/**
 * \file
 * \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
 *
 * File:   DeactivatedSubdomain.cpp
 *
 * Created on November 29, 2018, 10:50 AM
 */
#include "DeactivatedSubdomain.h"

#include "BaseLib/ConfigTree.h"
#include "BaseLib/Error.h"
#include "MeshLib/Elements/Element.h"
#include "MeshLib/Mesh.h"
#include "MeshLib/MeshEditing/DuplicateMeshComponents.h"
#include "MeshLib/Node.h"

namespace ProcessLib
{
const std::string DeactivatedSubdomain::zero_parameter_name =
    "zero_for_element_deactivation_approach";

DeactivatedSubdomainMesh::DeactivatedSubdomainMesh(
    std::unique_ptr<MeshLib::Mesh> deactivated_subdomain_mesh_,
    std::vector<MeshLib::Node*>&& inner_nodes_)
    : mesh(std::move(deactivated_subdomain_mesh_)),
      inner_nodes(std::move(inner_nodes_))
{
}

DeactivatedSubdomain::DeactivatedSubdomain(
    BaseLib::TimeInterval const& time_interval_,
    std::vector<int>&& materialIDs_,
    std::vector<std::unique_ptr<DeactivatedSubdomainMesh>>&&
        deactivated_subdomain_meshes_)
    : time_interval(time_interval_),
      materialIDs(std::move(materialIDs_)),
      deactivated_subdomain_meshes(std::move(deactivated_subdomain_meshes_))
{
}

bool DeactivatedSubdomain::includesTimeOf(double const t) const
{
    return time_interval.contains(t);
}

template <typename IsActive>
static std::vector<MeshLib::Node*> extractInnerNodes(
    MeshLib::Mesh const& mesh,
    MeshLib::Mesh const& sub_mesh,
    IsActive is_active)
{
    auto* const bulk_node_ids =
        sub_mesh.getProperties().template getPropertyVector<std::size_t>(
            "bulk_node_ids", MeshLib::MeshItemType::Node, 1);
    if (bulk_node_ids == nullptr)
    {
        OGS_FATAL(
            "Bulk node ids map is not available in the deactivate subdomain "
            "mesh.");
    }

    std::vector<MeshLib::Node*> inner_nodes;
    // Reserve for more than needed, but not much, because almost all nodes will
    // be found and copied.
    inner_nodes.reserve(sub_mesh.getNumberOfNodes());
    std::copy_if(begin(sub_mesh.getNodes()), end(sub_mesh.getNodes()),
                 back_inserter(inner_nodes), [&](MeshLib::Node* const n) {
                     auto const bulk_node =
                         mesh.getNode((*bulk_node_ids)[n->getID()]);
                     const auto& connected_elements = bulk_node->getElements();

                     // Check whether this node is connected to an active
                     // element.
                     return std::all_of(begin(connected_elements),
                                        end(connected_elements), is_active);
                 });

    return inner_nodes;
}

static std::unique_ptr<DeactivatedSubdomainMesh> createDeactivatedSubdomainMesh(
    MeshLib::Mesh const& mesh, int const material_id)
{
    // An element is active if its material id matches the selected material id.
    auto is_active = [material_id, material_ids = *materialIDs(mesh)](
                         MeshLib::Element const* const e) {
        return material_id == material_ids[e->getID()];
    };

    auto const& elements = mesh.getElements();
    std::vector<MeshLib::Element*> deactivated_elements;
    std::copy_if(begin(elements), end(elements),
                 back_inserter(deactivated_elements),
                 [&](auto const e) { return is_active(e); });

    // Subdomain mesh consisting of deactivated elements.
    auto sub_mesh = MeshLib::createMeshFromElementSelection(
        "deactivate_subdomain_" + std::to_string(material_id),
        MeshLib::cloneElements(deactivated_elements));

    auto inner_nodes = extractInnerNodes(mesh, *sub_mesh, is_active);
    return std::make_unique<DeactivatedSubdomainMesh>(
        std::move(sub_mesh), std::move(inner_nodes));
}

std::unique_ptr<DeactivatedSubdomain const> createDeactivatedSubdomain(
    BaseLib::ConfigTree const& config, MeshLib::Mesh const& mesh)
{
    //! \ogs_file_param{prj__process_variables__process_variable__deactivated_subdomains__deactivated_subdomain__time_interval}
    config.peekConfigParameter<std::string>("time_interval");
    auto time_interval = BaseLib::createTimeInterval(config);

    auto deactivated_subdomain_material_ids =
        //! \ogs_file_param{prj__process_variables__process_variable__deactivated_subdomains__deactivated_subdomain__material_ids}
        config.getConfigParameter("material_ids", std::vector<int>{});

    if (deactivated_subdomain_material_ids.empty())
    {
        OGS_FATAL(
            "The material IDs of the deactivated subdomains are not given. The "
            "program terminates now.");
    }

    std::sort(deactivated_subdomain_material_ids.begin(),
              deactivated_subdomain_material_ids.end());

    auto const* const material_ids = materialIDs(mesh);
    if (material_ids == nullptr)
    {
        OGS_FATAL(
            "The mesh doesn't contain materialIDs for subdomain deactivation. "
            "The program terminates now.");
    }

    std::vector<std::unique_ptr<DeactivatedSubdomainMesh>>
        deactivated_subdomain_meshes;
    deactivated_subdomain_meshes.reserve(
        deactivated_subdomain_material_ids.size());

    for (int const id : deactivated_subdomain_material_ids)
    {
        deactivated_subdomain_meshes.push_back(
            createDeactivatedSubdomainMesh(mesh, id));
    }

    return std::make_unique<DeactivatedSubdomain const>(
        time_interval,
        std::move(deactivated_subdomain_material_ids),
        std::move(deactivated_subdomain_meshes));
}

std::vector<std::unique_ptr<DeactivatedSubdomain const>>
createDeactivatedSubdomains(BaseLib::ConfigTree const& config,
                            MeshLib::Mesh const& mesh)
{
    std::vector<std::unique_ptr<DeactivatedSubdomain const>>
        deactivated_subdomains;
    // Deactivated subdomains
    if (auto subdomains_config =
            //! \ogs_file_param{prj__process_variables__process_variable__deactivated_subdomains}
        config.getConfigSubtreeOptional("deactivated_subdomains"))
    {
        INFO("There are subdomains being deactivated.");

        for (
            auto subdomain_config :
            //! \ogs_file_param{prj__process_variables__process_variable__deactivated_subdomains__deactivated_subdomain}
            subdomains_config->getConfigSubtreeList("deactivated_subdomain"))
        {
            deactivated_subdomains.emplace_back(
                createDeactivatedSubdomain(subdomain_config, mesh));
        }
    }
    return deactivated_subdomains;
}

}  // namespace ProcessLib