/*
NOTES

This driver is an asyn driver intended for use with turboPmacController
to allow communication over ethernet to a PMAC.

*** Ensure I3=2 and I6=1 on the PMAC before using this driver. ***

This driver supports sending ascii commands to the PMAC over asyn IP and
obtaining the response. The driver uses the PMAC ethernet packets
VR_PMAC_GETRESPONSE, VR_PMAC_READREADY and VR_PMAC_GETBUFFER to send commands
and get responses. The PMAC may send responses in several different formats.
1) PMAC ascii command responses for single/multiple commands (e.g. I113 I114
I130 I131 I133) are in an ACK terminated form as follows (CR seperates the
cmd responses): data<CR(13)>data<CR(13)>data<CR(13)><ACK(6)> 2) PMAC error
responses to ascii commands ARE NOT ACK terminated as follows:
        <BELL(7)>ERRxxx<CR(13)>
3) PMAC may also return the following:
        <STX(2)>data<CR(13)>

This driver can send ctrl commands (ctrl B/C/F/G/P/V) to the pmac (using
VR_CTRL_REPONSE packet) however because the resulting response data is not
terminated as above the driver does not know when all the response data has
been received. The response data will therefore only be returned after the
asynUser.timeout has expired.

This driver does NOT support large buffer transfers (VR_PMAC_WRITEBUFFER,
VR_FWDOWNLOAD) or set/get of DPRAM (VR_PMAC_SETMEM etc) or changing comms
setup (VR_IPADDRESS, VR_PMAC_PORT)

Unlike the original DLS driver, this is not an interpose layer on top of
drvAsynIPPort anymore. Instead the driver inherits from the C++ asynPortDriver
class, implements the socket handling itself and overrides the asynCommon,
asynOctet and asynInt32 methods.

REVISION HISTORY

10 Aug 07 - Pete Leicester - Diamond Light Source
Modified to handle responses other than those ending in <ACK> (e.g. errors) -
No longer used asyn EOS.

9 Aug 07 - Pete Leicester - Diamond Light Source
Initial version reliant on asyn EOS to return <ACK> terminated responses.

2 Feb 09 - Matthew Pearson - Diamond Light Source
Ported to work with Asyn 4-10. Still compiles with pre Asyn4-10 versions but
does not work. Also added new config function, pmacAsynIPPortConfigureEos(),
to be used when disabling low level EOS handling in the Asyn IP layer. This
new function should be used with Asyn 4-10 and above (it is not compatible
with Asyn 4-9).

10 Apr 25 - Stefan Mathis - Paul Scherrer Institut
Adjusted the driver to the requirements of SINQ:
- Added a lot of comments, removed the predecessor of
pmacAsynIPPortConfigureEos() since SINQ doesn't need it (see comment above)
- Removed the call to `pmacFlush` from `flushItOctet`: We want to flush the
communication buffer on the IOC side before each communication, but we do not
want to flush the PMAC controller itself, since this stalls the controller for
10 ms everytime (see Turbo PMAC User Manual, p. 414). Instead, a PV was added in
the higher level `turboPmac` driver to manually call the `pmacFlush` function.
*/

#include "pmacAsynIPPort.h"
#include "asynDriver.h"
#include "asynInterposeEos.h"
#include "asynPortDriver.h"
#include "epicsExport.h"
#include <cstdio>
#include <cstring>
#include <epicsThread.h>
#include <epicsTime.h>
#include <exception>
#include <fcntl.h>
#include <iocsh.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <osiSock.h>
#include <stdexcept>
#include <string>
#include <sys/poll.h>

/* PMAC ethernet commands - RequestType field */
constexpr uint8_t VR_UPLOAD = 0xC0;
constexpr uint8_t VR_DOWNLOAD = 0x40;

/* PMAC ethernet commands - Request field */
constexpr uint8_t VR_PMAC_FLUSH = 0xB3;
constexpr uint8_t VR_PMAC_GETRESPONSE = 0xBF;
constexpr uint8_t VR_PMAC_READREADY = 0xC2;
constexpr uint8_t VR_CTRL_RESPONSE = 0xC4;
constexpr uint8_t VR_PMAC_GETBUFFER = 0xC5;

constexpr size_t MAX_BUFFER_SIZE = 2097152;
constexpr size_t INPUT_SIZE =
    (ETHERNET_DATA_SIZE + 1) /* +1 to allow space to add terminating ACK */;

