/**
 * SPDX license identifier: MPL-2.0
 *
 * Copyright (C) 2012, BMW AG
 *
 * \author Christian Linke, christian.linke@bmw.de BMW 2011,2012
 * \author Aleksandar Donchev, aleksander.donchev@partner.bmw.de BMW 2017
 *
 * \copyright
 * This Source Code Form is subject to the terms of the
 * Mozilla Public License, v. 2.0. If a  copy of the MPL was not distributed with
 * this file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 *  \file CAmSocketHandler.h
 *  For further information see http://www.genivi.org/.
 */

#ifndef SOCKETHANDLER_H_
#define SOCKETHANDLER_H_

#include <sys/socket.h>
#include <stdint.h>
#include <sys/poll.h>
#include <list>
#include <map>
#include <set>
#include <signal.h>
#include <vector>
#include <functional>
#include <audiomanagerconfig.h>
#include "audiomanagertypes.h"


#ifdef WITH_TIMERFD

#include <stdio.h>
#include <string>
#include <stdexcept>
#include <unistd.h>
#include <fcntl.h>

#endif

namespace am
{

#define MAX_NS 1000000000L
#define MAX_TIMERHANDLE UINT16_MAX
#define MAX_POLLHANDLE UINT16_MAX

    typedef uint16_t sh_pollHandle_t; //!<this is a handle for a filedescriptor to be used with the SocketHandler
    typedef sh_pollHandle_t sh_timerHandle_t; //!<this is a handle for a timer to be used with the SocketHandler

    /**
     * prototype for poll prepared callback
     */
    class IAmShPollPrepare
    {
    public:
        virtual void Call(const sh_pollHandle_t handle, void* userData) = 0;
        virtual ~IAmShPollPrepare()
        {
        }
        ;
    };

    /**
     * prototype for poll fired callback
     */
    class IAmShPollFired
    {
    public:
        virtual void Call(const pollfd pollfd, const sh_pollHandle_t handle, void* userData) = 0;
        virtual ~ IAmShPollFired()
        {
        }
        ;
    };

    /**
     * prototype for poll check callback
     */
    class IAmShPollCheck
    {
    public:
        virtual bool Call(const sh_pollHandle_t handle, void* userData) = 0;
        virtual ~ IAmShPollCheck()
        {
        }
        ;
    };

    /**
     * prototype for dispatch callback
     */
    class IAmShPollDispatch
    {
    public:
        virtual bool Call(const sh_pollHandle_t handle, void* userData) = 0;
        virtual ~ IAmShPollDispatch()
        {
        }
        ;
    };

    /**
     * prototype for the timer callback
     */
    class IAmShTimerCallBack
    {
    public:
        IAmShTimerCallBack()
        {
        }
        virtual void Call(const sh_timerHandle_t handle, void* userData) = 0;
        virtual ~IAmShTimerCallBack()
        {
        }
    };

    /**make private, not public
     * template for a callback
     */
    template<class TClass> class TAmShPollFired: public IAmShPollFired
    {
    private:
        TClass* mInstance;
        void (TClass::*mFunction)(const pollfd pollfd, const sh_pollHandle_t handle, void* userData);

    public:
        TAmShPollFired(TClass* instance, void (TClass::*function)(const pollfd pollfd, const sh_pollHandle_t handle, void* userData)) :
                mInstance(instance), //
                mFunction(function)
        {
        }
        ;

        virtual void Call(const pollfd pollfd, const sh_pollHandle_t handle, void* userData)
        {
            (*mInstance.*mFunction)(pollfd, handle, userData);
        }
        ;
    };

    /**
     * template for a callback
     */
    template<class TClass> class TAmShPollCheck: public IAmShPollCheck
    {
    private:
        TClass* mInstance;
        bool (TClass::*mFunction)(const sh_pollHandle_t handle, void* userData);

    public:
        TAmShPollCheck(TClass* instance, bool (TClass::*function)(const sh_pollHandle_t handle, void* userData)) :
                mInstance(instance), //
                mFunction(function)
        {
        }
        ;

        virtual bool Call(const sh_pollHandle_t handle, void* userData)
        {
            return ((*mInstance.*mFunction)(handle, userData));
        }
        ;
    };

    /**
     * template for a callback
     */
    template<class TClass> class TAmShPollDispatch: public IAmShPollDispatch
    {
    private:
        TClass* mInstance;
        bool (TClass::*mFunction)(const sh_pollHandle_t handle, void* userData);

    public:
        TAmShPollDispatch(TClass* instance, bool (TClass::*function)(const sh_pollHandle_t handle, void* userData)) :
                mInstance(instance), //
                mFunction(function)
        {
        }
        ;

        virtual bool Call(const sh_pollHandle_t handle, void* userData)
        {
            return ((*mInstance.*mFunction)(handle, userData));
        }
        ;
    };

