/**
 *    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 "mongo/base/disallow_copying.h"
#include "mongo/base/string_data.h"
#include "mongo/db/jsobj.h"

namespace mongo {

/**
 * This class represents the layout and contents of documents contained in the
 * config.version collection. All manipulation of documents coming from that
 * collection should be done with this class.
 *
 * Usage Example:
 *
 *     // Contact the config. 'conn' has been obtained before.
 *     DBClientBase* conn;
 *     BSONObj query = QUERY(VersionType::exampleField("exampleFieldName"));
 *     exampleDoc = conn->findOne(VersionType::ConfigNS, query);
 *
 *     // Process the response.
 *     VersionType exampleType;
 *     std::string errMsg;
 *     if (!exampleType.parseBSON(exampleDoc, &errMsg) || !exampleType.isValid(&errMsg)) {
 *         // Can't use 'exampleType'. Take action.
 *     }
 *     // use 'exampleType'
 *
 */
class VersionType {
    MONGO_DISALLOW_COPYING(VersionType);

public:
    //
    // schema declarations
    //

    // Name of the version collection in the config server.
    static const std::string ConfigNS;

    // Field names and types in the version collection type.
    static const BSONField<int> minCompatibleVersion;
    static const BSONField<int> currentVersion;
    static const BSONField<BSONArray> excludingMongoVersions;
    static const BSONField<OID> clusterId;
    static const BSONField<OID> upgradeId;
    static const BSONField<BSONObj> upgradeState;

    //
    // version type methods
    //

    VersionType();
    ~VersionType();

    /**
     * Returns true if all the mandatory fields are present and have valid
     * representations. Otherwise returns false and fills in the optional 'errMsg' string.
     */
    bool isValid(std::string* errMsg) const;

    /**
     * Returns the BSON representation of the entry.
     */
    BSONObj toBSON() const;

    /**
     * Clears and populates the internal state using the 'source' BSON object if the
     * latter contains valid values. Otherwise sets errMsg and returns false.
     */
    bool parseBSON(const BSONObj& source, std::string* errMsg);

    /**
     * Clears the internal state.
     */
    void clear();

    /**
     * Copies all the fields present in 'this' to 'other'.
     */
    void cloneTo(VersionType* other) const;

    /**
     * Returns a std::string representation of the current internal state.
     */
    std::string toString() const;

    //
    // individual field accessors
    //

    // Mandatory Fields
    void setMinCompatibleVersion(const int minCompatibleVersion) {
        _minCompatibleVersion = minCompatibleVersion;
        _isMinCompatibleVersionSet = true;
    }

    void unsetMinCompatibleVersion() {
        _isMinCompatibleVersionSet = false;
    }

    bool isMinCompatibleVersionSet() const {
        return _isMinCompatibleVersionSet;
    }

    // Calling get*() methods when the member is not set results in undefined behavior
    int getMinCompatibleVersion() const {
        dassert(_isMinCompatibleVersionSet);
        return _minCompatibleVersion;
    }

    void setCurrentVersion(const int currentVersion) {
        _currentVersion = currentVersion;
        _isCurrentVersionSet = true;
    }

    void unsetCurrentVersion() {
        _isCurrentVersionSet = false;
    }

    bool isCurrentVersionSet() const {
        return _isCurrentVersionSet;
    }

    // Calling get*() methods when the member is not set results in undefined behavior
    int getCurrentVersion() const {
        dassert(_isCurrentVersionSet);
        return _currentVersion;
    }

    void setExcludingMongoVersions(const BSONArray& excludingMongoVersions) {
        _excludingMongoVersions = excludingMongoVersions;
        _isExcludingMongoVersionsSet = true;
    }

    void unsetExcludingMongoVersions() {
        _isExcludingMongoVersionsSet = false;
    }

    bool isExcludingMongoVersionsSet() const {
        return _isExcludingMongoVersionsSet || excludingMongoVersions.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    const BSONArray getExcludingMongoVersions() const {
        if (_isExcludingMongoVersionsSet) {
            return _excludingMongoVersions;
        } else {
            dassert(excludingMongoVersions.hasDefault());
            return excludingMongoVersions.getDefault();
        }
    }

    void setClusterId(const OID clusterId) {
        _clusterId = clusterId;
        _isClusterIdSet = true;
    }

    void unsetClusterId() {
        _isClusterIdSet = false;
    }

    bool isClusterIdSet() const {
        return _isClusterIdSet;
    }

    // Calling get*() methods when the member is not set results in undefined behavior
    const OID getClusterId() const {
        dassert(_isClusterIdSet);
        return _clusterId;
    }

    // Optional Fields
    void setUpgradeId(OID upgradeId) {
        _upgradeId = upgradeId;
        _isUpgradeIdSet = true;
    }

    void unsetUpgradeId() {
        _isUpgradeIdSet = false;
    }

    bool isUpgradeIdSet() const {
        return _isUpgradeIdSet || upgradeId.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    OID getUpgradeId() const {
        if (_isUpgradeIdSet) {
            return _upgradeId;
        } else {
            dassert(upgradeId.hasDefault());
            return upgradeId.getDefault();
        }
    }
    void setUpgradeState(const BSONObj& upgradeState) {
        _upgradeState = upgradeState.getOwned();
        _isUpgradeStateSet = true;
    }

    void unsetUpgradeState() {
        _isUpgradeStateSet = false;
    }

    bool isUpgradeStateSet() const {
        return _isUpgradeStateSet || upgradeState.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    BSONObj getUpgradeState() const {
        if (_isUpgradeStateSet) {
            return _upgradeState;
        } else {
            dassert(upgradeState.hasDefault());
            return upgradeState.getDefault();
        }
    }

private:
    // Convention: (M)andatory, (O)ptional, (S)pecial rule.
    int _minCompatibleVersion;  // (M)  minimum compatible version
    bool _isMinCompatibleVersionSet;
    int _currentVersion;  // (M)  current version
    bool _isCurrentVersionSet;
    BSONArray _excludingMongoVersions;  // (O)  range of disallowed versions to upgrade to
    bool _isExcludingMongoVersionsSet;
    OID _clusterId;  // (M)  clusterId
    bool _isClusterIdSet;
    OID _upgradeId;  // (O)  upgrade id of current or last upgrade
    bool _isUpgradeIdSet;
    BSONObj _upgradeState;  // (O)  upgrade state of current or last upgrade
    bool _isUpgradeStateSet;
};

}  // namespace mongo
