/**
 *    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.locks 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(LocksType::exampleField("exampleFieldName"));
 *     exampleDoc = conn->findOne(LocksType::ConfigNS, query);
 *
 *     // Process the response.
 *     LocksType exampleType;
 *     std::string errMsg;
 *     if (!exampleType.parseBSON(exampleDoc, &errMsg) || !exampleType.isValid(&errMsg)) {
 *         // Can't use 'exampleType'. Take action.
 *     }
 *     // use 'exampleType'
 *
 */
class LocksType {
    MONGO_DISALLOW_COPYING(LocksType);

public:
    //
    // schema declarations
    //

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

    // Field names and types in the locks collection type.
    static const BSONField<std::string> name;
    static const BSONField<int> state;
    static const BSONField<std::string> process;
    static const BSONField<OID> lockID;
    static const BSONField<std::string> who;
    static const BSONField<std::string> why;

    //
    // locks type methods
    //

    LocksType();
    ~LocksType();

    /**
     * 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(LocksType* other) const;

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

    //
    // individual field accessors
    //

    // Mandatory Fields
    void setName(const StringData& name) {
        _name = name.toString();
        _isNameSet = true;
    }

    void unsetName() {
        _isNameSet = false;
    }

    bool isNameSet() const {
        return _isNameSet;
    }

    // Calling get*() methods when the member is not set results in undefined behavior
    const std::string getName() const {
        dassert(_isNameSet);
        return _name;
    }

    void setState(const int state) {
        _state = state;
        _isStateSet = true;
    }

    void unsetState() {
        _isStateSet = false;
    }

    bool isStateSet() const {
        return _isStateSet;
    }

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

    // Optional Fields
    void setProcess(StringData& process) {
        _process = process.toString();
        _isProcessSet = true;
    }

    void unsetProcess() {
        _isProcessSet = false;
    }

    bool isProcessSet() const {
        return _isProcessSet || process.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    std::string getProcess() const {
        if (_isProcessSet) {
            return _process;
        } else {
            dassert(process.hasDefault());
            return process.getDefault();
        }
    }
    void setLockID(OID lockID) {
        _lockID = lockID;
        _isLockIDSet = true;
    }

    void unsetLockID() {
        _isLockIDSet = false;
    }

    bool isLockIDSet() const {
        return _isLockIDSet || lockID.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    OID getLockID() const {
        if (_isLockIDSet) {
            return _lockID;
        } else {
            dassert(lockID.hasDefault());
            return lockID.getDefault();
        }
    }
    void setWho(StringData& who) {
        _who = who.toString();
        _isWhoSet = true;
    }

    void unsetWho() {
        _isWhoSet = false;
    }

    bool isWhoSet() const {
        return _isWhoSet || who.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    std::string getWho() const {
        if (_isWhoSet) {
            return _who;
        } else {
            dassert(who.hasDefault());
            return who.getDefault();
        }
    }
    void setWhy(StringData& why) {
        _why = why.toString();
        _isWhySet = true;
    }

    void unsetWhy() {
        _isWhySet = false;
    }

    bool isWhySet() const {
        return _isWhySet || why.hasDefault();
    }

    // Calling get*() methods when the member is not set and has no default results in undefined
    // behavior
    std::string getWhy() const {
        if (_isWhySet) {
            return _why;
        } else {
            dassert(why.hasDefault());
            return why.getDefault();
        }
    }

private:
    // Convention: (M)andatory, (O)ptional, (S)pecial rule.
    std::string _name;  // (M)  name of the lock
    bool _isNameSet;
    int _state;  // (M)  0: Unlocked | 1: Locks in contention | 2: Lock held
    bool _isStateSet;
    std::string _process;  // (O)  optional if unlocked.  contains the (unique) identifier
    bool _isProcessSet;
    OID _lockID;  // (O)  optional if unlocked.  a unique identifier for the instance
    bool _isLockIDSet;
    std::string _who;  // (O)  optional if unlocked.  a note about why the lock is held,
    bool _isWhoSet;
    std::string _why;  // (O)  optional if unlocked.  a human readable description of the
    bool _isWhySet;
};

}  // namespace mongo
