/******************************************************************************
  Run for 20 minutes

  Nathan Seidle @ SparkFun Electronics
  Marshall Taylor @ SparkFun Electronics

  April 4, 2017

  https://github.com/sparkfun/CCS811_Air_Quality_Breakout
  https://github.com/sparkfun/SparkFun_CCS811_Arduino_Library

  Hardware Connections (Breakoutboard to Arduino):
  3.3V to 3.3V pin
  GND to GND pin
  SDA to A4
  SCL to A5

  Calculates the current run time and indicates when 20 minutes has passed

  Read the TVOC and CO2 values from the SparkFun CSS811 breakout board

  A new sensor requires at 48-burn in. Once burned in a sensor requires
  20 minutes of run in before readings are considered good.

  Resources:
  Uses Wire.h for i2c operation

  Development environment specifics:
  Arduino IDE 1.8.1

  This code is released under the [MIT License](http://opensource.org/licenses/MIT).

  Please review the LICENSE.md file included with this example. If you have any questions
  or concerns with licensing, please contact techsupport@sparkfun.com.

  Distributed as-is; no warranty is given.
******************************************************************************/
#include <Wire.h>

#include "SparkFunCCS811.h" //Click here to get the library: http://librarymanager/All#SparkFun_CCS811

#define CCS811_ADDR 0x5B //Default I2C Address
//#define CCS811_ADDR 0x5A //Alternate I2C Address

CCS811 myCCS811(CCS811_ADDR);

void setup()
{
  Serial.begin(115200);
  Serial.println("20 minute test");

  Wire.begin();

  //This begins the CCS811 sensor and prints error status of .beginWithStatus()
  CCS811Core::CCS811_Status_e returnCode = myCCS811.beginWithStatus();
  Serial.print("CCS811 begin exited with: ");
  Serial.println(myCCS811.statusString(returnCode));
}

void loop()
{
  if (myCCS811.dataAvailable())
  {
    myCCS811.readAlgorithmResults();

    Serial.print("CO2[");
    Serial.print(myCCS811.getCO2());
    Serial.print("] tVOC[");
    Serial.print(myCCS811.getTVOC());
    Serial.print("] millis[");
    Serial.print(millis());
    Serial.print("] ");
    printRunTime();
    Serial.println();
  }
  else if (myCCS811.checkForStatusError())
  {
    printSensorError();
  }

  delay(1000); //Wait for next reading
}

//Prints the amount of time the board has been running
//Does the hour, minute, and second calcs
void printRunTime()
{
  char buffer[50];

  unsigned long runTime = millis();

  int hours = runTime / (60 * 60 * 1000L);
  runTime %= (60 * 60 * 1000L);
  int minutes = runTime / (60 * 1000L);
  runTime %= (60 * 1000L);
  int seconds = runTime / 1000L;

  sprintf(buffer, "RunTime[%02d:%02d:%02d]", hours, minutes, seconds);
  Serial.print(buffer);

  if (hours == 0 && minutes < 20)
    Serial.print(" Not yet valid");
}

//printSensorError gets, clears, then prints the errors
//saved within the error register.
void printSensorError()
{
  uint8_t error = myCCS811.getErrorRegister();

  if (error == 0xFF) //comm error
  {
    Serial.println("Failed to get ERROR_ID register.");
  }
  else
  {
    Serial.print("Error: ");
    if (error & 1 << 5)
      Serial.print("HeaterSupply");
    if (error & 1 << 4)
      Serial.print("HeaterFault");
    if (error & 1 << 3)
      Serial.print("MaxResistance");
    if (error & 1 << 2)
      Serial.print("MeasModeInvalid");
    if (error & 1 << 1)
      Serial.print("ReadRegInvalid");
    if (error & 1 << 0)
      Serial.print("MsgInvalid");
    Serial.println();
  }
}