/*
*    Copyright (C) 2012 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/disallow_copying.h"
#include "mongo/base/status.h"
#include "mongo/db/auth/role_name.h"
#include "mongo/db/auth/user_name.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/stdx/functional.h"

namespace mongo {

    class OperationContext;

    /**
     * Public interface for a class that encapsulates all the information related to system
     * state not stored in AuthorizationManager.  This is primarily to make AuthorizationManager
     * easier to test as well as to allow different implementations for mongos and mongod.
     */
    class AuthzManagerExternalState {
        MONGO_DISALLOW_COPYING(AuthzManagerExternalState);

    public:

        virtual ~AuthzManagerExternalState();

        /**
         * Initializes the external state object.  Must be called after construction and before
         * calling other methods.  Object may not be used after this method returns something other
         * than Status::OK().
         */
        virtual Status initialize() = 0;

        /**
         * Retrieves the schema version of the persistent data describing users and roles.
         * Will leave *outVersion unmodified on non-OK status return values.
         */
        virtual Status getStoredAuthorizationVersion(OperationContext* txn, int* outVersion) = 0;

        /**
         * Writes into "result" a document describing the named user and returns Status::OK().  The
         * description includes the user credentials, if present, the user's role membership and
         * delegation information, a full list of the user's privileges, and a full list of the
         * user's roles, including those roles held implicitly through other roles (indirect roles).
         * In the event that some of this information is inconsistent, the document will contain a
         * "warnings" array, with std::string messages describing inconsistencies.
         *
         * If the user does not exist, returns ErrorCodes::UserNotFound.
         */
        virtual Status getUserDescription(
                            OperationContext* txn, const UserName& userName, BSONObj* result) = 0;

        /**
         * Writes into "result" a document describing the named role and returns Status::OK().  The
         * description includes the roles in which the named role has membership and a full list of
         * the roles of which the named role is a member, including those roles memberships held
         * implicitly through other roles (indirect roles). If "showPrivileges" is true, then the
         * description documents will also include a full list of the role's privileges.
         * In the event that some of this information is inconsistent, the document will contain a
         * "warnings" array, with std::string messages describing inconsistencies.
         *
         * If the role does not exist, returns ErrorCodes::RoleNotFound.
         */
        virtual Status getRoleDescription(const RoleName& roleName,
                                          bool showPrivileges,
                                          BSONObj* result) = 0;

        /**
         * Writes into "result" documents describing the roles that are defined on the given
         * database. Each role description document includes the other roles in which the role has
         * membership and a full list of the roles of which the named role is a member,
         * including those roles memberships held implicitly through other roles (indirect roles).
         * If showPrivileges is true, then the description documents will also include a full list
         * of the role's privileges.  If showBuiltinRoles is true, then the result array will
         * contain description documents for all the builtin roles for the given database, if it
         * is false the result will just include user defined roles.
         * In the event that some of the information in a given role description is inconsistent,
         * the document will contain a "warnings" array, with std::string messages describing
         * inconsistencies.
         */
        virtual Status getRoleDescriptionsForDB(const std::string dbname,
                                                bool showPrivileges,
                                                bool showBuiltinRoles,
                                                std::vector<BSONObj>* result) = 0;

        /**
         * Returns true if there exists at least one privilege document in the system.
         */
        bool hasAnyPrivilegeDocuments(OperationContext* txn);

        /**
         * Creates the given user object in the given database.
         *
         * TODO(spencer): remove dbname argument once users are only written into the admin db
         */
        Status insertPrivilegeDocument(const std::string& dbname,
                                       const BSONObj& userObj,
                                       const BSONObj& writeConcern);

        /**
         * Updates the given user object with the given update modifier.
         */
        Status updatePrivilegeDocument(const UserName& user,
                                       const BSONObj& updateObj,
                                       const BSONObj& writeConcern);

