/*
 * usbtmc.c
 *
 *  Created on: Sep 9, 2019
 *      Author: nconrad
 */

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 N Conrad
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * 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 OR COPYRIGHT HOLDERS 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.
 *
 * This file is part of the TinyUSB stack.
 */

#include "tusb_option.h"

// We don't do any cross-task anything here (everything is in tud or interrupt context).
// You must ensure thread safety in your own app.


//Limitations (not planned to be implemented):
// "vendor-specific" commands are not handled

// TODO:
// USBTMC 3.2.2 error conditions not strictly followed
// No local lock-out, REN, or GTL.
// Cannot issue clear.
// No "capabilities" supported
// Interrupt-IN endpoint
// 488 MsgID=Trigger
// Clear message available status byte at the correct time? (488 4.3.1.3)
// Split transfers
// No CLEAR_FEATURE/HALT (yet)

#if (TUSB_OPT_DEVICE_ENABLED && CFG_TUD_USBTMC)

#include "usbtmc.h"
#include "usbtmc_device.h"
#include "device/dcd.h"
#include "device/usbd.h"

// FIXME: I shouldn't need to include _pvt headers.
#include "device/usbd_pvt.h"

typedef enum
{
  STATE_IDLE,
  STATE_RCV,
  STATE_TX_REQUESTED,
  STATE_TX_INITIATED
} usbtmcd_state_enum;

typedef struct
{
  usbtmcd_state_enum state;
  uint8_t itf_id;
  uint8_t ep_bulk_in;
  uint8_t ep_bulk_out;
  uint8_t ep_int_in;
  uint8_t ep_bulk_in_buf[64];
  uint8_t ep_bulk_out_buf[64];
  uint8_t lastTag;

  uint32_t transfer_size_remaining;
  uint8_t const * devInBuffer;
} usbtmc_interface_state_t;

static usbtmc_interface_state_t usbtmc_state =
{
    .state = STATE_IDLE,
    .itf_id = 0xFF,
    .ep_bulk_in = 0,
    .ep_bulk_out = 0,
    .ep_int_in = 0
};

// We want everything to fit nicely in a single packet, so lets require EP size >32
// I'm not sure if this is really necessary, though.
TU_VERIFY_STATIC(USBTMCD_MAX_PACKET_SIZE >= 32u,"USBTMC dev EP packet size too small");

// called from app
// We keep a reference to the buffer, so it MUST not change until the app is
// notified that the transfer is complete.
// length of data is specified in the hdr.
bool usbtmcd_transmit_dev_msg_data(
    uint8_t rhport,
    usbtmc_msg_dev_dep_msg_in_header_t const * hdr,
    const void *data)
{
  TU_ASSERT(usbtmc_state.state == STATE_TX_REQUESTED);
  TU_ASSERT(hdr->TransferSize > 0u);

  // Copy in the header
  memcpy(usbtmc_state.ep_bulk_in_buf, hdr, sizeof(*hdr));
  uint packetLen = sizeof(*hdr);
  // Single-packet transfer
  if((packetLen + hdr->TransferSize) <= USBTMCD_MAX_PACKET_SIZE)
  {
    memcpy((uint8_t*)(usbtmc_state.ep_bulk_in_buf) + packetLen, data, hdr->TransferSize);
    packetLen = (uint16_t)(packetLen+ hdr->TransferSize);
    // Pad up to multiple of 4 bytes
    while((packetLen % 4) != 0)
    {
      usbtmc_state.ep_bulk_in_buf[packetLen] = 0;
      packetLen++;
    }
    usbtmc_state.transfer_size_remaining = 0;
    usbtmc_state.devInBuffer = NULL;
  }
  else
  {
    memcpy((uint8_t*)(usbtmc_state.ep_bulk_in_buf) + packetLen, data, USBTMCD_MAX_PACKET_SIZE - packetLen);
    usbtmc_state.transfer_size_remaining = hdr->TransferSize - (USBTMCD_MAX_PACKET_SIZE - packetLen);
    usbtmc_state.devInBuffer += (USBTMCD_MAX_PACKET_SIZE - packetLen);
    packetLen = USBTMCD_MAX_PACKET_SIZE;
  }
  usbtmc_state.state = STATE_TX_INITIATED;
  TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_in, usbtmc_state.ep_bulk_in_buf,(uint16_t)packetLen));
  return true;
}

void usbtmcd_init(void)
{

}

bool usbtmcd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint16_t *p_length)
{
  (void)rhport;
  uint8_t const * p_desc;
  uint8_t found_endpoints = 0;

