/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2016 - ROLI Ltd.

   Permission is granted to use this software under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license/

   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
   copyright notice and this permission notice appear in all copies.

   THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH REGARD
   TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT,
   OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
   USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
   TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
   OF THIS SOFTWARE.

   -----------------------------------------------------------------------------

   To release a closed-source product which uses other parts of JUCE not
   licensed under the ISC terms, commercial licenses are available: visit
   www.juce.com for more information.

  ==============================================================================
*/

class NamedPipe::Pimpl
{
public:
    Pimpl (const String& pipePath, bool createPipe)
       : pipeInName  (pipePath + "_in"),
         pipeOutName (pipePath + "_out"),
         pipeIn (-1), pipeOut (-1),
         createdFifoIn (false),
         createdFifoOut (false),
         createdPipe (createPipe),
         stopReadOperation (false)
    {
        signal (SIGPIPE, signalHandler);
        juce_siginterrupt (SIGPIPE, 1);
    }

    ~Pimpl()
    {
        if (pipeIn  != -1)  ::close (pipeIn);
        if (pipeOut != -1)  ::close (pipeOut);

        if (createdPipe)
        {
            if (createdFifoIn)  unlink (pipeInName.toUTF8());
            if (createdFifoOut) unlink (pipeOutName.toUTF8());
        }
    }

    int read (char* destBuffer, int maxBytesToRead, int timeOutMilliseconds)
    {
        const uint32 timeoutEnd = getTimeoutEnd (timeOutMilliseconds);

        if (pipeIn == -1)
        {
            pipeIn = openPipe (createdPipe ? pipeInName : pipeOutName, O_RDWR | O_NONBLOCK, timeoutEnd);

            if (pipeIn == -1)
                return -1;
        }

        int bytesRead = 0;

        while (bytesRead < maxBytesToRead)
        {
            const int bytesThisTime = maxBytesToRead - bytesRead;
            const int numRead = (int) ::read (pipeIn, destBuffer, (size_t) bytesThisTime);

            if (numRead <= 0)
            {
                if (errno != EWOULDBLOCK || stopReadOperation || hasExpired (timeoutEnd))
                    return -1;

                const int maxWaitingTime = 30;
                waitForInput (pipeIn, timeoutEnd == 0 ? maxWaitingTime
                                                      : jmin (maxWaitingTime,
                                                              (int) (timeoutEnd - Time::getMillisecondCounter())));
                continue;
            }

            bytesRead += numRead;
            destBuffer += numRead;
        }

        return bytesRead;
    }

    int write (const char* sourceBuffer, int numBytesToWrite, int timeOutMilliseconds)
    {
        const uint32 timeoutEnd = getTimeoutEnd (timeOutMilliseconds);

        if (pipeOut == -1)
        {
            pipeOut = openPipe (createdPipe ? pipeOutName : pipeInName, O_WRONLY, timeoutEnd);

            if (pipeOut == -1)
                return -1;
        }

        int bytesWritten = 0;

        while (bytesWritten < numBytesToWrite && ! hasExpired (timeoutEnd))
        {
            const int bytesThisTime = numBytesToWrite - bytesWritten;
            const int numWritten = (int) ::write (pipeOut, sourceBuffer, (size_t) bytesThisTime);

            if (numWritten <= 0)
                return -1;

            bytesWritten += numWritten;
            sourceBuffer += numWritten;
        }

        return bytesWritten;
    }

    static bool createFifo (const String& name, bool mustNotExist)
    {
        return mkfifo (name.toUTF8(), 0666) == 0 || ((! mustNotExist) && errno == EEXIST);
    }

    bool createFifos (bool mustNotExist)
    {
        createdFifoIn  = createFifo (pipeInName, mustNotExist);
        createdFifoOut = createFifo (pipeOutName, mustNotExist);

        return createdFifoIn && createdFifoOut;
    }

    const String pipeInName, pipeOutName;
    int pipeIn, pipeOut;
    bool createdFifoIn, createdFifoOut;

    const bool createdPipe;
    bool stopReadOperation;

private:
    static void signalHandler (int) {}

    static uint32 getTimeoutEnd (const int timeOutMilliseconds)
    {
        return timeOutMilliseconds >= 0 ? Time::getMillisecondCounter() + (uint32) timeOutMilliseconds : 0;
    }

    static bool hasExpired (const uint32 timeoutEnd)
    {
        return timeoutEnd != 0 && Time::getMillisecondCounter() >= timeoutEnd;
    }

    int openPipe (const String& name, int flags, const uint32 timeoutEnd)
    {
        for (;;)
        {
            const int p = ::open (name.toUTF8(), flags);

            if (p != -1 || hasExpired (timeoutEnd) || stopReadOperation)
                return p;

            Thread::sleep (2);
        }
    }

    static void waitForInput (const int handle, const int timeoutMsecs) noexcept
    {
        struct timeval timeout;
        timeout.tv_sec = timeoutMsecs / 1000;
        timeout.tv_usec = (timeoutMsecs % 1000) * 1000;

        fd_set rset;
        FD_ZERO (&rset);
        FD_SET (handle, &rset);

        select (handle + 1, &rset, nullptr, 0, &timeout);
    }

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Pimpl)
};

void NamedPipe::close()
{
    if (pimpl != nullptr)
    {
        pimpl->stopReadOperation = true;

        char buffer[1] = { 0 };
        ssize_t done = ::write (pimpl->pipeIn, buffer, 1);
        ignoreUnused (done);

        ScopedWriteLock sl (lock);
        pimpl = nullptr;
    }
}

bool NamedPipe::openInternal (const String& pipeName, const bool createPipe, bool mustNotExist)
{
   #if JUCE_IOS
    pimpl = new Pimpl (File::getSpecialLocation (File::tempDirectory)
                         .getChildFile (File::createLegalFileName (pipeName)).getFullPathName(), createPipe);
   #else
    String file (pipeName);

    if (! File::isAbsolutePath (file))
        file = "/tmp/" + File::createLegalFileName (file);

    pimpl = new Pimpl (file, createPipe);
   #endif

    if (createPipe && ! pimpl->createFifos (mustNotExist))
    {
        pimpl = nullptr;
        return false;
    }

    return true;
}

int NamedPipe::read (void* destBuffer, int maxBytesToRead, int timeOutMilliseconds)
{
    ScopedReadLock sl (lock);
    return pimpl != nullptr ? pimpl->read (static_cast<char*> (destBuffer), maxBytesToRead, timeOutMilliseconds) : -1;
}

int NamedPipe::write (const void* sourceBuffer, int numBytesToWrite, int timeOutMilliseconds)
{
    ScopedReadLock sl (lock);
    return pimpl != nullptr ? pimpl->write (static_cast<const char*> (sourceBuffer), numBytesToWrite, timeOutMilliseconds) : -1;
}
