/* Copyright (c) 2015-2020, The Linux Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
 *     * Neither the name of The Linux Foundation, nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#define LOG_TAG "LocSvc_SystemStatusOsObserver"

#include <algorithm>
#include <SystemStatus.h>
#include <SystemStatusOsObserver.h>
#include <IDataItemCore.h>
#include <DataItemsFactoryProxy.h>

namespace loc_core
{
template <typename CINT, typename COUT>
COUT SystemStatusOsObserver::containerTransfer(CINT& inContainer) {
    COUT outContainer(0);
    for (auto item : inContainer) {
        outContainer.insert(outContainer.begin(), item);
    }
    return outContainer;
}

SystemStatusOsObserver::~SystemStatusOsObserver() {
    // Close data-item library handle
    DataItemsFactoryProxy::closeDataItemLibraryHandle();

    // Destroy cache
    for (auto each : mDataItemCache) {
        if (nullptr != each.second) {
            delete each.second;
        }
    }

    mDataItemCache.clear();
}

void SystemStatusOsObserver::setSubscriptionObj(IDataItemSubscription* subscriptionObj)
{
    struct SetSubsObj : public LocMsg {
        ObserverContext& mContext;
        IDataItemSubscription* mSubsObj;
        inline SetSubsObj(ObserverContext& context, IDataItemSubscription* subscriptionObj) :
                mContext(context), mSubsObj(subscriptionObj) {}
        void proc() const {
            mContext.mSubscriptionObj = mSubsObj;

            if (!mContext.mSSObserver->mDataItemToClients.empty()) {
                list<DataItemId> dis(
                        containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                mContext.mSSObserver->mDataItemToClients.getKeys()));
                mContext.mSubscriptionObj->subscribe(dis, mContext.mSSObserver);
                mContext.mSubscriptionObj->requestData(dis, mContext.mSSObserver);
            }
        }
    };

    if (nullptr == subscriptionObj) {
        LOC_LOGw("subscriptionObj is NULL");
    } else {
        mContext.mMsgTask->sendMsg(new SetSubsObj(mContext, subscriptionObj));
    }
}

/******************************************************************************
 IDataItemSubscription Overrides
******************************************************************************/
void SystemStatusOsObserver::subscribe(const list<DataItemId>& l, IDataItemObserver* client,
                                       bool toRequestData)
{
    struct HandleSubscribeReq : public LocMsg {
        inline HandleSubscribeReq(SystemStatusOsObserver* parent,
                list<DataItemId>& l, IDataItemObserver* client, bool requestData) :
                mParent(parent), mClient(client),
                mDataItemSet(containerTransfer<list<DataItemId>, unordered_set<DataItemId>>(l)),
                diItemlist(l),
                mToRequestData(requestData) {}

        void proc() const {
            unordered_set<DataItemId> dataItemsToSubscribe(0);
            mParent->mDataItemToClients.add(mDataItemSet, {mClient}, &dataItemsToSubscribe);
            mParent->mClientToDataItems.add(mClient, mDataItemSet);

            mParent->sendCachedDataItems(mDataItemSet, mClient);

            // Send subscription set to framework
            if (nullptr != mParent->mContext.mSubscriptionObj) {
                if (mToRequestData) {
                    LOC_LOGD("Request Data sent to framework for the following");
                    mParent->mContext.mSubscriptionObj->requestData(diItemlist, mParent);
                } else if (!dataItemsToSubscribe.empty()) {
                    LOC_LOGD("Subscribe Request sent to framework for the following");
                    mParent->logMe(dataItemsToSubscribe);
                    mParent->mContext.mSubscriptionObj->subscribe(
                            containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                    std::move(dataItemsToSubscribe)),
                            mParent);
                }
            }
        }
        mutable SystemStatusOsObserver* mParent;
        IDataItemObserver* mClient;
        const unordered_set<DataItemId> mDataItemSet;
        const list<DataItemId> diItemlist;
        bool mToRequestData;
    };

    if (l.empty() || nullptr == client) {
        LOC_LOGw("Data item set is empty or client is nullptr");
    } else {
        mContext.mMsgTask->sendMsg(
                new HandleSubscribeReq(this, (list<DataItemId>&)l, client, toRequestData));
    }
}

