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

   This file is part of the JUCE 6 technical preview.
   Copyright (c) 2020 - Raw Material Software Limited

   You may use this code under the terms of the GPL v3
   (see www.gnu.org/licenses).

   For this technical preview, this file is not subject to commercial licensing.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

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

#include "../Application/jucer_Headers.h"
#include "../Application/jucer_Application.h"
#include "jucer_CompileEngineServer.h"
#include "jucer_CompileEngineDLL.h"
#include "jucer_MessageIDs.h"
#include "jucer_CppHelpers.h"
#include "jucer_SourceCodeRange.h"
#include "jucer_ClassDatabase.h"
#include "jucer_DiagnosticMessage.h"
#include "jucer_ProjectBuildInfo.h"
#include "jucer_ClientServerMessages.h"

#if JUCE_LINUX
 #include <sys/types.h>
 #include <unistd.h>
#endif

#ifndef RUN_CLANG_IN_CHILD_PROCESS
 #error
#endif

#if RUN_CLANG_IN_CHILD_PROCESS
 static bool parentProcessHasExited();
#endif

#if JUCE_WINDOWS
 static void setParentProcessID (int);
 static int getCurrentProcessID();
#else
 #include <unistd.h>
#endif

//==============================================================================
/** Detects whether this process has hung, and kills it if so. */
struct ZombiePatrol    : private Thread,
                         private AsyncUpdater,
                         private Timer
{
    explicit ZombiePatrol (MessageHandler& mh)
       : Thread ("Ping"), owner (mh)
    {
        startThread (2);
        startTimer (1000);
    }

    ~ZombiePatrol() override
    {
        stopThread (1000);
    }

private:
    MessageHandler& owner;
    int failedPings = 0;

    void run() override
    {
        while (! threadShouldExit())
        {
           #if RUN_CLANG_IN_CHILD_PROCESS
            if (parentProcessHasExited())
            {
                killProcess();
                break;
            }
           #endif

            wait (1000);
        }
    }

    void handleAsyncUpdate() override
    {
        DBG ("Server: quitting");
        stopTimer();
        ProjucerApplication::getApp().systemRequestedQuit();
    }

    void timerCallback() override
    {
        if (! MessageTypes::sendPing (owner))
        {
            if (++failedPings == 10)
            {
                killProcess();
                return;
            }
        }
        else
        {
            failedPings = 0;
        }
    }

    void killProcess()
    {
        triggerAsyncUpdate(); // give the messagequeue a chance to do things cleanly.
        static UnstoppableKillerThread* k = new UnstoppableKillerThread(); // (allowed to leak, but static so only one is created)
        ignoreUnused (k);
    }

    struct UnstoppableKillerThread  : public Thread
    {
        UnstoppableKillerThread() : Thread ("Killer")  { startThread(); }

        void run() override
        {
            wait (15000);

            if (! threadShouldExit())
                Process::terminate();
        }
    };
};

//==============================================================================
class ServerIPC  : public InterprocessConnection,
                   public MessageHandler
{
public:
    explicit ServerIPC (const StringArray& info)
       : InterprocessConnection (true), liveCodeBuilder (nullptr)
    {
        if (! createPipe (info[0], -1))
        {
            Logger::writeToLog ("*** Couldn't create pipe!");
            ProjucerApplication::getApp().systemRequestedQuit();
            return;
        }

        if (dll.isLoaded())
            liveCodeBuilder = dll.projucer_createBuilder (sendMessageCallback, this, info[1].toRawUTF8(), info[2].toRawUTF8());

       #if JUCE_WINDOWS
        setParentProcessID (info[3].getHexValue32());
       #endif

        zombieKiller.reset (new ZombiePatrol (*this));
    }

    ~ServerIPC() override
    {
        zombieKiller.reset();

        if (dll.isLoaded())
            dll.projucer_deleteBuilder (liveCodeBuilder);

        dll.shutdown();

