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

/// <summary>
/// 一键修复图集"渗色 / 串图 / 边缘被邻居图片填充"问题。
///
/// 症状：圆形等带透明边缘的图片，四周被其他图片的像素填充；正方形区域采样/裁剪时会取到邻居图。
/// 成因：padding 过小 + 紧致打包(透明边被裁掉) + 未开 Alpha 扩张 + 图集可能被降采样。
///
/// 本工具对图集的 packingSettings 统一设置：
///   padding           4 → 8       相邻 sprite 之间留出大于压缩块的间隙
///   enableTightPacking     off    不再裁掉透明边，sprite 保持完整矩形（正方形区域只含自己）
///   enableRotation         off    不在图集内旋转贴图，避免采样方向错乱（串图）
///   enableAlphaDilation    on     边缘颜色向外扩张，滤色采样不会取到邻居像素
///
/// 改完必须：重建 Addressables 内容 → 重出包。
/// </summary>
public static class AtlasPackingFix
{
    private const int Padding = 8;
    private const bool KeepRotation = false;   // 需要省图集空间时可改回 true

    [MenuItem("Tools/图集工具/修复所有图集(渗色·串图)")]
    public static void FixAll()
    {
        var list = new List<string>();
        foreach (var f in Directory.GetFiles("Assets", "*.spriteatlasv2", SearchOption.AllDirectories))
            list.Add(f.Replace('\\', '/'));
        foreach (var f in Directory.GetFiles("Assets", "*.spriteatlas", SearchOption.AllDirectories))
            list.Add(f.Replace('\\', '/'));

        if (list.Count == 0) { Debug.LogWarning("[图集修复] 没找到任何图集"); return; }
        Apply(list);
    }

    [MenuItem("Tools/图集工具/修复选中图集(渗色·串图)")]
    public static void FixSelected()
    {
        var list = new List<string>();
        foreach (var guid in Selection.assetGUIDs)
        {
            var p = AssetDatabase.GUIDToAssetPath(guid);
            if (p.EndsWith(".spriteatlas") || p.EndsWith(".spriteatlasv2"))
                list.Add(p);
        }
        if (list.Count == 0)
        {
            Debug.LogWarning("[图集修复] 请先在 Project 里选中至少一个 .spriteatlas / .spriteatlasv2");
            return;
        }
        Apply(list);
    }

    private static void Apply(List<string> paths)
    {
        int ok = 0, skip = 0;
        try
        {
            AssetDatabase.StartAssetEditing();
            foreach (var path in paths)
            {
                var importer = AssetImporter.GetAtPath(path);
                if (importer == null) { skip++; continue; }

                // 用反射拿 packingSettings，避免不同 Unity 版本字段可见性差异导致编译问题
                var prop = importer.GetType().GetProperty("packingSettings");
                if (prop == null || !prop.CanRead || !prop.CanWrite)
                {
                    Debug.LogWarning($"[图集修复] 跳过（无 packingSettings）: {path}");
                    skip++;
                    continue;
                }

                object boxed = prop.GetValue(importer);   // 装箱的结构体副本
                var st = boxed.GetType();
                SetField(st, boxed, "padding", Padding);
                SetField(st, boxed, "enableTightPacking", false);
                SetField(st, boxed, "enableRotation", KeepRotation);
                SetField(st, boxed, "enableAlphaDilation", true);
                prop.SetValue(importer, boxed);
                importer.SaveAndReimport();
                ok++;
                Debug.Log($"[图集修复] {Path.GetFileName(path)} → padding={Padding}, TightPacking=off, Rotation={(KeepRotation ? "on" : "off")}, AlphaDilation=on");
            }
        }
        finally
        {
            AssetDatabase.StopAssetEditing();
            AssetDatabase.Refresh();
        }
        Debug.Log($"[图集修复] 完成：处理 {ok} 个，跳过 {skip} 个。请重建 Addressables 内容后重出包。");
    }

    private static void SetField(Type t, object boxed, string name, object value)
    {
        var f = t.GetField(name, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
        if (f != null) f.SetValue(boxed, value);
        else Debug.LogWarning($"[图集修复] 字段不存在，已跳过: {name}");
    }
}