void SystemStatusOsObserver::updateSubscription(
        const list<DataItemId>& l, IDataItemObserver* client)
{
    struct HandleUpdateSubscriptionReq : public LocMsg {
        HandleUpdateSubscriptionReq(SystemStatusOsObserver* parent,
                                    list<DataItemId>& l, IDataItemObserver* client) :
                mParent(parent), mClient(client),
                mDataItemSet(containerTransfer<list<DataItemId>, unordered_set<DataItemId>>(l)) {}

        void proc() const {
            unordered_set<DataItemId> dataItemsToSubscribe(0);
            unordered_set<DataItemId> dataItemsToUnsubscribe(0);
            unordered_set<IDataItemObserver*> clients({mClient});
            // below removes clients from all entries keyed with the return of the
            // mClientToDataItems.update() call. If leaving an empty set of clients as the
            // result, the entire entry will be removed. dataItemsToUnsubscribe will be
            // populated to keep the keys of the removed entries.
            mParent->mDataItemToClients.trimOrRemove(
                    // this call updates <IDataItemObserver*, DataItemId> map; removes
                    // the DataItemId's that are not new to the clietn from mDataItemSet;
                    // and returns a set of mDataItemSet's that are no longer used by client.
                    // This unused set of mDataItemSet's is passed to trimOrRemove method of
                    // <DataItemId, IDataItemObserver*> map to remove the client from the
                    // corresponding entries, and gets a set of the entries that are
                    // removed from the <DataItemId, IDataItemObserver*> map as a result.
                    mParent->mClientToDataItems.update(mClient,
                                                       (unordered_set<DataItemId>&)mDataItemSet),
                    clients, &dataItemsToUnsubscribe, nullptr);
            // below adds mClient to <DataItemId, IDataItemObserver*> map, and populates
            // new keys added to that map, which are DataItemIds to be subscribed.
            mParent->mDataItemToClients.add(mDataItemSet, clients, &dataItemsToSubscribe);

            // Send First Response
            mParent->sendCachedDataItems(mDataItemSet, mClient);

            if (nullptr != mParent->mContext.mSubscriptionObj) {
                // Send subscription set to framework
                if (!dataItemsToSubscribe.empty()) {
                    LOC_LOGD("Subscribe Request sent to framework for the following");
                    mParent->logMe(dataItemsToSubscribe);

                    mParent->mContext.mSubscriptionObj->subscribe(
                            containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                    std::move(dataItemsToSubscribe)),
                            mParent);
                }

                // Send unsubscribe to framework
                if (!dataItemsToUnsubscribe.empty()) {
                    LOC_LOGD("Unsubscribe Request sent to framework for the following");
                    mParent->logMe(dataItemsToUnsubscribe);

                    mParent->mContext.mSubscriptionObj->unsubscribe(
                            containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                    std::move(dataItemsToUnsubscribe)),
                            mParent);
                }
            }
        }
        SystemStatusOsObserver* mParent;
        IDataItemObserver* mClient;
        unordered_set<DataItemId> mDataItemSet;
    };

    if (l.empty() || nullptr == client) {
        LOC_LOGw("Data item set is empty or client is nullptr");
    } else {
        mContext.mMsgTask->sendMsg(
                new HandleUpdateSubscriptionReq(this, (list<DataItemId>&)l, client));
    }
}

void SystemStatusOsObserver::unsubscribe(
        const list<DataItemId>& l, IDataItemObserver* client)
{
    struct HandleUnsubscribeReq : public LocMsg {
        HandleUnsubscribeReq(SystemStatusOsObserver* parent,
                list<DataItemId>& l, IDataItemObserver* client) :
                mParent(parent), mClient(client),
                mDataItemSet(containerTransfer<list<DataItemId>, unordered_set<DataItemId>>(l)) {}

        void proc() const {
            unordered_set<DataItemId> dataItemsUnusedByClient(0);
            unordered_set<IDataItemObserver*> clientToRemove(0);
            mParent->mClientToDataItems.trimOrRemove({mClient}, mDataItemSet,  &clientToRemove,
                                                     &dataItemsUnusedByClient);
            unordered_set<DataItemId> dataItemsToUnsubscribe(0);
            mParent->mDataItemToClients.trimOrRemove(dataItemsUnusedByClient, {mClient},
                                                     &dataItemsToUnsubscribe, nullptr);

            if (nullptr != mParent->mContext.mSubscriptionObj && !dataItemsToUnsubscribe.empty()) {
                LOC_LOGD("Unsubscribe Request sent to framework for the following data items");
                mParent->logMe(dataItemsToUnsubscribe);

