using System;
using UnityEngine;

namespace Assets.ThoMagic.Renderer
{
    public class RendererUtility
    {
        public static GameObject GetPrototypeToRender(DetailPrototype prototype) => prototype.prototype == null ? null : 
            prototype.prototype.transform.root.gameObject;

        public static bool SupportsProceduralInstancing(GameObject gameObject)
        {
            foreach (var componentsInChild in gameObject.GetComponentsInChildren<MeshRenderer>())
            {
                foreach (var sharedMaterial in componentsInChild.sharedMaterials)
                {
                    if (sharedMaterial != null && sharedMaterial.shader != null && !RendererUtility.SupportsProceduralInstancing(sharedMaterial))
                        return false;
                }
            }
            return true;
        }

        public static bool SupportsProceduralInstancing(Material material)
        {
            if (material == null)
                throw new ArgumentNullException(nameof(material));
            if (material.shader == null)
                throw new ArgumentNullException("material.shader");
            return true;
        }

        public static bool IsSupportedByUnity(DetailPrototype prototype) => !prototype.usePrototypeMesh || prototype.prototype == null || prototype.prototype.GetComponent<LODGroup>() == null;

        public static GameObject GetSupportedPlaceholder(DetailPrototype prototype) => IsSupportedByUnity(prototype) ? prototype.prototype : GetSupportedPlaceholder(prototype.prototype);

        public static GameObject GetSupportedPlaceholder(GameObject prototype)
        {
            if (prototype == null)
                return prototype;
            LODGroup component = prototype.GetComponent<LODGroup>();
            if (component == null)
                return prototype;
            foreach (LOD loD in component.GetLODs())
            {
                foreach (UnityEngine.Renderer renderer in loD.renderers)
                {
                    if (renderer != null)
                        return renderer.gameObject;
                }
            }
            return null;
        }
    }
}