/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
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/>.

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

#include "attachDetach.H"
#include "polyMesh.H"
#include "primitiveMesh.H"
#include "polyTopoChange.H"
#include "polyTopoChanger.H"
#include "polyAddPoint.H"
#include "polyModifyFace.H"
#include "polyAddFace.H"

// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

void Foam::attachDetach::detachInterface
(
    polyTopoChange& ref
) const
{
    // Algorithm:
    // 1. Create new points for points of the master face zone
    // 2. Modify all faces of the master zone, by putting them into the master
    //    patch (look for orientation) and their renumbered mirror images
    //    into the slave patch
    // 3. Create a point renumbering list, giving a new point index for original
    //    points in the face patch
    // 4. Grab all faces in cells on the master side and renumber them
    //    using the point renumbering list.  Exclude the ones that belong to
    //    the master face zone
    //
    // Note on point creation:
    // In order to take into account the issues related to partial
    // blocking in an attach/detach mesh modifier, special treatment
    // is required for the duplication of points on the edge of the
    // face zone.  Points which are shared only by internal edges need
    // not to be duplicated, as this would propagate the discontinuity
    // in the mesh beyond the face zone.  Therefore, before creating
    // the new points, check the external edge loop.  For each edge
    // check if the edge is internal (i.e. does not belong to a
    // patch); if so, exclude both of its points from duplication.

    if (debug)
    {
        Pout<< "void attachDetach::detachInterface("
            << "polyTopoChange& ref) const "
            << " for object " << name() << " : "
            << "Detaching interface" << endl;
    }

    const polyMesh& mesh = topoChanger().mesh();
    const faceZoneMesh& zoneMesh = mesh.faceZones();

    // Check that zone is in increasing order (needed since adding faces
    // in same order - otherwise polyTopoChange face ordering will mess up
    // correspondence)
    if (debug)
    {
        const labelList& faceLabels = zoneMesh[faceZoneID_.index()];
        if (faceLabels.size() > 0)
        {
            for (label i = 1; i < faceLabels.size(); i++)
            {
                if (faceLabels[i] <= faceLabels[i-1])
                {
                    FatalErrorIn
                    (
                        "attachDetach::detachInterface"
                        "(polyTopoChange&) const"
                    )   << "faceZone " << zoneMesh[faceZoneID_.index()].name()
                        << " does not have mesh face labels in"
                        << " increasing order." << endl
                        << "Face label " << faceLabels[i]
                        << " at position " << i
                        << " is smaller than the previous value "
                        << faceLabels[i-1]
                        << exit(FatalError);
                }
            }
        }
    }



    const primitiveFacePatch& masterFaceLayer = zoneMesh[faceZoneID_.index()]();
    const pointField& points = mesh.points();
    const labelListList& meshEdgeFaces = mesh.edgeFaces();

    const labelList& mp = masterFaceLayer.meshPoints();
    const edgeList& zoneLocalEdges = masterFaceLayer.edges();

    const labelList& meshEdges = zoneMesh[faceZoneID_.index()].meshEdges();

    // Create the points

    labelList addedPoints(mp.size(), -1);

    // Go through boundary edges of the master patch.  If all the faces from
    // this patch are internal, mark the points in the addedPoints lookup
    // with their original labels to stop duplication
    label nIntEdges = masterFaceLayer.nInternalEdges();

    for (label curEdgeID = nIntEdges; curEdgeID < meshEdges.size(); curEdgeID++)
    {
        const labelList& curFaces = meshEdgeFaces[meshEdges[curEdgeID]];

        bool edgeIsInternal = true;

        forAll(curFaces, faceI)
        {
            if (!mesh.isInternalFace(curFaces[faceI]))
            {
                // The edge belongs to a boundary face
                edgeIsInternal = false;
                break;
            }
        }

        if (edgeIsInternal)
        {
            const edge& e = zoneLocalEdges[curEdgeID];

            // Reset the point creation
            addedPoints[e.start()] = mp[e.start()];
            addedPoints[e.end()] = mp[e.end()];
        }
    }
// Pout<< "addedPoints before point creation: " << addedPoints << endl;

    // Create new points for face zone
    forAll(addedPoints, pointI)
    {
        if (addedPoints[pointI] < 0)
        {
            addedPoints[pointI] =
                ref.setAction
                (
                    polyAddPoint
                    (
                        points[mp[pointI]],        // point
                        mp[pointI],                // master point
                        -1,                        // zone ID
                        true                       // supports a cell
                    )
                );
            //Pout<< "Adding point " << addedPoints[pointI]
            //    << " coord1:" << points[mp[pointI]]
            //    << " coord2:" << masterFaceLayer.localPoints()[pointI]
            //    << " for original point " << mp[pointI] << endl;
        }
    }

