using UnityEngine;
using UnityEngine.UI;
using SFB;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;

public class MultiGroupSpriteMerger : MonoBehaviour
{
    public Button selectFolderButton;
    public Text statusText;

    void Start()
    {
        selectFolderButton.onClick.AddListener(OnSelectFolder);
    }

    void OnSelectFolder()
    {
        var paths = StandaloneFileBrowser.OpenFolderPanel("选择包含序列帧图片的文件夹", "", false);
        if (paths.Length > 0)
        {
            ProcessAllGroups(paths[0]);
        }
    }

    void ProcessAllGroups(string folderPath)
    {
        statusText.text = "开始读取图片...";

        string[] files = Directory.GetFiles(folderPath, "*.png");
        Dictionary<int, Dictionary<int, List<Texture2D>>> groupMap = new();

        Regex regex = new Regex(@"(\d+)_(\d+)\.png");

        foreach (var path in files)
        {
            string fileName = Path.GetFileName(path);
            Match match = regex.Match(fileName);
            if (!match.Success) continue;

            int x = int.Parse(match.Groups[1].Value);
            int groupIndex = (x - 1) / 8 + 1;
            int direction = (x - 1) % 8 + 1;

            Texture2D tex = new Texture2D(2, 2);
            if (!tex.LoadImage(File.ReadAllBytes(path)))
            {
                Debug.LogWarning($"加载图片失败: {fileName}");
                continue;
            }

            tex.name = fileName;

            if (!groupMap.ContainsKey(groupIndex))
                groupMap[groupIndex] = new Dictionary<int, List<Texture2D>>();

            if (!groupMap[groupIndex].ContainsKey(direction))
                groupMap[groupIndex][direction] = new List<Texture2D>();

            groupMap[groupIndex][direction].Add(tex);
        }

        int exportedCount = 0;

        foreach (var group in groupMap)
        {
            int groupId = group.Key;
            var directions = group.Value;

            List<int> rowHeights = new();
            List<List<Texture2D>> rows = new();
            List<int> rowWidths = new();

            foreach (var dir in directions)
            {
                var frames = dir.Value;
                int maxH = 0, totalW = 0;

                // 排序帧
                frames.Sort((a, b) =>
                {
                    var ma = Regex.Match(a.name, @"\d+_(\d+)");
                    var mb = Regex.Match(b.name, @"\d+_(\d+)");
                    return int.Parse(ma.Groups[1].Value).CompareTo(int.Parse(mb.Groups[1].Value));
                });

                foreach (var tex in frames)
                {
                    totalW += tex.width;
                    maxH = Mathf.Max(maxH, tex.height);
                }

                rowWidths.Add(totalW);
                rowHeights.Add(maxH);
                rows.Add(frames);
            }

            int totalHeight = 0;
            foreach (int h in rowHeights) totalHeight += h;

            int totalWidth = 0;
            foreach (int w in rowWidths) totalWidth = Mathf.Max(totalWidth, w);

            Texture2D result = new Texture2D(totalWidth, totalHeight, TextureFormat.RGBA32, false);
            Color[] clear = new Color[totalWidth * totalHeight];
            for (int i = 0; i < clear.Length; i++) clear[i] = new Color(0, 0, 0, 0);
            result.SetPixels(clear);

            int yOffset = totalHeight;
            for (int row = 0; row < rows.Count; row++)
            {
                List<Texture2D> frames = rows[row];
                int xOffset = 0;
                int rowHeight = rowHeights[row];
                yOffset -= rowHeight;

                foreach (var tex in frames)
                {
                    try
                    {
                        Color[] pixels = tex.GetPixels();
                        if (pixels.Length != tex.width * tex.height)
                        {
                            Debug.LogWarning($"跳过尺寸异常图像: {tex.name}");
                            continue;
                        }
                        result.SetPixels(xOffset, yOffset + (rowHeight - tex.height), tex.width, tex.height, pixels);
                        xOffset += tex.width;
                    }
                    catch (System.Exception ex)
                    {
                        Debug.LogError($"绘图出错: {tex.name} - {ex.Message}");
                    }
                }
            }

            result.Apply();
            string savePath = Path.Combine(folderPath, $"combined_group_{groupId}.png");
            File.WriteAllBytes(savePath, result.EncodeToPNG());
            Debug.Log($"导出完成：{savePath}");
            exportedCount++;
        }

        statusText.text = $"完成，共导出 {exportedCount} 张大图";
    }
}