/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    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 Server Side 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/pipeline/document_source_internal_split_pipeline.h"

namespace mongo {

REGISTER_DOCUMENT_SOURCE(_internalSplitPipeline,
                         LiteParsedDocumentSourceDefault::parse,
                         DocumentSourceInternalSplitPipeline::createFromBson,
                         AllowedWithApiStrict::kNeverInVersion1);

constexpr StringData DocumentSourceInternalSplitPipeline::kStageName;

boost::intrusive_ptr<DocumentSource> DocumentSourceInternalSplitPipeline::createFromBson(
    BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
    uassert(ErrorCodes::TypeMismatch,
            str::stream() << "$_internalSplitPipeline must take a nested object but found: "
                          << elem,
            elem.type() == BSONType::Object);

    auto specObj = elem.embeddedObject();

    HostTypeRequirement mergeType = HostTypeRequirement::kNone;

    for (auto&& elt : specObj) {
        if (elt.fieldNameStringData() == "mergeType"_sd) {
            uassert(ErrorCodes::BadValue,
                    str::stream() << "'mergeType' must be a string value but found: " << elt.type(),
                    elt.type() == BSONType::String);

            auto mergeTypeString = elt.valueStringData();

            if ("localOnly"_sd == mergeTypeString) {
                mergeType = HostTypeRequirement::kLocalOnly;
            } else if ("anyShard"_sd == mergeTypeString) {
                mergeType = HostTypeRequirement::kAnyShard;
            } else if ("primaryShard"_sd == mergeTypeString) {
                mergeType = HostTypeRequirement::kPrimaryShard;
            } else if ("mongos"_sd == mergeTypeString) {
                mergeType = HostTypeRequirement::kMongoS;
            } else {
                uasserted(ErrorCodes::BadValue,
                          str::stream() << "unrecognized field while parsing mergeType: '"
                                        << elt.fieldNameStringData() << "'");
            }
        } else {
            uasserted(ErrorCodes::BadValue,
                      str::stream() << "unrecognized field while parsing $_internalSplitPipeline: '"
                                    << elt.fieldNameStringData() << "'");
        }
    }

    return new DocumentSourceInternalSplitPipeline(expCtx, mergeType);
}

DocumentSource::GetNextResult DocumentSourceInternalSplitPipeline::doGetNext() {
    return pSource->getNext();
}

Value DocumentSourceInternalSplitPipeline::serialize(
    boost::optional<ExplainOptions::Verbosity> explain) const {
    std::string mergeTypeString;

    switch (_mergeType) {
        case HostTypeRequirement::kAnyShard:
            mergeTypeString = "anyShard";
            break;

        case HostTypeRequirement::kPrimaryShard:
            mergeTypeString = "primaryShard";
            break;

        case HostTypeRequirement::kLocalOnly:
            mergeTypeString = "localOnly";
            break;

        case HostTypeRequirement::kMongoS:
            mergeTypeString = "mongos";
            break;

        case HostTypeRequirement::kNone:
        default:
            break;
    }

    return Value(
        Document{{getSourceName(),
                  Value{Document{{"mergeType",
                                  mergeTypeString.empty() ? Value() : Value(mergeTypeString)}}}}});
}

}  // namespace mongo