/* Connect timeout in seconds, matching asyn's DEFAULT_AUTOCONNECT_TIMEOUT. */
constexpr double AUTO_CONNECT_TIMEOUT = 0.5;

constexpr char STX = '\2';
constexpr char ACK = '\6';
constexpr char BELL = '\7';

/* PMAC control character commands (VR_CTRL_RESPONSE cmd): ctrl B/C/F/G/P/V */
constexpr char ctrlCommands[] = "\002\003\006\007\016\022";

/* This delay is how long to wait in seconds after a send fails with errno ==
 * EAGAIN or EINTR before trying again */
constexpr double SEND_RETRY_DELAY = 0.01;

/*
   Notes on asyn
   use asynUser.timeout to specify I/O request timeouts in seconds
   asynStatus may return asynSuccess(0),asynTimeout(1),asynOverflow(2) or
   asynError(3) eomReason may return ASYN_EOM_CNT (1:Request count reached),
   ASYN_EOM_EOS (2:End of String detected), ASYN_EOM_END (4:End indicator
   detected) asynError indicates that asynUser.errorMessage has been populated
   by epicsSnprintf().
*/

/*
 * OSI function to control blocking/non-blocking I/O
 */
static int setNonBlock(SOCKET fd, int nonBlockFlag) {
#if defined(vxWorks)
    int flags = nonBlockFlag;
    if (ioctl(fd, FIONBIO, (int)&flags) < 0)
        return -1;
#elif defined(_WIN32)
    unsigned long int flags = nonBlockFlag;
    if (socket_ioctl(fd, FIONBIO, &flags) < 0)
        return -1;
#else
    int flags;
    if ((flags = fcntl(fd, F_GETFL, 0)) < 0)
        return -1;
    if (nonBlockFlag)
        flags |= O_NONBLOCK;
    else
        flags &= ~O_NONBLOCK;
    if (fcntl(fd, F_SETFL, flags) < 0)
        return -1;
#endif
    return 0;
}

/* Clamp the asyn I/O timeout to a poll() timeout in milliseconds: negative
 * values (infinite wait) pass through, a zero timeout becomes a 1 ms poll. */
static int pollmsecFromTimeout(double timeoutSeconds) {
    int pollmsec = (int)(timeoutSeconds * 1000.0);
    if (pollmsec == 0)
        return 1;
    return pollmsec;
}

pmacAsynIPPort::pmacAsynIPPort(const char *portName, const char *hostInfo)
    : asynPortDriver(portName, 1 /* maxAddr */, asynOctetMask | asynInt32Mask,
                     0 /* interruptMask */, ASYN_CANBLOCK, 1 /* autoConnect */,
                     0 /* priority */, 0 /* stackSize */),
      inBuf_(MAX_BUFFER_SIZE) {
    // The base class constructor mirrors drvAsynIPPortConfigure(portName,
    // hostInfo, priority, noAutoConnect) with ASYN_CANBLOCK and autoConnect
    // enabled. We register the asynOctet, asynInt32 and asynCommon interfaces.
    // The low level EOS processing is not enabled in the base class, since the
    // EOS interpose layer added in pmacAsynIPPortConfigure handles the
    // PMAC-specific message terminators instead.
    parseHostInfo(hostInfo);
}

pmacAsynIPPort::~pmacAsynIPPort() {
    if (fd_ != INVALID_SOCKET)
        epicsSocketDestroy(fd_);
}

void pmacAsynIPPort::parseHostInfo(const char *hostInfo) {
    std::string hostInfoString(hostInfo);
    size_t colon = hostInfoString.find(':');
    if (colon == std::string::npos) {
        std::string msg("pmacAsynIPPort: \"");
        msg += hostInfo;
        msg += "\" is not of the form \"<host>:<port>\"";
        throw std::runtime_error(msg);
    }
    IPHostName_ = hostInfoString.substr(0, colon);
    std::string portString = hostInfoString.substr(colon + 1);
    unsigned long port;
    try {
        port = std::stoul(portString);
    } catch (const std::exception &) {
        std::string msg("pmacAsynIPPort: invalid port \"");
        msg += portString + "\" in \"" + hostInfo + "\"";
        throw std::runtime_error(msg);
    }
    if (port == 0 || port > 65535) {
        std::string msg("pmacAsynIPPort: port \"");
        msg += portString + "\" out of range in \"" + hostInfo + "\"";
        throw std::runtime_error(msg);
    }
    port_ = static_cast<unsigned short>(port);
}

asynStatus pmacAsynIPPort::connectIt(asynUser *pasynUser) {
    SOCKET fd;
    int i = 1;
    char sockerrmsg[256];
    osiSockAddr farAddr;

    asynPrint(pasynUser, ASYN_TRACE_FLOW,
              "Attempting to connect to %s reason:%d fd:%lld\n",
              IPHostName_.c_str(), pasynUser->reason, (long long)fd_);

    if (fd_ != INVALID_SOCKET) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "%s: Link already open!", IPHostName_.c_str());
        return asynError;
    }

