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

   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.

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

struct InterprocessConnection::ConnectionThread  : public Thread
{
    ConnectionThread (InterprocessConnection& c)  : Thread ("JUCE IPC"), owner (c) {}

    void run() override     { owner.runThread(); }

private:
    InterprocessConnection& owner;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ConnectionThread)
};

//==============================================================================
InterprocessConnection::InterprocessConnection (const bool callbacksOnMessageThread,
                                                const uint32 magicMessageHeaderNumber)
    : callbackConnectionState (false),
      useMessageThread (callbacksOnMessageThread),
      magicMessageHeader (magicMessageHeaderNumber),
      pipeReceiveMessageTimeout (-1)
{
    thread = new ConnectionThread (*this);
}

InterprocessConnection::~InterprocessConnection()
{
    callbackConnectionState = false;
    disconnect();
    masterReference.clear();
    thread = nullptr;
}

//==============================================================================
bool InterprocessConnection::connectToSocket (const String& hostName,
                                              const int portNumber,
                                              const int timeOutMillisecs)
{
    disconnect();

    const ScopedLock sl (pipeAndSocketLock);
    socket = new StreamingSocket();

    if (socket->connect (hostName, portNumber, timeOutMillisecs))
    {
        connectionMadeInt();
        thread->startThread();
        return true;
    }

    socket = nullptr;
    return false;
}

bool InterprocessConnection::connectToPipe (const String& pipeName, const int timeoutMs)
{
    disconnect();

    ScopedPointer<NamedPipe> newPipe (new NamedPipe());

    if (newPipe->openExisting (pipeName))
    {
        const ScopedLock sl (pipeAndSocketLock);
        pipeReceiveMessageTimeout = timeoutMs;
        initialiseWithPipe (newPipe.release());
        return true;
    }

    return false;
}

bool InterprocessConnection::createPipe (const String& pipeName, const int timeoutMs, bool mustNotExist)
{
    disconnect();

    ScopedPointer<NamedPipe> newPipe (new NamedPipe());

    if (newPipe->createNewPipe (pipeName, mustNotExist))
    {
        const ScopedLock sl (pipeAndSocketLock);
        pipeReceiveMessageTimeout = timeoutMs;
        initialiseWithPipe (newPipe.release());
        return true;
    }

    return false;
}

void InterprocessConnection::disconnect()
{
    thread->signalThreadShouldExit();

    {
        const ScopedLock sl (pipeAndSocketLock);
        if (socket != nullptr)  socket->close();
        if (pipe != nullptr)    pipe->close();
    }

    thread->stopThread (4000);
    deletePipeAndSocket();
    connectionLostInt();
}

void InterprocessConnection::deletePipeAndSocket()
{
    const ScopedLock sl (pipeAndSocketLock);
    socket = nullptr;
    pipe = nullptr;
}

bool InterprocessConnection::isConnected() const
{
    const ScopedLock sl (pipeAndSocketLock);

    return ((socket != nullptr && socket->isConnected())
              || (pipe != nullptr && pipe->isOpen()))
            && thread->isThreadRunning();
}

String InterprocessConnection::getConnectedHostName() const
{
    {
        const ScopedLock sl (pipeAndSocketLock);

        if (pipe == nullptr && socket == nullptr)
            return String();

        if (socket != nullptr && ! socket->isLocal())
            return socket->getHostName();
    }

    return IPAddress::local().toString();
}

//==============================================================================
bool InterprocessConnection::sendMessage (const MemoryBlock& message)
{
    uint32 messageHeader[2] = { ByteOrder::swapIfBigEndian (magicMessageHeader),
                                ByteOrder::swapIfBigEndian ((uint32) message.getSize()) };

    MemoryBlock messageData (sizeof (messageHeader) + message.getSize());
    messageData.copyFrom (messageHeader, 0, sizeof (messageHeader));
    messageData.copyFrom (message.getData(), sizeof (messageHeader), message.getSize());

    return writeData (messageData.getData(), (int) messageData.getSize()) == (int) messageData.getSize();
}

int InterprocessConnection::writeData (void* data, int dataSize)
{
    const ScopedLock sl (pipeAndSocketLock);

    if (socket != nullptr)
        return socket->write (data, dataSize);

    if (pipe != nullptr)
        return pipe->write (data, dataSize, pipeReceiveMessageTimeout);

    return 0;
}

//==============================================================================
void InterprocessConnection::initialiseWithSocket (StreamingSocket* newSocket)
{
    jassert (socket == nullptr && pipe == nullptr);
    socket = newSocket;
    connectionMadeInt();
    thread->startThread();
}

void InterprocessConnection::initialiseWithPipe (NamedPipe* newPipe)
{
    jassert (socket == nullptr && pipe == nullptr);
    pipe = newPipe;
    connectionMadeInt();
    thread->startThread();
}

