/**
 *    Copyright (C) 2014 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    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 Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/service_context.h"

#include "mongo/bson/bsonobj.h"
#include "mongo/db/client.h"
#include "mongo/db/operation_context.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/mongoutils/str.h"

namespace mongo {

    namespace {

        ServiceContext* globalServiceContext = NULL;

    } // namespace

    bool hasGlobalServiceContext() { return globalServiceContext; }

    ServiceContext* getGlobalServiceContext() {
        fassert(17508, globalServiceContext);
        return globalServiceContext;
    }

    void setGlobalServiceContext(std::unique_ptr<ServiceContext>&& serviceContext) {
        fassert(17509, serviceContext.get());

        delete globalServiceContext;

        globalServiceContext = serviceContext.release();
    }

    bool _supportsDocLocking = false;

    bool supportsDocLocking() {
        return _supportsDocLocking;
    }

    bool isMMAPV1() {
        StorageEngine* globalStorageEngine = getGlobalServiceContext()->getGlobalStorageEngine();

        invariant(globalStorageEngine);
        return globalStorageEngine->isMmapV1();
    }

    Status validateStorageOptions(const BSONObj& storageEngineOptions,
       stdx::function<Status (const StorageEngine::Factory* const, const BSONObj&)> validateFunc) {

        BSONObjIterator storageIt(storageEngineOptions);
        while (storageIt.more()) {
            BSONElement storageElement = storageIt.next();
            StringData storageEngineName = storageElement.fieldNameStringData();
            if (storageElement.type() != mongo::Object) {
                return Status(ErrorCodes::BadValue, str::stream()
                    << "'storageEngine." << storageElement.fieldNameStringData()
                    << "' has to be an embedded document.");
            }

            boost::scoped_ptr<StorageFactoriesIterator> sfi(getGlobalServiceContext()->
                                                            makeStorageFactoriesIterator());
            invariant(sfi);
            bool found = false;
            while (sfi->more()) {
                const StorageEngine::Factory* const& factory = sfi->next();
                if (storageEngineName != factory->getCanonicalName()) {
                    continue;
                }
                Status status = validateFunc(factory, storageElement.Obj());
                if ( !status.isOK() ) {
                    return status;
                }
                found = true;
            }
            if (!found) {
                return Status(ErrorCodes::InvalidOptions, str::stream() << storageEngineName <<
                              " is not a registered storage engine for this server");
            }
        }
        return Status::OK();
    }

    ServiceContext::~ServiceContext() {
        boost::lock_guard<boost::mutex> lk(_mutex);
        invariant(_clients.empty());
    }

    ServiceContext::UniqueClient ServiceContext::makeClient(std::string desc,
                                                            AbstractMessagingPort* p) {
        std::unique_ptr<Client> client(new Client(std::move(desc), this, p));
        auto observer = _clientObservers.cbegin();
        try {
            for (; observer != _clientObservers.cend(); ++observer) {
                observer->get()->onCreateClient(this, client.get());
            }
        }
        catch (...) {
            try {
                while (observer != _clientObservers.cbegin()) {
                    --observer;
                    observer->get()->onDestroyClient(this, client.get());
                }
            }
            catch (...) {
                std::terminate();
            }
            throw;
        }
        {
            boost::lock_guard<boost::mutex> lk(_mutex);
            invariant(_clients.insert(client.get()).second);
        }
        return UniqueClient(client.release());
    }

    void ServiceContext::ClientDeleter::operator()(Client* client) const {
        ServiceContext* const service = client->getServiceContext();
        {
            boost::lock_guard<boost::mutex> lk(service->_mutex);
            invariant(service->_clients.erase(client));
        }
        try {
            for (const auto& observer : service->_clientObservers) {
                observer->onDestroyClient(service, client);
            }
        }
        catch (...) {
            std::terminate();
        }
        delete client;
    }

    void ServiceContext::registerClientObserver(std::unique_ptr<ClientObserver> observer) {
        _clientObservers.push_back(std::move(observer));
    }

    ServiceContext::LockedClientsCursor::LockedClientsCursor(ServiceContext* service)
        : _lock(service->_mutex),
          _curr(service->_clients.cbegin()),
          _end(service->_clients.cend()) {}

    Client* ServiceContext::LockedClientsCursor::next() {
        if (_curr == _end)
            return nullptr;
        Client* result = *_curr;
        ++_curr;
        return result;
    }

}  // namespace mongo