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

 *

 * GEOS - Geometry Engine Open Source

 * http://geos.osgeo.org

 *

 * Copyright (C) 2020 Paul Ramsey <pramsey@cleverelephant.ca>

 *

 * This is free software; you can redistribute and/or modify it under

 * the terms of the GNU Lesser General Public Licence as published

 * by the Free Software Foundation.

 * See the COPYING file for more information.

 *

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

#include <geos/geom/Coordinate.h>

#include <geos/triangulate/tri/Tri.h>

#include <geos/triangulate/tri/TriList.h>

#include <geos/triangulate/tri/TriangulationBuilder.h>

namespace geos {        // geos

namespace triangulate { // geos.triangulate

namespace tri {         // geos.triangulate.tri

/* public static */

void

TriangulationBuilder::build(TriList<Tri>& triList)

{

    TriangulationBuilder tb(triList);

}

/* private */

TriangulationBuilder::TriangulationBuilder(TriList<Tri>& triList)

{

    for (auto* tri : triList) {

        add(tri);

    }

}

/* private */

Tri*

TriangulationBuilder::find(const Coordinate& p0, const Coordinate& p1) const

{

    const TriEdge e(p0, p1);

    auto it = triMap.find(e);

    if (it == triMap.end()) {

        // not found

        return nullptr;

    }

    else {

        // found

        return it->second;

    }

}

/* private */

void

TriangulationBuilder::add(Tri* tri)

{

    const Coordinate& p0 = tri->getCoordinate(0);

    const Coordinate& p1 = tri->getCoordinate(1);

    const Coordinate& p2 = tri->getCoordinate(2);

    // get adjacent triangles, if any

    Tri* n0 = find(p0, p1);

    Tri* n1 = find(p1, p2);

    Tri* n2 = find(p2, p0);

    tri->setAdjacent(n0, n1, n2);

    addAdjacent(tri, n0, p0, p1);

    addAdjacent(tri, n1, p1, p2);

    addAdjacent(tri, n2, p2, p0);

}

/* private */

void

TriangulationBuilder::addAdjacent(Tri* tri, Tri* adj, const Coordinate& p0, const Coordinate& p1)

{

    /**

     * If adjacent is null, this tri is first one to be recorded for edge

     */

    if (adj == nullptr) {

        triMap.emplace(

            std::piecewise_construct,

            std::forward_as_tuple(p0, p1),

            std::forward_as_tuple(tri));

        // TriEdge e(p0, p1);

        // triMap.insert(std::make_pair(e, tri));

        return;

    }

    adj->setAdjacent(p1, tri);

}

} // namespace geos.triangulate.tri

} // namespace geos.triangulate

} // namespace geos