#include <avr/io.h>
#include <avr/sleep.h>

void disableADC() {
    ADCSRA &= ~(1 << ADEN);  // Clear ADC enable bit
}

void disableAnalogComparator() {
    ACSR |= (1 << ACD);  // Set analog comparator disable bit
}

#define INPUT_A_PIN PB5
#define INPUT_B_PIN PB2
#define OUTPUT_A_PIN PB3
#define OUTPUT_B_PIN PB1
#define OUTPUT_C_PIN PB4

// Variable to store the previous state of input pin 2
bool prevInputStateB = LOW; 
// Variable to track if output B has been triggered
bool outputBActive = false; 

void setup() {
  // Add a brief delay to allow the microcontroller to stabilize
  delay(300); 
  
  // Disable unused peripherals
  disableADC();
  disableAnalogComparator(); 

  // Disable EEPROM
  EECR &= ~(1 << EEMPE);  // Clear EEPROM master write enable bit
  EECR &= ~(1 << EEPE);   // Clear EEPROM write enable bit 

  // Declare Input and Output Pins
  pinMode(INPUT_A_PIN, INPUT_PULLUP);
  pinMode(INPUT_B_PIN, INPUT_PULLUP);
  pinMode(OUTPUT_A_PIN, OUTPUT);
  pinMode(OUTPUT_B_PIN, OUTPUT);
  pinMode(OUTPUT_C_PIN, OUTPUT);
}

void loop() {

  // Read the state of input pins
  bool inputA = digitalRead(INPUT_A_PIN);
  bool inputB = digitalRead(INPUT_B_PIN);

  // Process input condition when nothing is plugged into the two jacks
  if (!inputA && !inputB) {
      // If inputA is low and inputB is low, set output A and B low
      digitalWrite(OUTPUT_A_PIN, LOW);
      digitalWrite(OUTPUT_B_PIN, LOW);
      digitalWrite(OUTPUT_C_PIN, LOW);     
  } 
  
  // Process input condition when nothing is Headphone only is plugged in
  else if (inputA && !inputB) {
      // If inputA is low and inputB is low, set output A and B low
      digitalWrite(OUTPUT_A_PIN, HIGH);
      digitalWrite(OUTPUT_B_PIN, LOW);
      digitalWrite(OUTPUT_C_PIN, LOW);
  } 

  // Process input condition when AV Jack is plugged in
  else {
      // If inputA is low and inputB is high, set output A and B high
      digitalWrite(OUTPUT_A_PIN, HIGH);
      digitalWrite(OUTPUT_B_PIN, LOW);
      delay(200); // Delay for 200 milliseconds
      digitalWrite(OUTPUT_C_PIN, HIGH);
  } 

  // Check for rising edge on video out jack on input B
  if (!prevInputStateB && inputB) { // If input B was previously low and is now high
    outputBActive = true; // Set output B to be active
  }
  
  // Check for falling edge on video out jack on input B
  if (prevInputStateB && !inputB) { // If input B was previously high and is now low
    outputBActive = true; // Set output B to be active
  }

  if (outputBActive) {
    digitalWrite(OUTPUT_B_PIN, HIGH); // Set output B high
    delay(200); // Delay for 200 milliseconds
    digitalWrite(OUTPUT_B_PIN, LOW); // Set output B low
    outputBActive = false; // Reset the flag for output B
  }      
  
  // Store the current state of input B for the next iteration
  prevInputStateB = inputB; 

  // Enter idle mode to conserve power
  set_sleep_mode(SLEEP_MODE_IDLE);
  sleep_enable();
  sleep_cpu();
  // Code execution resumes from here when awakened
}