    /*
     * Create the socket
     */
    if ((fd = epicsSocketCreate(AF_INET, SOCK_STREAM, 0)) < 0) {
        epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "Can't create socket: %s", sockerrmsg);
        return asynError;
    }

    /*
     * Convert host name/number to IP address.
     * We delay doing this until now in case a device
     * has just appeared in a DNS database.
     */
    farAddr.ia.sin_family = AF_INET;
    farAddr.ia.sin_port = htons(port_);
    if (hostToIPAddr(IPHostName_.c_str(), &farAddr.ia.sin_addr) < 0) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "Unknown host \"%s\"", IPHostName_.c_str());
        epicsSocketDestroy(fd);
        return asynError;
    }

    if (setNonBlock(fd, 1) < 0) {
        epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "Can't set %s O_NONBLOCK option: %s", IPHostName_.c_str(),
                      sockerrmsg);
        epicsSocketDestroy(fd);
        return asynError;
    }

    {
        int connectResult = ::connect(fd, &farAddr.sa, sizeof(farAddr.ia));
        if (connectResult < 0 &&
            (SOCKERRNO == SOCK_EWOULDBLOCK || SOCKERRNO == SOCK_EINPROGRESS)) {
            int msConnectTimeout;
            struct pollfd pollfd;

            // Use asyn's default auto-connect timeout. Older asyn versions do
            // not provide asynManager::getAutoConnectTimeout.
            msConnectTimeout = (int)(1000 * AUTO_CONNECT_TIMEOUT);
            pollfd.fd = fd;
            pollfd.events = POLLOUT;

            /*
             * poll() returning 1 is the only case where connect might have
             * been successful. Otherwise connectResult will remain -1.
             */
            if (poll(&pollfd, 1, msConnectTimeout) == 1) {
                int so_error;
                osiSocklen_t len = sizeof so_error;

                /*
                 * We must verify SO_ERROR to make sure the connection was
                 * successful.
                 */
                int sockErrorStatus = getsockopt(fd, SOL_SOCKET, SO_ERROR,
                                                 (void *)&so_error, &len);
                if (sockErrorStatus == 0 && so_error == 0)
                    connectResult = 0;
            }
        }
        if (connectResult < 0) {
            epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "Can't connect to %s: %s", IPHostName_.c_str(),
                          sockerrmsg);
            epicsSocketDestroy(fd);
            return asynError;
        }
    }

    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (void *)&i, sizeof i) < 0) {
        epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "Can't set %s socket NODELAY option: %s",
                      IPHostName_.c_str(), sockerrmsg);
        epicsSocketDestroy(fd);
        return asynError;
    }

    asynPrint(pasynUser, ASYN_TRACE_FLOW, "Opened connection OK to %s\n",
              IPHostName_.c_str());
    fd_ = fd;
    return asynSuccess;
}

void pmacAsynIPPort::closeConnection(asynUser *pasynUser, const char *why) {
    asynPrint(pasynUser, ASYN_TRACE_FLOW,
              "Closing %s connection (fd %lld): %s\n", IPHostName_.c_str(),
              (long long)fd_, why);
    if (fd_ != INVALID_SOCKET) {
        epicsSocketDestroy(fd_);
        fd_ = INVALID_SOCKET;
    }
    pasynManager->exceptionDisconnect(pasynUser);
}

asynStatus pmacAsynIPPort::connect(asynUser *pasynUser) {
    int addr;
    asynStatus status = getAddress(pasynUser, &addr);
    if (status != asynSuccess)
        return status;
    status = connectIt(pasynUser);
    if (status == asynSuccess) {
        /* Clear any stale response data left from a previous connection */
        inBufTail_ = 0;
        inBufHead_ = 0;
        pasynManager->exceptionConnect(pasynUser);
    }
    return status;
}

asynStatus pmacAsynIPPort::disconnect(asynUser *pasynUser) {
    int addr;
    asynStatus status = getAddress(pasynUser, &addr);
    if (status != asynSuccess)
        return status;
    closeConnection(pasynUser, "Disconnect request");
    return asynSuccess;
}

