using System.Collections.Generic;

namespace Encompass {
    internal class EntityManager {
        private uint nextID = 1;

        private List<Entity> entities = new List<Entity>();
        private Dictionary<uint, Entity> IDToEntity = new Dictionary<uint, Entity>();

        private List<Entity> entitiesMarkedForDestroy = new List<Entity>();

        private ComponentManager componentManager;

        public EntityManager(
            ComponentManager componentManager
        ) {
            this.componentManager = componentManager;
        }

        public Entity CreateEntity() {
            return new Entity(NextID(), componentManager);
        }

        public Entity GetEntity(uint id) {
            return this.IDToEntity[id];
        }

        public void MarkForDestroy(Entity entity) {
            entitiesMarkedForDestroy.Add(entity);
        }

        internal void DestroyMarkedEntities() {
            foreach (var entity in entitiesMarkedForDestroy) {
                entity.RemoveAllComponents();
            }
        }

        private uint NextID() {
            var id = this.nextID;
            this.nextID++;
            return id;
        }
    }
}