docs: 为缩略图、最近文件相关新增类型补全中文 XML 文档注释

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

FileShare-Services/Services/FileLibrary/VideoThumbnailService.cs

@@ -4,12 +4,22 @@ using System.Text;
 
 namespace FileShare_Services.Services.FileLibrary
 {
+    /// <summary>
+    /// 视频缩略图服务实现，使用 ffmpeg 截取视频帧作为缩略图，使用 ffprobe 提取视频时长。
+    /// </summary>
     public sealed class VideoThumbnailService : IVideoThumbnailService
     {
+        /// <summary>缩略图文件存储目录的绝对路径。</summary>
         private readonly string _thumbnailDir;
+        /// <summary>ffmpeg 可执行文件路径。</summary>
         private readonly string _ffmpegPath;
+        /// <summary>ffprobe 可执行文件路径。</summary>
         private readonly string _ffprobePath;
 
+        /// <summary>
+        /// 初始化视频缩略图服务，解析并验证配置路径，创建缩略图存储目录。
+        /// </summary>
+        /// <param name="options">缩略图存储配置选项。</param>
         public VideoThumbnailService(ThumbnailStorageOptions options)
         {
             _thumbnailDir = Path.IsPathRooted(options.RootPath)
@@ -20,6 +30,7 @@ namespace FileShare_Services.Services.FileLibrary
             Directory.CreateDirectory(_thumbnailDir);
         }
 
+        /// <inheritdoc />
         public Task<GeneratedThumbnail?> GenerateThumbnailAsync(int libraryRootId, string videoPath, CancellationToken ct = default)
         {
             var hash = ComputeHash(videoPath);
@@ -69,6 +80,7 @@ namespace FileShare_Services.Services.FileLibrary
             }
         }
 
+        /// <inheritdoc />
         public string GetAbsolutePath(string relativePath)
         {
             var root = Path.GetFullPath(_thumbnailDir);
@@ -82,6 +94,11 @@ namespace FileShare_Services.Services.FileLibrary
             return fullPath;
         }
 
+        /// <summary>
+        /// 解析可执行文件路径，支持绝对路径和相对于应用程序基目录的相对路径。
+        /// </summary>
+        /// <param name="executablePath">配置中的原始可执行文件路径。</param>
+        /// <returns>可用的绝对路径。</returns>
         private static string ResolveExecutablePath(string executablePath)
         {
             if (Path.IsPathRooted(executablePath))
@@ -95,6 +112,7 @@ namespace FileShare_Services.Services.FileLibrary
                 : executablePath;
         }
 
+        /// <inheritdoc />
         public double? GetVideoDuration(string videoPath)
         {
             try
@@ -130,6 +148,11 @@ namespace FileShare_Services.Services.FileLibrary
             }
         }
 
+        /// <summary>
+        /// 计算视频文件路径的 MD5 哈希值，用于生成唯一的缩略图文件名。
+        /// </summary>
+        /// <param name="videoPath">视频文件的绝对路径。</param>
+        /// <returns>小写的十六进制 MD5 哈希字符串。</returns>
         public string ComputeHash(string videoPath) =>
             Convert.ToHexString(MD5.HashData(Encoding.UTF8.GetBytes(videoPath))).ToLowerInvariant();
     }