#define OLC_PGE_APPLICATION
#include "olcPixelGameEngine.h"

using namespace olc;

// Override base class with your custom functionality
class Example : public olc::PixelGameEngine
{
public:

	class Entity{
	protected:
		Entity(vf2d pos)
		:pos(pos),col(WHITE){}
		vf2d pos;
		Entity*copy=nullptr;
		Pixel col;
	public:
		#define className Entity
		static className*Create(vf2d pos){
			className*newEnt=new className(pos);
			newEnt->copy=new className(pos);
			return newEnt;
		};
		virtual void Reset(){
			pos=copy->pos;
		}
		virtual void Update(PixelGameEngine*pge){
			pge->DrawCircle(pos,5,col);
		};
	};

	class MovingEntity:public Entity{
	public:
		vf2d vel;
		#define className MovingEntity
		static className*Create(vf2d pos,vf2d vel){
			className*newEnt=new className(pos,vel);
			newEnt->copy=new className(pos,vel);
			return newEnt;
		};
		virtual void Update(PixelGameEngine*pge){
			pos+=vel*pge->GetElapsedTime();
			Entity::Update(pge);
		};

	protected:
		MovingEntity(vf2d pos,vf2d vel)
			:Entity(pos),vel(vel){}
		virtual void Reset()override{
			Entity::Reset();
			MovingEntity*defaultCopy=(MovingEntity*)copy;
			vel=defaultCopy->vel;
		}
	};

	class PlayerEntity:public MovingEntity{
	public:
		#define className PlayerEntity
		static className*Create(vf2d startingPos){
			className*newEnt=new className(startingPos);
			newEnt->copy=new className(startingPos);
			return newEnt;
		};
		virtual void Update(PixelGameEngine*pge){
			vel={0,0};
			if(pge->GetKey(A).bHeld){
				vel.x-=12;
			}
			if(pge->GetKey(D).bHeld){
				vel.x+=12;
			}
			if(pge->GetKey(W).bHeld){
				vel.y-=12;
			}
			if(pge->GetKey(S).bHeld){
				vel.y+=12;
			}
			MovingEntity::Update(pge);
		};

	protected:
		PlayerEntity(vf2d startingPos)
			:MovingEntity(startingPos,{0,0}){
			col=BLUE;
		}
		virtual void Reset()override{
			MovingEntity::Reset();
		}
	};

	Example()
	{
		// Name your application
		sAppName = "Example";
	}

	std::vector<Entity*>level1Entities;
	std::vector<Entity*>level2Entities;

	std::vector<Entity*>gameEntities;

	void LoadLevel(std::vector<Entity*>&entityList){
		//Clear out the old entities, we don't care about them anymore.
		gameEntities.clear();

		for(Entity*ent:entityList){
			//Reset the entity to default, so we have a fresh level to work with.
			ent->Reset();
			//Load in new entities to our game play area.
			gameEntities.push_back(ent);
		}
	}

public:
	bool OnUserCreate() override
	{
		// Called once at the start, so create things here
		level1Entities.push_back(Entity::Create({20,80}));
		level1Entities.push_back(Entity::Create({40,100}));
		level1Entities.push_back(PlayerEntity::Create({20,120}));
		level1Entities.push_back(MovingEntity::Create({10,70},{1,1}));

		level2Entities.push_back(Entity::Create({80,70}));
		level2Entities.push_back(Entity::Create({60,90}));
		level2Entities.push_back(PlayerEntity::Create({100,120}));
		level2Entities.push_back(MovingEntity::Create({240,240},{-1,-1}));
		return true;
	}

	bool OnUserUpdate(float fElapsedTime) override
	{
		Clear(BLACK);

		if(GetKey(K1).bPressed){
			LoadLevel(level1Entities);
		}
		if(GetKey(K2).bPressed){
			LoadLevel(level2Entities);
		}
		if(GetKey(SPACE).bPressed){
			((MovingEntity*)level2Entities[3])->vel={0,0};
		}

		// Called once per frame, draws random coloured pixels
		for(Entity*ent:gameEntities){
			ent->Update(this);
		}

		DrawString({1,1},"Press <1> to load Level 1,\nor <2> to load Level 2");
		DrawString({1,16},"WASD to move");
		return true;
	}
};

int main()
{
	Example demo;
	if (demo.Construct(256, 240, 4, 4))
		demo.Start();
	return 0;
}