using System;
using UnityEngine;

namespace Assets.ThoMagic.Renderer
{
    public interface IInstanceRenderSettings
    {
        InstanceRenderSettings Settings { get; }
    }

    public struct InstanceRenderSettings
    {
        int hashCodeCache;
        public bool Supported;
        public bool Render;
        public float RenderDistance;
        public float ShadowDistance;
        public bool Shadows;
        public float DensityInDistance;
        public Vector2 DensityInDistanceFalloff;
        public static InstanceRenderSettings Default(Camera camera) => new InstanceRenderSettings()
        {
            Supported = true,
            Render = true,
            Shadows = true,
            RenderDistance = camera.farClipPlane,
            ShadowDistance = camera.farClipPlane,
            DensityInDistance = 1f,
            DensityInDistanceFalloff = Vector2.zero,            
        };

        public void Merge(InstanceRenderSettings other)
        {
            Supported = Supported && other.Supported;
            Render = Render && other.Render;
            Shadows = Shadows && other.Shadows;
            if (RenderDistance > 0.0f && other.RenderDistance > 0.0f)
                RenderDistance = Mathf.Min(RenderDistance, other.RenderDistance);
            else if (other.RenderDistance > 0.0f)
                RenderDistance = other.RenderDistance;
            if (ShadowDistance > 0.0f && other.ShadowDistance > 0.0f)
                ShadowDistance = Mathf.Min(ShadowDistance, other.ShadowDistance);
            else if (other.ShadowDistance > 0.0f)
                ShadowDistance = other.ShadowDistance;
            DensityInDistance = Mathf.Min(DensityInDistance, other.DensityInDistance);
            DensityInDistanceFalloff.x = Mathf.Max(DensityInDistanceFalloff.x, other.DensityInDistanceFalloff.x);
            DensityInDistanceFalloff.y = Mathf.Max(DensityInDistanceFalloff.y, other.DensityInDistanceFalloff.y);

            hashCodeCache = HashCode.Combine(Render, Shadows, RenderDistance, ShadowDistance, DensityInDistance, DensityInDistanceFalloff.x, DensityInDistanceFalloff.y);
        }

        public override int GetHashCode()
        {     
            if(hashCodeCache == 0 || (Application.isEditor && !Application.isPlaying))
                hashCodeCache = HashCode.Combine(Render, Shadows, RenderDistance, ShadowDistance, DensityInDistance, DensityInDistanceFalloff.x, DensityInDistanceFalloff.y);

            return hashCodeCache;
        }
    }
}