/**
 * 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/db/update/current_date_node.h"

#include "mongo/db/logical_clock.h"
#include "mongo/db/logical_time.h"
#include "mongo/db/service_context.h"

namespace mongo {

namespace {
constexpr StringData kType = "$type"_sd;
constexpr StringData kDate = "date"_sd;
constexpr StringData kTimestamp = "timestamp"_sd;

void setValue(mutablebson::Element* element, bool typeIsDate) {
    if (typeIsDate) {
        invariantOK(element->setValueDate(mongo::jsTime()));
    } else {
        invariantOK(element->setValueTimestamp(
            LogicalClock::get(getGlobalServiceContext())->reserveTicks(1).asTimestamp()));
    }
}
}  // namespace

Status CurrentDateNode::init(BSONElement modExpr,
                             const boost::intrusive_ptr<ExpressionContext>& expCtx) {
    invariant(modExpr.ok());

    if (modExpr.type() == BSONType::Bool) {
        _typeIsDate = true;
    } else if (modExpr.type() == BSONType::Object) {
        auto foundValidType = false;
        for (auto&& elem : modExpr.Obj()) {
            if (elem.fieldNameStringData() == kType) {
                if (elem.type() == BSONType::String) {
                    if (elem.valueStringData() == kDate) {
                        _typeIsDate = true;
                        foundValidType = true;
                    } else if (elem.valueStringData() == kTimestamp) {
                        _typeIsDate = false;
                        foundValidType = true;
                    }
                }
            } else {
                return Status(ErrorCodes::BadValue,
                              str::stream() << "Unrecognized $currentDate option: "
                                            << elem.fieldNameStringData());
            }
        }

        if (!foundValidType) {
            return Status(ErrorCodes::BadValue,
                          "The '$type' string field is required "
                          "to be 'date' or 'timestamp': "
                          "{$currentDate: {field : {$type: 'date'}}}");
        }
    } else {
        return Status(ErrorCodes::BadValue,
                      str::stream() << typeName(modExpr.type())
                                    << " is not valid type for $currentDate."
                                       " Please use a boolean ('true')"
                                       " or a $type expression ({$type: 'timestamp/date'}).");
    }

    return Status::OK();
}

ModifierNode::ModifyResult CurrentDateNode::updateExistingElement(
    mutablebson::Element* element, std::shared_ptr<FieldRef> elementPath) const {
    setValue(element, _typeIsDate);
    return ModifyResult::kNormalUpdate;
}

void CurrentDateNode::setValueForNewElement(mutablebson::Element* element) const {
    setValue(element, _typeIsDate);
}

}  // namespace mongo
