#include <stdio.h>          // Standard input-output library
#include "pico/stdlib.h"   // Standard library for Raspberry Pi Pico
#include "hardware/gpio.h" // Hardware-specific GPIO library

class GPIOControl {
private:
    const uint FIRST_GPIO = 2; // Starting GPIO pin for 7-segment display
    const uint BUTTON_GPIO = FIRST_GPIO + 7; // GPIO pin for the button
    const int bits[10] = { // Bit patterns for displaying digits 0-9 on the 7-segment display
        0x3f,  // 0
        0x06,  // 1
        0x5b,  // 2
        0x4f,  // 3
        0x66,  // 4
        0x6d,  // 5
        0x7d,  // 6
        0x07,  // 7
        0x7f,  // 8
        0x67   // 9
    };

public:
    GPIOControl() {}

    void setup() {
        stdio_init_all(); // Initialize standard I/O

        // Initialize GPIO pins for 7-segment display
        for (uint gpio = FIRST_GPIO; gpio < FIRST_GPIO + 7; gpio++) {
            gpio_init(gpio); // Initialize GPIO pin
            gpio_set_dir(gpio, GPIO_OUT); // Set GPIO pin direction to output
            gpio_set_outover(gpio, GPIO_OVERRIDE_INVERT); // Set GPIO output override to invert
        }

        // Initialize button GPIO pin
        gpio_init(BUTTON_GPIO); // Initialize GPIO pin for the button
        gpio_set_dir(BUTTON_GPIO, GPIO_IN); // Set GPIO pin direction to input
        gpio_pull_up(BUTTON_GPIO); // Enable pull-up resistor for the button
    }

    void updateCounter() {
        int val = 0; // Initialize counter value

        // Continuous loop for updating counter
        while (true) {
            if (!gpio_get(BUTTON_GPIO)) {  // Check if the button is pressed
                if (val == 9) {
                    val = 0; // Reset counter if it reaches 9
                } else {
                    val++; // Increment counter
                }
            } else {  // Button not pressed
                if (val == 0) {
                    val = 9; // Reset counter to 9 if it reaches 0
                } else {
                    val--; // Decrement counter
                }
            }

            // Set GPIO pins based on the value of the counter to display the corresponding digit
            uint32_t mask = bits[val] << FIRST_GPIO; // Shift the bit pattern to the correct GPIO pins
            gpio_set_mask(mask); // Set GPIO pins according to the mask
            sleep_ms(1000); // Delay for 1 second
            gpio_clr_mask(mask); // Clear GPIO pins
        }
    }
};

int main() {
    stdio_init_all(); // Initialize standard I/O
    printf("Hello! Nice to see you! - press button to count up or down!\n"); // Print a greeting message
    GPIOControl gpioControl; // Create an instance of GPIOControl class
    gpioControl.setup(); // Call setup function to initialize GPIO pins
    gpioControl.updateCounter(); // Call updateCounter function to update counter based on button press
    return 0; // Return 0 to indicate successful execution
}