#if UNITY_EDITOR
using System.IO;
using System.Linq;
using UnityEditor;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.SceneManagement;

/// <summary>Temporarily force Ground to visualize bakedGI only, to verify lightmap sampling.</summary>
public static class DiagnoseHomeCampGiViz
{
    const string ScenePath = "Assets/Bundles/Scenes/Town/HomeCamp/HomeCamp.unity";
    const string Review = "D:/UD/AI/AIGame/Tools/output/homecamp_review";
    const string ShaderPath = "Assets/Bundles/Shaders/XShader/XTerrain.shader";

    public static string Run()
    {
        Directory.CreateDirectory(Review);
        var scene = EditorSceneManager.OpenScene(ScenePath, OpenSceneMode.Single);
        var root = scene.GetRootGameObjects().Single(g => g.name == "HomeCamp");
        var ground = root.transform.Find("Ground")?.GetComponentInChildren<MeshRenderer>();
        if (!ground) return "FAIL: no ground";

        var mesh = ground.GetComponent<MeshFilter>()?.sharedMesh;
        var uv1 = mesh != null && mesh.uv2 != null && mesh.uv2.Length == mesh.vertexCount;
        var uv0 = mesh != null ? mesh.uv.Length : 0;

        // Inject a debug return of bakedGI into XTerrain fragment temporarily via material replacement:
        // use Unlit with lightmap — simpler: create temp material using URP/Lit which we know samples LM.
        var lit = new Material(Shader.Find("Universal Render Pipeline/Lit"));
        lit.SetColor("_BaseColor", Color.white);
        lit.SetFloat("_Smoothness", 0f);
        var prev = ground.sharedMaterial;
        ground.sharedMaterial = lit;

        var cam = root.GetComponentInChildren<Camera>();
        Capture(cam, Review + "/diag_ground_urp_lit.png");

        // Also capture original
        ground.sharedMaterial = prev;
        Capture(cam, Review + "/diag_ground_xterrain.png");

        // Sample lightmap at ground renderer scaleOffset a few UV points
        var lm = LightmapSettings.lightmaps[0].lightmapColor;
        var so = ground.lightmapScaleOffset;
        string Samples(string label, float u, float v)
        {
            // Unity UV: v=0 bottom. Texture2D GetPixel v from bottom if we use GetPixelBilinear with Unity convention...
            float uu = u * so.x + so.z;
            float vv = v * so.y + so.w;
            var rt = RenderTexture.GetTemporary(lm.width, lm.height, 0, RenderTextureFormat.ARGBFloat);
            Graphics.Blit(lm, rt);
            var prevRt = RenderTexture.active; RenderTexture.active = rt;
            var tex = new Texture2D(lm.width, lm.height, TextureFormat.RGBAFloat, false, true);
            tex.ReadPixels(new Rect(0, 0, lm.width, lm.height), 0, 0); tex.Apply();
            RenderTexture.active = prevRt; RenderTexture.ReleaseTemporary(rt);
            // Texture2D: (0,0) bottom-left in GetPixelBilinear? Actually GetPixelBilinear y=0 is bottom.
            var c = tex.GetPixelBilinear(uu, vv);
            Object.DestroyImmediate(tex);
            float l = c.r * .3f + c.g * .59f + c.b * .11f;
            return label + "=(" + uu.ToString("F2") + "," + vv.ToString("F2") + ")->" + l.ToString("F3");
        }

        Object.DestroyImmediate(lit);
        return "uv1=" + uv1 + " uv0Count=" + uv0 + " verts=" + (mesh ? mesh.vertexCount : 0)
            + " idx=" + ground.lightmapIndex + " so=" + so
            + " " + Samples("center", .5f, .5f)
            + " " + Samples("near", .5f, .2f)
            + " " + Samples("far", .5f, .8f)
            + " " + Samples("left", .2f, .5f)
            + " " + Samples("right", .8f, .5f);
    }

    static void Capture(Camera camera, string file)
    {
        var rt = RenderTexture.GetTemporary(720, 1280, 24, RenderTextureFormat.ARGB32);
        var old = RenderTexture.active; var oldT = camera.targetTexture; var oldA = camera.aspect;
        var tex = new Texture2D(720, 1280, TextureFormat.RGB24, false);
        try
        {
            camera.aspect = 720f / 1280f; camera.targetTexture = rt; RenderTexture.active = rt;
            camera.Render();
            tex.ReadPixels(new Rect(0, 0, 720, 1280), 0, 0); tex.Apply();
            File.WriteAllBytes(file, tex.EncodeToPNG());
        }
        finally
        {
            camera.targetTexture = oldT; camera.aspect = oldA; RenderTexture.active = old;
            RenderTexture.ReleaseTemporary(rt); Object.DestroyImmediate(tex);
        }
    }
}
#endif