/**
 *    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/views/resolved_view.h"

#include "mongo/base/init.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/pipeline/document_source_index_stats.h"
#include "mongo/db/pipeline/document_source_internal_convert_bucket_index_stats.h"
#include "mongo/db/pipeline/document_source_internal_unpack_bucket.h"
#include "mongo/db/timeseries/timeseries_constants.h"
#include "mongo/db/timeseries/timeseries_index_schema_conversion_functions.h"
#include "mongo/rpc/get_status_from_command_result.h"

namespace mongo {

MONGO_INIT_REGISTER_ERROR_EXTRA_INFO(ResolvedView);

ResolvedView ResolvedView::fromBSON(const BSONObj& commandResponseObj) {
    uassert(40248,
            "command response expected to have a 'resolvedView' field",
            commandResponseObj.hasField("resolvedView"));

    auto viewDef = commandResponseObj.getObjectField("resolvedView");
    uassert(40249, "resolvedView must be an object", !viewDef.isEmpty());

    uassert(40250,
            "View definition must have 'ns' field of type string",
            viewDef.hasField("ns") && viewDef.getField("ns").type() == BSONType::String);

    uassert(40251,
            "View definition must have 'pipeline' field of type array",
            viewDef.hasField("pipeline") && viewDef.getField("pipeline").type() == BSONType::Array);

    std::vector<BSONObj> pipeline;
    for (auto&& item : viewDef["pipeline"].Obj()) {
        pipeline.push_back(item.Obj().getOwned());
    }

    BSONObj collationSpec;
    if (auto collationElt = viewDef["collation"]) {
        uassert(40639,
                "View definition 'collation' field must be an object",
                collationElt.type() == BSONType::Object);
        collationSpec = collationElt.embeddedObject().getOwned();
    }

    boost::optional<TimeseriesOptions> timeseriesOptions = boost::none;
    if (auto tsOptionsElt = viewDef[kTimeseriesOptions]) {
        if (tsOptionsElt.isABSONObj()) {
            timeseriesOptions = TimeseriesOptions::parse(IDLParserContext{"ResolvedView::fromBSON"},
                                                         tsOptionsElt.Obj());
        }
    }

    boost::optional<bool> mixedSchema = boost::none;
    if (auto mixedSchemaElem = viewDef[kTimeseriesMayContainMixedData]) {
        uassert(6067204,
                str::stream() << "view definition must have " << kTimeseriesMayContainMixedData
                              << " of type bool or no such field",
                mixedSchemaElem.type() == BSONType::Bool);

        mixedSchema = boost::optional<bool>(mixedSchemaElem.boolean());
    }

    boost::optional<bool> usesExtendedRange = boost::none;
    if (auto usesExtendedRangeElem = viewDef[kTimeseriesUsesExtendedRange]) {
        uassert(6646910,
                str::stream() << "view definition must have " << kTimeseriesUsesExtendedRange
                              << " of type bool or no such field",
                usesExtendedRangeElem.type() == BSONType::Bool);

        usesExtendedRange = boost::optional<bool>(usesExtendedRangeElem.boolean());
    }

    return {NamespaceString(viewDef["ns"].valueStringData()),
            std::move(pipeline),
            std::move(collationSpec),
            std::move(timeseriesOptions),
            std::move(mixedSchema),
            std::move(usesExtendedRange)};
}

void ResolvedView::serialize(BSONObjBuilder* builder) const {
    BSONObjBuilder subObj(builder->subobjStart("resolvedView"));
    subObj.append("ns", _namespace.ns());
    subObj.append("pipeline", _pipeline);
    if (_timeseriesOptions) {
        BSONObjBuilder tsObj(builder->subobjStart(kTimeseriesOptions));
        _timeseriesOptions->serialize(&tsObj);
    }
    // Only serialize if it doesn't contain mixed data.
    if ((_timeseriesMayContainMixedData && !(*_timeseriesMayContainMixedData)))
        subObj.append(kTimeseriesMayContainMixedData, *_timeseriesMayContainMixedData);

    if ((_timeseriesUsesExtendedRange && (*_timeseriesUsesExtendedRange)))
        subObj.append(kTimeseriesUsesExtendedRange, *_timeseriesUsesExtendedRange);

    if (!_defaultCollation.isEmpty()) {
        subObj.append("collation", _defaultCollation);
    }
}

std::shared_ptr<const ErrorExtraInfo> ResolvedView::parse(const BSONObj& cmdReply) {
    return std::make_shared<ResolvedView>(fromBSON(cmdReply));
}

