#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <libusb-1.0/libusb.h>

static int count = 0;

int hotplug_callback(struct libusb_context *ctx, struct libusb_device *dev,
        libusb_hotplug_event event, void *user_data) {
    static libusb_device_handle *dev_handle = NULL;
    struct libusb_device_descriptor desc;
    int rc;
    printf("Entering callback\n"); // DEBUG
    (void)libusb_get_device_descriptor(dev, &desc);

    printf("%04x:%04x (bus %d, device %d)\n",
        desc.idVendor, desc.idProduct,
        libusb_get_bus_number(dev), libusb_get_device_address(dev));

    if (LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED == event) {
        rc = libusb_open(dev, &dev_handle);
        if (LIBUSB_SUCCESS != rc) {
            printf("Could not open USB device\n");
        }
    } else if (LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT == event) {
        if (dev_handle) {
            libusb_close(dev_handle);
            dev_handle = NULL;
        }
    } else {
        printf("Unhandled event %d\n", event);
    }
    count++;

    return 0;
}

int main (void) {
    libusb_hotplug_callback_handle callback_handle;
    int rc;

    libusb_init(NULL);

    rc = libusb_hotplug_register_callback(
            NULL,
            LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED | LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT,
            0,
            LIBUSB_HOTPLUG_MATCH_ANY,
            LIBUSB_HOTPLUG_MATCH_ANY,
            LIBUSB_HOTPLUG_MATCH_ANY,
            hotplug_callback,
            NULL,
            &callback_handle);
    if (LIBUSB_SUCCESS != rc) {
        printf("Error creating a hotplug callback\n");
        libusb_exit(NULL);
        return EXIT_FAILURE;
    }

    while (count < 2) {
        libusb_handle_events_completed(NULL, NULL);
        nanosleep(&(struct timespec){0, 10000000UL}, NULL);
    }

    libusb_hotplug_deregister_callback(NULL, callback_handle);
    libusb_exit(NULL);

    return 0;
}