#include "UI/DoughLogger.h"
#include "config.h"

/**
 * This class is used to get a distance reading from an HCSR04 sensor.
 */
class SensorHCSR04
{
public:
    SensorHCSR04(int triggerPin, int echoPin);
    void setup();
    void setTemperature(int temperature);
    void setHumidity(int humidity);
    int readDistance();

private:
    DoughLogger _logger;
    int _triggerPin;
    int _echoPin;
    int _humidity;
    int _temperature;
    void _setSpeedOfSound();
    float _speedOfSound;
    void _setEchoTimeout();
    int _echoTimeout;
    float _samples[HCSR04_SAMPLES_TAKE];
    void _takeSamples();
    bool _haveEnoughSamples();
    int _takeSample();
    int _successfulSamples;
    void _sortSamples();
    int _computeAverage();
};

#endif