#pragma once
//
//    FILE: AGS02MA.h
//  AUTHOR: Rob Tillaart, Viktor Balint
//    DATE: 2021-08-12
// VERSION: 0.1.2
// PURPOSE: Arduino library for AGS02MA TVOC
//     URL: https://github.com/RobTillaart/AGS02MA
//


#include "Arduino.h"
#include "Wire.h"


#define AGS02MA_LIB_VERSION         (F("0.1.2"))

#define AGS02MA_OK                  0
#define AGS02MA_ERROR               -10
#define AGS02MA_ERROR_CRC           -11
#define AGS02MA_ERROR_READ          -12


#define AGS02MA_I2C_CLOCK           30000


class AGS02MA
{
public:
  // address 26 = 0x1A
  explicit AGS02MA(const uint8_t deviceAddress = 26, TwoWire *wire = &Wire);

#if defined (ESP8266) || defined(ESP32)
  bool     begin(uint8_t sda, uint8_t scl);
#endif
  bool     begin();
  bool     isConnected();
  void     reset();

  bool     isHeated() { return (millis() - _startTime) > 120000UL; };


  // CONFIGURATION
  bool     setAddress(const uint8_t deviceAddress);
  uint8_t  getAddress() { return _address; };
  uint8_t  getSensorVersion();

  // to set the speed the I2C bus should return to
  // as the device operates at very low bus speed of 30 kHz.
  void     setI2CResetSpeed(uint32_t s) { _I2CResetSpeed = s; };
  uint32_t getI2CResetSpeed() { return _I2CResetSpeed; };

  // to be called after at least 5 minutes in fresh air.
  bool     zeroCalibration();


  // MODE
  bool     setPPBMode();
  bool     setUGM3Mode();
  uint8_t  getMode()    { return _mode; };


  // READ functions
  uint32_t readPPB();   // parts per billion 10^9
  uint32_t readUGM3();  // microgram per cubic meter

  // derived read functions
  float    readPPM()    { return readPPB()  * 0.001; };         // parts per million
  float    readMGM3()   { return readUGM3() * 0.001; };         // milligram per cubic meter
  float    readUGF3()   { return readUGM3() * 0.0283168466; };  // microgram per cubic feet

  float    lastPPM()    { return _lastPPB   * 0.001; };
  uint32_t lastPPB()    { return _lastPPB;  };    // fetch last PPB measurement
  uint32_t lastUGM3()   { return _lastUGM3; };    // fetch last UGM3 measurement


  // STATUS
  uint32_t lastRead()   { return _lastRead; };    // timestamp last measurement
  int      lastError();
  uint8_t  lastStatus() { return _status; };
  uint8_t  dataReady()  { return _status & 0x01; };


private:
  uint32_t _readSensor();
  bool     _readRegister(uint8_t reg);
  bool     _writeRegister(uint8_t reg);

  uint32_t _I2CResetSpeed = 100000;
  uint32_t _startTime     = 0;
  uint32_t _lastRead      = 0;
  uint32_t _lastRegTime   = 0;
  uint32_t _lastPPB       = 0;
  uint32_t _lastUGM3      = 0;
  uint8_t  _address       = 0;
  uint8_t  _mode          = 255;
  uint8_t  _status        = 0;
  uint8_t  _buffer[5];

  uint8_t  _CRC8(uint8_t * buf, uint8_t size);

  int      _error = AGS02MA_OK;

  TwoWire*  _wire;
};


// -- END OF FILE --