/**
 * Copyright (C) 2017 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/bson/bsonobj.h"
#include "mongo/db/logical_session_id_helpers.h"
#include "mongo/db/matcher/expression_parser.h"
#include "mongo/db/matcher/extensions_callback_noop.h"
#include "mongo/db/pipeline/document_source_list_sessions.h"
#include "mongo/db/pipeline/document_source_list_sessions_gen.h"

namespace mongo {

const char* DocumentSourceListSessions::kStageName = "$listSessions";

REGISTER_DOCUMENT_SOURCE(listSessions,
                         DocumentSourceListSessions::LiteParsed::parse,
                         DocumentSourceListSessions::createFromBson);

boost::intrusive_ptr<DocumentSource> DocumentSourceListSessions::createFromBson(
    BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& pExpCtx) {
    const NamespaceString& nss = pExpCtx->ns;

    uassert(ErrorCodes::InvalidNamespace,
            str::stream() << kStageName << " may only be run against "
                          << NamespaceString::kLogicalSessionsNamespace.ns(),
            nss == NamespaceString::kLogicalSessionsNamespace);

    const auto& spec = listSessionsParseSpec(kStageName, elem);
    if (spec.getAllUsers()) {
        // No filtration. optimize() should later skip us.
        return new DocumentSourceListSessions(BSONObj(), pExpCtx, spec);
    }
    invariant(spec.getUsers() && !spec.getUsers()->empty());

    BSONArrayBuilder builder;
    for (const auto& uid : listSessionsUsersToDigests(spec.getUsers().get())) {
        ConstDataRange cdr = uid.toCDR();
        builder.append(BSONBinData(cdr.data(), cdr.length(), BinDataGeneral));
    }
    const auto& query = BSON("_id.uid" << BSON("$in" << builder.arr()));
    return new DocumentSourceListSessions(query, pExpCtx, spec);
}

}  // namespace mongo