        /**
         * Removes users for the given database matching the given query.
         * Writes into *numRemoved the number of user documents that were modified.
         */
        Status removePrivilegeDocuments(const BSONObj& query,
                                        const BSONObj& writeConcern,
                                        int* numRemoved);

        /**
         * Puts into the *dbnames vector the name of every database in the cluster.
         * May take a global lock, so should only be called during startup.
         */
        virtual Status getAllDatabaseNames(std::vector<std::string>* dbnames) = 0;

        /**
         * Finds a document matching "query" in "collectionName", and store a shared-ownership
         * copy into "result".
         *
         * Returns Status::OK() on success.  If no match is found, returns
         * ErrorCodes::NoMatchingDocument.  Other errors returned as appropriate.
         */
        virtual Status findOne(OperationContext* txn,
                               const NamespaceString& collectionName,
                               const BSONObj& query,
                               BSONObj* result) = 0;

        /**
         * Finds all documents matching "query" in "collectionName".  For each document returned,
         * calls the function resultProcessor on it.
         */
        virtual Status query(const NamespaceString& collectionName,
                             const BSONObj& query,
                             const BSONObj& projection,
                             const stdx::function<void(const BSONObj&)>& resultProcessor) = 0;

        /**
         * Inserts "document" into "collectionName".
         * If there is a duplicate key error, returns a Status with code DuplicateKey.
         */
        virtual Status insert(const NamespaceString& collectionName,
                              const BSONObj& document,
                              const BSONObj& writeConcern) = 0;

        /**
         * Update one document matching "query" according to "updatePattern" in "collectionName".
         *
         * If "upsert" is true and no document matches "query", inserts one using "query" as a
         * template.
         * If "upsert" is false and no document matches "query", return a Status with the code
         * NoMatchingDocument.  The Status message in that case is not very descriptive and should
         * not be displayed to the end user.
         */
        virtual Status updateOne(const NamespaceString& collectionName,
                                 const BSONObj& query,
                                 const BSONObj& updatePattern,
                                 bool upsert,
                                 const BSONObj& writeConcern);

        /**
         * Updates documents matching "query" according to "updatePattern" in "collectionName".
         */
        virtual Status update(const NamespaceString& collectionName,
                              const BSONObj& query,
                              const BSONObj& updatePattern,
                              bool upsert,
                              bool multi,
                              const BSONObj& writeConcern,
                              int* nMatched) = 0;

        /**
         * Removes all documents matching "query" from "collectionName".
         */
        virtual Status remove(const NamespaceString& collectionName,
                              const BSONObj& query,
                              const BSONObj& writeConcern,
                              int* numRemoved) = 0;

        /**
         * Creates an index with the given pattern on "collectionName".
         */
        virtual Status createIndex(const NamespaceString& collectionName,
                                   const BSONObj& pattern,
                                   bool unique,
                                   const BSONObj& writeConcern) = 0;

        /**
         * Drops indexes other than the _id index on "collectionName".
         */
        virtual Status dropIndexes(const NamespaceString& collectionName,
                                   const BSONObj& writeConcern) = 0;

        /**
         * Tries to acquire the global lock guarding modifications to all persistent data related
         * to authorization, namely the admin.system.users, admin.system.roles, and
         * admin.system.version collections.  This serializes all writers to the authorization
         * documents, but does not impact readers.
         */
        virtual bool tryAcquireAuthzUpdateLock(const StringData& why) = 0;

        /**
         * Releases the lock guarding modifications to persistent authorization data, which must
         * already be held.
         */
        virtual void releaseAuthzUpdateLock() = 0;

        virtual void logOp(
                const char* op,
                const char* ns,
                const BSONObj& o,
                BSONObj* o2,
                bool* b) {}


    protected:
        AuthzManagerExternalState(); // This class should never be instantiated directly.

        static const long long _authzUpdateLockAcquisitionTimeoutMillis = 5000;
    };

} // namespace mongo