asynStatus pmacAsynIPPort::pollSocket(asynUser *pasynUser,
                                      struct pollfd *pollfd, int pollmsec,
                                      int *pollstatus) {
    epicsTimeStamp startTime;
    epicsTimeStamp endTime;

    epicsTimeGetCurrent(&startTime);
    while ((*pollstatus = poll(pollfd, 1, pollmsec)) < 0) {
        if (SOCKERRNO != SOCK_EINTR) {
            char sockerrmsg[256];
            epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s poll() failed: %s", IPHostName_.c_str(),
                          sockerrmsg);
            return asynError;
        }
        epicsTimeGetCurrent(&endTime);
        if (epicsTimeDiffInSeconds(&endTime, &startTime) * 1000. > pollmsec)
            break;
    }
    return asynSuccess;
}

asynStatus pmacAsynIPPort::socketRead(asynUser *pasynUser, char *data,
                                      size_t maxchars, size_t *nbytesRead) {
    int thisRead;
    int readPollmsec;
    int pollstatus;
    asynStatus status = asynSuccess;
    char sockerrmsg[256];
    struct pollfd pollfd;

    *nbytesRead = 0;
    if (fd_ == INVALID_SOCKET) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "%s disconnected", IPHostName_.c_str());
        return asynError;
    }
    if (maxchars == 0) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "%s maxchars %d. Why <=0?", IPHostName_.c_str(),
                      (int)maxchars);
        return asynError;
    }
    readPollmsec = pollmsecFromTimeout(pasynUser->timeout);

    pollfd.fd = fd_;
    pollfd.events = POLLIN;
    status = pollSocket(pasynUser, &pollfd, readPollmsec, &pollstatus);
    if (status != asynSuccess)
        return status;

    thisRead = recv(fd_, data, (int)maxchars, 0);
    if (thisRead < 0) {
        epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
        if (SOCKERRNO == SOCK_EWOULDBLOCK || SOCKERRNO == SOCK_EINTR) {
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s timeout: %s", IPHostName_.c_str(), sockerrmsg);
            status = asynTimeout;
        } else {
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s read error: %s", IPHostName_.c_str(), sockerrmsg);
            closeConnection(pasynUser, "Read error");
            status = asynError;
        }
    }
    /* If recv() returns 0 on a SOCK_STREAM (TCP) socket, the connection has
     * closed */
    if (thisRead == 0) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "%s connection closed", IPHostName_.c_str());
        closeConnection(pasynUser, "Read from broken connection");
    }
    if (thisRead < 0)
        thisRead = 0;
    *nbytesRead = thisRead;
    /* If there is room add a null byte */
    if (thisRead < (int)maxchars)
        data[thisRead] = 0;
    return status;
}

asynStatus pmacAsynIPPort::socketWrite(asynUser *pasynUser, const char *data,
                                       size_t numchars,
                                       size_t *nbytesTransferred) {
    asynStatus status = asynSuccess;
    int thisWrite;
    int writePollmsec;
    int pollstatus;
    epicsTimeStamp startTime;
    epicsTimeStamp endTime;
    int haveStartTime = 0;
    char sockerrmsg[256];
    struct pollfd pollfd;

    asynPrint(pasynUser, ASYN_TRACE_FLOW, "%s write.\n", IPHostName_.c_str());
    if (nbytesTransferred)
        *nbytesTransferred = 0;
    if (fd_ == INVALID_SOCKET) {
        epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                      "%s disconnected", IPHostName_.c_str());
        return asynError;
    }
    if (numchars == 0)
        return asynSuccess;
    writePollmsec = pollmsecFromTimeout(pasynUser->timeout);
    for (;;) {
        pollfd.fd = fd_;
        pollfd.events = POLLOUT;
        status = pollSocket(pasynUser, &pollfd, writePollmsec, &pollstatus);
        if (status != asynSuccess)
            return status;
        if (pollstatus == 0) {
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s poll() timed out", IPHostName_.c_str());
            return asynTimeout;
        }
        for (;;) {
            thisWrite = send(fd_, data, (int)numchars, 0);
            if (thisWrite >= 0)
                break;
            if (SOCKERRNO == SOCK_EWOULDBLOCK || SOCKERRNO == SOCK_EINTR) {
                if (!haveStartTime) {
                    epicsTimeGetCurrent(&startTime);
                    haveStartTime = 1;
                } else if (pasynUser->timeout >= 0) {
                    epicsTimeGetCurrent(&endTime);
                    if (epicsTimeDiffInSeconds(&endTime, &startTime) >
                        pasynUser->timeout) {
                        thisWrite = 0;
                        break;
                    }
                }
                epicsThreadSleep(SEND_RETRY_DELAY);
            } else
                break;
        }
        if (thisWrite > 0) {
            if (nbytesTransferred)
                *nbytesTransferred += thisWrite;
            numchars -= thisWrite;
            if (numchars == 0)
                break;
            data += thisWrite;
        } else if (thisWrite == 0) {
            status = asynTimeout;
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s send() returned 0", IPHostName_.c_str());
            break;
        } else {
            epicsSocketConvertErrnoToString(sockerrmsg, sizeof(sockerrmsg));
            epicsSnprintf(pasynUser->errorMessage, pasynUser->errorMessageSize,
                          "%s write error: %s", IPHostName_.c_str(),
                          sockerrmsg);
            closeConnection(pasynUser, "Write error");
            status = asynError;
            break;
        }
    }
    asynPrint(pasynUser, ASYN_TRACE_FLOW, "wrote %lu to %s, return %s.\n",
              (unsigned long)(nbytesTransferred ? *nbytesTransferred : 0),
              IPHostName_.c_str(), pasynManager->strStatus(status));
    return status;
}

