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

public static class LocalImageLoader
{
    /// <summary>
    /// 加载文件夹下的所有图片，返回 Texture2D 列表
    /// </summary>
    /// <param name="folderPath">图片文件夹完整路径</param>
    public static List<Texture2D> LoadImages(string folderPath)
    {
        List<Texture2D> textures = new List<Texture2D>();

        if (!Directory.Exists(folderPath))
        {
            Debug.LogError($"[LocalImageLoader] 文件夹不存在: {folderPath}");
            return textures;
        }

        string[] files = Directory.GetFiles(folderPath);

        foreach (string file in files)
        {
            if (!IsImageFile(file))
                continue;

            byte[] data = File.ReadAllBytes(file);
            Texture2D tex = new Texture2D(2, 2, TextureFormat.RGBA32, false);

            if (tex.LoadImage(data))
            {
                tex.name = Path.GetFileNameWithoutExtension(file);
                textures.Add(tex);
            }
            else
            {
                Object.Destroy(tex);
                Debug.LogWarning($"图片加载失败: {file}");
            }
        }

        return textures;
    }

    /// <summary>
    /// 加载单张本地图片
    /// </summary>
    /// <param name="filePath">图片完整路径</param>
    /// <returns>Texture2D，失败返回 null</returns>
    public static Texture2D LoadImage(string filePath)
    {
        if (!File.Exists(filePath))
        {
            Debug.LogError($"[LocalImageLoader] 图片不存在: {filePath}");
            return null;
        }

        if (!IsImageFile(filePath))
        {
            Debug.LogError($"[LocalImageLoader] 非图片格式: {filePath}");
            return null;
        }

        try
        {
            byte[] data = File.ReadAllBytes(filePath);
            Texture2D tex = new Texture2D(2, 2, TextureFormat.RGBA32, false);

            if (!tex.LoadImage(data))
            {
                Object.Destroy(tex);
                Debug.LogError($"[LocalImageLoader] 图片解析失败: {filePath}");
                return null;
            }

            tex.name = Path.GetFileNameWithoutExtension(filePath);
            return tex;
        }
        catch (System.Exception e)
        {
            Debug.LogError($"[LocalImageLoader] 加载图片异常: {e.Message}");
            return null;
        }
    }

    private static bool IsImageFile(string path)
    {
        string ext = Path.GetExtension(path).ToLower();
        return ext == ".png" || ext == ".jpg" || ext == ".jpeg";
    }
}