/**
 * \file
 * \author Karsten Rink
 * \date   2010-11-01
 * \brief  Implementation of the MeshLayerMapper class.
 *
 * \copyright
 * Copyright (c) 2012-2021, OpenGeoSys Community (http://www.opengeosys.org)
 *            Distributed under a Modified BSD License.
 *              See accompanying file LICENSE.txt or
 *              http://www.opengeosys.org/project/license
 *
 */

#include "MeshLayerMapper.h"

#include <algorithm>

#include "BaseLib/Logging.h"

#include "GeoLib/Raster.h"

#include "MathLib/MathTools.h"

#include "MeshLib/Elements/Tet.h"
#include "MeshLib/Elements/Hex.h"
#include "MeshLib/Elements/Pyramid.h"
#include "MeshLib/Elements/Prism.h"
#include "MeshLib/MeshSurfaceExtraction.h"
#include "MeshLib/Properties.h"

namespace MeshLib
{

MeshLib::Mesh* MeshLayerMapper::createStaticLayers(MeshLib::Mesh const& mesh, std::vector<float> const& layer_thickness_vector, std::string const& mesh_name)
{
    std::vector<float> thickness;
    for (std::size_t i = 0; i < layer_thickness_vector.size(); ++i)
    {
        if (layer_thickness_vector[i] > std::numeric_limits<float>::epsilon())
        {
            thickness.push_back(layer_thickness_vector[i]);
        }
        else
        {
            WARN("Ignoring layer {:d} with thickness {:f}.", i,
                 layer_thickness_vector[i]);
        }
    }

    const std::size_t nLayers(thickness.size());
    if (nLayers < 1 || mesh.getDimension() != 2)
    {
        ERR("MeshLayerMapper::createStaticLayers(): A 2D mesh with nLayers > 0 is required as input.");
        return nullptr;
    }

    const std::size_t nNodes = mesh.getNumberOfNodes();
    // count number of 2d elements in the original mesh
    const std::size_t nElems (std::count_if(mesh.getElements().begin(), mesh.getElements().end(),
            [](MeshLib::Element const* elem) { return (elem->getDimension() == 2);}));

    const std::size_t nOrgElems (mesh.getNumberOfElements());
    const std::vector<MeshLib::Node*> &nodes = mesh.getNodes();
    const std::vector<MeshLib::Element*> &elems = mesh.getElements();
    std::vector<MeshLib::Node*> new_nodes(nNodes + (nLayers * nNodes));
    std::vector<MeshLib::Element*> new_elems;
    new_elems.reserve(nElems * nLayers);
    MeshLib::Properties properties;
    auto* const materials = properties.createNewPropertyVector<int>(
        "MaterialIDs", MeshLib::MeshItemType::Cell);
    if (!materials)
    {
        ERR("Could not create PropertyVector object 'MaterialIDs'.");
        return nullptr;
    }

    materials->reserve(nElems * nLayers);
    double z_offset (0.0);

    for (unsigned layer_id = 0; layer_id <= nLayers; ++layer_id)
    {
        // add nodes for new layer
        unsigned node_offset (nNodes * layer_id);
        if (layer_id > 0)
        {
            z_offset += thickness[layer_id - 1];
        }

        std::transform(nodes.cbegin(), nodes.cend(), new_nodes.begin() + node_offset,
            [&z_offset](MeshLib::Node* node){ return new MeshLib::Node((*node)[0], (*node)[1], (*node)[2]-z_offset); });

        // starting with 2nd layer create prism or hex elements connecting the last layer with the current one
        if (layer_id == 0)
        {
            continue;
        }

        node_offset -= nNodes;
        const unsigned mat_id (nLayers - layer_id);

        for (unsigned i = 0; i < nOrgElems; ++i)
        {
            const MeshLib::Element* sfc_elem( elems[i] );
            if (sfc_elem->getDimension() < 2)
            {  // ignore line-elements
                continue;
            }

            const unsigned nElemNodes(sfc_elem->getNumberOfBaseNodes());
            auto** e_nodes = new MeshLib::Node*[2 * nElemNodes];