  // Perhaps there are other application specific class drivers, so don't assert here.
  if( itf_desc->bInterfaceClass != USBTMC_APP_CLASS)
    return false;
  if( itf_desc->bInterfaceSubClass != USBTMC_APP_SUBCLASS)
    return false;

  // Only 2 or 3 endpoints are allowed for USBTMC.
  TU_ASSERT((itf_desc->bNumEndpoints == 2) || (itf_desc->bNumEndpoints ==3));

  // Interface
  (*p_length) = 0u;
  p_desc = (uint8_t const *) itf_desc;

  usbtmc_state.itf_id = itf_desc->bInterfaceNumber;

  while (found_endpoints < itf_desc->bNumEndpoints)
  {
    if ( TUSB_DESC_ENDPOINT == p_desc[DESC_OFFSET_TYPE])
    {
      tusb_desc_endpoint_t const *ep_desc = (tusb_desc_endpoint_t const *)p_desc;
      switch(ep_desc->bmAttributes.xfer) {
        case TUSB_XFER_BULK:
          if (tu_edpt_dir(ep_desc->bEndpointAddress) == TUSB_DIR_IN)
          {
            usbtmc_state.ep_bulk_in = ep_desc->bEndpointAddress;
          } else {
            usbtmc_state.ep_bulk_out = ep_desc->bEndpointAddress;
          }

          break;
        case TUSB_XFER_INTERRUPT:
          TU_ASSERT(tu_edpt_dir(ep_desc->bEndpointAddress) == TUSB_DIR_IN);
          TU_ASSERT(usbtmc_state.ep_int_in == 0);
          usbtmc_state.ep_int_in = ep_desc->bEndpointAddress;
          break;
        default:
          TU_ASSERT(false);
      }
      TU_VERIFY( dcd_edpt_open(rhport, ep_desc));
      found_endpoints++;
    }
    (*p_length) = (uint8_t)((*p_length) + p_desc[DESC_OFFSET_LEN]);
    p_desc = tu_desc_next(p_desc);
  }

  // bulk endpoints are required, but interrupt IN is optional
  TU_ASSERT(usbtmc_state.ep_bulk_in != 0);
  TU_ASSERT(usbtmc_state.ep_bulk_out != 0);
  if (itf_desc->bNumEndpoints == 2) {
    TU_ASSERT(usbtmc_state.ep_int_in == 0);
  }
  else if (itf_desc->bNumEndpoints == 2)
  {
    TU_ASSERT(usbtmc_state.ep_int_in != 0);
  }
  TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_out, usbtmc_state.ep_bulk_out_buf, 64));

  return true;
}
void usbtmcd_reset(uint8_t rhport)
{
  // FIXME: Do endpoints need to be closed here?
  (void)rhport;
}
static bool handle_devMsgOut(uint8_t rhport, void *data, size_t len)
{
  (void)rhport;
  bool shortPacket = (len < USBTMCD_MAX_PACKET_SIZE);
  if(usbtmc_state.state == STATE_IDLE)
  {
    // must be a header, should have been confirmed before calling here.
    usbtmc_msg_request_dev_dep_out *msg = (usbtmc_msg_request_dev_dep_out*)data;
    usbtmc_state.transfer_size_remaining = msg->TransferSize;
    TU_VERIFY(usbtmcd_app_msgBulkOut_start(msg));
    len -= sizeof(*msg);
    data = (uint8_t*)data + sizeof(*msg);
  }
  // Packet is to be considered complete when we get enough data or at a short packet.
  bool atEnd = false;
  if(len >= usbtmc_state.transfer_size_remaining || shortPacket)
    atEnd = true;
  if(len > usbtmc_state.transfer_size_remaining)
    len = usbtmc_state.transfer_size_remaining;
  usbtmcd_app_msg_data(data, len, atEnd);
  if(atEnd)
    usbtmc_state.state = STATE_IDLE;
  else
    usbtmc_state.state = STATE_RCV;
  return true;
}
static bool handle_devMsgIn(uint8_t rhport, void *data, size_t len)
{
  TU_VERIFY(len == sizeof(usbtmc_msg_request_dev_dep_in));
  usbtmc_msg_request_dev_dep_in *msg = (usbtmc_msg_request_dev_dep_in*)data;
  TU_VERIFY(usbtmc_state.state == STATE_IDLE);
  usbtmc_state.state = STATE_TX_REQUESTED;
  usbtmc_state.transfer_size_remaining = msg->TransferSize;
  TU_VERIFY(usbtmcd_app_msgBulkIn_request(rhport, msg));
  return true;
}