    /**
     * template to create the functor for a class
     */
    template<class TClass> class TAmShTimerCallBack: public IAmShTimerCallBack
    {
    private:
        TClass* mInstance;
        void (TClass::*mFunction)(sh_timerHandle_t handle, void* userData);

    public:
        TAmShTimerCallBack(TClass* instance, void (TClass::*function)(sh_timerHandle_t handle, void* userData)) :
                IAmShTimerCallBack(), mInstance(instance), //
                mFunction(function)
        {
        }
        ;

        virtual void Call(sh_timerHandle_t handle, void* userData)
        {
            (*mInstance.*mFunction)(handle, userData);
        }
    };

    /**
     * template for a callback
     */

    template<class TClass> class TAmShPollPrepare: public IAmShPollPrepare
    {
    private:
        TClass* mInstance;
        void (TClass::*mFunction)(const sh_pollHandle_t handle, void* userData);

    public:
        TAmShPollPrepare(TClass* instance, void (TClass::*function)(const sh_pollHandle_t handle, void* userData)) :
                mInstance(instance), //
                mFunction(function)
        {
        }
        ;

        virtual void Call(const sh_pollHandle_t handle, void* userData)
        {
            (*mInstance.*mFunction)(handle, userData);
        }
        ;
    };

    /**
     * The am::CAmSocketHandler implements a mainloop for the AudioManager. Plugins and different parts of the AudioManager add their filedescriptors to the handler
     * to get called on communication of the filedescriptors.\n
     * More information can be found here : \ref mainl
     */
    class CAmSocketHandler
    {
        struct sh_poll_s //!<struct that holds information about polls
        {
            sh_pollHandle_t handle; //!<handle to uniquely adress a filedesriptor
            pollfd pollfdValue; //!<the array for polling the filedescriptors
            std::function<void(const sh_pollHandle_t handle, void* userData)> prepareCB; //preperation callback
            std::function<void(const pollfd pollfd, const sh_pollHandle_t handle, void* userData)> firedCB; //fired callback
            std::function<bool(const sh_pollHandle_t handle, void* userData)> checkCB; //check callback
            std::function<bool(const sh_pollHandle_t handle, void* userData)> dispatchCB; //dispatch callback
            void* userData;

            sh_poll_s() :
                    handle(0), pollfdValue(), prepareCB(), firedCB(), checkCB(), dispatchCB(), userData(0)
            {
            }
        };

        struct sh_timer_s //!<struct that holds information of timers
        {
            sh_timerHandle_t handle; //!<the handle of the timer
#ifdef WITH_TIMERFD       
            int fd;
            itimerspec countdown; //!<the countdown, this value is decreased every time the timer is up
#else
            timespec countdown; //!<the countdown, this value is decreased every time the timer is up
#endif        
            std::function<void(const sh_timerHandle_t handle, void* userData)> callback; //timer callback
            void* userData;
            sh_timer_s() :
                    handle(0)
#ifdef WITH_TIMERFD
                            , fd(0)
#endif
                            , countdown(), callback(), userData(0)
            {
            }
        };

        typedef std::reverse_iterator<sh_timer_s> rListTimerIter; //!<typedef for reverseiterator on timer lists

        typedef std::vector<pollfd> VectorListPollfd_t; //!<vector of filedescriptors
        typedef std::vector<sh_poll_s> VectorListPoll_t; //!<list for the callbacks

    public:

        CAmSocketHandler();
        ~CAmSocketHandler();

        am_Error_e addFDPoll(const int fd, const short event, std::function<void(const sh_pollHandle_t handle, void* userData)> prepare, std::function<void(const pollfd pollfd, const sh_pollHandle_t handle, void* userData)> fired,
                std::function<bool(const sh_pollHandle_t handle, void* userData)> check, std::function<bool(const sh_pollHandle_t handle, void* userData)> dispatch, void* userData, sh_pollHandle_t& handle);

        am_Error_e addFDPoll(const int fd, const short event, IAmShPollPrepare *prepare, IAmShPollFired *fired, IAmShPollCheck *check, IAmShPollDispatch *dispatch, void* userData, sh_pollHandle_t& handle);
        am_Error_e removeFDPoll(const sh_pollHandle_t handle);
        am_Error_e updateEventFlags(const sh_pollHandle_t handle, const short events);
        am_Error_e addTimer(const timespec & timeouts, IAmShTimerCallBack* callback, sh_timerHandle_t& handle, void * userData,
#ifndef WITH_TIMERFD
                const bool __attribute__((__unused__)) repeats = false
#else
                const bool repeats = false
#endif
                );
        am_Error_e addTimer(const timespec & timeouts, std::function<void(const sh_timerHandle_t handle, void* userData)> callback, sh_timerHandle_t& handle, void* userData,
#ifndef WITH_TIMERFD
                const bool __attribute__((__unused__)) repeats = false
#else
                const bool repeats = false
#endif
                );
        am_Error_e removeTimer(const sh_timerHandle_t handle);
        am_Error_e restartTimer(const sh_timerHandle_t handle);
        am_Error_e updateTimer(const sh_timerHandle_t handle, const timespec & timeouts);
        am_Error_e stopTimer(const sh_timerHandle_t handle);
        void start_listenting();
        void stop_listening();
        void exit_mainloop();

    private:

        static CAmSocketHandler* mInstance;
        int mPipe[2];
        int mDispatchDone; //this starts / stops the mainloop

        bool fdIsValid(const int fd) const;

        timespec* insertTime(timespec& buffertime);
#ifdef WITH_TIMERFD      
        am_Error_e createTimeFD(const itimerspec & timeouts, int & fd);

