#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Adafruit_ILI9341.h>

#define SCREEN_WIDTH    128 // OLED display width, in pixels
#define SCREEN_HEIGHT   64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET      4 // Reset pin # (or -1 if sharing Arduino reset pin)
#define TFT_DC          9
#define TFT_CS          10
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

const float Pi = 3.14159265359;
int Radius = SCREEN_HEIGHT / 2;

float toRadians(float degrees) {
  return degrees * (Pi / 180);
}

int findYcoord(float Angle, float offset, int screenX, int screenY) {
  return floor(screenY / 2 + (sin(toRadians(Angle + offset)) * (screenY/2)));
}

void drawSineILI9341(float offset) {
  float Angle;
  int screenX = 320;
  int screenY = 240;
  int prevX = 0, prevY = findYcoord(Angle, offset, screenX, screenY);
  //tft.fillScreen(ILI9341_BLACK);
  for (float x=0; x<=screenX; x++) {    
    Angle = x*1.125;
    int y = findYcoord(Angle, offset, screenX, screenY);

    tft.drawLine(prevX, prevY, x, y, ILI9341_WHITE);
    prevX = x;
    prevY = y;
  }
  display.display();
}

void drawSine(float offset) {
  float Angle;
  float prevX = 0.0f, prevY = findYcoord(Angle, offset, SCREEN_WIDTH, SCREEN_HEIGHT);
  display.clearDisplay();
  for (float x=0; x<=SCREEN_WIDTH; x++) {    
    Angle = x * 2.8125;
    int y = findYcoord(Angle, offset, SCREEN_WIDTH, SCREEN_HEIGHT);

    display.drawLine(prevX, prevY, x, y, WHITE);
    prevX = x;
    prevY = y;
  }
  display.display();
}

void setup() {
  Serial.begin(9600);

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3D)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }

  pinMode(A0, INPUT);

  tft.begin();
  tft.setRotation(1);

  display.display();

  drawSine(0.0f);
}

float offset, prevOffset;
void loop() {
  int potentiometer = analogRead(A0);
  prevOffset = offset;
  offset = potentiometer * 0.3515625f;
  if(prevOffset != offset) {
    drawSine(offset);
  }
}