componentstorage.hpp

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#pragma once
 
#include <unordered_map>
#include <vector>
 
#include "../defs.hpp"
 
namespace Engine::ECS {
    struct IComponentStorage {
        virtual void Remove(EntityID id) = 0;

        virtual void Clear() = 0;
        
        virtual ~IComponentStorage() = default;
    };

    template<typename T>
    class ComponentStorage : public IComponentStorage {
        private:
            std::unordered_map<EntityID, std::vector<T*>> mComponents;
        
        public:
            void Add(EntityID entityID, T* component) {
                mComponents[entityID].push_back(component);
            }

            void Remove(EntityID entityID) override {
                mComponents.erase(entityID);
            }

            void Clear() override {
                for(auto [_, list] : mComponents) { 
                    for(auto t : list) delete t; 
                }
                mComponents.clear();
            }

            T* Get(EntityID entityID, int index = 0) {
                auto it = mComponents.find(entityID);
                return (it != mComponents.end() && index < it->second.size()) ? it->second[index] : nullptr;
            }

            std::vector<T*> GetMany(EntityID entityID) {
                auto it = mComponents.find(entityID);
                return (it != mComponents.end()) ? it->second : std::vector<T*>();
            }

            T& GetRef(EntityID entityID, int index = 0) {
                auto it = mComponents.find(entityID);
                if(it == mComponents.end() || (it->second.size() < index)) throw std::runtime_error("this entity does not have such a component");
                return *(mComponents.at(entityID)[index]);
            }

            const std::unordered_map<EntityID, std::vector<T*>>& GetRaw() const {
                return mComponents;
            }
    };
}