#pragma once

#include <CesiumGltf/AccessorSpec.h>
#include <CesiumGltf/Library.h>

#include <cstdint>

namespace CesiumGltf {
struct Model;

/** @copydoc AccessorSpec */
struct CESIUMGLTF_API Accessor final : public AccessorSpec {
  /**
   * @brief Computes the number of components for a given accessor type.
   *
   * For example `CesiumGltf::Accessor::Type::SCALAR` has 1 component while
   * `CesiumGltf::Accessor::Type::VEC4` has 4 components.
   *
   * @param type The accessor type.
   * @return The number of components. Returns 0 if {@link Accessor::type} is
   * not a valid enumeration value.
   */
  static int8_t computeNumberOfComponents(const std::string& type) noexcept;

  /**
   * @brief Computes the number of bytes for a given accessor component type.
   *
   * For example `CesiumGltf::Accessor::ComponentType::UNSIGNED_SHORT` is 2
   * bytes while `CesiumGltf::Accessor::ComponentType::FLOAT` is 4 bytes.
   *
   * @param componentType The accessor component type.
   * @return The number of bytes for the component type. Returns 0 if
   * {@link Accessor::componentType} is not a valid enumeration value.
   */
  static int8_t computeByteSizeOfComponent(int32_t componentType) noexcept;

  Accessor() = default;

  /**
   * @brief Computes the number of components for this accessor.
   *
   * For example if this accessor's {@link Accessor::type} is
   * `CesiumGltf::Accessor::Type::SCALAR`, then it has 1 component, while if
   * it's `CesiumGltf::Accessor::Type::VEC4` it has 4 components.
   *
   * @return The number of components in this accessor. Returns 0 if this
   * accessor's {@link Accessor::type} does not have a valid enumeration value.
   */
  int8_t computeNumberOfComponents() const noexcept;

  /**
   * @brief Computes the number of bytes for this accessor's component type.
   *
   * For example if this accessor's {@link Accessor::componentType} is
   * `CesiumGltf::Accessor::ComponentType::UNSIGNED_SHORT`, then the component
   * type is 2 bytes, while if it's `CesiumGltf::Accessor::ComponentType::FLOAT`
   * then it is 4 bytes.
   *
   * @return The number of bytes for this accessor's component type. Returns 0
   * if this accessor's {@link Accessor::componentType} does not have a valid
   * enumeration value.
   */
  int8_t computeByteSizeOfComponent() const noexcept;

  /**
   * @brief Computes the total number of bytes for this accessor in each vertex.
   *
   * This is computed by multiplying
   * {@link Accessor::computeByteSizeOfComponent} by
   * {@link Accessor::computeNumberOfComponents}.
   *
   * @return The total number of bytes for this accessor in each vertex. Returns
   * 0 if this accessor's {@link Accessor::type} or
   * {@link Accessor::componentType} does not have a valid enumeration
   * value.
   */
  int64_t computeBytesPerVertex() const noexcept;

  /**
   * @brief Computes this accessor's stride.
   *
   * The stride is the number of bytes between the same elements of successive
   * vertices. The returned value will be at least as large as
   * {@link Accessor::computeBytesPerVertex}, but maybe be larger if this
   * accessor's data is interleaved with other accessors.
   *
   * The behavior is undefined if this accessor is not part of the given model.
   *
   * @param model The model that this accessor is a part of.
   * @return The stride in bytes. Returns 0 if this accessor's
   * {@link Accessor::type} or {@link Accessor::componentType} does not have
   * a valid enumeration value, or if {@link Accessor::bufferView} does not
   * refer to a valid {@link BufferView}.
   */
  int64_t computeByteStride(const CesiumGltf::Model& model) const noexcept;
};
} // namespace CesiumGltf