// Including necessary libraries for OLED display and fonts.
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <Fonts/FreeSans9pt7b.h>
#include <Fonts/FreeSansBold12pt7b.h>
#include <Fonts/FreeSansBold9pt7b.h>

// Define the screen width and height
#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     -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Define the pin numbers for the LED, potentiometer, battery, and button
int ledPin1 = 5;
int potPin = A1;
int ledPin2 = 6;
int batPin = A2;
int buttonPin = 2; // Changed to pin 2 to support interrupts

// Variables to store the state and time of the button press
volatile unsigned long buttonPressTime = 0;
volatile bool isButtonPressed = false;

// Variables to store the values from the potentiometer and battery
int potIn;
int batIn;

// Variables to hold the PWM values for the LEDs
int brightness1;
int brightness2;

// Variable to hold the state of the LED
bool led1State = false;
bool led2State = true;
// Variables to control the LED blinking
unsigned long lastLedChange = 0; // Last time the LED state was changed
unsigned long ledOnTime = 150; // LED on time in milliseconds
unsigned long ledOffTime = 2000; // LED off time in milliseconds

// /**
//    Function to handle the button press interrupt.
// */
// void handleButtonPress() {
//   // Check if the button was just pressed
//   if (!isButtonPressed) {
//     isButtonPressed = true;
//     buttonPressTime = millis();
//   }
// }

/**
   Setup function that runs once at the start of the program.
*/
void setup()
{
  // Initialize the serial communication
  Serial.begin(57600);

  // Set the LED pins as output
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  // Set the button pin as input with internal pull-up resistor
  pinMode(buttonPin, INPUT_PULLUP);

  // // Attach an interrupt to the button pin
  // attachInterrupt(digitalPinToInterrupt(buttonPin), handleButtonPress, FALLING);

  // Initialize the SSD1306 display
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.display();
  display.setTextColor(WHITE);

  // Set initial value of ledPin2 to HIGH
  digitalWrite(ledPin2, HIGH);
}

/**
   Loop function that runs repeatedly after the setup function.
*/

void loop()
{
  // Read the value from the potentiometer
  potIn = analogRead(potPin);

  // Map the potentiometer value to the LED brightness range
  brightness1 = map(potIn, 0, 1023, 0, 255);

  // Map the brightness value to a percentage range
  brightness1 = map(brightness1, 0, 255, 0, 100);

  // Delay for stability
  delay(10);

  // Read the value from the battery
  batIn = analogRead(batPin);

  // Map the battery value to the LED brightness range
  brightness2 = map(batIn, 0, 1023, 0, 255);

  // Map the brightness value to a percentage range
  brightness2 = map(brightness2, 0, 255, 0, 100);

  // Delay for stability
  delay(10);

  // Check if the button is pressed
  if (digitalRead(buttonPin) == LOW) {
    // Check if the button was just pressed
    if (!isButtonPressed) {
      isButtonPressed = true;
      buttonPressTime = millis();
    }
    // Check if the button has been pressed for 5 seconds
    else if (millis() - buttonPressTime >= 2000) {
      // Blink the LED without delay
      if (led1State && millis() - lastLedChange >= ledOnTime) {
        led1State = false;
        lastLedChange = millis();
        digitalWrite(ledPin1, LOW);
      } else if (!led1State && millis() - lastLedChange >= ledOffTime) {
        led1State = true;
        lastLedChange = millis();
        digitalWrite(ledPin1, HIGH);
      }

      display.clearDisplay();
      display.display();
      // Turn off the LED when the button is pressed
      digitalWrite(ledPin2, LOW);
      // Set the button state to pressed
      isButtonPressed = true;

      // Exit the loop
      return;
    }
  } else {
    // Set the button state to not pressed
    isButtonPressed = false;


  }
  // Turn on the LED when the button is released
  digitalWrite(ledPin2, HIGH);
  // Update the display with the brightness values
  display.clearDisplay();
  display.setFont(&FreeSansBold9pt7b);
  display.invertDisplay(false);
  display.setCursor(0, 20);
  display.print("Output:");
  display.setFont(&FreeSansBold12pt7b);
  display.setCursor(68, 22);
  display.print(brightness1);
  display.print("%");

  display.setFont(&FreeSansBold9pt7b);
  display.setCursor(0, 54);
  display.print("Battery:");
  display.setFont(&FreeSansBold12pt7b);
  display.setCursor(68, 56);
  display.print(brightness2);
  display.print("%");

  // Update the display
  display.display();
}