/*
 * BRLTTY - A background process providing access to the console screen (when in
 *          text mode) for a blind person using a refreshable braille display.
 *
 * Copyright (C) 1995-2021 by The BRLTTY Developers.
 *
 * BRLTTY comes with ABSOLUTELY NO WARRANTY.
 *
 * This is free software, placed under the terms of the
 * GNU Lesser General Public License, as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at your option) any
 * later version. Please see the file LICENSE-LGPL for details.
 *
 * Web Page: http://brltty.app/
 *
 * This software is maintained by Dave Mielke <dave@mielke.cc>.
 */

#include "prologue.h"

#include <string.h>
#include <errno.h>

#include "log.h"
#include "strfmt.h"
#include "usb_serial.h"
#include "usb_cdc_acm.h"
#include "usb_internal.h"
#include "bitfield.h"

struct UsbSerialDataStruct {
  UsbDevice *device;
  const UsbInterfaceDescriptor *interface;
  const UsbEndpointDescriptor *endpoint;

  USB_CDC_ACM_LineCoding lineCoding;
};

static int
usbGetParameters_CDC_ACM (UsbDevice *device, uint8_t request, uint16_t value, void *data, uint16_t size) {
  ssize_t result = usbControlRead(device, UsbControlRecipient_Interface,
                                  UsbControlType_Class, request, value,
                                   device->serial.data->interface->bInterfaceNumber,
                                   data, size, 1000);

  return result != -1;
}

static int
usbGetParameter_CDC_ACM (UsbDevice *device, uint8_t request, void *data, uint16_t size) {
  return usbGetParameters_CDC_ACM(device, request, 0, data, size);
}

static int
usbSetParameters_CDC_ACM (UsbDevice *device, uint8_t request, uint16_t value, const void *data, uint16_t size) {
  ssize_t result = usbControlWrite(device, UsbControlRecipient_Interface,
                                   UsbControlType_Class, request, value,
                                   device->serial.data->interface->bInterfaceNumber,
                                   data, size, 1000);

  return result != -1;
}

static int
usbSetParameter_CDC_ACM (UsbDevice *device, uint8_t request, uint16_t value) {
  return usbSetParameters_CDC_ACM(device, request, value, NULL, 0);
}

static int
usbSetControlLines_CDC_ACM (UsbDevice *device, uint16_t lines) {
  return usbSetParameter_CDC_ACM(device, USB_CDC_ACM_CTL_SetControlLineState, lines);
}

static void
usbLogLineCoding_CDC_ACM (const USB_CDC_ACM_LineCoding *lineCoding) {
  char log[0X80];

  STR_BEGIN(log, sizeof(log));
  STR_PRINTF("CDC ACM line coding:");

  { // baud (bits per second)
    uint32_t baud = getLittleEndian32(lineCoding->dwDTERate);
    STR_PRINTF(" Baud:%" PRIu32, baud);
  }

  { // number of data bits
    STR_PRINTF(" Data:%u", lineCoding->bDataBits);
  }

  { // number of stop bits
    const char *bits;

#define USB_CDC_ACM_STOP(value,name) \
case USB_CDC_ACM_STOP_##value: bits = #name; break;
    switch (lineCoding->bCharFormat) {
      USB_CDC_ACM_STOP(1  , 1  )
      USB_CDC_ACM_STOP(1_5, 1.5)
      USB_CDC_ACM_STOP(2  , 2  )
      default: bits = "?"; break;
    }
#undef USB_CDC_ACM_STOP

    STR_PRINTF(" Stop:%s", bits);
  }

  { // type of parity
    const char *parity;

#define USB_CDC_ACM_PARITY(value,name) \
case USB_CDC_ACM_PARITY_##value: parity = #name; break;
    switch (lineCoding->bParityType) {
      USB_CDC_ACM_PARITY(NONE , none )
      USB_CDC_ACM_PARITY(ODD  , odd  )
      USB_CDC_ACM_PARITY(EVEN , even )
      USB_CDC_ACM_PARITY(MARK , mark )
      USB_CDC_ACM_PARITY(SPACE, space)
      default: parity = "?"; break;
    }
#undef USB_CDC_ACM_PARITY

    STR_PRINTF(" Parity:%s", parity);
  }

  STR_END;
  logMessage(LOG_CATEGORY(USB_IO), "%s", log);
}

static int
usbSetLineProperties_CDC_ACM (UsbDevice *device, unsigned int baud, unsigned int dataBits, SerialStopBits stopBits, SerialParity parity) {
  USB_CDC_ACM_LineCoding lineCoding;
  memset(&lineCoding, 0, sizeof(lineCoding));

  putLittleEndian32(&lineCoding.dwDTERate, baud);

  switch (dataBits) {
    case  5:
    case  6:
    case  7:
    case  8:
    case 16:
      lineCoding.bDataBits = dataBits;
      break;

    default:
      logMessage(LOG_WARNING, "unsupported CDC ACM data bits: %u", dataBits);
      errno = EINVAL;
      return 0;
  }

  switch (stopBits) {
    case SERIAL_STOP_1:
      lineCoding.bCharFormat = USB_CDC_ACM_STOP_1;
      break;

    case SERIAL_STOP_1_5:
      lineCoding.bCharFormat = USB_CDC_ACM_STOP_1_5;
      break;

    case SERIAL_STOP_2:
      lineCoding.bCharFormat = USB_CDC_ACM_STOP_2;
      break;

    default:
      logMessage(LOG_WARNING, "unsupported CDC ACM stop bits: %u", stopBits);
      errno = EINVAL;
      return 0;
  }

  switch (parity) {
    case SERIAL_PARITY_NONE:
      lineCoding.bParityType = USB_CDC_ACM_PARITY_NONE;
      break;

    case SERIAL_PARITY_ODD:
      lineCoding.bParityType = USB_CDC_ACM_PARITY_ODD;
      break;

    case SERIAL_PARITY_EVEN:
      lineCoding.bParityType = USB_CDC_ACM_PARITY_EVEN;
      break;

    case SERIAL_PARITY_MARK:
      lineCoding.bParityType = USB_CDC_ACM_PARITY_MARK;
      break;

    case SERIAL_PARITY_SPACE:
      lineCoding.bParityType = USB_CDC_ACM_PARITY_SPACE;
      break;

    default:
      logMessage(LOG_WARNING, "unsupported CDC ACM parity: %u", parity);
      errno = EINVAL;
      return 0;
  }

