/**
 *    Copyright (C) 2013 10gen 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.
 */

#pragma once

#include <string>
#include <vector>

#include "mongo/base/owned_pointer_vector.h"
#include "mongo/base/status.h"
#include "mongo/bson/mutable/document.h"
#include "mongo/db/field_ref_set.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/ops/modifier_interface.h"
#include "mongo/db/ops/modifier_table.h"
#include "mongo/db/query/canonical_query.h"
#include "mongo/db/update_index_data.h"

namespace mongo {

    class UpdateDriver {
    public:

        struct Options;
        UpdateDriver(const Options& opts);

        ~UpdateDriver();

        /**
         * Returns OK and fills in '_mods' if 'updateExpr' is correct. Otherwise returns an
         * error status with a corresponding description.
         */
        Status parse(const BSONObj& updateExpr, const bool multi = false);

        /**
         * Fills in document with any fields in the query which are valid.
         *
         * Valid fields include equality matches like "a":1, or "a.b":false
         *
         * Each valid field will be expanded (from dot notation) and conflicts will be
         * checked for all fields added to the underlying document.
         *
         * Returns Status::OK() if the document can be used. If there are any error or
         * conflicts along the way then those errors will be returned.
         */
        Status populateDocumentWithQueryFields(const BSONObj& query,
                                               mutablebson::Document& doc) const;

        Status populateDocumentWithQueryFields(const CanonicalQuery* query,
                                               mutablebson::Document& doc) const;

        /**
         * return a BSONObj with the _id field of the doc passed in, or the doc itself.
         * If no _id and multi, error.
         */
        BSONObj makeOplogEntryQuery(const BSONObj& doc, bool multi) const;

        /**
         * Returns OK and executes '_mods' over 'doc', generating 'newObj'. If any mod is
         * positional, use 'matchedField' (index of the array item matched). If doc allows
         * mods to be applied in place and no index updating is involved, then the mods may
         * be applied "in place" over 'doc'.
         *
         * If the driver's '_logOp' mode is turned on, and if 'logOpRec' is not NULL, fills in
         * the latter with the oplog entry corresponding to the update. If '_mods' can't be
         * applied, returns an error status with a corresponding description.
         *
         * If a non-NULL updatedField vector* is supplied,
         * then all updated fields will be added to it.
         */
        Status update(const StringData& matchedField,
                      mutablebson::Document* doc,
                      BSONObj* logOpRec = NULL,
                      FieldRefSet* updatedFields = NULL);

        //
        // Accessors
        //

        size_t numMods() const;

        bool isDocReplacement() const;

        bool modsAffectIndices() const;
        void refreshIndexKeys(const UpdateIndexData* indexedFields);

        bool logOp() const;
        void setLogOp(bool logOp);

        ModifierInterface::Options modOptions() const;
        void setModOptions(ModifierInterface::Options modOpts);

        ModifierInterface::ExecInfo::UpdateContext context() const;
        void setContext(ModifierInterface::ExecInfo::UpdateContext context);

        mutablebson::Document& getDocument() {
            return _objDoc;
        }

        const mutablebson::Document& getDocument() const {
            return _objDoc;
        }

        bool needMatchDetails() const {
            return _positional;
        }

    private:

        /** Resets the state of the class associated with mods (not the error state) */
        void clear();

        /** Create the modifier and add it to the back of the modifiers vector */
        inline Status addAndParse(const modifiertable::ModifierType type,
                                  const BSONElement& elem);

        //
        // immutable properties after parsing
        //

        // Is there a list of $mod's on '_mods' or is it just full object replacement?
        bool _replacementMode;

        // Collection of update mod instances. Owned here.
        vector<ModifierInterface*> _mods;

        // What are the list of fields in the collection over which the update is going to be
        // applied that participate in indices?
        //
        // NOTE: Owned by the collection's info cache!.
        const UpdateIndexData* _indexedFields;

        //
        // mutable properties after parsing
        //

        // Should this driver generate an oplog record when it applies the update?
        bool _logOp;

        // The options to initiate the mods with
        ModifierInterface::Options _modOptions;

        // Are any of the fields mentioned in the mods participating in any index? Is set anew
        // at each call to update.
        bool _affectIndices;

        // Do any of the mods require positional match details when calling 'prepare'?
        bool _positional;

        // Is this update going to be an upsert?
        ModifierInterface::ExecInfo::UpdateContext _context;

        // The document used to represent or store the object being updated.
        mutablebson::Document _objDoc;

        // The document used to build the oplog entry for the update.
        mutablebson::Document _logDoc;
    };

    struct UpdateDriver::Options {
        bool logOp;
        ModifierInterface::Options modOptions;

        Options() : logOp(false), modOptions() {}
    };

} // namespace mongo
