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

public class MaterialEntry
{
    public string shader;
    public Material material;
}

// unit 镜头效果，和image effect的区别在于不光是后处理
public abstract class LensEffectBase
{
    public enum EStage
    {
        Before ,  // 迭代之前
        Iterate , // 迭代renderer
        After ,   // 迭代之后
        Finished, // 渲染角色之后（所有lens effect结束）
    }

    public abstract ERenderingEvent renderingEvents { get; }

    protected static Dictionary<string/*shaderName*/, List<MaterialEntry>> m_MaterailPool = new Dictionary<string, List<MaterialEntry>>();

    private List<MaterialEntry> m_InUseMaterials = new List<MaterialEntry>();

    #region upvalues
    public BodyPartRenderer curBodypartRenderer;
    public UnitController owner;
    #endregion

    private static MaterialEntry _ClaimMaterial(string shader)
    {
        List<MaterialEntry> mats;
        if (m_MaterailPool.TryGetValue(shader, out mats) && mats.Count > 0)
        {
            MaterialEntry me = mats[mats.Count - 1];
            mats.RemoveAt(mats.Count - 1);
            return me;
        }
        Material mat = new Material(Shader.Find(shader));
        MaterialEntry entry = new MaterialEntry();
        entry.material = mat;
        entry.shader = shader;
        return entry;
    }

    private static void _ReleaseMaterial(MaterialEntry entry)
    {
        List<MaterialEntry> mats;
        if (!m_MaterailPool.TryGetValue(entry.shader, out mats))
        {
            mats = new List<MaterialEntry>();
            m_MaterailPool.Add(entry.shader, mats);
        }
        mats.Add(entry);
    }

    protected MaterialEntry ClaimMaterial(string shader)
    {
        MaterialEntry entry = _ClaimMaterial(shader);
        m_InUseMaterials.Add(entry);
        return entry;
    }

    protected void ReleaseMaterial(MaterialEntry entry)
    {
        m_InUseMaterials.Remove(entry);
        _ReleaseMaterial(entry);
    }

    protected void ReleaseAllInUsedMaterials()
    {
        for(int i = 0; i < m_InUseMaterials.Count; ++i)
        {
            _ReleaseMaterial(m_InUseMaterials[i]);
        }
        m_InUseMaterials.Clear();
    }

    public virtual void BeforeDepthTexture(EStage stage, CommandBuffer cb) { }
    public virtual void AfterDepthTexture(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeDepthNormalsTexture(EStage stage, CommandBuffer cb) { }
    public virtual void AfterDepthNormalsTexture(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeForwardOpaque(EStage stage, CommandBuffer cb) { }
    public virtual void AfterForwardOpaque(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeImageEffectsOpaque(EStage stage, CommandBuffer cb) { }
    public virtual void AfterImageEffectsOpaque(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeSkybox(EStage stage, CommandBuffer cb) { }
    public virtual void AfterSkybox(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeForwardAlpha(EStage stage, CommandBuffer cb) { }
    public virtual void AfterForwardAlpha(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeImageEffects(EStage stage, CommandBuffer cb) { }
    public virtual void AfterImageEffects(EStage stage, CommandBuffer cb) { }

    public virtual void BeforeEverything(EStage stage, CommandBuffer cb) { }
    public virtual void AfterEverything(EStage stage, CommandBuffer cb) { }

    public virtual bool CanDestroy() { return false; }

    public virtual void OnDestroy() { }

    // 角色渲染完毕
    public virtual void OnRenderFinish()
    {
        ReleaseAllInUsedMaterials();
    }

}