asynStatus pmacAsynIPPort::sendPmacCommand(asynUser *pasynUser,
                                           EthernetCmd &cmd,
                                           uint8_t requestType, uint8_t request,
                                           uint16_t wValue, uint16_t wLength,
                                           size_t *nbytesTransfered) {
    cmd.RequestType = requestType;
    cmd.Request = request;
    cmd.wValue = wValue;
    cmd.wIndex = 0;
    cmd.wLength = htons(wLength);
    return socketWrite(pasynUser, reinterpret_cast<const char *>(&cmd),
                       ETHERNET_CMD_HEADER, nbytesTransfered);
}

/*
    Read reponse data from PMAC into buffer inBuf_. If there is no data in the
   socket buffer then issue pmac GETBUFFER command to get any outstanding data
   still on the PMAC.
*/
asynStatus pmacAsynIPPort::readResponse(asynUser *pasynUser, size_t maxchars,
                                        size_t *nbytesTransfered,
                                        int *eomReason) {
    asynStatus status = asynSuccess;
    size_t thisRead = 0;
    *nbytesTransfered = 0;
    if (maxchars > INPUT_SIZE)
        maxchars = INPUT_SIZE;

    asynPrint(pasynUser, ASYN_TRACE_FLOW,
              "pmacAsynIPPort::readResponse. Performing socketRead().\n");

    status = socketRead(pasynUser, inBuf_.data(), maxchars, &thisRead);

    asynPrint(pasynUser, ASYN_TRACE_FLOW,
              "%s readResponse1 maxchars=%zd, thisRead=%zd, eomReason=%d, "
              "status=%u\n",
              portName, maxchars, thisRead, *eomReason,
              static_cast<unsigned>(status));
    if (status == asynTimeout && thisRead == 0 && pasynUser->timeout > 0) {
        /* failed to read as many characters as required into the input buffer,
           check for more response data on the PMAC */
        if (pmacReadReady(pasynUser)) {

            status = sendPmacGetBuffer(pasynUser, maxchars);
            asynPrintIO(pasynUser, ASYN_TRACE_FLOW,
                        reinterpret_cast<const char *>(&pinCmd_),
                        ETHERNET_CMD_HEADER, "%s write GETBUFFER\n", portName);

            /* We have nothing to return at the moment so read again */
            status = socketRead(pasynUser, inBuf_.data(), maxchars, &thisRead);

            asynPrint(pasynUser, ASYN_TRACE_FLOW,
                      "%s readResponse2 maxchars=%zd, thisRead=%zd, "
                      "eomReason=%d, status=%u\n",
                      portName, maxchars, thisRead, *eomReason,
                      static_cast<unsigned>(status));
        }
    }

    if (thisRead > 0) {
        if (status == asynTimeout)
            status = asynSuccess;
        *nbytesTransfered = thisRead;
        inBufTail_ = 0;
        inBufHead_ = thisRead;
    }

    asynPrint(pasynUser, ASYN_TRACE_FLOW,
              "pmacAsynIPPort::readResponse. END\n");

    return status;
}

/*
   Send ReadReady command to PMAC to discover if there is any data to read from
   it. Returns: 0 - no data available 1 - data available
*/
int pmacAsynIPPort::pmacReadReady(asynUser *pasynUser) {
    EthernetCmd cmd{};
    char data[2] = {0};
    asynStatus status;
    size_t thisRead = 0;
    int retval = 0;