bool usbtmcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_t xferred_bytes)
{
  TU_VERIFY(result == XFER_RESULT_SUCCESS);
  if(ep_addr == usbtmc_state.ep_bulk_out)
  {
    switch(usbtmc_state.state)
    {
    case STATE_IDLE:
      TU_VERIFY(xferred_bytes >= sizeof(usbtmc_msg_generic_t));
      usbtmc_msg_generic_t *msg = (usbtmc_msg_generic_t*)(usbtmc_state.ep_bulk_out_buf);
      uint8_t invInvTag = (uint8_t)~(msg->header.bTagInverse);
      TU_VERIFY(msg->header.bTag == invInvTag);
      TU_VERIFY(msg->header.bTag != 0x00);
      usbtmc_state.lastTag = msg->header.bTag;

      switch(msg->header.MsgID) {
      case USBTMC_MSGID_DEV_DEP_MSG_OUT:
        TU_VERIFY(handle_devMsgOut(rhport, msg, xferred_bytes));
        TU_VERIFY(usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_out, usbtmc_state.ep_bulk_out_buf, 64));
        break;
      case USBTMC_MSGID_DEV_DEP_MSG_IN:
        TU_VERIFY(handle_devMsgIn(rhport, msg, xferred_bytes));
        break;
      case USBTMC_MSGID_VENDOR_SPECIFIC_MSG_OUT:
      case USBTMC_MSGID_VENDOR_SPECIFIC_IN:
      case USBTMC_MSGID_USB488_TRIGGER:
      default:
        TU_VERIFY(false);
      }
      return true;

    case STATE_RCV:
      TU_VERIFY(handle_devMsgOut(rhport, usbtmc_state.ep_bulk_out_buf, xferred_bytes));
      TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_out, usbtmc_state.ep_bulk_out_buf, 64));
      return true;
      break;

    default:
      TU_VERIFY(false);
    }
  }
  else if(ep_addr == usbtmc_state.ep_bulk_in)
  {
    TU_ASSERT(usbtmc_state.state == STATE_TX_INITIATED);
    if(usbtmc_state.transfer_size_remaining == 0)
    {
      usbtmc_state.state = STATE_IDLE;
      TU_VERIFY(usbtmcd_app_msgBulkIn_complete(rhport));
      TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_out, usbtmc_state.ep_bulk_out_buf, 64));
    }
    else if(usbtmc_state.transfer_size_remaining >= USBTMCD_MAX_PACKET_SIZE)
    {
      memcpy(usbtmc_state.ep_bulk_in_buf, usbtmc_state.devInBuffer, USBTMCD_MAX_PACKET_SIZE);
      usbtmc_state.devInBuffer += USBTMCD_MAX_PACKET_SIZE;
      usbtmc_state.transfer_size_remaining -= USBTMCD_MAX_PACKET_SIZE;
      TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_in, usbtmc_state.ep_bulk_in_buf,USBTMCD_MAX_PACKET_SIZE));
    }
    else // short packet
    {
      uint packetLen = usbtmc_state.transfer_size_remaining;
      memcpy(usbtmc_state.ep_bulk_in_buf, usbtmc_state.devInBuffer, usbtmc_state.transfer_size_remaining);
      while((packetLen % 4) != 0)
      {
        usbtmc_state.ep_bulk_in_buf[packetLen] = 0;
        packetLen++;
      }
      usbtmc_state.transfer_size_remaining = 0;
      usbtmc_state.devInBuffer = NULL;
      TU_VERIFY( usbd_edpt_xfer(rhport, usbtmc_state.ep_bulk_in, usbtmc_state.ep_bulk_in_buf,(uint16_t)packetLen));
    }
    return true;
  }
  else if (ep_addr == usbtmc_state.ep_int_in) {
    // Good?
    return true;
  }
  return false;
}

bool usbtmcd_control_request(uint8_t rhport, tusb_control_request_t const * request) {

