using UnityEngine;
using UnityEditor;
using UnityEngine.Experimental.Rendering;
using NUnit.Framework;
using UnityEngine.Rendering;

[ExecuteInEditMode]
public class RenderLoopTestFixture : RenderPipelineAsset
{
    protected override IRenderPipeline InternalCreatePipeline()
    {
        return new BasicRenderLoopInstance();
    }
}

public class RenderLoopTestFixtureInstance : RenderPipeline
{
    public delegate void TestDelegate(Camera camera, CullResults cullResults, ScriptableRenderContext renderContext);

    private static TestDelegate s_Callback;

    private static RenderLoopTestFixture m_Instance;
    
    public override void Render(ScriptableRenderContext renderContext, Camera[] cameras)
    {
        base.Render(renderContext, cameras);

        foreach (var camera in cameras)
        {
            if (!camera.enabled)
                continue;

            CullingParameters cullingParams;
            bool gotCullingParams = CullResults.GetCullingParameters(camera, out cullingParams);
            Assert.IsTrue(gotCullingParams);

            CullResults cullResults = CullResults.Cull(ref cullingParams, renderContext);

            if (s_Callback != null)
                s_Callback(camera, cullResults, renderContext);
        }

        renderContext.Submit();
    }

    public static void Run(TestDelegate renderCallback)
    {
        if (m_Instance == null)
        {
            m_Instance = ScriptableObject.CreateInstance<RenderLoopTestFixture>();
        }

        var sceneCamera = Camera.main;
        var camObject = sceneCamera.gameObject;

        GraphicsSettings.renderPipelineAsset = m_Instance;
        s_Callback = renderCallback;
        Transform t = camObject.transform;

        // Can't use AlignViewToObject because it animates over time, and we want the first frame
        float size = SceneView.lastActiveSceneView.size;
        float fov = 90; // hardcoded in SceneView
        float camDist = size / Mathf.Tan(fov * 0.5f * Mathf.Deg2Rad);
        SceneView.lastActiveSceneView.LookAtDirect(t.position + t.forward * camDist, t.rotation, size);

        sceneCamera.Render();
        GraphicsSettings.renderPipelineAsset = null;
    }
}