    status = sendPmacCommand(pasynUser, cmd, VR_UPLOAD, VR_PMAC_READREADY, 0, 2,
                             nullptr);

    if (status != asynSuccess) {
        asynPrintIO(pasynUser, ASYN_TRACE_ERROR,
                    reinterpret_cast<const char *>(&cmd), ETHERNET_CMD_HEADER,
                    "%s write pmacReadReady fail\n", portName);
    }

    status = socketRead(pasynUser, data, 2, &thisRead);

    if (status == asynSuccess) {
        if (thisRead == 2 && data[0] != 0) {
            retval = 1;
        }
        asynPrintIO(pasynUser, ASYN_TRACE_FLOW, data, thisRead,
                    "%s read pmacReadReady OK thisRead=%zd\n", portName,
                    thisRead);
    } else {
        asynPrint(pasynUser, ASYN_TRACE_ERROR,
                  "%s read pmacReadReady failed status=%d, retval=%d\n",
                  portName, static_cast<int>(status), retval);
    }
    return retval;
}

/**
 * @brief Flush the PMAC communication buffer
 *
 * Send a Flush command to PMAC and wait for confirmation ctrlX to be returned
 * according to the Turbo PMAC user manual, p. 414.
 *
 * @return 0 - failed, 1 - success
 */
int pmacAsynIPPort::pmacFlush(asynUser *pasynUser) {
    EthernetCmd cmd{};
    char data[2] = {0};
    asynStatus status = asynSuccess;
    size_t thisRead = 0;
    int retval = 0;

    status = sendPmacCommand(pasynUser, cmd, VR_DOWNLOAD, VR_PMAC_FLUSH, 0, 0,
                             nullptr);

    if (status != asynSuccess) {
        asynPrintIO(pasynUser, ASYN_TRACE_ERROR,
                    reinterpret_cast<const char *>(&cmd), ETHERNET_CMD_HEADER,
                    "%s write pmacFlush fail\n", portName);
    }

    /* read flush acknowledgement character */
    /* NB we don't check what the character is (manual sais ctrlX, we get 0x40
     * i.e.VR_DOWNLOAD) */
    status = socketRead(pasynUser, data, 1, &thisRead);

    if (status == asynSuccess) {
        asynPrint(pasynUser, ASYN_TRACE_FLOW, "%s read pmacFlush OK\n",
                  portName);
        retval = 1;
    } else {
        asynPrint(pasynUser, ASYN_TRACE_ERROR,
                  "%s read pmacFlush failed - thisRead=%zd, status=%d\n",
                  portName, thisRead, static_cast<int>(status));
    }

    inBufTail_ = 0;
    inBufHead_ = 0;

    return retval;
}

asynStatus pmacAsynIPPort::sendPmacGetBuffer(asynUser *pasynUser,
                                             size_t maxchars) {
    return sendPmacCommand(pasynUser, pinCmd_, VR_UPLOAD, VR_PMAC_GETBUFFER, 0,
                           maxchars, nullptr);
}

/*
This function sends either a ascii string command to the PMAC using
   VR_PMAC_GETRESPONSE or a single control character (ctrl B/C/F/G/P/V) using
   VR_CTRL_RESPONSE
*/
asynStatus pmacAsynIPPort::writeOctet(asynUser *pasynUser, const char *data,
                                      size_t numchars,
                                      size_t *nbytesTransfered) {
    asynStatus status;
    size_t nbytesActual = 0;
    asynPrint(pasynUser, ASYN_TRACE_FLOW, "pmacAsynIPPort::writeOctet\n");

    /* NB currently we assume control characters arrive as individual
       characters/calls to this routine. Idealy we should probably scan the data
       buffer for control commands and do PMAC_GETRESPONSE and CTRL_RESPONSE
       commands as necessary,  */
    if (numchars == 1 && strchr(ctrlCommands, data[0])) {
        status = sendPmacCommand(pasynUser, poutCmd_, VR_UPLOAD,
                                 VR_CTRL_RESPONSE, data[0], 0, &nbytesActual);
        *nbytesTransfered = nbytesActual == ETHERNET_CMD_HEADER ? numchars : 0;
    } else {
        if (numchars > ETHERNET_DATA_SIZE) {
            /* NB large data should probably be sent using PMAC_WRITEBUFFER
             * which isnt implemented yet - for the moment just truncate */
            numchars = ETHERNET_DATA_SIZE;
            asynPrint(pasynUser, ASYN_TRACE_ERROR,
                      "writeOctet - ERROR TRUNCATED\n");
        }

