/* Copyright (C) 2017 MariaDB Corporaton

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

#include <sstream>
#include <map>
#include <boost/thread/mutex.hpp>
#include <time.h>
#include "messagequeuepool.h"
#include "messagequeue.h"

namespace messageqcpp
{

boost::mutex queueMutex;
// Make linker happy
std::multimap<std::string, ClientObject*> MessageQueueClientPool::clientMap;

// 300 seconds idle until cleanup
#define MAX_IDLE_TIME 300

static uint64_t TimeSpecToSeconds(struct timespec* ts)
{
    return (uint64_t)ts->tv_sec + (uint64_t)ts->tv_nsec / 1000000000;
}

MessageQueueClient* MessageQueueClientPool::getInstance(const std::string& ip, uint64_t port)
{
    boost::mutex::scoped_lock lock(queueMutex);

    std::ostringstream oss;
    oss << ip << "_" << port;
    std::string searchString = oss.str();

    MessageQueueClient* returnClient = MessageQueueClientPool::findInPool(searchString);

    // We found one, return it
    if (returnClient != NULL)
    {
        return returnClient;
    }

    // We didn't find one, create new one
    ClientObject* newClientObject = new ClientObject();
    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);
    uint64_t nowSeconds = TimeSpecToSeconds(&now);

    newClientObject->client = new MessageQueueClient(ip, port);
    newClientObject->inUse = true;
    newClientObject->lastUsed = nowSeconds;
    clientMap.insert(std::pair<std::string, ClientObject*>(searchString, newClientObject));
    return newClientObject->client;
}

MessageQueueClient* MessageQueueClientPool::getInstance(const std::string& module)
{
    boost::mutex::scoped_lock lock(queueMutex);

    MessageQueueClient* returnClient = MessageQueueClientPool::findInPool(module);

    // We found one, return it
    if (returnClient != NULL)
    {
        return returnClient;
    }

    // We didn't find one, create new one
    ClientObject* newClientObject = new ClientObject();
    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);
    uint64_t nowSeconds = TimeSpecToSeconds(&now);

    newClientObject->client = new MessageQueueClient(module);
    newClientObject->inUse = true;
    newClientObject->lastUsed = nowSeconds;
    clientMap.insert(std::pair<std::string, ClientObject*>(module, newClientObject));
    return newClientObject->client;
}

MessageQueueClient* MessageQueueClientPool::findInPool(const std::string& search)
{
    struct timespec now;
    clock_gettime(CLOCK_MONOTONIC, &now);
    uint64_t nowSeconds = TimeSpecToSeconds(&now);
    MessageQueueClient* returnClient = NULL;

    std::multimap<std::string, ClientObject*>::iterator it = clientMap.begin();

    // Scan pool
    while (it != clientMap.end())
    {
        ClientObject* clientObject = it->second;
        uint64_t elapsedTime = nowSeconds - clientObject->lastUsed;

        // If connection hasn't been used for MAX_IDLE_TIME we probably don't need it so drop it
        // Don't drop in use connections that have been in use a long time
        if ((elapsedTime >= MAX_IDLE_TIME) && (!clientObject->inUse))
        {
            delete clientObject->client;
            delete clientObject;
            // Do this so we don't invalidate current interator
            std::multimap<std::string, ClientObject*>::iterator toDelete = it;
            it++;
            clientMap.erase(toDelete);
            continue;
        }

        if (!clientObject->inUse)
        {
            MessageQueueClient* client = clientObject->client;

            // If the unused socket isn't connected or has data pending read, destroy it
            if (!client->isConnected() || client->hasData())
            {
                delete client;
                delete clientObject;
                // Do this so we don't invalidate current interator
                std::multimap<std::string, ClientObject*>::iterator toDelete = it;
                it++;
                clientMap.erase(toDelete);
                continue;
            }

        }

        // If connection matches store it for later, but keep scanning the pool for more timeout prunes
        if (it->first.compare(search) == 0)
        {
            if ((returnClient == NULL) && (!clientObject->inUse))
            {
                returnClient = clientObject->client;
                clientObject->inUse = true;
                return returnClient;
            }
        }

        it++;
    }

    return NULL;
}

void MessageQueueClientPool::releaseInstance(MessageQueueClient* client)
{
    // Scan pool for pointer and release
    // Set the last used and mark as not in use

    if (client == NULL)
        return;

    boost::mutex::scoped_lock lock(queueMutex);
    std::multimap<std::string, ClientObject*>::iterator it = clientMap.begin();

    while (it != clientMap.end())
    {
        if (it->second->client == client)
        {
            struct timespec now;
            clock_gettime(CLOCK_MONOTONIC, &now);
            uint64_t nowSeconds = TimeSpecToSeconds(&now);
            it->second->inUse = false;
            it->second->lastUsed = nowSeconds;
            return;
        }

        it++;
    }
}

// WriteEngine needs this as it forces connections closed and can't reuse. Also good for connection errors
void MessageQueueClientPool::deleteInstance(MessageQueueClient* client)
{
    // Scan pool for pointer and delete
    // Set the last used and mark as not in use

    if (client == NULL)
        return;

    boost::mutex::scoped_lock lock(queueMutex);
    std::multimap<std::string, ClientObject*>::iterator it = clientMap.begin();

    while (it != clientMap.end())
    {
        if (it->second->client == client)
        {
            delete it->second->client;
            delete it->second;
            clientMap.erase(it);
            return;
        }

        it++;
    }

}
}