/*
  AHT10_Soft - A Humidity Library for Arduino.

  Supported Sensor modules:
    AHT10_Soft-Breakout Module - https://www.aliexpress.com/item/33002710848.html

  Created by Thinary Eletronic at Modern Device on April 2019.
 
 * This file is part of Thinary_AHT10_Soft.
 *
 * Thinary_AHT10_Soft is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or(at your option) any later version.
 *
 * Thinary_AHT10_Soft is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Thinary_AHT10_Soft.  If not, see
 * <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include <math.h>
#include <Arduino.h>
#include <SoftwareWire.h>
#include "Thinary_AHT10_Soft.h"


// Specify the constants for water vapor and barometric pressure.
#define WATER_VAPOR 17.62f
#define BAROMETRIC_PRESSURE 243.5f

Sensor_CMD eSensorCalibrateCmd[3] = {0xE1, 0x08, 0x00};
Sensor_CMD eSensorNormalCmd[3]    = {0xA8, 0x00, 0x00};
Sensor_CMD eSensorMeasureCmd[3]   = {0xAC, 0x33, 0x00};
Sensor_CMD eSensorResetCmd        = 0xBA;
boolean    GetRHumidityCmd        = true;
boolean    GetTempCmd             = false;

/******************************************************************************
 * Global Functions
 ******************************************************************************/
AHT10_SoftClass::AHT10_SoftClass() {
}

bool AHT10_SoftClass::begin(unsigned char _AHT10_Soft_address, SoftwareWire *theWire)
{
    _wire = theWire;
    AHT10_Soft_address = _AHT10_Soft_address;
    //Serial.begin(9600);
    //Serial.println("\x54\x68\x69\x6E\x61\x72\x79\x20\x45\x6C\x65\x74\x72\x6F\x6E\x69\x63\x20\x41\x48\x54\x31\x30\x20\x4D\x6F\x64\x75\x6C\x65\x2E");
    _wire->begin();
    _wire->beginTransmission(AHT10_Soft_address);
    _wire->write(eSensorCalibrateCmd, 3);
    _wire->endTransmission();
    //Serial.println("https://thinaryelectronic.aliexpress.com");
    delay(500);
    if((readStatus()&0x68) == 0x08)
        return true;
    else
    {
        return false;
    }
    
}

/**********************************************************
 * GetHumidity
 *  Gets the current humidity from the sensor.
 *
 * @return float - The relative humidity in %RH
 **********************************************************/
float AHT10_SoftClass::GetHumidity(void)
{
    float value = readSensor(GetRHumidityCmd);
    if (value == 0) {
        return 0;                       // Some unrealistic value
    }
    return value * 100 / 1048576;
}

/**********************************************************
 * GetTemperature
 *  Gets the current temperature from the sensor.
 *
 * @return float - The temperature in Deg C
 **********************************************************/
float AHT10_SoftClass::GetTemperature(void)
{
    float value = readSensor(GetTempCmd);
    return ((200 * value) / 1048576) - 50;
}

/**********************************************************
 * GetDewPoint
 *  Gets the current dew point based on the current humidity and temperature
 *
 * @return float - The dew point in Deg C
 **********************************************************/
float AHT10_SoftClass::GetDewPoint(void)
{
  float humidity = GetHumidity();
  float temperature = GetTemperature();

  // Calculate the intermediate value 'gamma'
  float gamma = log(humidity / 100) + WATER_VAPOR * temperature / (BAROMETRIC_PRESSURE + temperature);
  // Calculate dew point in Celsius
  float dewPoint = BAROMETRIC_PRESSURE * gamma / (WATER_VAPOR - gamma);

  return dewPoint;
}

/******************************************************************************
 * Private Functions
 ******************************************************************************/

unsigned long AHT10_SoftClass::readSensor(boolean GetDataCmd)
{
    unsigned long result, temp[6];

    _wire->beginTransmission(AHT10_Soft_address);
    _wire->write(eSensorMeasureCmd, 3);
    _wire->endTransmission();
    delay(100);

    _wire->requestFrom(AHT10_Soft_address, 6);

    for(unsigned char i = 0; _wire->available() > 0; i++)
    {
        temp[i] = _wire->read();
    }   

    if(GetDataCmd)
    {
        result = ((temp[1] << 16) | (temp[2] << 8) | temp[3]) >> 4;
    }
    else
    {
        result = ((temp[3] & 0x0F) << 16) | (temp[4] << 8) | temp[5];
    }

    return result;
}

unsigned char AHT10_SoftClass::readStatus(void)
{
    unsigned char result = 0;

    _wire->requestFrom(AHT10_Soft_address, 1);
    result = _wire->read();
    return result;
}

void AHT10_SoftClass::Reset(void)
{
    _wire->beginTransmission(AHT10_Soft_address);
    _wire->write(eSensorResetCmd);
    _wire->endTransmission();
    delay(20);
}