using System;
using UnityEngine;

namespace X.Rendering.Feature
{
    public class FakeShadowPlayer : MonoBehaviour
    {
        private static readonly int PROP_LIGHTS_ARRAY = Shader.PropertyToID("_FakeShadowsLights");
        private static readonly int PROP_PLAYER_SHADOW_POSITION = Shader.PropertyToID("_PlayerPosition");
        private static readonly int PROP_FAKE_SHADOWS_ARGS = Shader.PropertyToID("_FakeShadowsArgs");

        
        private static readonly Vector4 DEFAULT_LIGHT_VALUE = new Vector4(0f, 0f, 0f, 1f);

        private Vector4[] lightsData = new Vector4[4]
        {
            DEFAULT_LIGHT_VALUE,
            DEFAULT_LIGHT_VALUE,
            DEFAULT_LIGHT_VALUE,
            DEFAULT_LIGHT_VALUE
        };

        [SerializeField] private Vector3 playerPositionOffset = new Vector3(0f, 0.1f, 0f);
        [SerializeField] private float playerRadius = 0.1f;
        [SerializeField, Range(0f, 1f)] private float shadowStrength = 0.7f;

        
        private void OnTriggerEnter(Collider other)
        {
            if (other.GetComponent<FakeShadowLightConfig>() is FakeShadowLightConfig fsc && fsc)
            {
                lightsData = fsc.lightData;
            }
        }

#if UNITY_EDITOR
        private void OnTriggerStay(Collider other)
        {
            if (other.GetComponent<FakeShadowLightConfig>() is FakeShadowLightConfig fsc && fsc)
            {
                lightsData = fsc.lightData;
            }
        }
#endif

        private void OnTriggerExit(Collider other)
        {
            lightsData[0] = DEFAULT_LIGHT_VALUE;
            lightsData[1] = DEFAULT_LIGHT_VALUE;
            lightsData[2] = DEFAULT_LIGHT_VALUE;
            lightsData[3] = DEFAULT_LIGHT_VALUE;
        }

        private void Update()
        {
            Shader.SetGlobalVectorArray(PROP_LIGHTS_ARRAY, lightsData);
            Shader.SetGlobalVector(PROP_PLAYER_SHADOW_POSITION, this.transform.position + playerPositionOffset);
            Shader.SetGlobalVector(PROP_FAKE_SHADOWS_ARGS, new Vector4(playerRadius, shadowStrength, 0, 0));
        }
    }
}