/**
 * Copyright (C) 2015 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/ftdc/collector.h"

#include "mongo/base/string_data.h"
#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/client.h"
#include "mongo/db/ftdc/constants.h"
#include "mongo/db/ftdc/util.h"
#include "mongo/db/jsobj.h"
#include "mongo/util/time_support.h"

namespace mongo {

void FTDCCollectorCollection::add(std::unique_ptr<FTDCCollectorInterface> collector) {
    // TODO: ensure the collectors all have unique names.
    _collectors.emplace_back(std::move(collector));
}

std::tuple<BSONObj, Date_t> FTDCCollectorCollection::collect(Client* client) {
    // If there are no collectors, just return an empty BSONObj so that that are caller knows we did
    // not collect anything
    if (_collectors.empty()) {
        return std::tuple<BSONObj, Date_t>(BSONObj(), Date_t());
    }

    BSONObjBuilder builder;

    Date_t start = client->getServiceContext()->getPreciseClockSource()->now();
    Date_t end;
    bool firstLoop = true;

    builder.appendDate(kFTDCCollectStartField, start);

    for (auto& collector : _collectors) {
        BSONObjBuilder subObjBuilder(builder.subobjStart(collector->name()));

        // Add a Date_t before and after each BSON is collected so that we can track timing of the
        // collector.
        Date_t now = start;

        if (!firstLoop) {
            now = client->getServiceContext()->getPreciseClockSource()->now();
        }

        firstLoop = false;

        subObjBuilder.appendDate(kFTDCCollectStartField, now);

        {
            // Create a operation context per command so that we do not share operation contexts
            // across multiple command invocations.
            auto txn = client->makeOperationContext();

            collector->collect(txn.get(), subObjBuilder);
        }

        end = client->getServiceContext()->getPreciseClockSource()->now();
        subObjBuilder.appendDate(kFTDCCollectEndField, end);
    }

    builder.appendDate(kFTDCCollectEndField, end);

    return std::tuple<BSONObj, Date_t>(builder.obj(), start);
}

}  // namespace mongo