AggregateCommandRequest ResolvedView::asExpandedViewAggregation(
    const AggregateCommandRequest& request) const {
    // Perform the aggregation on the resolved namespace.  The new pipeline consists of two parts:
    // first, 'pipeline' in this ResolvedView; then, the pipeline in 'request'.
    std::vector<BSONObj> resolvedPipeline;
    resolvedPipeline.reserve(_pipeline.size() + request.getPipeline().size());
    resolvedPipeline.insert(resolvedPipeline.end(), _pipeline.begin(), _pipeline.end());
    resolvedPipeline.insert(
        resolvedPipeline.end(), request.getPipeline().begin(), request.getPipeline().end());

    // $indexStats needs special handling for time-series-collections. Normally for a regular read,
    // $_internalUnpackBucket unpacks the buckets entries into time-series document format and then
    // passes the time-series documents on through the pipeline. Instead we need to read the buckets
    // collection's index stats unmodified and then pass the results through an additional stage to
    // specially convert them to the time-series collection's schema, and then onward. There is no
    // need for the $_internalUnpackBucket stage with $indexStats, so we remove it.
    if (resolvedPipeline.size() >= 2 &&
        resolvedPipeline[0][DocumentSourceInternalUnpackBucket::kStageNameInternal] &&
        resolvedPipeline[1][DocumentSourceIndexStats::kStageName]) {
        // Clear the $_internalUnpackBucket stage.
        auto unpackStage = resolvedPipeline[0];
        resolvedPipeline[0] = resolvedPipeline[1];

        // Grab the $_internalUnpackBucket stage's time-series collection schema options and pass
        // them into the $_internalConvertBucketIndexStats stage to use for schema conversion.
        BSONObjBuilder builder;
        for (const auto& elem :
             unpackStage[DocumentSourceInternalUnpackBucket::kStageNameInternal].Obj()) {
            if (elem.fieldNameStringData() == timeseries::kTimeFieldName ||
                elem.fieldNameStringData() == timeseries::kMetaFieldName) {
                builder.append(elem);
            }
        }

        resolvedPipeline[1] =
            BSON(DocumentSourceInternalConvertBucketIndexStats::kStageName << builder.obj());
    } else if (resolvedPipeline.size() >= 1 &&
               resolvedPipeline[0][DocumentSourceInternalUnpackBucket::kStageNameInternal]) {
        auto unpackStage = resolvedPipeline[0];

        BSONObjBuilder builder;
        for (const auto& elem :
             unpackStage[DocumentSourceInternalUnpackBucket::kStageNameInternal].Obj()) {
            builder.append(elem);
        }
        builder.append(DocumentSourceInternalUnpackBucket::kAssumeNoMixedSchemaData,
                       ((_timeseriesMayContainMixedData && !(*_timeseriesMayContainMixedData))));

        builder.append(DocumentSourceInternalUnpackBucket::kUsesExtendedRange,
                       ((_timeseriesUsesExtendedRange && *_timeseriesUsesExtendedRange)));

        resolvedPipeline[0] =
            BSON(DocumentSourceInternalUnpackBucket::kStageNameInternal << builder.obj());
    }

    AggregateCommandRequest expandedRequest{_namespace, resolvedPipeline};

    if (request.getExplain()) {
        expandedRequest.setExplain(request.getExplain());
    } else {
        expandedRequest.setCursor(request.getCursor());
    }

    // If we have an index hint on a time-series view, we may need to rewrite the index spec to
    // match the index on the underlying buckets collection.
    if (request.getHint() && _timeseriesOptions) {
        BSONObj original = *request.getHint();
        BSONObj rewritten = original;
        // Only convert if we are given an index spec, not an index name or a $natural hint.
        if (timeseries::isHintIndexKey(original)) {
            auto converted = timeseries::createBucketsIndexSpecFromTimeseriesIndexSpec(
                *_timeseriesOptions, original);
            if (converted.isOK()) {
                rewritten = converted.getValue();
            }
        }
        expandedRequest.setHint(rewritten);
    } else {
        expandedRequest.setHint(request.getHint());
    }

    expandedRequest.setMaxTimeMS(request.getMaxTimeMS());
    expandedRequest.setReadConcern(request.getReadConcern());
    expandedRequest.setUnwrappedReadPref(request.getUnwrappedReadPref());
    expandedRequest.setBypassDocumentValidation(request.getBypassDocumentValidation());
    expandedRequest.setAllowDiskUse(request.getAllowDiskUse());
    expandedRequest.setIsMapReduceCommand(request.getIsMapReduceCommand());
    expandedRequest.setLet(request.getLet());

    // Operations on a view must always use the default collation of the view. We must have already
    // checked that if the user's request specifies a collation, it matches the collation of the
    // view.
    expandedRequest.setCollation(_defaultCollation);

    return expandedRequest;
}

}  // namespace mongo