#ifndef FESA_ELEMENTS_MITC4_SHELL_DEFINITION_H_
#define FESA_ELEMENTS_MITC4_SHELL_DEFINITION_H_

#include <array>
#include <string_view>
#include <vector>

#include "fesa/elements/element_definition.h"

namespace fesa {

class Domain;

/// @brief Preserves the source shell type independently of formulation.
enum class ShellSourceElementType { kS4, kS4r };

/// @brief Names the internal shell formulation selected by S4 and S4R.
inline constexpr std::string_view kMitc4InternalFormulation{"FESA-MITC4"};

/// @brief Defines one four-node S4/S4R semantic element.
class Mitc4ShellDefinition final : public ElementDefinition {
 public:
  /// @brief Constructs a parser-validated semantic definition.
  Mitc4ShellDefinition(SourceEntityId source_id,
                       ShellSourceElementType source_type,
                       std::array<EntityIndex, 4> node_indices,
                       EntityIndex material_index, 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;

  SourceEntityId source_id;
  ShellSourceElementType source_type;
  std::array<EntityIndex, 4> node_indices;
  EntityIndex material_index;
  EntityIndex section_index;
  SourceLocation location;

 private:
  friend class Domain;

  /// @brief Rebinds a shell-local section index to the unified property view.
  void SetPropertyIndex(EntityIndex property_index) noexcept;

  /// @brief Synchronizes the base view after parser-candidate construction.
  void SynchronizeNodeIndices();

  EntityIndex property_index_;
  std::vector<EntityIndex> node_indices_view_;
};


}  // namespace fesa

#endif  // FESA_ELEMENTS_MITC4_SHELL_DEFINITION_H_