#include <Adafruit_SSD1306.h>
#include <math.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)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void setup()
{
  Serial.begin(9600);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3c);
  display.clearDisplay();

  display.setTextSize(1); // Draw 2X-scale text
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(4, 4);

  display.println(F("f(x) = x^2"));
  display.drawLine(64, 0, 64, 64, SSD1306_WHITE);
  display.drawLine(0, 32, 128, 32, SSD1306_WHITE);
  display.display();

  // Set the origin (0,0) to the center of the display
  int originX = SCREEN_WIDTH / 2;
  int originY = SCREEN_HEIGHT / 2;

  // Scale factor to fit the parable in the screen
  float scale = 0.1;

  // Variables to store the previous point
  int prevX = -originX;
  int prevY = scale * prevX * prevX;

  // Draw the parable y = x^2 using lines
  for (int x = -originX + 1; x < originX; x++) {
    int y = scale * x * x;
    if (originY - y >= 0
        && originY - y < SCREEN_HEIGHT
        && originY - prevY >= 0
        && originY - prevY < SCREEN_HEIGHT) {
      display.drawLine(originX + prevX, originY - prevY, originX + x, originY - y, SSD1306_WHITE);
    }
    // Update previous point
    prevX = x;
    prevY = y;
  }
  display.display();
}

void loop()
{

}