/**
 *    Copyright (C) 2016 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.
 */

#pragma once

#include <cstdint>
#include <initializer_list>
#include <memory>

#include "mongo/db/jsobj.h"
#include "mongo/db/operation_context_noop.h"
#include "mongo/db/record_id.h"
#include "mongo/db/service_context.h"
#include "mongo/db/storage/sorted_data_interface.h"
#include "mongo/stdx/functional.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/unowned_ptr.h"

namespace mongo {

/**
 * Sets up an OperationContext with a Recovery Unit. Uses a ServiceContextNoop.
 *
 * A particular HarnessHelper implementation will implement registerHarnessHelperFactory() and
 * newHarnessHelper() such that generic unit tests can create and test that particular
 * HarnessHelper implementation. The newRecoveryUnit() implementation dictates what RecoveryUnit
 * implementation the OperationContext has.
 */
class HarnessHelper {
public:
    virtual ~HarnessHelper();

    explicit HarnessHelper();

    virtual ServiceContext::UniqueOperationContext newOperationContext(Client* const client) {
        auto opCtx = client->makeOperationContext();
        opCtx->setRecoveryUnit(newRecoveryUnit(),
                               WriteUnitOfWork::RecoveryUnitState::kNotInUnitOfWork);
        return opCtx;
    }

    virtual ServiceContext::UniqueOperationContext newOperationContext() {
        return newOperationContext(client());
    }

    Client* client() const {
        return Client::getCurrent();
    }

    ServiceContext* serviceContext() {
        return getGlobalServiceContext();
    }

    const ServiceContext* serviceContext() const {
        return getGlobalServiceContext();
    }

    virtual std::unique_ptr<RecoveryUnit> newRecoveryUnit() = 0;
};

namespace harness_helper_detail {
template <typename Target, typename Current>
std::unique_ptr<Target> noexcept_ptr_conversion(std::unique_ptr<Current>&& p, Target& t) noexcept {
    p.release();
    return std::unique_ptr<Target>(std::addressof(t));
}
}  // namespace harness_helper_detail

extern void registerHarnessHelperFactory(stdx::function<std::unique_ptr<HarnessHelper>()> factory);

template <typename Target, typename Current>
std::unique_ptr<Target> dynamic_ptr_cast(std::unique_ptr<Current>&& p) {
    if (!p) {
        throw std::runtime_error("Must not be null.");
    }
    Target& target = dynamic_cast<Target&>(*p);
    return harness_helper_detail::noexcept_ptr_conversion(std::move(p), target);
}

std::unique_ptr<HarnessHelper> newHarnessHelper();
}  // namespace mongo