/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  dev
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// In the case system/blockMeshDict, set the following variables:

/*
    nBlades         4;      // Number of rotor blades

    rHub            0.005;  // Radius of the hub
    rTip            0.02;   // Radius of the blade tips
    rFreestream     0.1;    // Radius of the freestream boundary

    halfDepth       0.005;  // Half-depth of the 2-D slab

    nCellsHubTip    6;      // Number of cells radially from hub to blade tip
    nCellsTipFreestream 24; // Number of cells radially from blade tip to the
                            // freestream boundary
    nCellsBladeBlade 24;    // Number of cells tangentially between blades
*/

// Then #include this file:

/*
    #include "$FOAM_TUTORIALS/resources/blockMesh/rotor2D"
*/

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

vertices #codeStream
{
    codeInclude
    #{
        #include "pointField.H"
        #include "SubField.H"
        #include "transformField.H"
    #};

    code
    #{
        // Get the radii. Note using $<scalar>rHub instead of $rHub means that
        // rHub can change without needing to recompile this code. The same is
        // true for access of other settings throughout this file.
        const scalarField rs
        ({
            $<scalar>rHub,
            $<scalar>rHub,
            $<scalar>rTip,
            $<scalar>rFreestream
        });

        // Create points for the blade aligned with the X-axis
        pointField points(4, point(0, 0, -$<scalar>halfDepth));
        points.replace(0, -rs);

        // Create equivalent points for other blades by rotating
        for (label i = 1; i < $<label>nBlades; i ++)
        {
            points.append
            (
                transform
                (
                    Rz(degToRad(i*360/scalar($<label>nBlades))),
                    SubField<point>(points, 4)
                )
            );
        }

        // Add the points on the other side of the slab
        points.append(points + vector(0, 0, 2*$<scalar>halfDepth));

        // Write out
        os  << points;
    #};
};

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

blocks
(
    #codeStream
    {
        codeInclude
        #{
            #include "labelField.H"
        #};

        code
        #{
            const label viN = 4*$<label>nBlades;

            auto makeBlock = [&]
            (
                const label v0,
                const label v1,
                const label v2,
                const label v3,
                const label nCellsRadial
            )
            {
                labelList vs({v0%viN, v1%viN, v2%viN, v3%viN});
                vs.append(labelField(vs) + viN);
                os  << "hex " << vs << " all "
                    << Vector<label>(nCellsRadial, $<label>nCellsBladeBlade, 1)
                    << " simpleGrading " << Vector<label>(1, 1, 1) << nl;
            };

            for (label i = 0; i < $<label>nBlades; i ++)
            {
                const label vi0 = i*4;
                makeBlock(vi0+1, vi0+2, vi0+6, vi0+4, $<label>nCellsHubTip);
                makeBlock(vi0+2, vi0+3, vi0+7, vi0+6, $<label>nCellsTipFreestream);
            }
        #};
    }
);

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

edges
(
    #codeStream
    {
        code
        #{
            const label viN = 4*$<label>nBlades;

            auto makeArc = [&](const label v0, const label v1)
            {
                for (label i = 0; i < 2; ++ i)
                {
                    os  << "arc " << v0%viN + i*viN << ' ' << v1%viN + i*viN << ' '
                        << 360/scalar($<label>nBlades) << ' ' << vector(0, 0, 1) << nl;
                }
            };

            for (label i = 0; i < $<label>nBlades; i ++)
            {
                const label vi0 = i*4;
                makeArc(vi0+1, vi0+4);
                makeArc(vi0+2, vi0+6);
                makeArc(vi0+3, vi0+7);
            }
        #};
    }
);

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

defaultPatch
{
    name frontAndBack;
    type empty;
}

boundary
(
    rotor
    {
        type wall;
        faces
        (
            #codeStream
            {
                code
                #{
                    const label viN = 4*$<label>nBlades;

                    auto makeFace = [&](const label v0, const label v1)
                    {
                        os  << labelList({v0%viN, v1%viN, v1%viN+viN, v0%viN+viN});
                    };

                    for (label i = 0; i < $<label>nBlades; i ++)
                    {
                        const label vi0 = i*4;
                        makeFace(vi0+2, vi0+1);
                        makeFace(vi0+1, vi0+4);
                        makeFace(vi0+4, vi0+6);
                    }
                #};
            }
        );
    }

    freestream
    {
        type wall;
        faces
        (
            #codeStream
            {
                code
                #{
                    const label viN = 4*$<label>nBlades;

                    auto makeFace = [&](const label v0, const label v1)
                    {
                        os  << labelList({v0%viN, v1%viN, v1%viN+viN, v0%viN+viN});
                    };

                    for (label i = 0; i < $<label>nBlades; i ++)
                    {
                        const label vi0 = i*4;
                        makeFace(vi0+3, vi0+7);
                    }
                #};
            }
        );
    }
);

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