/**
 * \file
 * \copyright
 * Copyright (c) 2012-2022, OpenGeoSys Community (http://www.opengeosys.org)
 *            Distributed under a Modified BSD License.
 *              See accompanying file LICENSE.txt or
 *              http://www.opengeosys.org/project/license
 *
 */

#pragma once
#ifdef OGS_USE_PYTHON
#include <pybind11/pybind11.h>
#endif  // OGS_USE_PYTHON
#include <algorithm>
#include <iostream>
#include <vector>

#include "BHEInflowPythonBoundaryConditionPythonSideInterface.h"
#include "BaseLib/Error.h"
#include "NumLib/IndexValueVector.h"
#include "ProcessLib/BoundaryConditionAndSourceTerm/BoundaryCondition.h"
#include "ProcessLib/BoundaryConditionAndSourceTerm/GenericNaturalBoundaryConditionLocalAssembler.h"
#include "ProcessLib/HeatTransportBHE/BHE/BHETypes.h"
#include "ProcessLib/Utils/CreateLocalAssemblers.h"
#include "ProcessLib/Utils/ProcessUtils.h"
#include "PythonBoundaryConditionLocalAssembler.h"

namespace ProcessLib
{
//! A boundary condition whose values are computed by a Python script.
template <typename BHEType>
class BHEInflowPythonBoundaryCondition final : public BoundaryCondition
{
public:
    BHEInflowPythonBoundaryCondition(
        std::pair<GlobalIndexType, GlobalIndexType>&& in_out_global_indices,
        BHEType& bhe,
        BHEInflowPythonBoundaryConditionPythonSideInterface& py_bc_object)
        : _in_out_global_indices(std::move(in_out_global_indices)),
          _bhe(bhe),
          _py_bc_object(py_bc_object)
    {
        const auto g_idx_T_out =
            static_cast<int>(_in_out_global_indices.second);

        // store the bc node ids to BHE network dataframe
        std::get<3>(_py_bc_object.dataframe_network).emplace_back(g_idx_T_out);
    }

    void getEssentialBCValues(
        const double t, const GlobalVector& /* x */,
        NumLib::IndexValueVector<GlobalIndexType>& bc_values) const override
    {
        bc_values.ids.resize(1);
        bc_values.values.resize(1);
        auto const& data_exchange = _py_bc_object.dataframe_network;
        // get the number of all boundary nodes
        const std::size_t n_bc_nodes = std::get<3>(data_exchange).size();

        // get T_in bc_id
        bc_values.ids[0] = _in_out_global_indices.first;

        // get T_out bc_id
        auto const boundary_node_id = _in_out_global_indices.second;

        // return T_in from currently BHE dataframe column 2,
        // update flowrate and HeatTransferCoefficients for each BHE
        for (std::size_t i = 0; i < n_bc_nodes; i++)
        {
            // auto pair_flag_value =
            // _bc_data.bc_object->getDirichletBCValue(boundary_node_id);
            auto const dataframe_node_id = std::get<3>(data_exchange);
            auto const dataframe_Tin_val = std::get<1>(data_exchange);
            auto const dataframe_BHE_flowrate = std::get<4>(data_exchange);
            if (dataframe_node_id[i] == boundary_node_id)
            {
                bc_values.values[0] = dataframe_Tin_val[i];
                _bhe.updateHeatTransferCoefficients(dataframe_BHE_flowrate[i]);
                break;
            }
        }

        // store the current time to network dataframe
        std::get<0>(_py_bc_object.dataframe_network) = t;
    }

private:
    std::pair<GlobalIndexType, GlobalIndexType> const _in_out_global_indices;
    BHEType& _bhe;
    BHEInflowPythonBoundaryConditionPythonSideInterface& _py_bc_object;
};

template <typename BHEType>
std::unique_ptr<BHEInflowPythonBoundaryCondition<BHEType>>
createBHEInflowPythonBoundaryCondition(
    std::pair<GlobalIndexType, GlobalIndexType>&& in_out_global_indices,
    BHEType& bhe,
    BHEInflowPythonBoundaryConditionPythonSideInterface& py_bc_object)

{
    DBUG("Constructing BHEInflowPythonBoundaryCondition.");

    // In case of partitioned mesh the boundary could be empty, i.e. there is no
    // boundary condition.
#ifdef USE_PETSC
    // For this special boundary condition the boundary condition is not empty
    // if the global indices are non-negative.
    if (in_out_global_indices.first < 0 && in_out_global_indices.second < 0)
    {
        return nullptr;
    }
    // If only one of the global indices (in or out) is negative the
    // implementation is not valid.
    if (in_out_global_indices.first < 0 || in_out_global_indices.second < 0)
    {
        OGS_FATAL(
            "The partition cuts the BHE into two independent parts. This "
            "behaviour is not implemented.");
    }
#endif  // USE_PETSC
    return std::make_unique<BHEInflowPythonBoundaryCondition<BHEType>>(
        std::move(in_out_global_indices), bhe, py_bc_object);
}
}  // namespace ProcessLib