//==============================================================================
struct ConnectionStateMessage  : public MessageManager::MessageBase
{
    ConnectionStateMessage (InterprocessConnection* ipc, bool connected) noexcept
        : owner (ipc), connectionMade (connected)
    {}

    void messageCallback() override
    {
        if (InterprocessConnection* const ipc = owner)
        {
            if (connectionMade)
                ipc->connectionMade();
            else
                ipc->connectionLost();
        }
    }

    WeakReference<InterprocessConnection> owner;
    bool connectionMade;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ConnectionStateMessage)
};

void InterprocessConnection::connectionMadeInt()
{
    if (! callbackConnectionState)
    {
        callbackConnectionState = true;

        if (useMessageThread)
            (new ConnectionStateMessage (this, true))->post();
        else
            connectionMade();
    }
}

void InterprocessConnection::connectionLostInt()
{
    if (callbackConnectionState)
    {
        callbackConnectionState = false;

        if (useMessageThread)
            (new ConnectionStateMessage (this, false))->post();
        else
            connectionLost();
    }
}

struct DataDeliveryMessage  : public Message
{
    DataDeliveryMessage (InterprocessConnection* ipc, const MemoryBlock& d)
        : owner (ipc), data (d)
    {}

    void messageCallback() override
    {
        if (InterprocessConnection* const ipc = owner)
            ipc->messageReceived (data);
    }

    WeakReference<InterprocessConnection> owner;
    MemoryBlock data;
};

void InterprocessConnection::deliverDataInt (const MemoryBlock& data)
{
    jassert (callbackConnectionState);

    if (useMessageThread)
        (new DataDeliveryMessage (this, data))->post();
    else
        messageReceived (data);
}

//==============================================================================
bool InterprocessConnection::readNextMessageInt()
{
    uint32 messageHeader[2];
    const int bytes = socket != nullptr ? socket->read (messageHeader, sizeof (messageHeader), true)
                                        : pipe  ->read (messageHeader, sizeof (messageHeader), -1);

    if (bytes == sizeof (messageHeader)
         && ByteOrder::swapIfBigEndian (messageHeader[0]) == magicMessageHeader)
    {
        int bytesInMessage = (int) ByteOrder::swapIfBigEndian (messageHeader[1]);

        if (bytesInMessage > 0)
        {
            MemoryBlock messageData ((size_t) bytesInMessage, true);
            int bytesRead = 0;

            while (bytesInMessage > 0)
            {
                if (thread->threadShouldExit())
                    return false;

                const int numThisTime = jmin (bytesInMessage, 65536);
                void* const data = addBytesToPointer (messageData.getData(), bytesRead);

                const int bytesIn = socket != nullptr ? socket->read (data, numThisTime, true)
                                                      : pipe  ->read (data, numThisTime, -1);

                if (bytesIn <= 0)
                    break;

                bytesRead += bytesIn;
                bytesInMessage -= bytesIn;
            }

            if (bytesRead >= 0)
                deliverDataInt (messageData);
        }
    }
    else if (bytes < 0)
    {
        if (socket != nullptr)
            deletePipeAndSocket();

        connectionLostInt();
        return false;
    }

    return true;
}

void InterprocessConnection::runThread()
{
    while (! thread->threadShouldExit())
    {
        if (socket != nullptr)
        {
            const int ready = socket->waitUntilReady (true, 0);

            if (ready < 0)
            {
                deletePipeAndSocket();
                connectionLostInt();
                break;
            }

            if (ready == 0)
            {
                thread->wait (1);
                continue;
            }
        }
        else if (pipe != nullptr)
        {
            if (! pipe->isOpen())
            {
                deletePipeAndSocket();
                connectionLostInt();
                break;
            }
        }
        else
        {
            break;
        }

        if (thread->threadShouldExit() || ! readNextMessageInt())
            break;
    }
}
