#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "driver/gpio.h"

// Pin definitions
#define BUTTON_PIN 4 // Button connected to GPIO 4
uint8_t led_pins[] = {38, 37, 36, 35, 0, 45, 48, 47};

// Function declarations
int readPinStateWithDebounce(int pin);
void writeToPins(uint8_t pins[], uint8_t val);
void printbin8(uint8_t val);

void app_main() {
  uint8_t counter = 0; // 8-bit counter variable
  int lastButtonState = 1; // Tracks the last button state 
  
  // Configure GPIO pins
  gpio_set_direction(BUTTON_PIN, GPIO_MODE_INPUT);
  gpio_set_pull_mode(BUTTON_PIN, GPIO_PULLUP_ONLY); // pull-up resistor
  
  for (int i = 0; i < 8; i++) {
    gpio_set_direction(led_pins[i], GPIO_MODE_OUTPUT);
  }
  
  // Main loop
  while (1) {
    int buttonState = readPinStateWithDebounce(BUTTON_PIN);
    
    // Check for button press 
    if (buttonState == 0 && lastButtonState == 1) {
      counter++; // increase counter
      printf("Button pressed! Counter = %d\n", counter);
      printbin8(counter);
      writeToPins(led_pins, counter);
    }
    
    lastButtonState = buttonState;
    vTaskDelay(pdMS_TO_TICKS(10)); // delay
  }
}

/**
 * Function Name - readPinStateWithDebounce
 * Description - Reads a GPIO pin with debounce logic
 * Return type - int 
 * Parameters -  GPIO pin number to read
 */
int readPinStateWithDebounce(int pin) {
  int istate = gpio_get_level(pin);
  if (istate == 0) {
    vTaskDelay(pdMS_TO_TICKS(50)); // Debounce delay
    int cstate = gpio_get_level(pin);
    if (cstate == 0) {
      return 0; // Button is pressed
    }
    else {
      return 1; // something there 
    }
  }
  else {
    return 1; // Button not pressed
  }
}

/**
 * Function Name - writeToPins
 * Description - Writes a byte value to an array of GPIO pins
 * Return type - void
 * Parameters - array of GPIO pin numbers  8-bit value to write
 */
void writeToPins(uint8_t pins[], uint8_t val) {
  for (int i = 0; i < 8; i++) {
    // Write each bit to an LED
    gpio_set_level(pins[i], (val >> i) & 1);
  }
}

/**
 * Function Name - printbin8
 * Description - Prints an 8bit value in binary
 * Return type - void
 * Parameters -  8-bit value to print
 */
void printbin8(uint8_t val) {
  printf("The value of %u in binary is: 0b", val);
  for (int i = 7; i >= 0; i--) {
    printf("%d", (val >> i) & 1);
  }
  printf("\n");
}