        /*
        The message protocol of the turboPmac used at PSI looks as follows (all
        characters immediately following each other without a newline):
        0x40 (ASCII value of @) -> Request for download
        0xBF (ASCII value of ¿) -> Select mode "get_response"
        0x00 (ASCII value of 0)
        0x00 (ASCII value of 0)
        0x00 (ASCII value of 0)
        0x00 (ASCII value of 0)
        0x00 (ASCII value of 0)
        [message length in network byte order] -> Use the htons function for
        this value [Actual message] It is not necessary to append a terminator,
        since this protocol encodes the message length at the beginning. See
        Turbo PMAC User Manual, page 418 in VR_PMAC_GETRESPONSE x0D (ASCII value
        of carriage return) -> The controller needs a carriage return at the end
        of a "send" command (a command were we transmit data via
        =). For "request" commands (e.g. read status or position), this is not
        necessary, but it doesn't hurt either, therefore we always add a
        carriage return.

        The message has to be build manually into the buffer fullCommand, since
        it contains NULL terminators in its middle, therefore the string
        manipulation methods of C don't work.
        */
        poutCmd_.RequestType = VR_DOWNLOAD;
        poutCmd_.Request = VR_PMAC_GETRESPONSE;
        poutCmd_.wValue = 0;
        poutCmd_.wIndex = 0;
        poutCmd_.wLength = htons(numchars);
        memcpy(poutCmd_.bData, data, numchars);
        status =
            socketWrite(pasynUser, reinterpret_cast<const char *>(&poutCmd_),
                        numchars + ETHERNET_CMD_HEADER, &nbytesActual);
        if (nbytesActual > ETHERNET_CMD_HEADER)
            *nbytesTransfered = nbytesActual - ETHERNET_CMD_HEADER;
        else
            *nbytesTransfered = 0;
    }

    asynPrintIO(pasynUser, ASYN_TRACE_FLOW,
                reinterpret_cast<const char *>(&poutCmd_),
                numchars + ETHERNET_CMD_HEADER, "%s writeOctet\n", portName);

    return status;
}

/*
This function reads data using read() into a local buffer and then look for
message terminating characters and returns a complete response (or times
out), adding on ACK if neccessary. The PMAC command response may be any of
the following:- data<CR>data<CR>....data<CR><ACK> <BELL>data<CR> e.g. an
error <BELL>ERRxxx<CR> <STX>data<CR> (NB asyn EOS only allows one message
terminator to be specified. We add on ACK for the EOS layer above.)
*/
asynStatus pmacAsynIPPort::readOctet(asynUser *pasynUser, char *data,
                                     size_t maxchars, size_t *nbytesTransfered,
                                     int *eomReason) {
    asynStatus status = asynSuccess;
    size_t thisRead = 0;
    size_t nRead = 0;
    bool bell = false;
    bool initialRead = true;

    asynPrint(pasynUser, ASYN_TRACE_FLOW, "pmacAsynIPPort::readOctet. START\n");

    if (maxchars > 0) {
        for (;;) {
            if (inBufTail_ != inBufHead_) {
                *data = inBuf_[inBufTail_++];
                if (*data == BELL || *data == STX)
                    bell = true;
                if (*data == '\r' && bell) {
                    /* <BELL>xxxxxx<CR> or <STX>xxxxx<CR> received - its
                     * probably an error response (<BELL>ERRxxx<CR>) - assume
                     * there is no more response data to come */
                    nRead++; /* make sure the <CR> is passed to the client app
                              */
                    /*Add on ACK, because that's what we expect to be EOS in EOS
                     * interpose layer.*/
                    if ((nRead + 1) > maxchars) {
                        /*If maxchars is reached overwrite <CR> with ACK, so
                         * that no more reads will be done from EOS layer.*/
                        *data = ACK;
                    } else {
                        data++;
                        nRead++;
                        *data = ACK;
                    }
                    break;
                }
                if (*data == ACK || *data == '\n') {
                    /* <ACK> or <LF> received - assume there is no more response
                     * data to come */
                    /* If <LF>, replace with an ACK.*/
                    if (*data == '\n') {
                        *data = ACK;
                    }
                    asynPrint(pasynUser, ASYN_TRACE_FLOW,
                              "Message was terminated with ACK in "
                              "pmacAsynIPPort::readOctet.\n");
                    /*Pass ACK up to Asyn EOS handling layer.*/
                    data++;
                    nRead++;
                    break;
                }
                data++;
                nRead++;
                if (nRead >= maxchars)
                    break;
                continue;
            }

