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


uint16_t vendor_id = 0;
uint16_t product_id = 0;
uint8_t reset = 0;
uint8_t oneline = 0;
uint8_t debug = 0;

#define USBERR(msg, rc) { dprintf(2, "%s: %s\n", msg, libusb_strerror(rc)); }
#define DEBUG(...) { if (debug) { dprintf(2, __VA_ARGS__); } }

uint32_t vidpid[] = {
  0x0c2e0b01,
  0x0c2e0b02,
  0x0c2e0b07,
};


int config(int argc, char **args) {
  uint8_t cmd[64] = { 0 };
  char tokbuf[1024] = { 0 };
  libusb_context *ctx = NULL;
  libusb_device *dev = NULL;
  libusb_device_handle *devh = NULL;
  struct libusb_device_descriptor devd = { 0 };
  struct libusb_config_descriptor *devc = NULL;
  const struct libusb_interface *devi = NULL;
  const struct libusb_interface_descriptor *devid = NULL;
  const struct libusb_endpoint_descriptor *deved = NULL;
  char devdesc[256] = { 0 };
  int rc = 0;

  uint8_t ints[32] = { 0 };
  uint8_t inti = 0;
  uint8_t endpoint = 0;

  //
  // Find and open the device
  //
  rc = libusb_init(&ctx);
  if (!ctx) {
    USBERR("failed to initialize libusb", rc);
    return 1;
  }

  if (vendor_id || product_id) {
    devh = libusb_open_device_with_vid_pid(ctx, vendor_id, product_id);
    if (!devh) {
      dprintf(2, "device %04x:%04x not found\n", vendor_id, product_id);
      return 1;
    }
  } else {
    devh = NULL;
    for (uint8_t i = 0; i < sizeof(vidpid)/sizeof(vidpid[0]) && !devh; ++i) {
      devh = libusb_open_device_with_vid_pid(ctx, vidpid[i] >> 16, vidpid[i] & 0xffff);
    }
    if (!devh) {
      dprintf(2, "default devices not found, please provide vendor and product id\n");
      return 1;
    }
  }

  // Get endpoint infos
  dev = libusb_get_device(devh);
  rc = libusb_get_device_descriptor(dev, &devd);
  if (rc) {
    USBERR("failed to get device descriptor", rc);
    return 1;
  }
  for (uint8_t c = 0; c < devd.bNumConfigurations; ++c) {
    libusb_free_config_descriptor(devc);
    rc = libusb_get_config_descriptor(dev, c, &devc);
    if (rc) {
      USBERR("failed to get config descriptor", rc);
      continue;
    }
    rc = libusb_get_string_descriptor_ascii(devh, devc->iConfiguration, (uint8_t *) devdesc, 256);
    if (rc < 0) {
      USBERR("failed to get config string descriptor", rc);
      continue;
    }
    DEBUG("- configuration %d: %s\n", c, devdesc);
    for (uint8_t i = 0; i < devc->bNumInterfaces; ++i) {
      DEBUG("  - interface %d\n", i);
      devi = &(devc->interface[i]);
      for (uint8_t a = 0; a < devi->num_altsetting; ++a) {
	devid = &(devi->altsetting[a]);
	rc = libusb_get_string_descriptor_ascii(devh, devid->iInterface, (uint8_t *) devdesc, 256);
	if (rc < 0) {
	  USBERR("failed to get interface string descriptor", rc);
	  continue;
	}
	DEBUG("    - altsetting %d: interface=%d, desc=%s class=%d subclass=%d protocol=%d\n",
		devid->bAlternateSetting, devid->bInterfaceNumber, devdesc,
		devid->bInterfaceClass, devid->bInterfaceSubClass, devid->bInterfaceProtocol);
	for (uint8_t e = 0; e < devid->bNumEndpoints; ++e) {
	  deved = &(devid->endpoint[e]);
	  char type = "csbi"[deved->bmAttributes & 0b00000011];
	  DEBUG("      - endpoint %x: t=%c\n", deved->bEndpointAddress, type);
	  // build a list of interfaces so that we can claim all of them
	  ints[inti++] = devid->bInterfaceNumber;
	  // endpoint selection:
	  if ((deved->bmAttributes & 0b11) == LIBUSB_ENDPOINT_TRANSFER_TYPE_INTERRUPT  // must be an interrupt endpoint
	      && ((deved->bEndpointAddress & 0x80) == LIBUSB_ENDPOINT_IN)  // must be a device to host endpoint
	      && !strncmp("REM", devdesc, 3)  // human readable description of the interface must be "REM" (Honeywell "Remote MasterMind" control interface)
	      ) {
	    endpoint = deved->bEndpointAddress;
	  }
	}
      }
    }
  }

  DEBUG("chose endpoint %x\n", endpoint);

