#if UNITY_EDITOR
using System;
using System.Collections.Generic;
using System.IO;
using UnityEditor;
using UnityEngine;

/// <summary>
/// Imports the authored battlefield component FBX/XPbr files and creates one
/// reusable prefab per component. Ground is built separately so its collider
/// and read/write mesh settings cannot be confused with decoration assets.
/// </summary>
public static class BuildBattlefieldAssets
{
    const string Root = "Assets/Bundles/Scenes/Prototype/Battlefield/A/Components";
    const string GroundRoot = "Assets/Bundles/Scenes/Prototype/Battlefield/A/Ground";
    const string GroundPrefab = "Assets/Bundles/Scenes/Prototype/Battlefield/GreenfieldGround.prefab";
    const string XpbrShader = "Test/XPbr";

    static readonly string[] Parts = { "tree", "rock", "bridge", "sign", "shrub" };

    public static string BuildComponents()
    {
        AssetDatabase.Refresh();
        var reports = new List<string>();
        foreach (var type in Parts) reports.Add(BuildPart(type));
        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();
        return string.Join(" | ", reports);
    }

    /// <summary>
    /// Builds the independently authored ground asset once Hunyuan has produced
    /// Ground/ground.fbx and its XPbr textures. The ground keeps a readable mesh
    /// so the authored prefab can carry a non-convex MeshCollider.
    /// </summary>
    public static string BuildGround()
    {
        AssetDatabase.Refresh();
        string fbxPath = GroundRoot + "/ground.fbx";
        if (!File.Exists(fbxPath)) return "ground: missing fbx";
        string basePath = GroundRoot + "/ground_base.png";
        string mixPath = GroundRoot + "/ground_mix.png";
        ConfigureTexture(basePath, true, true);
        ConfigureTexture(mixPath, false, false);
        var importer = AssetImporter.GetAtPath(fbxPath) as ModelImporter;
        if (importer != null)
        {
            importer.globalScale = 1f;
            importer.useFileScale = false;
            importer.bakeAxisConversion = true;
            importer.materialImportMode = ModelImporterMaterialImportMode.ImportViaMaterialDescription;
            importer.meshCompression = ModelImporterMeshCompression.Medium;
            importer.isReadable = true;
            importer.addCollider = false;
            importer.SaveAndReimport();
        }
        var mat = GetOrCreateMaterial(GroundRoot + "/ground.mat", "ground", basePath, mixPath);
        var model = AssetDatabase.LoadAssetAtPath<GameObject>(fbxPath);
        if (model == null) return "ground: fbx not loaded";
        var root = new GameObject("GreenfieldGround");
        try
        {
            var instance = (GameObject)PrefabUtility.InstantiatePrefab(model);
            instance.name = "GroundMesh";
            instance.transform.SetParent(root.transform, false);
            PrefabUtility.UnpackPrefabInstance(instance, PrefabUnpackMode.Completely, InteractionMode.AutomatedAction);
            foreach (var renderer in instance.GetComponentsInChildren<Renderer>(true)) renderer.sharedMaterial = mat;
            foreach (var filter in instance.GetComponentsInChildren<MeshFilter>(true))
            {
                if (filter.sharedMesh == null) continue;
                var collider = filter.gameObject.GetComponent<MeshCollider>();
                if (collider == null) collider = filter.gameObject.AddComponent<MeshCollider>();
                collider.convex = false;
                collider.sharedMesh = filter.sharedMesh;
            }
            PrefabUtility.SaveAsPrefabAsset(root, GroundPrefab);
        }
        finally { UnityEngine.Object.DestroyImmediate(root); }
        AssetDatabase.SaveAssets();
        AssetDatabase.Refresh();
        return "ground: " + GroundPrefab;
    }

    public static string BuildAll()
    {
        var components = BuildComponents();
        var ground = BuildGround();
        return components + " | " + ground;
    }

    static string BuildPart(string type)
    {
        string dir = Root + "/" + type;
        string fbxPath = dir + "/" + type + ".fbx";
        string matPath = dir + "/" + type + ".mat";
        string basePath = dir + "/" + type + "_base.png";
        string mixPath = dir + "/" + type + "_mix.png";
        string prefabPath = dir + "/" + type + ".prefab";
        if (!File.Exists(fbxPath)) return type + ": missing fbx";

        ConfigureTexture(basePath, true, true);
        ConfigureTexture(mixPath, false, false);
        var importer = AssetImporter.GetAtPath(fbxPath) as ModelImporter;
        if (importer != null)
        {
            importer.globalScale = 1f;
            importer.useFileScale = false;
            importer.bakeAxisConversion = true;
            importer.materialImportMode = ModelImporterMaterialImportMode.ImportViaMaterialDescription;
            importer.meshCompression = ModelImporterMeshCompression.Medium;
            importer.isReadable = false;
            importer.addCollider = false;
            importer.SaveAndReimport();
        }

        var mat = GetOrCreateMaterial(matPath, type, basePath, mixPath);

        var model = AssetDatabase.LoadAssetAtPath<GameObject>(fbxPath);
        if (model == null) return type + ": fbx not loaded";
        var instance = (GameObject)PrefabUtility.InstantiatePrefab(model);
        instance.name = type;
        foreach (var renderer in instance.GetComponentsInChildren<Renderer>()) renderer.sharedMaterial = mat;
        instance.transform.localPosition = Vector3.zero;
        instance.transform.localRotation = Quaternion.identity;
        instance.transform.localScale = Vector3.one;
        PrefabUtility.SaveAsPrefabAsset(instance, prefabPath);
        UnityEngine.Object.DestroyImmediate(instance);
        return type + ": " + prefabPath;
    }

    static Material GetOrCreateMaterial(string matPath, string name, string basePath, string mixPath)
    {
        var baseMap = AssetDatabase.LoadAssetAtPath<Texture2D>(basePath);
        var mixMap = AssetDatabase.LoadAssetAtPath<Texture2D>(mixPath);
        var shader = Shader.Find(XpbrShader) ?? Shader.Find("Universal Render Pipeline/Lit") ?? Shader.Find("Standard");
        var mat = AssetDatabase.LoadAssetAtPath<Material>(matPath);
        if (mat == null)
        {
            mat = new Material(shader) { name = name };
            AssetDatabase.CreateAsset(mat, matPath);
        }
        else mat.shader = shader;
        if (mat.HasProperty("_MainTex")) mat.SetTexture("_MainTex", baseMap);
        if (mat.HasProperty("_MixTex")) mat.SetTexture("_MixTex", mixMap);
        if (mat.HasProperty("_BaseColor")) mat.SetColor("_BaseColor", Color.white);
        if (mat.HasProperty("_Metallic")) mat.SetFloat("_Metallic", 1f);
        if (mat.HasProperty("_Roughness")) mat.SetFloat("_Roughness", 1f);
        if (mat.HasProperty("_AO")) mat.SetFloat("_AO", 1f);
        EditorUtility.SetDirty(mat);
        return mat;
    }

    static void ConfigureTexture(string path, bool srgb, bool alpha)
    {
        if (!File.Exists(path)) return;
        var importer = AssetImporter.GetAtPath(path) as TextureImporter;
        if (importer == null) return;
        importer.textureType = TextureImporterType.Default;
        importer.sRGBTexture = srgb;
        importer.mipmapEnabled = true;
        importer.alphaIsTransparency = alpha;
        importer.SaveAndReimport();
    }
}
#endif