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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 32
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Button and buzzer pins
const int buttonPin = 7;
const int buzzerPin = 8;

unsigned long lastUpdate = 0;
int remaining = 0;
bool running = false;

// ------------------------------------------------------------
// Draw a star-shaped sparkle
// ------------------------------------------------------------
void drawStar(int x, int y) {
  display.drawPixel(x, y, SSD1306_WHITE);
  display.drawPixel(x - 1, y, SSD1306_WHITE);
  display.drawPixel(x + 1, y, SSD1306_WHITE);
  display.drawPixel(x, y - 1, SSD1306_WHITE);
  display.drawPixel(x, y + 1, SSD1306_WHITE);

  display.drawPixel(x - 1, y - 1, SSD1306_WHITE);
  display.drawPixel(x + 1, y - 1, SSD1306_WHITE);
  display.drawPixel(x - 1, y + 1, SSD1306_WHITE);
  display.drawPixel(x + 1, y + 1, SSD1306_WHITE);
}

// ------------------------------------------------------------
// Celebration animation with glow + sparkles
// ------------------------------------------------------------
void showSmiley() {
  int cx = 64;
  int cy = 16;

  unsigned long startTime = millis();

  // --- 1. Sparkle burst at the start ---
  for (int burst = 0; burst < 12; burst++) {
    display.clearDisplay();

    int sx, sy, dx, dy, dist;

    // Keep sparkles OUTSIDE the face radius
    do {
      sx = random(0, 128);
      sy = random(0, 32);

      dx = sx - cx;
      dy = sy - cy;
      dist = sqrt(dx * dx + dy * dy);

    } while (dist < 22);

    drawStar(sx, sy);

    display.display();
    delay(60);
  }

  // --- 2. Main 15-second animation ---
  while (millis() - startTime < 15000) {
    display.clearDisplay();

    // Pulsing glow radius
    float t = (millis() - startTime) * 0.008;
    int pulse = 2 + (sin(t) * 3);

    // Glow ring
    display.drawCircle(cx, cy, 14 + pulse, SSD1306_WHITE);

    // Face outline
    display.drawCircle(cx, cy, 14, SSD1306_WHITE);

    // Eyes
    display.fillCircle(cx - 6, cy - 4, 2, SSD1306_WHITE);
    display.fillCircle(cx + 6, cy - 4, 2, SSD1306_WHITE);

    // Smile (correct orientation)
    for (int angle = 20; angle <= 160; angle += 5) {
      float rad = angle * 0.0174533;
      int x = cx + cos(rad) * 10;
      int y = cy + sin(rad) * 10;
      display.drawPixel(x, y, SSD1306_WHITE);
    }

    // --- Twinkling sparkles (outside the face) ---
    for (int i = 0; i < 5; i++) {
      int sx, sy, dx, dy, dist;

      do {
        sx = random(0, 128);
        sy = random(0, 32);

        dx = sx - cx;
        dy = sy - cy;
        dist = sqrt(dx * dx + dy * dy);

      } while (dist < 22);  // keep sparkles OUTSIDE the face + glow

      drawStar(sx, sy);
    }

    display.display();
    delay(120);
  }

  // Turn off the display after animation
  display.clearDisplay();
  display.display();
  display.ssd1306_command(SSD1306_DISPLAYOFF);
}

// ------------------------------------------------------------
// Draw the horizontal countdown bar + digits
// ------------------------------------------------------------
void drawTimer() {
  display.clearDisplay();

  // Bar dimensions
  int barHeight = 32;
  int barWidth = 96;

  // Map remaining seconds to bar width
  int currentWidth = map(remaining, 0, 90, 0, barWidth);

  // Draw bar left → right
  display.fillRect(0, 0, currentWidth, barHeight, SSD1306_WHITE);

  // Digits on the right
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);

  int digitX = 100;
  int digitY = 10;

  display.setCursor(digitX, digitY);
  display.print(remaining);

  display.display();
}

// ------------------------------------------------------------
// Setup
// ------------------------------------------------------------
void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(buzzerPin, OUTPUT);

  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setRotation(0);  // horizontal
  display.display();
}

// ------------------------------------------------------------
// Main loop
// ------------------------------------------------------------
void loop() { 
  // Start timer on button press
  if (!running && digitalRead(buttonPin) == LOW) {
    remaining = 90;
    running = true;
    display.ssd1306_command(SSD1306_DISPLAYON);
    
    delay(200); // debounce
  }

  if (running) {
    unsigned long now = millis();

    // Update once per second
    if (now - lastUpdate >= 1000) {
      lastUpdate = now;
      remaining--;

      // Final 5-second countdown beeps (higher pitch)
      if (remaining > 0 && remaining <= 5) {
        tone(buzzerPin, 3000, 150);   // 3 kHz beep
      }
      // Regular 10-second interval beeps
      else if (remaining > 0 && remaining % 10 == 0) {
        tone(buzzerPin, 2000, 150);   // 2 kHz beep
      }

      if (remaining <= 0) {
        running = false;
        showSmiley();
      }
    }

    drawTimer();
  }
}