  //
  // Disconnect usbhid driver from both device interfaces
  //
  rc = libusb_set_auto_detach_kernel_driver(devh, 1);
  if (rc) {
    USBERR("auto-attaching kernel driver not possible; please replug USB when done", rc);
    for (uint8_t i = 0; i < inti; ++i) {
      rc = libusb_kernel_driver_active(devh, ints[i]);
      if (rc < 0) {
	USBERR("failed to query kernel driver state", rc);
	return 1;
      }
      if (rc > 0) {
	rc = libusb_detach_kernel_driver(devh, ints[i]);
	if (rc) {
	  USBERR("failed to detach kernel driver", rc);
	  return 1;
	}
      }
    }
  }

  for (uint8_t i = 0; i < inti; ++i) {
    rc = libusb_claim_interface(devh, ints[i]);
    if (rc) {
      USBERR("failed to claim interface", rc);
      return 1;
    }
  }

  //
  // Prepare and send a message on the control channel for each config argument
  //
  for (int i = 0; i < argc; ++i) {
    memset(cmd+5, 0, 59);
    cmd[0] = 0xfd;
    cmd[1] = strlen(args[i])+3;
    cmd[2] = 0x16;
    cmd[3] = 0x4d;
    cmd[4] = 0x0d;
    memcpy(cmd+5, args[i], strlen(args[i]));
    rc = libusb_control_transfer(devh, 0x21, 0x09, 0x02fd, 1, cmd, 64, 0);
    if (rc < 0) {
      USBERR("failed to send control message", rc);
    } else {
      DEBUG("> %s\n", args[i]);
    }
    int tx;
    tokbuf[64] = 0;
    char *start, *end, *tok = tokbuf;
    uint8_t eot = 0;
    // Repeat until a "." (EOT) is encountered in the response.
    while (!eot) {
      rc = libusb_interrupt_transfer(devh, endpoint, cmd, 64, &tx, 1000);
      if (rc) {
	USBERR("failed to receive response from device", rc);
	break;
      }
      // strip 2-byte header and AIMID
      start = (char *) cmd+5;
      DEBUG("< %s\n", start);
      while (1) {
	// non-final tokens: terminated by ;
	end = strchr(start, ';');
	if (end) {
	  if (end > start) {
	    memcpy(tok, start, end-start-1);
	    tok += end-start-1;
	  }
	  *tok = 0;
	  if (oneline) {
	    printf("%s;", tokbuf);
	  } else {
	    printf("%s.\n", tokbuf);
	  }
	  tok = tokbuf;
	  *tok = 0;
	  start = end + 1;
	  continue;
	}
	// last token: terminated by .
	end = strchr(start, '.');
	if (end) {
	  eot = 1;
	  if (end > start) {
	    memcpy(tok, start, end-start-1);
	    tok += end-start-1;
	  }
	  *tok = 0;
	  printf("%s.\n", tokbuf);
	  tok = tokbuf;
	  *tok = 0;
	  break;
	}
	// incomplete tokens continued in the next message
	end = strchr(start, '?');
	if (end) {
	  *end = 0;
	}
	strcpy(tok, start);
	tok += strlen(start);
	break;
      }
    }
  }

  //
  // Cleanup
  //
  for (uint8_t i = 0; i < inti; ++i) {
    rc = libusb_release_interface(devh, ints[i]);
    if (rc) {
      USBERR("failed to release interface", rc);
      return 1;
    }
  }
  if (reset) {
    libusb_reset_device(devh);
  }
  libusb_close(devh);
  libusb_exit(ctx);
  return 0;
}


int main(int argc, char **argv) {
  int opt;
  char *end;
  long parsed;
  while ((opt = getopt(argc, argv, "v:p:ord")) != -1) {
    switch (opt) {
    case 'v':
      end = optarg;
      parsed = strtol(optarg, &end, 16);
      if (*end != 0) {
	perror("failed to parse vendor id");
	return 1;
      }
      if (parsed <= 0 || parsed > 0xffff) {
	puts("invalid vendor id");
	return 1;
      }
      vendor_id = (uint16_t) parsed;
      break;
    case 'p':
      end = optarg;
      parsed = strtol(optarg, &end, 16);
      if (*end != 0) {
	perror("failed to parse product id");
	return 1;
      }
      if (parsed <= 0 || parsed > 0xffff) {
	puts("invalid product id");
	return 1;
      }
      product_id = (uint16_t) parsed;
      break;
    case 'r':
      reset = 1;
      break;
    case 'o':
      oneline = 1;
      break;
    case 'd':
      debug = 1;
      break;
    default:
      printf("usage: %s [-v vendor] [-p product] [-o] [-r] [-d] command1 [command2 [... commandN]]\n", argv[0]);
      puts("  -v vendor\tUSB vendor ID of the barcode scanner");
      puts("  -p product\tUSB product ID of the barcode scanner");
      puts("  -o\t\tPrint response on one line, rather than one token per line");
      puts("  -r\t\tReset device after configuration");
      puts("  -d\t\tDebug mode (more verbose output)");
      return 1;
    }
  }
  return config(argc-optind, argv+optind);
}