#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/fb.h>
#include <sys/ioctl.h>

int main() {
    const char *fb_path = "/dev/fb0";
    const char *output_dir = "/mnt/onboard/screenshots/";

    int fb = open(fb_path, O_RDONLY);
    if (fb < 0) {
        perror("open framebuffer");
        return 1;
    }

    struct fb_var_screeninfo vinfo;
    if (ioctl(fb, FBIOGET_VSCREENINFO, &vinfo)) {
        perror("ioctl");
        close(fb);
        return 1;
    }

    int width  = vinfo.xres;
    int height = vinfo.yres;
    int bpp    = vinfo.bits_per_pixel;

    size_t screensize = width * height * (bpp / 8);
    unsigned char *buffer = malloc(screensize);
    if (!buffer) {
        perror("malloc");
        close(fb);
        return 1;
    }

    int counter = 0;
    while (1) {
        if (lseek(fb, 0, SEEK_SET) < 0) {  // torna all'inizio del framebuffer
            perror("lseek");
            break;
        }

        if (read(fb, buffer, screensize) != screensize) {
            perror("read");
            break;
        }

        char filename[256];
        snprintf(filename, sizeof(filename), "%s/screen%03d.raw", output_dir, counter++);
        FILE *out = fopen(filename, "wb");
        if (!out) {
            perror("fopen");
            break;
        }

        fwrite(buffer, 1, screensize, out);
        fclose(out);

        sleep(1);
    }

    free(buffer);
    close(fb);
    return 0;
}