#else 
        void timerUp();
        void timerCorrection();

        /**
         * compares countdown values
         * @param a
         * @param b
         * @return true if b greater a
         */
        inline static bool compareCountdown(const sh_timer_s& a, const sh_timer_s& b)
        {
            return ((a.countdown.tv_sec == b.countdown.tv_sec) ? (a.countdown.tv_nsec < b.countdown.tv_nsec) : (a.countdown.tv_sec < b.countdown.tv_sec));
        }

        /**
         * Subtracts b from a
         * @param a
         * @param b
         * @return subtracted value
         */
        inline static timespec timespecSub(const timespec& a, const timespec& b)
        {
            timespec result;

            if ((a.tv_sec < b.tv_sec) || ((a.tv_sec == b.tv_sec) && (a.tv_nsec <= b.tv_nsec)))
            {
                result.tv_sec = result.tv_nsec = 0;
            }
            else
            {
                result.tv_sec = a.tv_sec - b.tv_sec;
                if (a.tv_nsec < b.tv_nsec)
                {
                    result.tv_nsec = a.tv_nsec + MAX_NS - b.tv_nsec;
                    result.tv_sec--; /* Borrow a second. */
                }
                else
                {
                    result.tv_nsec = a.tv_nsec - b.tv_nsec;
                }
            }
            return (result);
        }

        /**
         * adds timespec values
         * @param a
         * @param b
         * @return the added values
         */
        inline timespec timespecAdd(const timespec& a, const timespec& b)
        {
            timespec result;
            result.tv_sec = a.tv_sec + b.tv_sec;
            result.tv_nsec = a.tv_nsec + b.tv_nsec;
            if (result.tv_nsec >= MAX_NS)
            {
                result.tv_sec++;
                result.tv_nsec = result.tv_nsec - MAX_NS;
            }
            return (result);
        }

        /**
         * comapares timespec values
         * @param a
         * @param b
         * @return
         */
        inline int timespecCompare(const timespec& a, const timespec& b)
        {
            //less
            if (a.tv_sec < b.tv_sec)
            return (-1);
            //greater
            else if (a.tv_sec > b.tv_sec)
            return (1);
            //less
            else if (a.tv_nsec < b.tv_nsec)
            return (-1);
            //greater
            else if (a.tv_nsec > b.tv_nsec)
            return (1);
            //equal
            return (0);
        }
#endif  

        /**
         * functor to prepare all fire events
         * @param a
         * @return
         */
        inline static void prepare(am::CAmSocketHandler::sh_poll_s& row);
    
        /**
         * functor to return all fired events
         * @param a
         * @return
         */
        inline static void fire(sh_poll_s* a);


        /**
         * functor to return all fired events
         * @param a
         * @return
         */
        inline static bool eventFired(const pollfd& a);
 

        /**
         * functor to help find the items that do not need dispatching
         * @param a
         * @return
         */
        inline static bool noDispatching(const sh_poll_s* a);

        /**
         * checks if dispatching is already finished
         * @param a
         * @return
         */
        inline static bool dispatchingFinished(const sh_poll_s* a);

        /**
         * timer fire callback
         * @param a
         * @return
         */
        inline static void callTimer(sh_timer_s& a);
 
        VectorListPollfd_t mfdPollingArray; //!<the polling array for ppoll
        std::set<sh_pollHandle_t> mSetPollKeys; //!A set of all used ppoll keys
        VectorListPoll_t mListPoll; //!<list that holds all information for the ppoll
        std::set<sh_timerHandle_t> mSetTimerKeys; //!A set of all used timer keys
        std::list<sh_timer_s> mListTimer; //!<list of all timers
        std::list<sh_timer_s> mListActiveTimer; //!<list of all currently active timers
        sh_timerHandle_t mLastInsertedHandle; //!<keeps track of the last inserted timer handle
        sh_pollHandle_t mLastInsertedPollHandle; //!<keeps track of the last inserted poll handle
        bool mRecreatePollfds; //!<when this is true, the poll list needs to be recreated
#ifndef WITH_TIMERFD
        timespec mStartTime; //!<here the actual time is saved for timecorrection
#endif
    };

} /* namespace am */
#endif /* SOCKETHANDLER_H_ */