#include <Adafruit_SSD1306.h>
#include <Wire.h>
#include <Adafruit_GFX.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0X3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

int analogPin = A0;
int Pressure = 0;
#define maxPress 100
#define minPress 20

int measurePressure() {
  int val = analogRead(analogPin);
  
  if(val<=102) {
    Serial.print(val);
    Serial.println(": Sensor voltage low.");
    return -1;
  } else if (val >= 3686) {
    Serial.print(val);
    Serial.println(": Sensor voltage high");
    return maxPress + 1;
  } else {
  int readPress = map(val, 103, 3685, 0, maxPress);
  //Serial.print(": Mapped pressure: ");
  //Serial.print(readPress);
  //Serial.println("psi");
  return readPress;
  }
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Begin Program");
  
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSC1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }

  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);      
  display.setCursor(1,0); 
  display.println("Display initialized");
  display.display();
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(500); // this speeds up the simulation
  int newPressure = measurePressure();
  if (Pressure != newPressure) {
    Pressure = newPressure;
    printPressure(Pressure);
  }

}


void printPressure(int pressVal) {
  Serial.print(Pressure);
  Serial.println("psi");

  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(10,0);
  display.println("PRESSURE");
  display.setCursor(20,24);
  display.print(pressVal);
  display.println(" psi");

  int width = map(pressVal, 0, maxPress, 0, SCREEN_WIDTH-1);
  int minPressStart = map(minPress, 0, maxPress, 0, SCREEN_WIDTH-1);
  Serial.println(width);
  display.fillRect(0, 52, width, 10, WHITE);
  display.fillRect(minPressStart, 50, 2, 14, WHITE);
  if (pressVal <= minPress) {
    display.setTextSize(1);
    display.setCursor(minPressStart+10, 54);
    display.print("Low Pressure");
  }


  display.display();
}