#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include "usb.h"

static const char *progname = "minimon";

struct usb_device *find_dev() {
  struct usb_bus *bus;
  struct usb_device *dev;

  usb_init();
  usb_find_busses();
  usb_find_devices();

  for (bus = usb_busses; bus; bus = bus->next) {
    for (dev = bus->devices; dev; dev = dev->next) {
      if (dev->descriptor.idVendor == 0x04e8 &&
          dev->descriptor.idProduct == 0x2028) {
            return dev;
      }
    }
  }

  return NULL;
}

usb_dev_handle *dev_open(struct usb_device *dev) {
  int res = -1;
  char buf[256];
  usb_dev_handle *udev;
  int numeps = 0;

  udev = usb_open(dev);
  if (!udev) {
    fprintf(stderr, "%s: failed to open device, exit.\n", progname);
    exit(EXIT_FAILURE);
  }

  setuid(getuid());

  res = usb_set_configuration(udev, 1);

  usb_claim_interface(udev, 0);
  numeps = dev->config[0].interface[0].altsetting[0].bNumEndpoints;
  if (numeps == 0) {
    fprintf(stderr, "%s: no endpoints, exit.\n", progname);
    exit(EXIT_FAILURE);
  }

  strcpy(buf, "** no string **");
  res = usb_get_string_simple(udev, dev->descriptor.iManufacturer, buf, sizeof(buf));
  fprintf(stderr, "usb_get_string_simple => %d, %s\n", res, buf);

  {
    int eplist[] = { 0x2, 0x81, 0x83 };
    int eplength = sizeof(eplist)/sizeof(eplist[0]);
    int *endpoint = eplist;
    int i;
    for (i=0; i<eplength; i++) {
      res = usb_resetep(udev, *endpoint);
      res = usb_clear_halt(udev, *endpoint);
      endpoint++;
    }
  }

  return udev;
}


void send_jpeg(FILE *f, usb_dev_handle *udev) {
  fseek(f, 0, SEEK_END);
  int sz = ftell(f);
  fseek(f, 0, SEEK_SET);

  #define URBBUF_MAX 0x20000
  char buf[URBBUF_MAX];

  #define HDR_LEN 12
  char hdr[HDR_LEN] = {0xa5, 0x5a, 0x18, 0x04, 0xff, 0xff, 0xff, 0xff, 0x48, 0x00, 0x00, 0x00};
  *(int *)(hdr+4) = sz;

  memcpy(buf, hdr, HDR_LEN);
  int off = HDR_LEN;

  while(!feof(f)) {
    int nr = fread(buf+off, 1, URBBUF_MAX - off, f);
    if (nr < 0) break;
    // pad
    memset(buf + off + nr, 0, URBBUF_MAX - off - nr);

    // write it out chunk by chunk
    int timeout = 1000;
    int endpoint = 0x2;
    int res = usb_bulk_write(udev, endpoint, buf, URBBUF_MAX, timeout);

    assert(res >= 0);
    off = 0; // no header on subsequent chunks
  }
}

int main(int argc, char *argv[]) {
  if (argc != 2) {
    fprintf(stderr, "Usage: %s FILE", progname);
    return EXIT_FAILURE;
  }

  struct usb_device *dev = find_dev(index);
  assert(dev != NULL);

  usb_dev_handle *udev = dev_open(dev);

  FILE *f = fopen(argv[1], "rb");
  if (f == NULL) {
    fprintf(stderr, "%s: failed to open file '%s', exit.\n", progname, argv[1]);
    exit(EXIT_FAILURE);
  }
  send_jpeg(f, udev);
  fclose(f);

  return EXIT_SUCCESS;
}