            asynPrint(pasynUser, ASYN_TRACE_FLOW,
                      "pmacAsynIPPort::readOctet. Calling readResponse().\n");
            if (!initialRead) {
                if (pmacReadReady(pasynUser)) {
                    status = sendPmacGetBuffer(pasynUser, maxchars);
                }
            }
            status =
                readResponse(pasynUser, maxchars - nRead, &thisRead, eomReason);
            initialRead = false;
            if (status != asynSuccess || thisRead == 0)
                break;
        }
    }
    *nbytesTransfered = nRead;

    asynPrintIO(pasynUser, ASYN_TRACE_FLOW, data, *nbytesTransfered,
                "%s pmacAsynIPPort readOctet nbytesTransfered=%zd, "
                "eomReason=%d, status=%d\n",
                portName, *nbytesTransfered, *eomReason,
                static_cast<int>(status));

    asynPrint(pasynUser, ASYN_TRACE_FLOW, "pmacAsynIPPort::readOctet. END\n");

    return status;
}

asynStatus pmacAsynIPPort::flushOctet(asynUser *pasynUser) {
    int numRecv, numTotal = 0;
    char cbuf[512];

    asynPrint(pasynUser, ASYN_TRACE_FLOW, "pmacAsynIPPort::flushOctet\n");

    if (fd_ != INVALID_SOCKET) {
        /*
         * Toss characters until there are none left
         */
        while (1) {
            numRecv = recv(fd_, cbuf, sizeof cbuf, 0);
            if (numRecv <= 0)
                break;
            numTotal += numRecv;
        }
    }
    if (numTotal > 0) {
        asynPrint(pasynUser, ASYN_TRACEIO_DRIVER, "%s flushed %d bytes\n",
                  portName, numTotal);
    }
    return asynSuccess;
}

asynStatus pmacAsynIPPort::writeInt32(asynUser *pasynUser, epicsInt32 value) {
    asynPrint(pasynUser, ASYN_TRACE_FLOW, "pmacAsynIPPort::writeInt32\n");

    if (pasynUser->reason != FLUSH_HARDWARE)
        return asynPortDriver::writeInt32(pasynUser, value);

    /* Turbo PMAC User Manual, p. 414: 0 - failed, 1 - success */
    if (pmacFlush(pasynUser) == 1)
        return asynSuccess;
    return asynError;
}

// =============================================================================

int pmacAsynIPPortConfigure(const char *portName, const char *hostInfo) {
    /*
    The port is registered with asynManager in the asynPortDriver base class
    constructor. The object lives for the whole IOC lifetime and is therefore
    intentionally never deleted (see turboPmacCreateAxis in turboPmacAxis.cpp
    for a similar pattern).
    */
    try {
        new pmacAsynIPPort(portName, hostInfo);
    } catch (const std::exception &e) {
        printf("pmacAsynIPPortConfigure: error from pmacAsynIPPort "
               "constructor. ");
        printf("Port: %s (%s)\n", portName, e.what());
        return -1;
    }

    /* Interpose EOS handling layer, above the PMAC IP layer. */
    asynInterposeEosConfig(portName, 0, 1, 1);

    return asynSuccess;
}

// =============================================================================

/* register pmacAsynIPPortConfigure*/
static const iocshArg pmacAsynIPPortConfigureArg0 = {"portName",
                                                     iocshArgString};
static const iocshArg pmacAsynIPPortConfigureArg1 = {"hostInfo",
                                                     iocshArgString};
static const iocshArg *pmacAsynIPPortConfigureArgs[] = {
    &pmacAsynIPPortConfigureArg0, &pmacAsynIPPortConfigureArg1};
static const iocshFuncDef pmacAsynIPPortConfigFuncDef = {
    "pmacAsynIPPortConfigure", 2, pmacAsynIPPortConfigureArgs, ""};
static void pmacAsynIPPortConfigureCallFunc(const iocshArgBuf *args) {
    pmacAsynIPPortConfigure(args[0].sval, args[1].sval);
}

static void pmacAsynIPPortRegister(void) {
    static bool firstTime = true;
    if (firstTime) {
        firstTime = false;
        iocshRegister(&pmacAsynIPPortConfigFuncDef,
                      pmacAsynIPPortConfigureCallFunc);
    }
}
epicsExportRegistrar(pmacAsynIPPortRegister);