        DBG ("Server: finished closing down");
    }

    void connectionMade() override
    {
        DBG ("Server: client connected");
    }

    void connectionLost() override
    {
        Logger::writeToLog ("Server: client lost");
        JUCEApplication::quit();
    }

    void sendQuitMessageToIDE()
    {
        MessageTypes::sendShouldCloseIDE (*this);
    }

    bool sendMessage (const ValueTree& m) override
    {
        return InterprocessConnection::sendMessage (MessageHandler::convertMessage (m));
    }

    void messageReceived (const MemoryBlock& message) override
    {
        jassert (dll.isLoaded());
        dll.projucer_sendMessage (liveCodeBuilder, message.getData(), message.getSize());
    }

    static bool sendMessageCallback (void* userInfo, const void* data, size_t dataSize)
    {
        return static_cast<InterprocessConnection*> (static_cast<ServerIPC*> (userInfo))
                  ->sendMessage (MemoryBlock (data, dataSize));
    }

    CompileEngineDLL dll;
    LiveCodeBuilder liveCodeBuilder;
    std::unique_ptr<ZombiePatrol> zombieKiller;
};

//==============================================================================
const char* commandPrefix = "--server:";
const char* commandTokenSeparator = "\x01";

String createCommandLineForLaunchingServer (const String& pipeName, const String& projectUID, const File& cacheLocation)
{
    StringArray info;
    info.add (pipeName);
    info.add (projectUID);
    info.add (cacheLocation.getFullPathName());

   #if JUCE_WINDOWS
    info.add (String::toHexString (getCurrentProcessID()));
   #endif

    const File exe (File::getSpecialLocation (File::currentExecutableFile).getFullPathName());

    return "\"" + exe.getFullPathName() + "\" " + commandPrefix + info.joinIntoString (commandTokenSeparator);
}

static ServerIPC* currentServer = nullptr;

static void crashCallback (const char* message)
{
    if (currentServer != nullptr)
    {
       #if RUN_CLANG_IN_CHILD_PROCESS
        MessageTypes::sendCrash (*currentServer, message);
        Logger::writeToLog ("*** Crashed! " + String (message));
       #else
        ignoreUnused (message);
        jassertfalse;
       #endif

        currentServer->disconnect();
    }
}

static void quitCallback()
{
    ProjucerApplication::getApp().systemRequestedQuit();
}

void* createClangServer (const String& commandLine)
{
    StringArray info;
    info.addTokens (commandLine.fromFirstOccurrenceOf (commandPrefix, false, false), commandTokenSeparator, "");

    std::unique_ptr<ServerIPC> ipc (new ServerIPC (info));

    if (ipc->dll.isLoaded())
    {
        ipc->dll.initialise (crashCallback, quitCallback, (bool) RUN_CLANG_IN_CHILD_PROCESS);

        currentServer = ipc.release();
        return currentServer;
    }

    return nullptr;
}

void destroyClangServer (void* server)
{
    currentServer = nullptr;
    delete static_cast<ServerIPC*> (server);
}

void sendQuitMessageToIDE (void* server)
{
    static_cast<ServerIPC*> (server)->sendQuitMessageToIDE();
}

//==============================================================================
#if JUCE_WINDOWS
 #define STRICT 1
 #define WIN32_LEAN_AND_MEAN 1
 #include <windows.h>

 static HANDLE parentProcessHandle = nullptr;
 static void setParentProcessID (int pid)  { parentProcessHandle = OpenProcess (SYNCHRONIZE, FALSE, (DWORD) pid); }
 static int getCurrentProcessID()          { return (int) GetCurrentProcessId(); }
#endif

#if RUN_CLANG_IN_CHILD_PROCESS
bool parentProcessHasExited()
{
   #if JUCE_WINDOWS
    return WaitForSingleObject (parentProcessHandle, 0) == WAIT_OBJECT_0;
   #else
    return getppid() == 1;
   #endif
}
#endif