/* Copyright (c) 2017-2018, 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.
 *
 */

#ifndef __LOC_IPC__
#define __LOC_IPC__

#include <string>
#include <memory>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unordered_set>
#include <mutex>
#include <LocThread.h>

using namespace std;

namespace loc_util {

class LocIpcRecver;
class LocIpcSender;
class LocIpcRunnable;

class ILocIpcListener {
protected:
    inline virtual ~ILocIpcListener() {}
public:
    // LocIpc client can overwrite this function to get notification
    // when the socket for LocIpc is ready to receive messages.
    inline virtual void onListenerReady() {}
    virtual void onReceive(const char* data, uint32_t len, const LocIpcRecver* recver) = 0;
};

class LocIpcQrtrWatcher {
    const unordered_set<int> mServicesToWatch;
    unordered_set<int> mClientsToWatch;
    mutex mMutex;
    inline bool isInWatch(const unordered_set<int>& idsToWatch, int id) {
        return idsToWatch.find(id) != idsToWatch.end();
    }
protected:
    inline virtual ~LocIpcQrtrWatcher() {}
    inline LocIpcQrtrWatcher(unordered_set<int> servicesToWatch)
            : mServicesToWatch(servicesToWatch) {}
public:
    enum class ServiceStatus { UP, DOWN };
    inline bool isServiceInWatch(int serviceId) {
        return isInWatch(mServicesToWatch, serviceId);
    }
    inline bool isClientInWatch(int nodeId) {
        lock_guard<mutex> lock(mMutex);
        return isInWatch(mClientsToWatch, nodeId);
    }
    inline void addClientToWatch(int nodeId) {
        lock_guard<mutex> lock(mMutex);
        mClientsToWatch.emplace(nodeId);
    }
    virtual void onServiceStatusChange(int sericeId, int instanceId, ServiceStatus status,
                                       const LocIpcSender& sender) = 0;
    inline virtual void onClientGone(int nodeId, int portId) {}
    inline const unordered_set<int>& getServicesToWatch() { return mServicesToWatch; }
};

class LocIpc {
public:
    inline LocIpc() : mRunnable(nullptr) {}
    inline virtual ~LocIpc() {
        stopNonBlockingListening();
    }

    static shared_ptr<LocIpcSender>
            getLocIpcLocalSender(const char* localSockName);
    static shared_ptr<LocIpcSender>
            getLocIpcInetUdpSender(const char* serverName, int32_t port);
    static shared_ptr<LocIpcSender>
            getLocIpcInetTcpSender(const char* serverName, int32_t port);
    static shared_ptr<LocIpcSender>
            getLocIpcQrtrSender(int service, int instance);

    static unique_ptr<LocIpcRecver>
            getLocIpcLocalRecver(const shared_ptr<ILocIpcListener>& listener,
                                 const char* localSockName);
    static unique_ptr<LocIpcRecver>
            getLocIpcInetUdpRecver(const shared_ptr<ILocIpcListener>& listener,
                                 const char* serverName, int32_t port);
    static unique_ptr<LocIpcRecver>
            getLocIpcInetTcpRecver(const shared_ptr<ILocIpcListener>& listener,
                                   const char* serverName, int32_t port);
    inline static unique_ptr<LocIpcRecver>
            getLocIpcQrtrRecver(const shared_ptr<ILocIpcListener>& listener,
                                int service, int instance) {
        const shared_ptr<LocIpcQrtrWatcher> qrtrWatcher = nullptr;
        return getLocIpcQrtrRecver(listener, service, instance, qrtrWatcher);
    }
    static unique_ptr<LocIpcRecver>
            getLocIpcQrtrRecver(const shared_ptr<ILocIpcListener>& listener,
                                int service, int instance,
                                const shared_ptr<LocIpcQrtrWatcher>& qrtrWatcher);

    static pair<shared_ptr<LocIpcSender>, unique_ptr<LocIpcRecver>>
            getLocIpcQmiLocServiceSenderRecverPair(const shared_ptr<ILocIpcListener>& listener,
                                                   int instance);

    // Listen for new messages in current thread. Calling this funciton will
    // block current thread.
    // The listening can be stopped by calling stopBlockingListening() passing
    // in the same ipcRecver obj handle.
    static bool startBlockingListening(LocIpcRecver& ipcRecver);
    static void stopBlockingListening(LocIpcRecver& ipcRecver);

