chore: improve validation and error handling in audio processing

- Added a check for a non-empty request clip in the ProcessAudio method
- Added ArgumentNullExceptions to the DownloadAudioAsync methods if the input is null or empty
- Implemented a check in the SoundButtons class to return a BadRequestResult if there source.VideoId, req.Form.GetFirstValue("clip") and req.Form.Files.Count are all empty
- Created a SourceCheck function to validate a Source object
- Refactored time invalidation check and error message to be more descriptive

Signed-off-by: 陳鈞 <jim60105@gmail.com>

SoundButtons/Functions/ProcessAudio.cs

@@ -39,7 +39,7 @@ public static async Task<string> ProcessAudioAsync(
             await ProcessAudioHelper.DownloadAudioAsync(youtubeDLPath, tempPath, request.Source);
             await ProcessAudioHelper.CutAudioAsync(tempPath, request.Source);
         }
-        else
+        else if (!string.IsNullOrEmpty(request.Clip))
         {
             await ProcessAudioHelper.DownloadAudioAsync(youtubeDLPath, tempPath, request.Clip);
         }

SoundButtons/Helper/ProcessAudioHelper.cs

@@ -64,6 +64,8 @@ string UseBuiltInYtdlp()
 
     internal static Task<int> DownloadAudioAsync(string youtubeDLPath, string tempPath, Source source)
     {
+        if (string.IsNullOrEmpty(source.VideoId)) throw new ArgumentNullException(nameof(source));
+
         OptionSet optionSet = new()
         {
             // 最佳音質
@@ -95,6 +97,8 @@ internal static Task<int> DownloadAudioAsync(string youtubeDLPath, string tempPa
 
     internal static Task<int> DownloadAudioAsync(string youtubeDLPath, string tempPath, string url)
     {
+        if (string.IsNullOrEmpty(url)) throw new ArgumentNullException(nameof(url));
+
         OptionSet optionSet = new()
         {
             NoCheckCertificates = true,

SoundButtons/SoundButtons.cs

@@ -31,7 +31,15 @@ public static async Task<IActionResult> HttpStart(
         if (!req.ContentType.Contains("multipart/form-data;"))
             return new BadRequestResult();
 
-        Source source = GetSourceInfo(req);
+        Source source = SourceCheck(GetSourceInfo(req));
+
+        if (string.IsNullOrEmpty(source.VideoId)
+            && string.IsNullOrEmpty(req.Form.GetFirstValue("clip"))
+            && req.Form.Files.Count == 0)
+        {
+            Logger.Error("No source found.");
+            return new BadRequestResult();
+        }
 
         // 啟動長輪詢
         return await StartOrchestrator(req: req,
@@ -213,17 +221,27 @@ private static async Task<string> ProcessAudioFileAsync(HttpRequest req, Source
         {
             return await ProcessAudioFromFileUpload(files);
         }
-        // source檢核
 
-        if (string.IsNullOrEmpty(source.VideoId)
-            || source.End - source.Start <= 0
+        return "";
+    }
+
+    private static Source SourceCheck(Source source)
+    {
+        if (string.IsNullOrEmpty(source.VideoId))
+        {
+            source.Start = 0;
+            source.End = 0;
+            return source;
+        }
+
+        if (source.End - source.Start <= 0
             || source.End - source.Start > 180)
         {
-            Logger.Error("video time invalid: {start}, {end}", source.Start, source.End);
-            throw new Exception($"video time invalid: {source.Start}, {source.End}");
+            Logger.Error("Video time invalid: {start}, {end}", source.Start, source.End);
+            throw new Exception($"Video time invalid: {source.Start}, {source.End}");
         }
 
-        return "";
+        return source;
     }
 
     private static async Task<string> ProcessAudioFromFileUpload(IFormFileCollection files)