Entity.hpp

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#pragma once
#include <entt/entt.hpp>
#include "Utility/StringHash.hpp"
 
namespace Cori {
    namespace World {
        namespace Systems {
            class Hierarchy;
        }
        class Entity;
        namespace Internal {
            struct SceneID {
                explicit SceneID(const uint32_t id) : m_OwningSceneID(id) {}
 
            private:
                friend Entity;
                uint32_t m_OwningSceneID;
            };
        }

        class Entity {
        public:
            Entity() = default;
 
            Entity(entt::handle handle) : m_EntityHandle(handle) {} // NOLINT

            template<typename T, typename... Args>
            T& AddComponent(Args&&... args) {
                return m_EntityHandle.emplace<T>(std::forward<Args>(args)...);
            }

            template<typename T, typename... Args>
            T& ReplaceComponent(Args&&... args) {
                return m_EntityHandle.replace<T>(std::forward<Args>(args)...);
            }

            template<typename T, typename... Args>
            T& AddOrReplaceComponent(Args&&... args) {
                return m_EntityHandle.emplace_or_replace<T>(std::forward<Args>(args)...);
            }

            template<typename... T>
            [[nodiscard]] decltype(auto) GetComponents() {
                if (!HasComponents<T...>()) {
                    CORI_CORE_FATAL_TAGGED({ Logger::Tags::World::Self, Logger::Tags::World::Entity::Self }, "Failed to get component(s) from entity. Entity '{}' does not have one or more of the following component type(s) '{}'", GetDebugData(), ([] {
                        std::ostringstream oss;
                        ((oss << ", " << CORI_CLEAN_TYPE_NAME(T)), ...);
                        return oss.str();
                    })());
                }
                return m_EntityHandle.get<T...>();
            }

            template<typename... T>
            [[nodiscard]] decltype(auto) GetComponents() const {
                if (!HasComponents<T...>()) {
                    CORI_CORE_FATAL_TAGGED({ Logger::Tags::World::Self, Logger::Tags::World::Entity::Self }, "Failed to get const component(s) from entity. Entity '{}' does not have one or more of the following component type(s) '{}'", GetDebugData(), ([] {
                        std::ostringstream oss;
                        ((oss << ", " << CORI_CLEAN_TYPE_NAME(T)), ...);
                        return oss.str();
                    })());
                }
 
                return m_EntityHandle.get<const T...>();
            }

            template<typename T, typename... Args>
            T& GetOrAddComponent(Args&&... args) {
                return m_EntityHandle.get_or_emplace<T>(std::forward<Args>(args)...);
            }

            template<typename... T>
            [[nodiscard]] bool HasComponents() const {
                return m_EntityHandle.all_of<T...>();
            }

            template<typename... T>
            entt::handle::size_type RemoveComponents() { // NOLINT
                return m_EntityHandle.remove<T...>();
            }
 
            // erases the components without checking if an entity have they
            template<typename... T>
            void EraseComponents() { // NOLINT
                m_EntityHandle.erase<T...>();
            }
 
            explicit operator bool() const { return static_cast<bool>(m_EntityHandle); }
 
            bool operator==(const Entity& other) const {
                return m_EntityHandle == other.m_EntityHandle;
            }
            bool operator!=(const Entity& other) const {
                return m_EntityHandle != other.m_EntityHandle;
            }

            [[nodiscard]] bool IsValid() const {
                return static_cast<bool>(m_EntityHandle);
            }

            void SetActive(const bool state);

            [[nodiscard]] bool IsActiveLocally() const;

            [[nodiscard]] bool IsActiveGlobally() const;

            [[nodiscard]] uint32_t GetID() const {
                return entt::to_integral(m_EntityHandle.entity());
            }

            [[nodiscard]] uint32_t GetVersion() const {
                return entt::to_version(m_EntityHandle.entity());
            }

            [[nodiscard]] uint64_t GetEUID() const {
                return static_cast<uint64_t>(GetID()) << 32 | GetVersion();
            }

            [[nodiscard]] uint32_t GetOwnerSceneID() const {
                return GetComponents<Internal::SceneID>().m_OwningSceneID;
            }

            [[nodiscard]] std::string GetDebugData(bool showUUID = false) const;

            std::expected<void, Core::CoriError<>> SetParent(Entity parent);

            [[nodiscard]] std::expected<std::vector<Entity>, Core::CoriError<>> GetSiblings() const;

            [[nodiscard]] std::expected<Entity, Core::CoriError<>> GetParent() const;

            [[nodiscard]] std::expected<std::vector<Entity>, Core::CoriError<>> GetChildren() const;

            [[nodiscard]] std::expected<Entity, Core::CoriError<>> FindChildByName(const char* name) const;

            [[nodiscard]] std::expected<Entity, Core::CoriError<>> FindChildByName(const std::string_view name) const;

            [[nodiscard]] std::expected<Entity, Core::CoriError<>> FindChildByName(const std::string& name) const;

            void DestroyChildren();

            [[nodiscard]] entt::entity GetRawEntity() const { return m_EntityHandle.entity(); }

            [[nodiscard]] entt::handle GetRawHandle() const { return m_EntityHandle; }

            void PrintHierarchy() const;

            [[nodiscard]] std::string_view GetName() const;

            void SetName(const std::string& name);

            void UnlinkFromParent();
        protected:
            friend Systems::Hierarchy;
            void UpdateInactivityFlagsRecursive(entt::entity parent, bool parentIsActive);
        private:
 
            static void DrawHierarchyRecursive(const Entity& entity, const std::string& prefix, const bool isLast);
 
            entt::handle m_EntityHandle;
 
            friend class Scene;
        };
    }
}