#pragma once

#include <utility>

#include <amdis/Assembler.hpp>
#include <amdis/LocalOperator.hpp>
#include <amdis/typetree/Traversal.hpp>
#include <amdis/utility/AssembleOperators.hpp>

namespace AMDiS {

template <class RB, class CB, class T, class Traits>
  template <class ContextTag, class Expr, class RowTreePath, class ColTreePath>
void BiLinearForm<RB,CB,T,Traits>::
addOperator(ContextTag contextTag, Expr const& expr,
            RowTreePath row, ColTreePath col)
{
  static_assert( Concepts::PreTreePath<RowTreePath>,
      "row must be a valid treepath, or an integer/index-constant");
  static_assert( Concepts::PreTreePath<ColTreePath>,
      "col must be a valid treepath, or an integer/index-constant");

  auto i = makeTreePath(row);
  auto node_i = child(this->rowBasis().localView().treeCache(), i);
  auto j = makeTreePath(col);
  auto node_j = child(this->colBasis().localView().treeCache(), j);

  using LocalContext = typename ContextTag::type;
  using Tr = DefaultAssemblerTraits<LocalContext, ElementMatrix>;
  auto op = makeLocalOperator<LocalContext>(expr, this->rowBasis().gridView());
  auto localAssembler = makeUniquePtr(makeAssembler<Tr>(std::move(op), node_i, node_j));

  operators_[i][j].push(contextTag, std::move(localAssembler));
  updatePattern_ = true;
}


template <class RB, class CB, class T, class Traits>
  template <class RowLocalView, class ColLocalView,
    REQUIRES_(Concepts::LocalView<RowLocalView>),
    REQUIRES_(Concepts::LocalView<ColLocalView>)>
void BiLinearForm<RB,CB,T,Traits>::
assemble(RowLocalView const& rowLocalView, ColLocalView const& colLocalView)
{
  elementMatrix_.resize(rowLocalView.size(), colLocalView.size());
  elementMatrix_ = 0;

  auto const& gv = this->rowBasis().gridView();
  auto const& element = rowLocalView.element();
  auto geometry = element.geometry();

  for_each_node(rowLocalView.treeCache(), [&](auto const& rowNode, auto rowTp) {
    for_each_node(colLocalView.treeCache(), [&](auto const& colNode, auto colTp) {
      auto& matOp = operators_[rowTp][colTp];
      if (matOp) {
        matOp.bind(element, geometry);
        assembleOperators(gv, element, matOp, makeMatrixAssembler(rowNode, colNode, elementMatrix_));
        matOp.unbind();
      }
    });
  });

  this->scatter(rowLocalView, colLocalView, elementMatrix_);
}


template <class RB, class CB, class T, class Traits>
void BiLinearForm<RB,CB,T,Traits>::
assemble()
{
  auto rowLocalView = this->rowBasis().localView();
  auto colLocalView = this->colBasis().localView();

  this->init();
  for (auto const& element : elements(this->rowBasis().gridView(), typename Traits::PartitionSet{})) {
    rowLocalView.bind(element);
    if (this->rowBasis() == this->colBasis())
      this->assemble(rowLocalView, rowLocalView);
    else {
      colLocalView.bind(element);
      this->assemble(rowLocalView, colLocalView);
      colLocalView.unbind();
    }
    rowLocalView.unbind();
  }
  this->finish();
}


} // end namespace AMDiS