#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <math.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);

// Eye & face settings
const int eyeRadius = 22;
const int pupilRadius = 6;
const int eyeBaseLeftX = 32;
const int eyeBaseRightX = 96;
const int eyeBaseY = 24;
const int mouthBaseX = 45;
const int mouthBaseY = 50;

// Pupil behavior
int pupilOffsetX = 0;
int pupilOffsetY = 0;

int currentState = 0;  // 0 = default, 1 = look, 2 = second look, 3 = return to center
unsigned long stateStartTime = 0;
unsigned long stateDuration = 0;

int yOffset = 0;
int sideSway = 0;

void drawEyes(int yOffset, int sideSway, int eyeHeight) {
  display.clearDisplay();

  for (int y = -eyeHeight; y <= eyeHeight; y++) {
    int h = sqrt((float)(eyeRadius * eyeRadius) - ((float)(eyeRadius * y) / eyeHeight) * ((float)(eyeRadius * y) / eyeHeight));
    display.drawFastHLine(eyeBaseLeftX + sideSway - h, eyeBaseY + yOffset + y, h * 2, WHITE);
    display.drawFastHLine(eyeBaseRightX + sideSway - h, eyeBaseY + yOffset + y, h * 2, WHITE);
  }

  if (eyeHeight > pupilRadius) {
    display.fillCircle(eyeBaseLeftX + sideSway + pupilOffsetX, eyeBaseY + yOffset + pupilOffsetY, pupilRadius, BLACK);
    display.fillCircle(eyeBaseRightX + sideSway + pupilOffsetX, eyeBaseY + yOffset + pupilOffsetY, pupilRadius, BLACK);
  }

  display.fillRect(mouthBaseX + sideSway, mouthBaseY + yOffset, 40, 5, WHITE);
  display.display();
}

void setPupilOffset(int x, int y) {
  pupilOffsetX = x;
  pupilOffsetY = y;
}

void enterState(int newState, unsigned long duration) {
  currentState = newState;
  stateStartTime = millis();
  stateDuration = duration;
}

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

  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    while (true);
  }

  display.clearDisplay();
  display.display();

  randomSeed(analogRead(A0));
  enterState(0, random(3000, 4000));  // Start with default face
}

void loop() {
  // You can add gentle motion here later if you want
  yOffset = 0;
  sideSway = 0;

  drawEyes(yOffset, sideSway, eyeRadius);

  // State timing logic
  if (millis() - stateStartTime >= stateDuration) {
    switch (currentState) {
      case 0: // Default face → dart
        setPupilOffset(random(-6, 7), random(-3, 4));
        enterState(1, random(300, 600));
        break;

      case 1: // First dart → maybe second dart or center
        if (random(0, 100) < 10) {
          setPupilOffset(random(-6, 7), random(-3, 4));
          enterState(2, random(300, 500));
        } else {
          setPupilOffset(0, 0);
          enterState(3, 200);
        }
        break;

      case 2: // Second dart → center
        setPupilOffset(0, 0);
        enterState(3, 200);
        break;

      case 3: // Back to default
        setPupilOffset(0, 0);
        enterState(0, random(3000, 4000));
        break;
    }
  }

  // 👁 Faster blinking ONLY in default state
  if (currentState == 0 && random(0, 100) < 1) { // 1% chance
    int blinkSteps = 4;
    int blinkDelay = 8;

    for (int h = eyeRadius; h >= 0; h -= (eyeRadius / blinkSteps)) {
      drawEyes(yOffset, sideSway, h);
      delay(blinkDelay);
    }

    delay(80); // Eyes closed pause

    for (int h = 0; h <= eyeRadius; h += (eyeRadius / blinkSteps)) {
      drawEyes(yOffset, sideSway, h);
      delay(blinkDelay);
    }
  }

  delay(20); // Main loop pace (50 FPS-ish)
}