    // Create a new LocThread and listen for new messages in it.
    // Calling this function will return immediately and won't block current thread.
    // The listening can be stopped by calling stopNonBlockingListening().
    bool startNonBlockingListening(unique_ptr<LocIpcRecver>& ipcRecver);
    void stopNonBlockingListening();

    // Send out a message.
    // Call this function to send a message in argument data to socket in argument name.
    //
    // Argument name contains the name of the target unix socket. data contains the
    // message to be sent out. Convert your message to a string before calling this function.
    // The function will return true on success, and false on failure.
    static bool send(LocIpcSender& sender, const uint8_t data[],
                     uint32_t length, int32_t msgId = -1);

private:
    LocThread mThread;
    LocIpcRunnable *mRunnable;
};

/* this is only when client needs to implement Sender / Recver that are not already provided by
   the factor methods prvoided by LocIpc. */

class LocIpcSender {
protected:
    LocIpcSender() = default;
    virtual bool isOperable() const = 0;
    virtual ssize_t send(const uint8_t data[], uint32_t length, int32_t msgId) const = 0;
public:
    virtual ~LocIpcSender() = default;
    inline bool isSendable() const { return isOperable(); }
    inline bool sendData(const uint8_t data[], uint32_t length, int32_t msgId) const {
        return isSendable() && (send(data, length, msgId) > 0);
    }
    virtual unique_ptr<LocIpcRecver> getRecver(const shared_ptr<ILocIpcListener>& listener) {
        return nullptr;
    }
    inline virtual void copyDestAddrFrom(const LocIpcSender& otherSender) {}
};

class LocIpcRecver {
    LocIpcSender& mIpcSender;
protected:
    const shared_ptr<ILocIpcListener> mDataCb;
    inline LocIpcRecver(const shared_ptr<ILocIpcListener>& listener, LocIpcSender& sender) :
            mIpcSender(sender), mDataCb(listener) {}
    LocIpcRecver(LocIpcRecver const& recver) = delete;
    LocIpcRecver& operator=(LocIpcRecver const& recver) = delete;
    virtual ssize_t recv() const = 0;
public:
    virtual ~LocIpcRecver() = default;
    inline bool recvData() const { return isRecvable() && (recv() > 0); }
    inline bool isRecvable() const { return mDataCb != nullptr && mIpcSender.isSendable(); }
    virtual void onListenerReady() { if (mDataCb != nullptr) mDataCb->onListenerReady(); }
    inline virtual unique_ptr<LocIpcSender> getLastSender() const {
        return nullptr;
    }
    virtual void abort() const = 0;
    virtual const char* getName() const = 0;
};

class Sock {
    static const char MSG_ABORT[];
    static const char LOC_IPC_HEAD[];
    const uint32_t mMaxTxSize;
    ssize_t sendto(const void *buf, size_t len, int flags, const struct sockaddr *destAddr,
                   socklen_t addrlen) const;
    ssize_t recvfrom(const LocIpcRecver& recver, const shared_ptr<ILocIpcListener>& dataCb,
                     int sid, int flags, struct sockaddr *srcAddr, socklen_t *addrlen) const;
public:
    int mSid;
    inline Sock(int sid, const uint32_t maxTxSize = 8192) : mMaxTxSize(maxTxSize), mSid(sid) {}
    inline ~Sock() { close(); }
    inline bool isValid() const { return -1 != mSid; }
    ssize_t send(const void *buf, uint32_t len, int flags, const struct sockaddr *destAddr,
                 socklen_t addrlen) const;
    ssize_t recv(const LocIpcRecver& recver, const shared_ptr<ILocIpcListener>& dataCb, int flags,
                 struct sockaddr *srcAddr, socklen_t *addrlen, int sid = -1) const;
    ssize_t sendAbort(int flags, const struct sockaddr *destAddr, socklen_t addrlen);
    inline void close() {
        if (isValid()) {
            ::close(mSid);
            mSid = -1;
        }
    }
};

class SockRecver : public LocIpcRecver {
    shared_ptr<Sock> mSock;
protected:
    inline virtual ssize_t recv() const override {
        return mSock->recv(*this, mDataCb, 0, nullptr, nullptr);
    }
public:
    inline SockRecver(const shared_ptr<ILocIpcListener>& listener,
                  LocIpcSender& sender, shared_ptr<Sock> sock) :
            LocIpcRecver(listener, sender), mSock(sock) {
    }
    inline virtual const char* getName() const override {
        return "SockRecver";
    }
    inline virtual void abort() const override {}
};

}

#endif //__LOC_IPC__