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

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

        private readonly Dictionary<Type, EntityRenderer> drawComponentTypeToEntityRenderer = new Dictionary<Type, EntityRenderer>();

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

        public void RegisterEntityRenderer(EntityRenderer renderer)
        {
            var rendersAttribute = renderer.GetType().GetCustomAttribute<Renders>(false);
            if (rendersAttribute != null)
            {
                drawComponentTypeToEntityRenderer.Add(rendersAttribute.drawComponentType, renderer);
            }
        }

        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 component = componentManager.GetComponentByID(componentID);
                    var componentType = componentManager.GetComponentTypeByID(componentID);

                    if (drawComponentTypeToEntityRenderer.ContainsKey(componentType))
                    {
                        var renderer = drawComponentTypeToEntityRenderer[componentType];
                        var entityID = componentManager.GetEntityIDByComponentID(componentID);

                        if (renderer.IsTracking(entityID) && entityManager.EntityExists(entityID))
                        {
                            var entity = entityManager.GetEntity(entityID);
                            renderer.Render(entity);
                        }
                    }
                }

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