/*
 * This is free and unencumbered software released into the public domain.
 *
 * Anyone is free to copy, modify, publish, use, compile, sell, or
 * distribute this software, either in source code form or as a compiled
 * binary, for any purpose, commercial or non-commercial, and by any
 * means.
 *
 * In jurisdictions that recognize copyright laws, the author or authors
 * of this software dedicate any and all copyright interest in the
 * software to the public domain. We make this dedication for the benefit
 * of the public at large and to the detriment of our heirs and
 * successors. We intend this dedication to be an overt act of
 * relinquishment in perpetuity of all present and future rights to this
 * software under copyright law.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * For more information, please refer to <http://unlicense.org/>
 */

#include <libusb.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#define VENDOR  0x1d6b
#define PRODUCT 0x0105

#define BUF_LEN         8192

/*
 * struct test_state - describes test program state
 * @list: list of devices returned by libusb_get_device_list function
 * @found: pointer to struct describing tested device
 * @ctx: context, set to NULL
 * @handle: handle of tested device
 * @attached: indicates that device was attached to kernel, and has to be
 *            reattached at the end of test program
 */

struct test_state {
        libusb_device *found;
        libusb_context *ctx;
        libusb_device_handle *handle;
        int attached;
};

/*
 * test_init - initialize test program
 */

int test_init(struct test_state *state)
{
        int i, ret;
        ssize_t cnt;
        libusb_device **list;

        state->found = NULL;
        state->ctx = NULL;
        state->handle = NULL;
        state->attached = 0;

        ret = libusb_init(&state->ctx);
        if (ret) {
                printf("cannot init libusb: %s\n", libusb_error_name(ret));
                return 1;
        }

        cnt = libusb_get_device_list(state->ctx, &list);
        if (cnt <= 0) {
                printf("no devices found\n");
                goto error1;
        }

        for (i = 0; i < cnt; ++i) {
                libusb_device *dev = list[i];
                struct libusb_device_descriptor desc;
                ret = libusb_get_device_descriptor(dev, &desc);
                if (ret) {
                        printf("unable to get device descriptor: %s\n",
                               libusb_error_name(ret));
                        goto error2;
                }
                if (desc.idVendor == VENDOR && desc.idProduct == PRODUCT) {
                        state->found = dev;
                        break;
                }
        }

        if (!state->found) {
                printf("no devices found\n");
                goto error2;
        }

        ret = libusb_open(state->found, &state->handle);
        if (ret) {
                printf("cannot open device: %s\n", libusb_error_name(ret));
                goto error2;
        }

        if (libusb_claim_interface(state->handle, 0)) {
                ret = libusb_detach_kernel_driver(state->handle, 0);
                if (ret) {
                        printf("unable to detach kernel driver: %s\n",
                               libusb_error_name(ret));
                        goto error3;
                }
                state->attached = 1;
                ret = libusb_claim_interface(state->handle, 0);
                if (ret) {
                        printf("cannot claim interface: %s\n",
                               libusb_error_name(ret));
                        goto error4;
                }
        }

        return 0;

error4:
        if (state->attached == 1)
                libusb_attach_kernel_driver(state->handle, 0);

error3:
        libusb_close(state->handle);

error2:
        libusb_free_device_list(list, 1);

error1:
        libusb_exit(state->ctx);
        return 1;
}

/*
 * test_exit - cleanup test program
 */

void test_exit(struct test_state *state)
{
        libusb_release_interface(state->handle, 0);
        if (state->attached == 1)
                libusb_attach_kernel_driver(state->handle, 0);
        libusb_close(state->handle);
        libusb_exit(state->ctx);
}

int main(void)
{
        struct test_state state;
        struct libusb_config_descriptor *conf;
        struct libusb_interface_descriptor const *iface;
        unsigned char in_addr, out_addr;

        if (test_init(&state))
                return 1;

        libusb_get_config_descriptor(state.found, 0, &conf);
        iface = &conf->interface[0].altsetting[0];
        in_addr = iface->endpoint[0].bEndpointAddress;
        out_addr = iface->endpoint[1].bEndpointAddress;

        while (1) {
                static unsigned char buffer[BUF_LEN];
                int bytes;
                libusb_bulk_transfer(state.handle, in_addr, buffer, BUF_LEN,
                                     &bytes, 500);
                libusb_bulk_transfer(state.handle, out_addr, buffer, BUF_LEN,
                                     &bytes, 500);
        }
        test_exit(&state);
}