    // Modify faces in the master zone and duplicate for the slave zone

    const labelList& mf = zoneMesh[faceZoneID_.index()];
    const boolList& mfFlip = zoneMesh[faceZoneID_.index()].flipMap();
    const faceList& zoneFaces = masterFaceLayer.localFaces();

    const faceList& faces = mesh.faces();
    const labelList& own = mesh.faceOwner();
    const labelList& nei = mesh.faceNeighbour();

    forAll(mf, faceI)
    {
        const label curFaceID = mf[faceI];

        // Build the face for the slave patch by renumbering
        const face oldFace = zoneFaces[faceI].reverseFace();

        face newFace(oldFace.size());

        forAll(oldFace, pointI)
        {
            newFace[pointI] = addedPoints[oldFace[pointI]];
        }

        if (mfFlip[faceI])
        {
            // Face needs to be flipped for the master patch
            ref.setAction
            (
                polyModifyFace
                (
                    faces[curFaceID].reverseFace(), // modified face
                    curFaceID,                   // label of face being modified
                    nei[curFaceID],                 // owner
                    -1,                             // neighbour
                    true,                           // face flip
                    masterPatchID_.index(),         // patch for face
                    false,                          // remove from zone
                    faceZoneID_.index(),            // zone for face
                    !mfFlip[faceI]                  // face flip in zone
                )
            );

            // Add renumbered face into the slave patch
            //label addedFaceI =
            ref.setAction
            (
                polyAddFace
                (
                    newFace,                        // face
                    own[curFaceID],                 // owner
                    -1,                             // neighbour
                    -1,                             // master point
                    -1,                             // master edge
                    curFaceID,                      // master face
                    false,                          // flip flux
                    slavePatchID_.index(),          // patch to add the face to
                    -1,                             // zone for face
                    false                           // zone flip
                )
            );
            //{
            //    pointField newPts(ref.points());
            //Pout<< "Flip.  Modifying face: " << ref.faces()[curFaceID]
            //    << " fc:" <<  ref.faces()[curFaceID].centre(newPts)
            //    << " next to cell: " << nei[curFaceID]
            //    << " and adding face: " << newFace
            //    << " fc:" << ref.faces()[addedFaceI].centre(newPts)
            //    << " next to cell: " << own[curFaceID] << endl;
            //}
        }
        else
        {
            // No flip
            ref.setAction
            (
                polyModifyFace
                (
                    faces[curFaceID],         // modified face
                    curFaceID,                // label of face being modified
                    own[curFaceID],           // owner
                    -1,                       // neighbour
                    false,                    // face flip
                    masterPatchID_.index(),   // patch for face
                    false,                    // remove from zone
                    faceZoneID_.index(),      // zone for face
                    mfFlip[faceI]             // face flip in zone
                )
            );

            // Add renumbered face into the slave patch
            //label addedFaceI =
            ref.setAction
            (
                polyAddFace
                (
                    newFace,                        // face
                    nei[curFaceID],                 // owner
                    -1,                             // neighbour
                    -1,                             // master point
                    -1,                             // master edge
                    curFaceID,                      // master face
                    true,                           // flip flux
                    slavePatchID_.index(),          // patch to add the face to
                    -1,                             // zone for face
                    false                           // face flip in zone
                )
            );
            //{
            //    pointField newPts(ref.points());
            //Pout<< "No flip.  Modifying face: " << ref.faces()[curFaceID]
            //    << " fc:" <<  ref.faces()[curFaceID].centre(newPts)
            //    << " next to cell: " << own[curFaceID]
            //    << " and adding face: " << newFace
            //    << " fc:" << ref.faces()[addedFaceI].centre(newPts)
            //    << " next to cell: " << nei[curFaceID] << endl;
            //}
        }
    }

    // Modify the remaining faces of the master cells to reconnect to the new
    // layer of faces.

    // Algorithm: Go through all the cells of the master zone and make
    // a map of faces to avoid duplicates.  Do not insert the faces in
    // the master patch (as they have already been dealt with).  Make
    // a master layer point renumbering map, which for every point in
    // the master layer gives its new label. Loop through all faces in
    // the map and attempt to renumber them using the master layer
    // point renumbering map.  Once the face is renumbered, compare it
    // with the original face; if they are the same, the face has not
    // changed; if not, modify the face but keep all of its old
    // attributes (apart from the vertex numbers).