                // Send unsubscribe to framework
                mParent->mContext.mSubscriptionObj->unsubscribe(
                        containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                  std::move(dataItemsToUnsubscribe)),
                        mParent);
            }
        }
        SystemStatusOsObserver* mParent;
        IDataItemObserver* mClient;
        unordered_set<DataItemId> mDataItemSet;
    };

    if (l.empty() || nullptr == client) {
        LOC_LOGw("Data item set is empty or client is nullptr");
    } else {
        mContext.mMsgTask->sendMsg(new HandleUnsubscribeReq(this, (list<DataItemId>&)l, client));
    }
}

void SystemStatusOsObserver::unsubscribeAll(IDataItemObserver* client)
{
    struct HandleUnsubscribeAllReq : public LocMsg {
        HandleUnsubscribeAllReq(SystemStatusOsObserver* parent,
                IDataItemObserver* client) :
                mParent(parent), mClient(client) {}

        void proc() const {
            unordered_set<DataItemId> diByClient = mParent->mClientToDataItems.getValSet(mClient);
            if (!diByClient.empty()) {
                unordered_set<DataItemId> dataItemsToUnsubscribe;
                mParent->mClientToDataItems.remove(mClient);
                mParent->mDataItemToClients.trimOrRemove(diByClient, {mClient},
                                                         &dataItemsToUnsubscribe, nullptr);

                if (!dataItemsToUnsubscribe.empty() &&
                    nullptr != mParent->mContext.mSubscriptionObj) {

                    LOC_LOGD("Unsubscribe Request sent to framework for the following data items");
                    mParent->logMe(dataItemsToUnsubscribe);

                    // Send unsubscribe to framework
                    mParent->mContext.mSubscriptionObj->unsubscribe(
                            containerTransfer<unordered_set<DataItemId>, list<DataItemId>>(
                                    std::move(dataItemsToUnsubscribe)),
                            mParent);
                }
            }
        }
        SystemStatusOsObserver* mParent;
        IDataItemObserver* mClient;
    };

    if (nullptr == client) {
        LOC_LOGw("Data item set is empty or client is nullptr");
    } else {
        mContext.mMsgTask->sendMsg(new HandleUnsubscribeAllReq(this, client));
    }
}

/******************************************************************************
 IDataItemObserver Overrides
******************************************************************************/
void SystemStatusOsObserver::notify(const list<IDataItemCore*>& dlist)
{
    struct HandleNotify : public LocMsg {
        HandleNotify(SystemStatusOsObserver* parent, vector<IDataItemCore*>& v) :
                mParent(parent), mDiVec(std::move(v)) {}

        inline virtual ~HandleNotify() {
            for (auto item : mDiVec) {
                delete item;
            }
        }

        void proc() const {
            // Update Cache with received data items and prepare
            // list of data items to be sent.
            unordered_set<DataItemId> dataItemIdsToBeSent(0);
            for (auto item : mDiVec) {
                if (mParent->updateCache(item)) {
                    dataItemIdsToBeSent.insert(item->getId());
                }
            }

            // Send data item to all subscribed clients
            unordered_set<IDataItemObserver*> clientSet(0);
            for (auto each : dataItemIdsToBeSent) {
                auto clients = mParent->mDataItemToClients.getValSetPtr(each);
                if (nullptr != clients) {
                    clientSet.insert(clients->begin(), clients->end());
                }
            }

            for (auto client : clientSet) {
                unordered_set<DataItemId> dataItemIdsForThisClient(
                        mParent->mClientToDataItems.getValSet(client));
                for (auto itr = dataItemIdsForThisClient.begin();
                        itr != dataItemIdsForThisClient.end(); ) {
                    if (dataItemIdsToBeSent.find(*itr) == dataItemIdsToBeSent.end()) {
                        itr = dataItemIdsForThisClient.erase(itr);
                    } else {
                        itr++;
                    }
                }