  {
    USB_CDC_ACM_LineCoding *oldCoding = &device->serial.data->lineCoding;

    if (memcmp(&lineCoding, oldCoding, sizeof(lineCoding)) != 0) {
      if (!usbSetParameters_CDC_ACM(device, USB_CDC_ACM_CTL_SetLineCoding, 0,
                                    &lineCoding, sizeof(lineCoding))) {
        return 0;
      }

      *oldCoding = lineCoding;
      usbLogLineCoding_CDC_ACM(&lineCoding);
    }
  }

  return 1;
}

static int
usbSetFlowControl_CDC_ACM (UsbDevice *device, SerialFlowControl flow) {
  if (flow) {
    logMessage(LOG_WARNING, "unsupported CDC ACM flow control: %02X", flow);
    errno = EINVAL;
    return 0;
  }

  return 1;
}

static const UsbInterfaceDescriptor *
usbFindCommunicationInterface (UsbDevice *device) {
  const UsbDescriptor *descriptor = NULL;

  while (usbNextDescriptor(device, &descriptor)) {
    if (descriptor->header.bDescriptorType == UsbDescriptorType_Interface) {
      if (descriptor->interface.bInterfaceClass == 0X02) {
        return &descriptor->interface;
      }
    }
  }

  logMessage(LOG_WARNING, "USB: communication interface descriptor not found");
  errno = ENOENT;
  return NULL;
}

static const UsbEndpointDescriptor *
usbFindInterruptInputEndpoint (UsbDevice *device, const UsbInterfaceDescriptor *interface) {
  const UsbDescriptor *descriptor = (const UsbDescriptor *)interface;

  while (usbNextDescriptor(device, &descriptor)) {
    if (descriptor->header.bDescriptorType == UsbDescriptorType_Interface) break;

    if (descriptor->header.bDescriptorType == UsbDescriptorType_Endpoint) {
      if (USB_ENDPOINT_DIRECTION(&descriptor->endpoint) == UsbEndpointDirection_Input) {
        if (USB_ENDPOINT_TRANSFER(&descriptor->endpoint) == UsbEndpointTransfer_Interrupt) {
          return &descriptor->endpoint;
        }
      }
    }
  }

  logMessage(LOG_WARNING, "USB: interrupt input endpoint descriptor not found");
  errno = ENOENT;
  return NULL;
}

static int
usbMakeData_CDC_ACM (UsbDevice *device, UsbSerialData **serialData) {
  UsbSerialData *usd;

  if ((usd = malloc(sizeof(*usd)))) {
    memset(usd, 0, sizeof(*usd));
    usd->device = device;

    if ((usd->interface = usbFindCommunicationInterface(device))) {
      unsigned char interfaceNumber = usd->interface->bInterfaceNumber;

      if (usbClaimInterface(device, interfaceNumber)) {
        if (usbSetAlternative(device, usd->interface->bInterfaceNumber, usd->interface->bAlternateSetting)) {
          if ((usd->endpoint = usbFindInterruptInputEndpoint(device, usd->interface))) {
            usbBeginInput(device, USB_ENDPOINT_NUMBER(usd->endpoint));
            *serialData = usd;
            return 1;
          }
        }

        usbReleaseInterface(device, interfaceNumber);
      }
    }

    free(usd);
  } else {
    logMallocError();
  }

  return 0;
}

static void
usbDestroyData_CDC_ACM (UsbSerialData *usd) {
  usbReleaseInterface(usd->device, usd->interface->bInterfaceNumber);
  free(usd);
}

static int
usbEnableAdapter_CDC_ACM (UsbDevice *device) {
  UsbSerialData *usd = device->serial.data;

  if (!usbSetControlLines_CDC_ACM(device, 0)) return 0;
  if (!usbSetControlLines_CDC_ACM(device, USB_CDC_ACM_LINE_DTR)) return 0;

  {
    USB_CDC_ACM_LineCoding *lineCoding = &usd->lineCoding;

    if (!usbGetParameter_CDC_ACM(device, USB_CDC_ACM_CTL_GetLineCoding,
                                  lineCoding, sizeof(*lineCoding))) {
      return 0;
    }

    usbLogLineCoding_CDC_ACM(lineCoding);
  }

  return 1;
}

static void
usbDisableAdapter_CDC_ACM (UsbDevice *device) {
  usbSetControlLines_CDC_ACM(device, 0);
}

const UsbSerialOperations usbSerialOperations_CDC_ACM = {
  .name = "CDC_ACM",

  .makeData = usbMakeData_CDC_ACM,
  .destroyData = usbDestroyData_CDC_ACM,

  .setLineProperties = usbSetLineProperties_CDC_ACM,
  .setFlowControl = usbSetFlowControl_CDC_ACM,

  .enableAdapter = usbEnableAdapter_CDC_ACM,
  .disableAdapter = usbDisableAdapter_CDC_ACM
};