using System;
using System.Collections.Generic;
using UnityEngine;

namespace Toria.Game
{
	[RequireComponent(typeof(CapsuleCollider))]
	public class LeavesHidingDither : MonoBehaviour
	{
		[NonSerialized]
		List<Material> treeMaterials;

		static RPGController player = null;
		static new Camera camera = null;

		[NonSerialized]
		bool shouldHide = false;

		void Start()
		{
			treeMaterials = new List<Material>();

			foreach (Renderer renderer in GetComponentsInChildren<Renderer>())
			{
				MakeShadowClone(renderer);

				Material mat = Instantiate(renderer.sharedMaterial);
				renderer.shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.Off;
				renderer.sharedMaterial = mat;
				treeMaterials.Add(mat);
			}
		}

		void MakeShadowClone(Renderer renderer)
		{
			GameObject shadowClone = Instantiate(renderer.gameObject);

			for (int i = shadowClone.transform.childCount - 1; i >= 0; i--)
				Destroy(shadowClone.transform.GetChild(i).gameObject);

			shadowClone.name = "Shadow clone";
			shadowClone.transform.SetParent(renderer.transform);
			shadowClone.transform.SetLocalPositionAndRotation(Vector3.zero, Quaternion.identity);
			shadowClone.transform.localScale = Vector3.one;

			foreach (Component comp in shadowClone.GetComponents<Component>())
			{
				if (comp is not MeshRenderer && comp is not MeshFilter && comp is not Transform)
					Destroy(comp);
			}

			shadowClone.GetComponent<Renderer>().shadowCastingMode = UnityEngine.Rendering.ShadowCastingMode.ShadowsOnly;
		}

		void Update()
		{
			if (!player)
				player = FindAnyObjectByType<RPGController>();

			if (shouldHide)
			{
				Vector2 viewPortPoint = camera.WorldToViewportPoint(player.transform.position);

				foreach (Material mat in treeMaterials)
					mat.SetVector("_PlayerPosition", viewPortPoint);
			}

			if (!camera)
				camera = Camera.main;

			if (!player || !camera)
				return;

			Vector3 playerPos = player.transform.position + Vector3.up;
			Vector3 cameraPos = camera.transform.position;

			Vector3 rayDir = (playerPos - cameraPos).normalized;

			//move back the origin point so the raycast doesn't start from within a tree collider
			RaycastHit[] hits = Physics.RaycastAll(cameraPos + rayDir * -100f, rayDir, float.PositiveInfinity, 1 << gameObject.layer, QueryTriggerInteraction.Collide);

			for (int i = 0; i < hits.Length; i++)
			{
				if (hits[i].collider.gameObject == gameObject)
				{
					SetCutoutEnabled(true);
					return;
				}
			}

			SetCutoutEnabled(false);
		}

		void SetCutoutEnabled(bool enabled)
		{
			if (shouldHide == enabled)
				return;

			shouldHide = enabled;

			foreach (Material mat in treeMaterials)
				mat.SetFloat("_ShouldHide", enabled ? 1 : 0);
		}
	}
}