#include <Adafruit_GFX.h>
#include <Adafruit_PCD8544.h>
#include <SPI.h>

#define DISPLAY_WIDTH 84
#define DISPLAY_HEIGHT 48

#define ARDUINO_PRECISION 1023.0
Adafruit_PCD8544 display = Adafruit_PCD8544(10, 5, 3);

//Analog Pins
int channelAI = A0;      // probe

//#define DELAY_POTENTIMETER //disabled it I don't have it connected
#ifdef DELAY_POTENTIMETER
int delayAI = A1;       // delay potentiometer
#endif

float delayVariable = 0;
float scale = 0;
int xCounter = 0;
int yPosition = 0;
int readings[DISPLAY_WIDTH+1];
int counter = 0;

unsigned long drawtime = 0;
unsigned long lastdraw = 0;
int frames = 0;

void setup(void)
{
  display.begin();
  display.setContrast(30);// you might have a slightly different display so it might not be the optimal value for you
  display.clearDisplay();
}

void loop()
{
  #ifdef DELAY_POTENTIMETER
  delayVariable = analogRead(delayAI);
  delayVariable = (delayVariable/10);
  #endif
  scale = (float)(DISPLAY_HEIGHT-1)/ARDUINO_PRECISION;

  //record readings
  for(xCounter = 0; xCounter <= DISPLAY_WIDTH; xCounter++)
  {
    yPosition = analogRead(channelAI);
    readings[xCounter] = (yPosition*scale);
    #ifdef DELAY_POTENTIMETER
    delay (delayVariable);
    #endif
  }

  display.clearDisplay();

  //Draw Voltage Ref Lines
  display.drawLine( 10, 0, 10, DISPLAY_HEIGHT-1, BLACK);
  display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale), BLACK);
  display.drawLine( 0, (DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale), BLACK);
  display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale), BLACK);
  display.drawLine( 0, (DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale), BLACK);
  //display.drawLine( 5, (DISPLAY_HEIGHT-1)-(.84 *ARDUINO_PRECISION * scale), 10, (DISPLAY_HEIGHT-1)-(.84 *ARDUINO_PRECISION * scale), BLACK);

  //Draw Voltage Ref Numbers
  display.setCursor(0,((DISPLAY_HEIGHT-1)-(.2 *ARDUINO_PRECISION * scale))-3);
  display.print((int)(5.0*0.2));
  display.setCursor(0,((DISPLAY_HEIGHT-1)-(.4 *ARDUINO_PRECISION * scale))-3);
  display.print((int)(5.0*0.4));
  display.setCursor(0,((DISPLAY_HEIGHT-1)-(.6 *ARDUINO_PRECISION * scale))-3);
  display.print((int)(5.0*0.6));
  display.setCursor(0,((DISPLAY_HEIGHT-1)-(.8 *ARDUINO_PRECISION * scale))-3);
  display.print((int)(5.0*0.8));

  for(xCounter = 0; xCounter <= DISPLAY_WIDTH; xCounter++)
  {
    display.drawPixel(xCounter, (DISPLAY_HEIGHT-1)-readings[xCounter], BLACK);
    if(xCounter>1){
      display.drawLine(xCounter-1, (DISPLAY_HEIGHT-1)-readings[xCounter-1], xCounter, (DISPLAY_HEIGHT-1)-readings[xCounter], BLACK);
    }
  }
  //Draw FPS
  display.setCursor((DISPLAY_WIDTH-1)-11,0);
  display.print(frames);

  //Draw Voltage
  display.setCursor(((DISPLAY_WIDTH-1)/2),0);
  display.print(analogRead(channelAI)/ARDUINO_PRECISION*5.0);

  display.display();

  //Calculate FPS
  drawtime = micros();
  frames=1000000/*a second*//(drawtime-lastdraw);
  lastdraw = drawtime;
}