            for (unsigned j=0; j<nElemNodes; ++j)
            {
                const unsigned node_id = sfc_elem->getNode(j)->getID() + node_offset;
                e_nodes[j] = new_nodes[node_id+nNodes];
                e_nodes[j+nElemNodes] = new_nodes[node_id];
            }
            if (sfc_elem->getGeomType() == MeshLib::MeshElemType::TRIANGLE)
            {
                // extrude triangles to prism
                new_elems.push_back(new MeshLib::Prism(e_nodes));
            }
            else if (sfc_elem->getGeomType() == MeshLib::MeshElemType::QUAD)
            {
                // extrude quads to hexes
                new_elems.push_back(new MeshLib::Hex(e_nodes));
            }
            else
            {
                OGS_FATAL("MeshLayerMapper: Unknown element type to extrude.");
            }
            materials->push_back(mat_id);
        }
    }
    return new MeshLib::Mesh(mesh_name, new_nodes, new_elems, properties);
}

bool MeshLayerMapper::createRasterLayers(
    MeshLib::Mesh const& mesh,
    std::vector<GeoLib::Raster const*> const& rasters,
    double minimum_thickness,
    double noDataReplacementValue)
{
    const std::size_t nLayers(rasters.size());
    if (nLayers < 2 || mesh.getDimension() != 2)
    {
        ERR("MeshLayerMapper::createRasterLayers(): A 2D mesh and at least two rasters required as input.");
        return false;
    }

    auto top = std::make_unique<MeshLib::Mesh>(mesh);
    if (!layerMapping(*top, *rasters.back(), noDataReplacementValue))
    {
        return false;
    }

    auto bottom = std::make_unique<MeshLib::Mesh>(mesh);
    if (!layerMapping(*bottom, *rasters[0], 0))
    {
        return false;
    }

    this->_minimum_thickness = minimum_thickness;
    std::size_t const nNodes = mesh.getNumberOfNodes();
    _nodes.reserve(nLayers * nNodes);

    // number of triangles in the original mesh
    std::size_t const nElems (std::count_if(mesh.getElements().begin(), mesh.getElements().end(),
        [](MeshLib::Element const* elem)
            { return (elem->getGeomType() == MeshLib::MeshElemType::TRIANGLE);}));
    _elements.reserve(nElems * (nLayers-1));
    _materials.reserve(nElems *  (nLayers-1));

    // add bottom layer
    std::vector<MeshLib::Node*> const& nodes = bottom->getNodes();
    std::transform(nodes.begin(), nodes.end(), std::back_inserter(_nodes),
                   [](auto const* node) { return new MeshLib::Node(*node); });

    // add the other layers
    for (std::size_t i = 0; i < nLayers - 1; ++i)
    {
        addLayerToMesh(*top, i, *rasters[i + 1]);
    }

    return true;
}

void MeshLayerMapper::addLayerToMesh(const MeshLib::Mesh &dem_mesh, unsigned layer_id, GeoLib::Raster const& raster)
{
    const unsigned pyramid_base[3][4] =
    {
        {1, 3, 4, 2}, // Point 4 missing
        {2, 4, 3, 0}, // Point 5 missing
        {0, 3, 4, 1}, // Point 6 missing
    };

    std::size_t const nNodes = dem_mesh.getNumberOfNodes();
    std::vector<MeshLib::Node*> const& nodes = dem_mesh.getNodes();
    int const last_layer_node_offset = layer_id * nNodes;

    // add nodes for new layer
    for (std::size_t i = 0; i < nNodes; ++i)
    {
        _nodes.push_back(getNewLayerNode(*nodes[i],
                                         *_nodes[last_layer_node_offset + i],
                                         raster, _nodes.size()));
    }

    std::vector<MeshLib::Element*> const& elems = dem_mesh.getElements();
    std::size_t const nElems (dem_mesh.getNumberOfElements());