    // Create the map of faces in the master cell layer
    const labelList& mc =
        mesh.faceZones()[faceZoneID_.index()].masterCells();

    labelHashSet masterCellFaceMap(6*mc.size());

    const cellList& cells = mesh.cells();

    forAll(mc, cellI)
    {
        const labelList& curFaces = cells[mc[cellI]];

        forAll(curFaces, faceI)
        {
            // Check if the face belongs to the master patch; if not add it
            if (zoneMesh.whichZone(curFaces[faceI]) != faceZoneID_.index())
            {
                masterCellFaceMap.insert(curFaces[faceI]);
            }
        }
    }

    // Extend the map to include first neighbours of the master cells to
    // deal with multiple corners.
    { // Protection and memory management
        // Make a map of master cells for quick reject
        labelHashSet mcMap(2*mc.size());

        forAll(mc, mcI)
        {
            mcMap.insert(mc[mcI]);
        }

        // Go through all the faces in the masterCellFaceMap.  If the
        // cells around them are not already used, add all of their
        // faces to the map
        const labelList mcf = masterCellFaceMap.toc();

        forAll(mcf, mcfI)
        {
            // Do the owner side
            const label ownCell = own[mcf[mcfI]];

            if (!mcMap.found(ownCell))
            {
                // Cell not found. Add its faces to the map
                const cell& curFaces = cells[ownCell];

                forAll(curFaces, faceI)
                {
                    masterCellFaceMap.insert(curFaces[faceI]);
                }
            }

            // Do the neighbour side if face is internal
            if (mesh.isInternalFace(mcf[mcfI]))
            {
                const label neiCell = nei[mcf[mcfI]];

                if (!mcMap.found(neiCell))
                {
                    // Cell not found. Add its faces to the map
                    const cell& curFaces = cells[neiCell];

                    forAll(curFaces, faceI)
                    {
                        masterCellFaceMap.insert(curFaces[faceI]);
                    }
                }
            }
        }
    }

    // Create the master layer point map
    Map<label> masterLayerPointMap(2*mp.size());

    forAll(mp, pointI)
    {
        masterLayerPointMap.insert
        (
            mp[pointI],
            addedPoints[pointI]
        );
    }

    // Grab the list of faces of the master layer
    const labelList masterCellFaces = masterCellFaceMap.toc();

    forAll(masterCellFaces, faceI)
    {
        // Attempt to renumber the face using the masterLayerPointMap.
        // Missing point remain the same

        const label curFaceID = masterCellFaces[faceI];

        const face& oldFace = faces[curFaceID];

        face newFace(oldFace.size());

        bool changed = false;

        forAll(oldFace, pointI)
        {
            if (masterLayerPointMap.found(oldFace[pointI]))
            {
                changed = true;

                newFace[pointI] = masterLayerPointMap.find(oldFace[pointI])();
            }
            else
            {
                newFace[pointI] = oldFace[pointI];
            }
        }

        // If the face has changed, create a modification entry
        if (changed)
        {
            if (mesh.isInternalFace(curFaceID))
            {
                ref.setAction
                (
                    polyModifyFace
                    (
                        newFace,                    // face
                        curFaceID,                  // master face
                        own[curFaceID],             // owner
                        nei[curFaceID],             // neighbour
                        false,                      // flip flux
                        -1,                         // patch for face
                        false,                      // remove from zone
                        -1,                         // zone for face
                        false                       // face zone flip
                    )
                );

                // Pout<< "modifying stick-out face. Internal Old face: "
                //     << oldFace
                //     << " new face: " << newFace
                //     << " own: " << own[curFaceID]
                //     << " nei: " << nei[curFaceID]
                //     << endl;
            }
            else
            {
                ref.setAction
                (
                    polyModifyFace
                    (
                        newFace,                     // face
                        curFaceID,                   // master face
                        own[curFaceID],              // owner
                        -1,                          // neighbour
                        false,                       // flip flux
                        mesh.boundaryMesh().whichPatch(curFaceID), // patch
                        false,                        // remove from zone
                        -1,                           // zone for face
                        false                         // face zone flip
                    )
                );

                // Pout<< "modifying stick-out face. Boundary Old face: "
                //     << oldFace
                //     << " new face: " << newFace
                //     << " own: " << own[curFaceID]
                //     << " patch: "
                //     << mesh.boundaryMesh().whichPatch(curFaceID)
                //     << endl;
            }
        }
    }

    if (debug)
    {
        Pout<< "void attachDetach::detachInterface("
            << "polyTopoChange& ref) const "
            << " for object " << name() << " : "
            << "Finished detaching interface" << endl;
    }
}


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