using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using UnityEngine.SceneManagement;

namespace Funly.SkyStudio
{
  public class SkyBuilder : System.Object
  {
    public SkyProfile profile;
    public Material skyboxMaterial;
    public bool starLayer1Enabled;
    public bool starLayer2Enabled;
    public bool starLayer3Enabled;

    public float starLayer1Density;
    public float starLayer2Density;
    public float starLayer3Density;

    public float starLayer1MaxRadius;
    public float starLayer2MaxRadius;
    public float starLayer3MaxRadius;

    private int m_ImageSize = 256;
    private int m_BusyRenderingCount;
    private bool m_IsCancelled;

    public bool IsComplete
    {
      get { return m_BusyRenderingCount == 0; }
    }

    public delegate void SkyBuilderProgressCallback(SkyBuilder builder, float progress);
    public event SkyBuilderProgressCallback progressCallback;

    public delegate void SkyBuilderCompletionCallback(SkyBuilder builder, bool success);
    public event SkyBuilderCompletionCallback completionCallback;

    private List<BaseStarDataRenderer> m_Renderers = new List<BaseStarDataRenderer>();

    // Stars and async task to rebuild the skyColors system data.
    public void BuildSkySystem()
    {
      m_Renderers.Clear();

      if (skyboxMaterial == null) {
        Debug.LogError("Can't build skyColors system without skybox material.");
        return;
      }

      m_BusyRenderingCount = CountToRender();

      if (starLayer1Enabled) {
        RebuildStarLayer("1",
                         starLayer1Density,
                         starLayer1MaxRadius);
      }

      if (starLayer2Enabled) {
        RebuildStarLayer("2",
                         starLayer2Density,
                         starLayer2MaxRadius);
      }

      if (starLayer3Enabled) {
        RebuildStarLayer("3", 
                         starLayer3Density,
                         starLayer3MaxRadius);
      }
    }

    public string TextureNameForStarLayer(int layerId)
    {
      return TextureNameForStarLayer(layerId.ToString());
    }

    public string TextureNameForStarLayer(string layerId)
    {
      return "StarData" + layerId.ToString();
    }

    public void CancelBuild()
    {
      m_IsCancelled = true;
      completionCallback = null;
      progressCallback = null;

      foreach (BaseStarDataRenderer r in m_Renderers)
      {
        r.Cancel();
      }

      m_Renderers.Clear();
    }

    int CountToRender()
    {
      int count = 0;
      if (starLayer1Enabled) {
        count += 1;
      }

      if (starLayer2Enabled) {
        count += 1;
      }

      if (starLayer3Enabled) {
        count += 1;
      }

      return count;
    }

    void RebuildStarLayer(string layerId, float density, float radius)
    {
      BaseStarDataRenderer renderer = GetBestRendererForPlatform();
      renderer.layerId = layerId;
      renderer.imageSize = m_ImageSize;
      renderer.density = density;
      renderer.maxRadius = radius;
      renderer.completionCallback += OnStarRenderingComplete;
      renderer.progressCallback += OnStarRenderingProgress;

      m_Renderers.Add(renderer);

      EditorCoroutine.start(renderer.ComputeStarData());
    }

    private BaseStarDataRenderer GetBestRendererForPlatform()
    {
      return new NearbyStarRenderer();
    }

    

    // Remove an texture associated with a material.
    private void RemoveAllObjectsWithName(string textureName, Material mat)
    {
      string assetPath = AssetDatabase.GetAssetPath(skyboxMaterial);
      UnityEngine.Object[] objs = AssetDatabase.LoadAllAssetsAtPath(assetPath);
      foreach (UnityEngine.Object obj in objs) {
        if (obj == null) {
          continue;
        }

        if (obj.name == textureName) {
          UnityEngine.Object.DestroyImmediate(obj, true);
        }
      }

      AssetDatabase.ImportAsset(assetPath);
    }

    private void OnStarRenderingProgress(BaseStarDataRenderer renderer, float progress)
    {
      if (progressCallback != null) {
        progressCallback(this, progress);
      }
    }

    private void OnStarRenderingComplete(BaseStarDataRenderer renderer, Texture2D texture, bool success)
    {
      if (m_IsCancelled)
      {
        m_BusyRenderingCount = 0;
        return;
      }

      texture.name = TextureNameForStarLayer(renderer.layerId);
      SkyEditorUtility.AddSkyResource(profile, texture);

      AssetDatabase.Refresh();

      if (renderer.layerId == "1") {
        profile.starLayer1DataTexture = texture;
      } else if (renderer.layerId == "2") {
        profile.starLayer2DataTexture = texture;
      } else if (renderer.layerId == "3") {
        profile.starLayer3DataTexture = texture;
      }

      m_BusyRenderingCount -= 1;

      if (completionCallback != null) {
        completionCallback(this, true);
      }
    }
  }
}