/**
 * @file llpluginprocessparent.h
 * @brief LLPluginProcessParent handles the parent side of the external-process plugin API.
 *
 * @cond
 * $LicenseInfo:firstyear=2008&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 * @endcond
 */

#ifndef LL_LLPLUGINPROCESSPARENT_H
#define LL_LLPLUGINPROCESSPARENT_H

#include <queue>
#include <boost/enable_shared_from_this.hpp>

#include "llapr.h"
#include "llprocess.h"
#include "llpluginmessage.h"
#include "llpluginmessagepipe.h"
#include "llpluginsharedmemory.h"

#include "lliosocket.h"
#include "llthread.h"
#include "llsd.h"
#include "llevents.h"

class LLPluginProcessParentOwner : public std::enable_shared_from_this < LLPluginProcessParentOwner >
{
public:
    virtual ~LLPluginProcessParentOwner();
    virtual void receivePluginMessage(const LLPluginMessage &message) = 0;
    virtual bool receivePluginMessageEarly(const LLPluginMessage &message) {return false;};
    // This will only be called when the plugin has died unexpectedly
    virtual void pluginLaunchFailed() {};
    virtual void pluginDied() {};
};

class LLPluginProcessParent : public LLPluginMessagePipeOwner
{
    LOG_CLASS(LLPluginProcessParent);

    LLPluginProcessParent(LLPluginProcessParentOwner *owner);
public:
    typedef std::shared_ptr<LLPluginProcessParent> ptr_t;

    ~LLPluginProcessParent();

    void init(const std::string &launcher_filename,
              const std::string &plugin_dir,
              const std::string &plugin_filename,
              bool debug);

    void idle(void);

    // returns true if the plugin is on its way to steady state
    bool isLoading(void);

    // returns true if the plugin is in the steady state (processing messages)
    bool isRunning(void);

    // returns true if the process has exited or we've had a fatal error
    bool isDone(void);

    // returns true if the process is currently waiting on a blocking request
    bool isBlocked(void) { return mBlocked; };

    void killSockets(void);

    // Go to the proper error state
    void errorState(void);

    void setSleepTime(F64 sleep_time, bool force_send = false);
    F64 getSleepTime(void) const { return mSleepTime; };

    void sendMessage(const LLPluginMessage &message);

    void receiveMessage(const LLPluginMessage &message);

    static ptr_t create(LLPluginProcessParentOwner *owner);
    void requestShutdown();

    // Inherited from LLPluginMessagePipeOwner
    /*virtual*/ void receiveMessageRaw(const std::string &message);
    /*virtual*/ void receiveMessageEarly(const LLPluginMessage &message);
    /*virtual*/ void setMessagePipe(LLPluginMessagePipe *message_pipe) ;

    // This adds a memory segment shared with the client, generating a name for the segment.  The name generated is guaranteed to be unique on the host.
    // The caller must call removeSharedMemory first (and wait until getSharedMemorySize returns 0 for the indicated name) before re-adding a segment with the same name.
    std::string addSharedMemory(size_t size);
    // Negotiates for the removal of a shared memory segment.  It is the caller's responsibility to ensure that nothing touches the memory
    // after this has been called, since the segment will be unmapped shortly thereafter.
    void removeSharedMemory(const std::string &name);
    size_t getSharedMemorySize(const std::string &name);
    void *getSharedMemoryAddress(const std::string &name);

    // Returns the version string the plugin indicated for the message class, or an empty string if that class wasn't in the list.
    std::string getMessageClassVersion(const std::string &message_class);

    std::string getPluginVersion(void);

    bool getDisableTimeout() { return mDisableTimeout; };
    void setDisableTimeout(bool disable) { mDisableTimeout = disable; };

    void setLaunchTimeout(F32 timeout) { mPluginLaunchTimeout = timeout; };
    void setLockupTimeout(F32 timeout) { mPluginLockupTimeout = timeout; };

    F64 getCPUUsage() { return mCPUUsage; };

    static void poll(F64 timeout);
    static bool canPollThreadRun() { return (sPollSet || sPollsetNeedsRebuild || sUseReadThread); };
    static void setUseReadThread(bool use_read_thread);
    static bool getUseReadThread() { return sUseReadThread; };

    static void shutdown();
private:
    typedef std::map<void *, ptr_t> mapInstances_t;

    enum EState
    {
        STATE_UNINITIALIZED,
        STATE_INITIALIZED,      // init() has been called
        STATE_LISTENING,        // listening for incoming connection
        STATE_LAUNCHED,         // process has been launched
        STATE_CONNECTED,        // process has connected
        STATE_HELLO,            // first message from the plugin process has been received
        STATE_LOADING,          // process has been asked to load the plugin
        STATE_RUNNING,          //
        STATE_GOODBYE,
        STATE_LAUNCH_FAILURE,   // Failure before plugin loaded
        STATE_ERROR,            // generic bailout state
        STATE_CLEANUP,          // clean everything up
        STATE_EXITING,          // Tried to kill process, waiting for it to exit
        STATE_DONE              //

    };
    EState mState;
    void setState(EState state);

    bool wantsPolling() const;
    void removeFromProcessing();

    bool pluginLockedUp();
    bool pluginLockedUpOrQuit();

    bool accept();

    LLSocket::ptr_t mListenSocket;
    LLSocket::ptr_t mSocket;
    U32 mBoundPort;

    LLProcess::Params mProcessParams;
    LLProcessPtr mProcess;
    bool mProcessCreationRequested = false;

    std::string mPluginFile;
    std::string mPluginDir;

    LLPluginProcessParentOwner *mOwner;

    typedef std::map<std::string, LLPluginSharedMemory*> sharedMemoryRegionsType;
    sharedMemoryRegionsType mSharedMemoryRegions;

    LLSD mMessageClassVersions;
    std::string mPluginVersionString;

    LLTimer mHeartbeat;
    F64     mSleepTime;
    F64     mCPUUsage;

    bool mDisableTimeout;
    bool mDebug;
    bool mBlocked;
    bool mPolledInput;

    LLProcessPtr mDebugger;

    F32 mPluginLaunchTimeout;       // Somewhat longer timeout for initial launch.
    F32 mPluginLockupTimeout;       // If we don't receive a heartbeat in this many seconds, we declare the plugin locked up.

    static bool sUseReadThread;
    apr_pollfd_t mPollFD;
    static apr_pollset_t *sPollSet;
    static bool sPollsetNeedsRebuild;
    static LLCoros::Mutex *sInstancesMutex;
    static mapInstances_t sInstances;
    static void dirtyPollSet();
    static void updatePollset();
    void servicePoll();
    static LLThread *sReadThread;

    LLTempBoundListener mPolling;
    bool pollTick();

    LLMutex mIncomingQueueMutex;
    std::queue<LLPluginMessage> mIncomingQueue;
};

#endif // LL_LLPLUGINPROCESSPARENT_H