#ifndef FESA_ELEMENTS_DS4_THERMAL_H_
#define FESA_ELEMENTS_DS4_THERMAL_H_

#include <array>
#include <limits>
#include <utility>
#include <vector>

#include "fesa/elements/element_definition.h"

namespace fesa {

/// @brief Defines one four-node uncoupled transient thermal DS4 element.
/// @note This semantic definition contains no geometry kernel or equation
/// state.
class Ds4ThermalDefinition final : public ElementDefinition {
 public:
  /// @brief Marks that DS4 has no entry in Domain::Properties().
  static constexpr EntityIndex kNoPropertyIndex =
      (std::numeric_limits<EntityIndex>::max)();
  Ds4ThermalDefinition(SourceEntityId source_id,
                       std::array<EntityIndex, 4> node_indices,
                       EntityIndex section_index, SourceLocation location);

  ElementDefinitionKind Kind() const noexcept override;
  const SourceEntityId& SourceId() const noexcept override;
  std::string_view SourceElementType() const noexcept override;
  const std::vector<EntityIndex>& NodeIndices() const noexcept override;
  EntityIndex MaterialIndex() const noexcept override;
  EntityIndex PropertyIndex() const noexcept override;

  /// @brief Returns the stable thermal-section collection position.
  EntityIndex ThermalSectionIndex() const noexcept;
  /// @brief Returns the source location defining this element.
  const SourceLocation& Location() const noexcept;

 private:
  friend class Domain;

  void BindMaterialIndex(EntityIndex material_index) noexcept;

  SourceEntityId source_id_;
  std::array<EntityIndex, 4> node_indices_;
  std::vector<EntityIndex> node_indices_view_;
  EntityIndex section_index_;
  EntityIndex material_index_{0U};
  SourceLocation location_;
};

inline Ds4ThermalDefinition::Ds4ThermalDefinition(
    SourceEntityId source_id, std::array<EntityIndex, 4> node_indices,
    EntityIndex section_index, SourceLocation location)
    : source_id_{std::move(source_id)},
      node_indices_{node_indices},
      node_indices_view_{node_indices.begin(), node_indices.end()},
      section_index_{section_index},
      location_{std::move(location)} {}

inline ElementDefinitionKind Ds4ThermalDefinition::Kind() const noexcept {
  return ElementDefinitionKind::kDs4Thermal;
}

inline const SourceEntityId& Ds4ThermalDefinition::SourceId() const noexcept {
  return source_id_;
}

inline std::string_view Ds4ThermalDefinition::SourceElementType() const noexcept {
  return "DS4";
}

inline const std::vector<EntityIndex>& Ds4ThermalDefinition::NodeIndices()
    const noexcept {
  return node_indices_view_;
}

inline EntityIndex Ds4ThermalDefinition::MaterialIndex() const noexcept {
  return material_index_;
}

inline EntityIndex Ds4ThermalDefinition::PropertyIndex() const noexcept {
  return kNoPropertyIndex;
}

inline EntityIndex Ds4ThermalDefinition::ThermalSectionIndex() const noexcept {
  return section_index_;
}

inline const SourceLocation& Ds4ThermalDefinition::Location() const noexcept {
  return location_;
}

inline void Ds4ThermalDefinition::BindMaterialIndex(
    EntityIndex material_index) noexcept {
  material_index_ = material_index;
}

}  // namespace fesa

#endif  // FESA_ELEMENTS_DS4_THERMAL_H_