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

#pragma once

#include "mongo/db/commands.h"
#include "mongo/db/query/plan_cache.h"

namespace mongo {

/**
 * DB commands for plan cache.
 * These are in a header to facilitate unit testing. See plan_cache_commands_test.cpp.
 */

/**
 * PlanCacheCommand
 * Defines common attributes for all plan cache related commands
 * such as slaveOk.
 */
class PlanCacheCommand : public Command {
public:
    PlanCacheCommand(const std::string& name, const std::string& helpText, ActionType actionType);

    /**
     * Entry point from command subsystem.
     * Implementation provides standardization of error handling
     * such as adding error code and message to BSON result.
     *
     * Do not override in derived classes.
     * Override runPlanCacheCommands instead to
     * implement plan cache command functionality.
     */

    bool run(OperationContext* txn,
             const std::string& dbname,
             BSONObj& cmdObj,
             int options,
             std::string& errmsg,
             BSONObjBuilder& result);

    virtual bool supportsWriteConcern(const BSONObj& cmd) const override;

    virtual bool slaveOk() const;

    virtual bool slaveOverrideOk() const;

    virtual void help(std::stringstream& ss) const;

    /**
     * Two action types defined for plan cache commands:
     * - planCacheRead
     * - planCacheWrite
     */
    virtual Status checkAuthForCommand(Client* client,
                                       const std::string& dbname,
                                       const BSONObj& cmdObj);
    /**
     * Subset of command arguments used by plan cache commands
     * Override to provide command functionality.
     * Should contain just enough logic to invoke run*Command() function
     * in plan_cache.h
     */
    virtual Status runPlanCacheCommand(OperationContext* txn,
                                       const std::string& ns,
                                       BSONObj& cmdObj,
                                       BSONObjBuilder* bob) = 0;

    /**
     * Validatess query shape from command object and returns canonical query.
     */
    static StatusWith<std::unique_ptr<CanonicalQuery>> canonicalize(OperationContext* txn,
                                                                    const std::string& ns,
                                                                    const BSONObj& cmdObj);

private:
    std::string helpText;
    ActionType actionType;
};

/**
 * planCacheListQueryShapes
 *
 * { planCacheListQueryShapes: <collection> }
 *
 */
class PlanCacheListQueryShapes : public PlanCacheCommand {
public:
    PlanCacheListQueryShapes();
    virtual Status runPlanCacheCommand(OperationContext* txn,
                                       const std::string& ns,
                                       BSONObj& cmdObj,
                                       BSONObjBuilder* bob);

    /**
     * Looks up cache keys for collection's plan cache.
     * Inserts keys for query into BSON builder.
     */
    static Status list(const PlanCache& planCache, BSONObjBuilder* bob);
};

/**
 * planCacheClear
 *
 * {
 *     planCacheClear: <collection>,
 *     query: <query>,
 *     sort: <sort>,
 *     projection: <projection>
 * }
 *
 */
class PlanCacheClear : public PlanCacheCommand {
public:
    PlanCacheClear();
    virtual Status runPlanCacheCommand(OperationContext* txn,
                                       const std::string& ns,
                                       BSONObj& cmdObj,
                                       BSONObjBuilder* bob);

    /**
     * Clears collection's plan cache.
     * If query shape is provided, clears plans for that single query shape only.
     */
    static Status clear(OperationContext* txn,
                        PlanCache* planCache,
                        const std::string& ns,
                        const BSONObj& cmdObj);
};

/**
 * planCacheListPlans
 *
 * {
 *     planCacheListPlans: <collection>,
 *     query: <query>,
 *     sort: <sort>,
 *     projection: <projection>
 * }
 *
 */
class PlanCacheListPlans : public PlanCacheCommand {
public:
    PlanCacheListPlans();
    virtual Status runPlanCacheCommand(OperationContext* txn,
                                       const std::string& ns,
                                       BSONObj& cmdObj,
                                       BSONObjBuilder* bob);

    /**
     * Displays the cached plans for a query shape.
     */
    static Status list(OperationContext* txn,
                       const PlanCache& planCache,
                       const std::string& ns,
                       const BSONObj& cmdObj,
                       BSONObjBuilder* bob);
};

}  // namespace mongo