                mParent->sendCachedDataItems(dataItemIdsForThisClient, client);
            }
        }
        SystemStatusOsObserver* mParent;
        const vector<IDataItemCore*> mDiVec;
    };

    if (!dlist.empty()) {
        vector<IDataItemCore*> dataItemVec(dlist.size());

        for (auto each : dlist) {

            IDataItemCore* di = DataItemsFactoryProxy::createNewDataItem(each->getId());
            if (nullptr == di) {
                LOC_LOGw("Unable to create dataitem:%d", each->getId());
                continue;
            }

            // Copy contents into the newly created data item
            di->copy(each);

            // add this dataitem if updated from last one
            dataItemVec.push_back(di);
            IF_LOC_LOGD {
                string dv;
                di->stringify(dv);
                LOC_LOGd("notify: DataItem In Value:%s", dv.c_str());
            }
        }

        if (!dataItemVec.empty()) {
            mContext.mMsgTask->sendMsg(new HandleNotify(this, dataItemVec));
        }
    }
}

/******************************************************************************
 IFrameworkActionReq Overrides
******************************************************************************/
void SystemStatusOsObserver::turnOn(DataItemId dit, int timeOut)
{
    if (nullptr == mContext.mFrameworkActionReqObj) {
        LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
        return;
    }

    // Check if data item exists in mActiveRequestCount
    DataItemIdToInt::iterator citer = mActiveRequestCount.find(dit);
    if (citer == mActiveRequestCount.end()) {
        // Data item not found in map
        // Add reference count as 1 and add dataitem to map
        pair<DataItemId, int> cpair(dit, 1);
        mActiveRequestCount.insert(cpair);
        LOC_LOGD("Sending turnOn request");

        // Send action turn on to framework
        struct HandleTurnOnMsg : public LocMsg {
            HandleTurnOnMsg(IFrameworkActionReq* framework,
                    DataItemId dit, int timeOut) :
                    mFrameworkActionReqObj(framework), mDataItemId(dit), mTimeOut(timeOut) {}
            virtual ~HandleTurnOnMsg() {}
            void proc() const {
                mFrameworkActionReqObj->turnOn(mDataItemId, mTimeOut);
            }
            IFrameworkActionReq* mFrameworkActionReqObj;
            DataItemId mDataItemId;
            int mTimeOut;
        };
        mContext.mMsgTask->sendMsg(
                new (nothrow) HandleTurnOnMsg(mContext.mFrameworkActionReqObj, dit, timeOut));
    }
    else {
        // Found in map, update reference count
        citer->second++;
        LOC_LOGD("turnOn - Data item:%d Num_refs:%d", dit, citer->second);
    }
}

void SystemStatusOsObserver::turnOff(DataItemId dit)
{
    if (nullptr == mContext.mFrameworkActionReqObj) {
        LOC_LOGE("%s:%d]: Framework action request object is NULL", __func__, __LINE__);
        return;
    }

    // Check if data item exists in mActiveRequestCount
    DataItemIdToInt::iterator citer = mActiveRequestCount.find(dit);
    if (citer != mActiveRequestCount.end()) {
        // found
        citer->second--;
        LOC_LOGD("turnOff - Data item:%d Remaining:%d", dit, citer->second);
        if(citer->second == 0) {
            // if this was last reference, remove item from map and turn off module
            mActiveRequestCount.erase(citer);

            // Send action turn off to framework
            struct HandleTurnOffMsg : public LocMsg {
                HandleTurnOffMsg(IFrameworkActionReq* framework, DataItemId dit) :
                    mFrameworkActionReqObj(framework), mDataItemId(dit) {}
                virtual ~HandleTurnOffMsg() {}
                void proc() const {
                    mFrameworkActionReqObj->turnOff(mDataItemId);
                }
                IFrameworkActionReq* mFrameworkActionReqObj;
                DataItemId mDataItemId;
            };
            mContext.mMsgTask->sendMsg(
                    new (nothrow) HandleTurnOffMsg(mContext.mFrameworkActionReqObj, dit));
        }
    }
}

