#include <Wire.h>
#include "Adafruit_ADS1015.h"
#include <SPI.h>
#include <SD.h>

File myFile;

Adafruit_ADS1115 ads(0x48);  /* Use this for the 16-bit version */
//Adafruit_ADS1015 ads;     /* Use thi for the 12-bit version */


int GAIN[6] = {GAIN_TWOTHIRDS, GAIN_ONE, GAIN_TWO, GAIN_FOUR, GAIN_EIGHT, GAIN_SIXTEEN};
float factor[6] = {         3,        2,        1,       0.5,       0.25,        0.125};

void setup(void) 
{
  Serial.begin(9600);
  Serial.print("Initializing SD card...");
  // On the Ethernet Shield, CS is pin 4. It's set as an output by default.
  // Note that even if it's not used as the CS pin, the hardware SS pin
  // (10 on most Arduino boards, 53 on the Mega) must be left as an output
  // or the SD library functions will not work.
  pinMode(MOSI, OUTPUT);
  pinMode(SCK, OUTPUT);

  if (!SD.begin(11)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
  
    // delete the file:
  Serial.println("Removing example.txt...");
  SD.remove("example.txt");
  
  if (SD.exists("example.txt")) {
    Serial.println("example.txt exists.");
  }
  else {
    Serial.println("example.txt doesn't exist.");
  }

  // open a new file and immediately close it:
  Serial.println("Creating example.txt...");
  myFile = SD.open("example.txt", FILE_WRITE);
  myFile.close();
  
  // The ADC input range (or gain) can be changed via the following
  // functions, but be careful never to exceed VDD +0.3V max, or to
  // exceed the upper and lower limits if you adjust the input range!
  // Setting these values incorrectly may destroy your ADC!
  //                                                                ADS1015  ADS1115
  //                                                                -------  -------
   //ads.setGain(GAIN_TWOTHIRDS);  // 2/3x gain +/- 6.144V  1 bit = 3mV      0.1875mV (default)
  // ads.setGain(GAIN_ONE);        // 1x gain   +/- 4.096V  1 bit = 2mV      0.125mV
   ads.setGain(GAIN_TWO);        // 2x gain   +/- 2.048V  1 bit = 1mV      0.0625mV
  // ads.setGain(GAIN_FOUR);       // 4x gain   +/- 1.024V  1 bit = 0.5mV    0.03125mV
  // ads.setGain(GAIN_EIGHT);      // 8x gain   +/- 0.512V  1 bit = 0.25mV   0.015625mV
  // ads.setGain(GAIN_SIXTEEN);    // 16x gain  +/- 0.256V  1 bit = 0.125mV  0.0078125mV
  
  ads.begin();
}

  int16_t adc0, adc1, adc2, adc3;
  
void loop(void) 
{
  myFile = SD.open("example.txt", FILE_WRITE);
  if (myFile) {
    adc0 = ads.readADC_SingleEnded(2);
    adc1 = ads.readADC_SingleEnded(3);
    Serial.print("AN2: "); Serial.print(adc0*0.0625); Serial.println("mV"); //Serial.print(((float)(adc0*0.0625 - 200.56)/(344))*1000. ); Serial.println("ppb"); 
    Serial.print("AN3: "); Serial.print(adc1*0.0625); Serial.println("mV"); //Serial.print(((float)(adc0*0.0625 - 200.56)/(344))*1000. ); Serial.println("ppb"); 
    myFile.print(adc0*0.0625);
    myFile.print(" ");
    myFile.println(adc1*0.0625);
  //  Serial.print("CO: "); Serial.print(adc0*0.5); Serial.print("mV, "); Serial.print((float)(430 - adc0*0.5)*0.473); Serial.println("ppb"); 
  //  Serial.print("NO2: "); Serial.print(adc1*0.5); Serial.print("mV, "); Serial.print((float)(adc1*0.5 - 273)*0.278 ); Serial.println("ppb"); 
  //  Serial.print("AIN2: "); Serial.println(adc2);
  //  Serial.print("AIN3: "); Serial.println(adc3);
    delay(1000);
    myFile.close();
  }
}