// Assignment - Task A
// Embedded IoT System Fall 2025
// Name: Malaika
// Reg#: 1291

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

// --- Pin Configuration ---
#define LED1 4
#define LED2 19
#define BTN1 32   // Button 1 → Change mode
#define BTN2 33   // Button 2 → Reset to OFF

// --- OLED Setup ---
Adafruit_SSD1306 display(128, 64, &Wire, -1);

// --- Variables ---
int mode = 0;  // 0=OFF, 1=Alternate, 2=Both ON, 3=PWM Fade

// --- Function to Show Mode on OLED ---
void showMode() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(10, 25);
  display.print("Mode: ");
  switch (mode) {
    case 0: display.print("Both OFF"); break;
    case 1: display.print("Alternate Blink"); break;
    case 2: display.print("Both ON"); break;
    case 3: display.print("PWM Fade"); break;
  }
  display.display();
}

void setup() {
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(BTN1, INPUT_PULLUP);
  pinMode(BTN2, INPUT_PULLUP);

  // --- Initialize OLED Display ---
  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    while (true); // stop if OLED not found
  }

  showMode(); // Display initial mode
}

void loop() {
  // --- Button 1: Cycle Modes ---
  if (digitalRead(BTN1) == LOW) {
    delay(200); // debounce
    mode = (mode + 1) % 4; // Cycle through 0–3
    showMode();
    while (digitalRead(BTN1) == LOW); // wait until released
  }

  // --- Button 2: Reset to OFF ---
  if (digitalRead(BTN2) == LOW) {
    delay(200);
    mode = 0;
    showMode();
    while (digitalRead(BTN2) == LOW);
  }

  // --- LED Behaviors ---
  switch (mode) {
    case 0: // Both OFF
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, LOW);
      break;

    case 1: // Alternate Blink
      digitalWrite(LED1, HIGH);
      digitalWrite(LED2, LOW);
      delay(300);
      digitalWrite(LED1, LOW);
      digitalWrite(LED2, HIGH);
      delay(300);
      break;

    case 2: // Both ON
      digitalWrite(LED1, HIGH);
      digitalWrite(LED2, HIGH);
      break;

    case 3: // PWM Fade
      for (int i = 0; i <= 255; i++) {
        analogWrite(LED1, i);
        analogWrite(LED2, 255 - i);
        delay(5);
      }
      for (int i = 255; i >= 0; i--) {
        analogWrite(LED1, i);
        analogWrite(LED2, 255 - i);
        delay(5);
      }
      break;
  }
}