#include "fix_fft.h"                                  //library to perfom the Fast Fourier Transform

#include <SPI.h>                                      //SPI library
#include <Wire.h>                                     //I2C library for OLED
#include <Adafruit_GFX.h>                             //graphics library for OLED
#include <Adafruit_SSD1306.h>                         //OLED driver

#include <DHT.h>

//#include <C402_Steam_Air_MQ7_CO.h>
#include <MQ7.h>

// OLED
#define OLED_RESET 4                                  //OLED reset, not hooked up but required by library
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels


// DHT22 sensor settings
#define DHTPIN 8
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

// CO Sensor Pin
#define COSENSORPIN A1
#define VOLTAGE 5

// Audio
#define AUDIOIN A0

//SteamMQ7 mq7(COSENSORPIN);
//MQ7 mq7(COSENSORPIN, VOLTAGE);


Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);                 //declare instance of OLED library called display

char im[128], data[128];                              //variables for the FFT
char x = 2, ylim = 60;                                //variables for drawing the graphics
int i = 0, val;                                       //counters
int printsize = 84;

int temperature = 0, humidity = 0;
int text_pos_x = 98;
int text_pos_y = 21;
int text_v_offset = 17;
//string temp_co = "";
int temp_ppm = 0;

void setup()
{
  //Serial.begin(9600);                                 //serial comms for debuging

  //mq7.calibrate();
  

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);          //begin OLED @ hex addy 0x3C
  display.setTextSize(1);                             //set OLED text size to 1 (1-6)
  display.setTextColor(WHITE);                        //set text color to white
  display.clearDisplay();                             //clear display
  analogReference(DEFAULT);                           // Use default (5v) aref voltage.

  dht.begin();
};

void loop()
{
  int min = 1024, max = 0;                            //set minumum & maximum ADC values
  for (i = 0; i < 128; i++) {                         //take 128 samples
    val = analogRead(AUDIOIN);                             //get audio from Analog 0
    data[i] = val / 4 - 128;                          //each element of array is val/4-128
    im[i] = 0;                                        //
    if (val > max) max = val;                         //capture maximum level
    if (val < min) min = val;                         //capture minimum level
  };

  fix_fft(data, im, 7, 0);

  MQ7 mq7(COSENSORPIN, 5.0);

  temperature = (dht.readTemperature());
  humidity = (dht.readHumidity());
  //temp_co = mq7.read();
  //temp_ppm = mq7.readPpm();

  display.clearDisplay();

  display.drawFastHLine(0, 17, 128, WHITE);
  display.drawFastVLine(89, 17, 48, WHITE);

  display.drawFastHLine(91, 32, 36, WHITE);
  display.drawFastHLine(91, 49, 36, WHITE);

  for (i = 1; i < printsize; i++) {
    int dat = sqrt(data[i] * data[i] + im[i] * im[i]);
    //int pos_x = i * 2 + x;
    int pos_x = i + x;
    int pos_y = ylim;
    int height = ylim - dat;
    height = height < 20 ? 20 : height;

    display.drawLine(pos_x, pos_y, pos_x, height, WHITE);
  };



  display.setCursor(text_pos_x, text_pos_y);
  display.print(temperature);
  display.println("C");
  
  display.setCursor(text_pos_x, text_pos_y + text_v_offset);
  display.print(temp_ppm);

  display.setCursor(text_pos_x, text_pos_y + (text_v_offset * 2));
  display.print(humidity);
  display.println("%");

  //show the buffer
  display.display();
};