using System;
using System.Reflection;
using System.Collections.Generic;

namespace Encompass
{
    internal class RenderManager
    {
        private readonly ComponentManager componentManager;
        private readonly DrawLayerManager drawLayerManager;
        private readonly EntityManager entityManager;

        private readonly Dictionary<Type, Action<Entity, IComponent>> drawComponentTypeToOrderedRenderer = new Dictionary<Type, Action<Entity, IComponent>>();

        public RenderManager(
            ComponentManager componentManager,
            DrawLayerManager drawLayerManager,
            EntityManager entityManager
        )
        {
            this.componentManager = componentManager;
            this.drawLayerManager = drawLayerManager;
            this.entityManager = entityManager;
        }

        public void RegisterOrderedRenderer<TComponent>(Action<Entity, IComponent> renderAction) where TComponent : struct, IComponent
        {
            drawComponentTypeToOrderedRenderer.Add(typeof(TComponent), renderAction);
        }

        public void RegisterGeneralRendererWithLayer(GeneralRenderer renderer, int layer)
        {
            drawLayerManager.RegisterGeneralRendererWithLayer(renderer, layer);
        }

        public void Draw()
        {
            foreach (var layer in drawLayerManager.LayerOrder)
            {
                var componentIDSet = drawLayerManager.ComponentIDsByLayer(layer);
                var generalRendererSet = drawLayerManager.GeneralRenderersByLayer(layer);

                foreach (var componentID in componentIDSet)
                {
                    var componentType = componentManager.GetComponentTypeByID(componentID);
                    var component = componentManager.GetComponentByID(componentType, componentID);
                    var entityID = componentManager.GetEntityIDByComponentID(componentID);
                    var entity = entityManager.GetEntity(entityID);

                    if (drawComponentTypeToOrderedRenderer.ContainsKey(componentType))
                    {
                        var internalRenderAction = drawComponentTypeToOrderedRenderer[componentType];
                        internalRenderAction(entity, component);
                    }
                }

                foreach (var generalRenderer in generalRendererSet)
                {
                    generalRenderer.Render();
                }
            }
        }
    }
}