EntitySystem.hpp

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#pragma once
#include "Engine/api.hpp"
#include "Engine/Entity/Entity.hpp"

#include <ThirdParty/EASTL-master/include/EASTL/shared_ptr.h>
#include <ThirdParty/EASTL-master/include/EASTL/string.h>

namespace Engine
{
    class ENGINE_API EntitySystem
    {
    public:
        void RemoveAllEntities();

        eastl::weak_ptr<Entity> CreateEntity(eastl::string entityName = "", int teamId = 0);

        template<typename EntityType>
        eastl::weak_ptr<EntityType> CreateEntity(eastl::string entityName = "");

        template<class EntityType, class... Args>
        eastl::weak_ptr<EntityType> CreateEntity(eastl::string entityName = "", Args&&... args);

        eastl::weak_ptr<Entity> GetEntity(uint64_t Id);

        eastl::vector<eastl::shared_ptr<Entity>> GetAllEntities() const;

        template<typename ComponentType>
        eastl::vector<eastl::weak_ptr<ComponentType>> GetAllComponents();

        template<typename ComponentType>
        eastl::vector<eastl::weak_ptr<Entity>> GetAllEntitiesWithComponent();

        void AddEntity(eastl::shared_ptr<Entity> entityToAdd);

        void RemoveEntity(eastl::shared_ptr<Entity> entityToRemove);

    private:
        eastl::vector<eastl::shared_ptr<Entity>> system;

        friend class Engine;

        EntitySystem() = default;
    public:
        ~EntitySystem();
    private:

        void Update();
    };

    template <typename EntityType>
    eastl::weak_ptr<EntityType> EntitySystem::CreateEntity(eastl::string entityName)
    {
        AddEntity(eastl::shared_ptr<EntityType>(new EntityType(entityName)));

        system.back()->InitializeEntity();

        return eastl::static_pointer_cast<EntityType, Entity>(system.back());
    }

    template <class EntityType, class... Args>
    eastl::weak_ptr<EntityType> EntitySystem::CreateEntity(eastl::string entityName, Args&&... args)
    {
        AddEntity(eastl::shared_ptr<EntityType>(new EntityType(eastl::forward<Args>(args)...)));

        system.back()->name = entityName;
        system.back()->InitializeEntity();

        return eastl::static_pointer_cast<EntityType, Entity>(system.back());
    }

    template <typename ComponentType>
    eastl::vector<eastl::weak_ptr<ComponentType>> EntitySystem::GetAllComponents()
    {
        eastl::vector<eastl::weak_ptr<ComponentType>> componentsToReturn = eastl::vector<eastl::weak_ptr<ComponentType>>();

        for (eastl::vector<eastl::shared_ptr<Entity>>::iterator it = system.begin(), end = system.end(); it != end; ++it)
        {
            eastl::vector<eastl::weak_ptr<ComponentType>> componentsToAdd = it->get()->GetComponents<ComponentType>();

            componentsToReturn.reserve(componentsToReturn.size() + componentsToAdd.size());
            componentsToReturn.insert(componentsToReturn.end(), componentsToAdd.begin(), componentsToAdd.end());
        }

        return componentsToReturn;
    }

    template <typename ComponentType>
    eastl::vector<eastl::weak_ptr<Entity>> EntitySystem::GetAllEntitiesWithComponent()
    {
        eastl::vector<eastl::weak_ptr<Entity>> entitiesToReturn = eastl::vector<eastl::weak_ptr<Entity>>();

        for (size_t i = 0, size = system.size(); i < size; ++i)
        {
            if (system[i].get()->GetComponent<ComponentType>().expired() != false)
                entitiesToReturn.push_back(system[i]);
        }

        return entitiesToReturn;
    }
} // namespace Engine