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

public class Proximity : MonoBehaviour
{
  public GameObject Head;

  public Material DiffuseMaterial;
  public Material FadeMaterial;

  private Material localDiffuseMaterial;
  private Material localFadeMaterial;

  private float fadeStart = 0.45f;
  private float fadeEnd = 0.4f;
  private GameObject cam;
  private Colors colors;
  private SkinnedMeshRenderer meshRenderer;

  private enum MaterialType { Diffuse, Fade }
  private MaterialType lastMaterialType;

  private void Awake()
  {
    localDiffuseMaterial = Instantiate(DiffuseMaterial);
    localFadeMaterial = Instantiate(FadeMaterial);

    meshRenderer = GetComponent<SkinnedMeshRenderer>();
    meshRenderer.material.SetFloat("_Distance", 0f);
    meshRenderer.enabled = false;

    colors = GameObject.Find("Colors").GetComponent<Colors>();
    cam = GameObject.Find("CenterEyeAnchor");

    meshRenderer.material = localDiffuseMaterial;
    lastMaterialType = MaterialType.Diffuse;

    if (colors.ReplayColors.Count > 0)
    {
      int randomIndex = Random.Range(0, colors.ReplayColors.Count - 1);
      Color newColor = colors.ReplayColors[randomIndex];
      localDiffuseMaterial.color = newColor;
      localFadeMaterial.color = newColor;
      meshRenderer.material.color = newColor;
      colors.ReplayColors.RemoveAt(randomIndex);
    }
  }

  private void Update()
  {
    float distance = Vector3.Distance(cam.transform.position, Head.transform.position);

    // Handle fading case
    if (lastMaterialType == MaterialType.Fade)
    {
      meshRenderer.material.SetFloat("_Distance", distance);
    }

    // Changing state between fading and not
    if (distance > fadeStart && lastMaterialType == MaterialType.Fade)
    {
      meshRenderer.material = localDiffuseMaterial;
      lastMaterialType = MaterialType.Diffuse;
    }
    else if (distance <= fadeStart && lastMaterialType == MaterialType.Diffuse)
    {
      meshRenderer.material = localFadeMaterial;
      meshRenderer.material.SetFloat("_FadeStartDistance", fadeStart);
      meshRenderer.material.SetFloat("_FadeCompleteDistance", fadeEnd);
      lastMaterialType = MaterialType.Fade;
    }

    // Disable mesh renderer when it's at alpha 0
    if (lastMaterialType == MaterialType.Fade && distance < fadeEnd) {
      meshRenderer.enabled = false;
    } else {
      meshRenderer.enabled = true;
    }
  }
}