#if (USBTMC_CFG_ENABLE_488)
  ushort bTag;
#endif
  // We only handle class requests.
  if(request->bmRequestType_bit.type != TUSB_REQ_TYPE_CLASS)
    return false;

  switch(request->bRequest)
  {
  // USBTMC required requests
  case USBTMC_bREQUEST_INITIATE_ABORT_BULK_OUT:
  case USBTMC_bREQUEST_CHECK_ABORT_BULK_OUT_STATUS:
  case USBTMC_bREQUEST_INITIATE_ABORT_BULK_IN:
  case USBTMC_bREQUEST_CHECK_ABORT_BULK_IN_STATUS:
  case USBTMC_bREQUEST_INITIATE_CLEAR:
  case USBTMC_bREQUEST_CHECK_CLEAR_STATUS:
    TU_VERIFY(false);
    break;

  case USBTMC_bREQUEST_GET_CAPABILITIES:
    TU_VERIFY(request->bmRequestType == 0xA1);
    TU_VERIFY(request->wValue == 0x0000);
    TU_VERIFY(request->wIndex == usbtmc_state.itf_id);
    TU_VERIFY(request->wLength == sizeof(usbtmcd_app_capabilities));
    TU_VERIFY(tud_control_xfer(rhport, request, (void*)&usbtmcd_app_capabilities, sizeof(usbtmcd_app_capabilities)));
    return true;
  // USBTMC Optional Requests
  case USBTMC_bREQUEST_INDICATOR_PULSE: // Optional
    TU_VERIFY(false);
    return false;

#if (USBTMC_CFG_ENABLE_488)
    // USB488 required requests
  case USBTMC488_bREQUEST_READ_STATUS_BYTE:

    bTag = request->wValue & 0x7F;
    TU_VERIFY(request->bmRequestType == 0xA1);
    TU_VERIFY((request->wValue & (~0x7F)) == 0u); // Other bits are required to be zero
    TU_VERIFY(bTag >= 0x02 && bTag <= 127);
    TU_VERIFY(request->wIndex == usbtmc_state.itf_id);
    TU_VERIFY(request->wLength == 0x0003);
    usbtmc_read_stb_rsp_488_t rsp;
    rsp.bTag = (uint8_t)bTag;
    if(usbtmc_state.ep_int_in != 0)
    {
      rsp.USBTMC_status = USBTMC_STATUS_SUCCESS;
      rsp.statusByte = 0x00; // Use interrupt endpoint, instead.

      usbtmc_read_stb_interrupt_488_t intMsg =
      {
          .bNotify1   = (uint8_t)(0x80 | bTag),
          .StatusByte = usbtmcd_app_get_stb(rhport, &(rsp.USBTMC_status))
      };
      usbd_edpt_xfer(rhport, usbtmc_state.ep_int_in, (void*)&intMsg,sizeof(intMsg));

    }
    else
    {
      rsp.statusByte = usbtmcd_app_get_stb(rhport, &(rsp.USBTMC_status));
    }
    TU_VERIFY(tud_control_xfer(rhport, request, (void*)&rsp, sizeof(rsp)));
    return true;

    // USB488 optional requests
  case USBTMC488_bREQUEST_REN_CONTROL:
  case USBTMC488_bREQUEST_GO_TO_LOCAL:
  case USBTMC488_bREQUEST_LOCAL_LOCKOUT:
    TU_VERIFY(false);
    return false;
#endif

  default:
    TU_VERIFY(false);
  }
  TU_VERIFY(false);
}

bool usbtmcd_control_complete(uint8_t rhport, tusb_control_request_t const * request)
{
  (void)rhport;
  //------------- Class Specific Request -------------//
  TU_VERIFY (request->bmRequestType_bit.type == TUSB_REQ_TYPE_CLASS);

  return true;
}

#endif /* CFG_TUD_TSMC */