#include <iostream>
#include "ECS/ECS.h"

struct Position
{
	// Components must have a default constructor.
	Position() : x(10.0), y(10.0) {}

	// Components can have any other direct constructors.
	Position(double x, double y) : x(x), y(y) {}

	double x;
	double y;
};

struct Name
{
	Name(std::string name) : name(name) {}
	Name() : name("default") {}

	std::string name;
};

struct Dummy {};

struct DecreseNamedPositionSystem : ECS::System
{
	DecreseNamedPositionSystem() {}

	virtual void Init() override {}
	virtual void Update(double delta_time) override
	{
		this->world_ptr->ForEach<Position, Name>(
			[&](const ECS::Entity* entity_ptr, Position* pos_ptr, Name* name_ptr) -> void {
			pos_ptr->x -= delta_time * 2;
			pos_ptr->y -= delta_time;

			std::cout << "Processing entity " << name_ptr->name <<
				", x: " << pos_ptr->x << " y: " << pos_ptr->y << std::endl;
		});
	}
};

int main()
{
	ECS::World world;
	ECS::EntityManager& entity_mgr = world.GetEntityManager();

	world.AddSystem(new DecreseNamedPositionSystem());

	// Create entities with a list of components, which will be constructed by default.
	ECS::Entity entity_1 = entity_mgr.CreateEntity();
	ECS::Entity entity_2 = entity_mgr.CreateEntity<Position>();
	ECS::Entity entity_3 = entity_mgr.CreateEntity<Position>();
	ECS::Entity entity_4 = entity_mgr.CreateEntity<Position, Name, Dummy>();
	ECS::Entity entity_5 = entity_mgr.CreateEntity<Name>();

	// Add or set a component to an entity, and directly consturct the component with given arguments.
	entity_mgr.AddEntityComponent<Name>(entity_2, "Entity 2");
	entity_mgr.SetEntityComponent<Name>(entity_4, "Entity 4");

	// Systems are being called, ordered by their priority
	std::cout << "Update 1.0:" << std::endl;
	world.Update(1.0);

	// Component removal
	entity_mgr.RemoveEntityComponent<Name>(entity_4);
	entity_mgr.RemoveEntityAllComponents(entity_2);

	entity_mgr.AddEntityComponent<Position>(entity_1, 20.0, 30.0);
	entity_mgr.AddEntityComponent<Name>(entity_1, "Entity 1");

	entity_mgr.AddEntityComponent<Position>(entity_5, 50.0, 60.0);
	entity_mgr.SetEntityComponent<Name>(entity_5, "Entity 5");

	// Another set of entities will be visited by the system.
	std::cout << "\nUpdate 2.0:" << std::endl;
	world.Update(2.0);

	// Directly access an entity's component.
	std::cout << "\nEntity 4's x: " << entity_mgr.GetEntityComponent<Position>(entity_4)->x << std::endl;
}