#ifdef USE_GLIB
bool SystemStatusOsObserver::connectBackhaul()
{
    bool result = false;

    if (mContext.mFrameworkActionReqObj != NULL) {
        struct HandleConnectBackhaul : public LocMsg {
            HandleConnectBackhaul(IFrameworkActionReq* fwkActReq) :
                    mFwkActionReqObj(fwkActReq) {}
            virtual ~HandleConnectBackhaul() {}
            void proc() const {
                LOC_LOGD("HandleConnectBackhaul");
                mFwkActionReqObj->connectBackhaul();
            }
            IFrameworkActionReq* mFwkActionReqObj;
        };
        mContext.mMsgTask->sendMsg(
                new (nothrow) HandleConnectBackhaul(mContext.mFrameworkActionReqObj));
        result = true;
    }
    else {
        ++mBackHaulConnectReqCount;
        LOC_LOGE("Framework action request object is NULL.Caching connect request: %d",
                        mBackHaulConnectReqCount);
        result = false;
    }
    return result;

}

bool SystemStatusOsObserver::disconnectBackhaul()
{
    bool result = false;

    if (mContext.mFrameworkActionReqObj != NULL) {
        struct HandleDisconnectBackhaul : public LocMsg {
            HandleDisconnectBackhaul(IFrameworkActionReq* fwkActReq) :
                    mFwkActionReqObj(fwkActReq) {}
            virtual ~HandleDisconnectBackhaul() {}
            void proc() const {
                LOC_LOGD("HandleDisconnectBackhaul");
                mFwkActionReqObj->disconnectBackhaul();
            }
            IFrameworkActionReq* mFwkActionReqObj;
        };
        mContext.mMsgTask->sendMsg(
                new (nothrow) HandleDisconnectBackhaul(mContext.mFrameworkActionReqObj));
    }
    else {
        if (mBackHaulConnectReqCount > 0) {
            --mBackHaulConnectReqCount;
        }
        LOC_LOGE("Framework action request object is NULL.Caching disconnect request: %d",
                        mBackHaulConnectReqCount);
        result = false;
    }
    return result;
}
#endif
/******************************************************************************
 Helpers
******************************************************************************/
void SystemStatusOsObserver::sendCachedDataItems(
        const unordered_set<DataItemId>& s, IDataItemObserver* to)
{
    if (nullptr == to) {
        LOC_LOGv("client pointer is NULL.");
    } else {
        string clientName;
        to->getName(clientName);
        list<IDataItemCore*> dataItems(0);

        for (auto each : s) {
            auto citer = mDataItemCache.find(each);
            if (citer != mDataItemCache.end()) {
                string dv;
                citer->second->stringify(dv);
                LOC_LOGI("DataItem: %s >> %s", dv.c_str(), clientName.c_str());
                dataItems.push_front(citer->second);
            }
        }

        if (dataItems.empty()) {
            LOC_LOGv("No items to notify.");
        } else {
            to->notify(dataItems);
        }
    }
}

bool SystemStatusOsObserver::updateCache(IDataItemCore* d)
{
    bool dataItemUpdated = false;

    // Request systemstatus to record this dataitem in its cache
    // if the return is false, it means that SystemStatus is not
    // handling it, so SystemStatusOsObserver also doesn't.
    // So it has to be true to proceed.
    if (nullptr != d && mSystemStatus->eventDataItemNotify(d)) {
        auto citer = mDataItemCache.find(d->getId());
        if (citer == mDataItemCache.end()) {
            // New data item; not found in cache
            IDataItemCore* dataitem = DataItemsFactoryProxy::createNewDataItem(d->getId());
            if (nullptr != dataitem) {
                // Copy the contents of the data item
                dataitem->copy(d);
                // Insert in mDataItemCache
                mDataItemCache.insert(std::make_pair(d->getId(), dataitem));
                dataItemUpdated = true;
            }
        } else {
            // Found in cache; Update cache if necessary
            citer->second->copy(d, &dataItemUpdated);
        }

        if (dataItemUpdated) {
            LOC_LOGV("DataItem:%d updated:%d", d->getId(), dataItemUpdated);
        }
    }

    return dataItemUpdated;
}

} // namespace loc_core