/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2012-2016 OpenFOAM Foundation
     \\/     M anipulation  | Copyright (C) 2015-2016 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM 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 General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Class
    Foam::functionObjects::fieldValues::fieldValueDelta

Group
    grpFieldFunctionObjects

Description
    Provides an operation between two 'field value' function objects.

    The operation is applied to all results of each fieldValue object.
    Accordingly, each object must generate the same number and type of results.

Usage
    Example of function object specification:
    \verbatim
    fieldValueDelta1
    {
        type            fieldValueDelta;
        libs            ("libfieldFunctionObjects.so");
        operation       subtract;

        region1
        {
            ...
        }
        region2
        {
            ...
        }
    }
    \endverbatim

    Where the entries comprise:
    \table
        Property     | Description             | Required    | Default value
        type         | type name: fieldValueDelta   | yes    |
    \endtable

    The \c operation is one of:
    \plaintable
       add           | add
       subtract      | subtract
       min           | minimum
       max           | maximum
       average       | average
    \endplaintable

See also
    Foam::functionObject
    Foam::functionObjects::fieldValue
    Foam::functionObjects::regionFunctionObject
    Foam::functionObjects::writeFile

SourceFiles
    fieldValueDelta.C

\*---------------------------------------------------------------------------*/

#ifndef functionObjects_fieldValueDelta_H
#define functionObjects_fieldValueDelta_H

#include "stateFunctionObject.H"
#include "writeFile.H"
#include "fieldValue.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{
namespace functionObjects
{
namespace fieldValues
{

/*---------------------------------------------------------------------------*\
                       Class fieldValueDelta Declaration
\*---------------------------------------------------------------------------*/

class fieldValueDelta
:
    public fvMeshFunctionObject,
    public writeFile
{
public:
        //- Operation type enumeration
        enum operationType
        {
            opAdd,              //!< Add
            opSubtract,         //!< Subtract
            opMin,              //!< Minimum
            opMax,              //!< Maximum
            opAverage           //!< Average
        };

        //- Operation type names
        static const NamedEnum<operationType, 5> operationTypeNames_;


private:

    // Private data

        //- Operation to apply to values
        operationType operation_;

        //- Field value region object 1
        autoPtr<fieldValue> region1Ptr_;

        //- Field value region object 2
        autoPtr<fieldValue> region2Ptr_;


    // Private Member Functions

        //- Templated function to apply the operation
        template<class Type>
        void applyOperation
        (
            const word& resultType,
            const word& name1,
            const word& name2,
            const word& entryName1,
            const word& entryName2,
            bool& found
        );


protected:

    // Protected Member Functions

        //- Output file header information
        virtual void writeFileHeader(Ostream& os) const;


public:

    //- Run-time type information
    TypeName("fieldValueDelta");


    // Constructors

        //- Construct from Time and dictionary
        fieldValueDelta
        (
            const word& name,
            const Time& runTime,
            const dictionary& dict
        );


    //- Destructor
    virtual ~fieldValueDelta();


    // Public Member Functions

        //- Read from dictionary
        virtual bool read(const dictionary&);

        //- Do nothing
        virtual bool execute();

        //- Calculate and write
        virtual bool write();
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace fieldValues
} // End namespace functionObjects
} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#ifdef NoRepository
    #include "fieldValueDeltaTemplates.C"
#endif

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //