#include <Wire.h>
#include <Adafruit_PCF8574.h>

#define PCF8574_ADDRESS 0x27  // I2C address of the PCF8574

Adafruit_PCF8574 pcf8574;

const int INPUT_PIN_1 = 0;   // Input pin 1
const int INPUT_PIN_2 = 1;   // Input pin 2
const int INPUT_PIN_3 = 2;   // Input pin 3
const int INPUT_PIN_4 = 3;   // Input pin 4

const int OUTPUT_PIN_1 = 4;  // Output pin 1
const int OUTPUT_PIN_2 = 5;  // Output pin 2
const int OUTPUT_PIN_3 = 6;  // Output pin 3
const int OUTPUT_PIN_4 = 7;  // Output pin 4

void setup() {
  Wire.begin();
  
  // Initialize the PCF8574
  if (!pcf8574.begin(PCF8574_ADDRESS)) {
    Serial.println("Failed to initialize PCF8574!");
    while (1);
  }
  
  // Set the input pins to INPUT_PULLUP mode
  pcf8574.pinMode(INPUT_PIN_1, INPUT);
  pcf8574.pinMode(INPUT_PIN_2, INPUT);
  pcf8574.pinMode(INPUT_PIN_3, INPUT);
  pcf8574.pinMode(INPUT_PIN_4, INPUT);
  
  // Set the output pins to OUTPUT mode
  pcf8574.pinMode(OUTPUT_PIN_1, OUTPUT);
  pcf8574.pinMode(OUTPUT_PIN_2, OUTPUT);
  pcf8574.pinMode(OUTPUT_PIN_3, OUTPUT);
  pcf8574.pinMode(OUTPUT_PIN_4, OUTPUT);
  
  // Initialize the serial communication
  Serial.begin(9600);
  Serial.println('Running');
}

void loop() {
  // Read the state of the input pins
  bool inputState1 = !pcf8574.digitalRead(INPUT_PIN_1);
  bool inputState2 = !pcf8574.digitalRead(INPUT_PIN_2);
  bool inputState3 = !pcf8574.digitalRead(INPUT_PIN_3);
  bool inputState4 = !pcf8574.digitalRead(INPUT_PIN_4);
  
  // Toggle the state of the output pins
  pcf8574.digitalWrite(OUTPUT_PIN_1, !pcf8574.digitalRead(OUTPUT_PIN_1));
  pcf8574.digitalWrite(OUTPUT_PIN_2, !pcf8574.digitalRead(OUTPUT_PIN_2));
  pcf8574.digitalWrite(OUTPUT_PIN_3, !pcf8574.digitalRead(OUTPUT_PIN_3));
  pcf8574.digitalWrite(OUTPUT_PIN_4, !pcf8574.digitalRead(OUTPUT_PIN_4));
  
  // Print the state of the input and output pins
  Serial.print("Input states: ");
  Serial.print(inputState1);
  Serial.print(" ");
  Serial.print(inputState2);
  Serial.print(" ");
  Serial.print(inputState3);
  Serial.print(" ");
  Serial.print(inputState4);
  Serial.print(" | Output states: ");
  Serial.print(pcf8574.digitalRead(OUTPUT_PIN_1));
  Serial.print(" ");
  Serial.print(pcf8574.digitalRead(OUTPUT_PIN_2));
  Serial.print(" ");
  Serial.print(pcf8574.digitalRead(OUTPUT_PIN_3));
  Serial.print(" ");
  Serial.println(pcf8574.digitalRead(OUTPUT_PIN_4));
  
  delay(1000);
}