    for (std::size_t i=0; i<nElems; ++i)
    {
        MeshLib::Element* elem (elems[i]);
        if (elem->getGeomType() != MeshLib::MeshElemType::TRIANGLE)
        {
            continue;
        }
        unsigned node_counter(3);
        unsigned missing_idx(0);
        std::array<MeshLib::Node*, 6> new_elem_nodes{};
        for (unsigned j=0; j<3; ++j)
        {
            new_elem_nodes[j] = _nodes[_nodes[last_layer_node_offset + elem->getNodeIndex(j)]->getID()];
            new_elem_nodes[node_counter] = (_nodes[last_layer_node_offset + elem->getNodeIndex(j) + nNodes]);
            if (new_elem_nodes[j]->getID() !=
                new_elem_nodes[node_counter]->getID())
            {
                node_counter++;
            }
            else
            {
                missing_idx = j;
            }
        }

        switch (node_counter)
        {
        case 6:
            _elements.push_back(new MeshLib::Prism(new_elem_nodes));
            _materials.push_back(layer_id);
            break;
        case 5:
        {
            std::array<MeshLib::Node*, 5> pyramid_nodes;
            pyramid_nodes[0] = new_elem_nodes[pyramid_base[missing_idx][0]];
            pyramid_nodes[1] = new_elem_nodes[pyramid_base[missing_idx][1]];
            pyramid_nodes[2] = new_elem_nodes[pyramid_base[missing_idx][2]];
            pyramid_nodes[3] = new_elem_nodes[pyramid_base[missing_idx][3]];
            pyramid_nodes[4] = new_elem_nodes[missing_idx];
            _elements.push_back(new MeshLib::Pyramid(pyramid_nodes));
            _materials.push_back(layer_id);
            break;
        }
        case 4:
        {
            std::array<MeshLib::Node*, 4> tet_nodes;
            std::copy(new_elem_nodes.begin(), new_elem_nodes.begin() + node_counter, tet_nodes.begin());
            _elements.push_back(new MeshLib::Tet(tet_nodes));
            _materials.push_back(layer_id);
            break;
        }
        default:
            continue;
        }
    }
}

bool MeshLayerMapper::layerMapping(MeshLib::Mesh const& mesh,
                                   GeoLib::Raster const& raster,
                                   double const nodata_replacement,
                                   bool const ignore_nodata)
{

    if (mesh.getDimension() != 2)
    {
        ERR("MshLayerMapper::layerMapping() - requires 2D mesh");
        return false;
    }

    GeoLib::RasterHeader const& header (raster.getHeader());
    const double x0(header.origin[0]);
    const double y0(header.origin[1]);
    const double delta(header.cell_size);

    const std::pair<double, double> xDim(x0, x0 + header.n_cols * delta); // extension in x-dimension
    const std::pair<double, double> yDim(y0, y0 + header.n_rows * delta); // extension in y-dimension

    const std::size_t nNodes (mesh.getNumberOfNodes());
    const std::vector<MeshLib::Node*> &nodes = mesh.getNodes();
    for (unsigned i = 0; i < nNodes; ++i)
    {
        if (!ignore_nodata && !raster.isPntOnRaster(*nodes[i]))
        {
            // use either default value or elevation from layer above
            nodes[i]->updateCoordinates((*nodes[i])[0], (*nodes[i])[1],
                                        nodata_replacement);
            continue;
        }

        double elevation (raster.getValueAtPoint(*nodes[i]));
        constexpr double eps = std::numeric_limits<double>::epsilon();
        if (std::abs(elevation - header.no_data) < eps)
        {
            if (ignore_nodata)
            {
                continue;
            }
            elevation = nodata_replacement;
        }
        else
        {
            elevation = raster.interpolateValueAtPoint(*nodes[i]);
        }
        nodes[i]->updateCoordinates((*nodes[i])[0], (*nodes[i])[1], elevation);
    }

    return true;
}

bool MeshLayerMapper::mapToStaticValue(MeshLib::Mesh const& mesh,
                                       double const value)
{
    if (mesh.getDimension() != 2)
    {
        ERR("MshLayerMapper::mapToStaticValue() - requires 2D mesh");
        return false;
    }

    std::vector<MeshLib::Node*> const& nodes (mesh.getNodes());
    for (MeshLib::Node* node : nodes)
    {
        node->updateCoordinates((*node)[0], (*node)[1], value);
    }
    return true;
}

} // end namespace MeshLib