#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <bcm2835.h>
#include <unistd.h>

/* Button pin definitions (BCM numbering) */
#define BUTTON_UP   RPI_V2_GPIO_P1_36 // GPIO 16
#define BUTTON_DOWN RPI_V2_GPIO_P1_28 // GPIO 1
#define BUTTON_LEFT RPI_V2_GPIO_P1_26 // GPIO 7
#define BUTTON_RIGHT RPI_V2_GPIO_P1_24 // GPIO 8

/* Array of button pins */
const uint8_t buttons[] = {BUTTON_UP, BUTTON_DOWN, BUTTON_LEFT, BUTTON_RIGHT};

/* Array of direction names */
const char *direction_map[] = {"Up", "Down", "Left", "Right"};

/* Configure button pins */
void configura_pinos() {
    for (int i = 0; i < 4; i++) {
        bcm2835_gpio_fsel(buttons[i], BCM2835_GPIO_FSEL_INPT); // Set as input
        bcm2835_gpio_set_pud(buttons[i], BCM2835_GPIO_PUD_UP); // Enable pull-up
        bcm2835_gpio_fen(buttons[i]); // Enable falling edge detection
    }
}

/* Signal handler for clean exit */
void trata_interrupcao(int sinal) {
    bcm2835_close();
    exit(0);
}

int main(int argc, char **argv) {
    if (!bcm2835_init()) {
        printf("Failed to initialize bcm2835 library\n");
        return 1;
    }

    configura_pinos();
    signal(SIGINT, trata_interrupcao);

    while (1) {
        for (int i = 0; i < 4; i++) {
            bcm2835_gpio_set_eds(buttons[i]); // Clear event status
            if (bcm2835_gpio_eds(buttons[i])) { // Check for event
                printf("Direction: %s\n", direction_map[i]);
                fflush(stdout);
                /* Wait for button release to prevent multiple triggers */
                while (bcm2835_gpio_lev(buttons[i]) == LOW) {
                    usleep(100000); // 100ms delay for debouncing
                }
            }
        }
        usleep(100000); // 100ms sleep to reduce CPU usage
    }

    bcm2835_close();
    return 0;
}