Fixed attached files silently reaching the AI as empty documents (#904)

app/MindWork AI Studio/Tools/FileExtractionErrorCode.cs

@@ -0,0 +1,86 @@
+namespace AIStudio.Tools;
+
+/// <summary>
+/// Why reading a file failed. The Rust runtime reports these codes as part of the content
+/// stream, so the app can tell the user what happened instead of showing an empty document.
+/// </summary>
+public enum FileExtractionErrorCode
+{
+    /// <summary>
+    /// No failure happened.
+    /// </summary>
+    NONE,
+
+    /// <summary>
+    /// A code this version does not know, e.g. from a newer runtime.
+    /// </summary>
+    UNKNOWN,
+
+    //
+    // Codes reported by the Rust runtime:
+    //
+
+    INVALID_REQUEST,
+    FILE_NOT_FOUND,
+    FILE_NOT_READABLE,
+
+    /// <summary>
+    /// Another program holds the file open and denies reading it.
+    /// </summary>
+    FILE_LOCKED,
+
+    FORMAT_DETECTION_FAILED,
+    NOT_A_VALID_PDF,
+    NOT_A_VALID_SPREADSHEET,
+    PDFIUM_UNAVAILABLE,
+    PDF_ENCRYPTED,
+    PAGE_EXTRACTION_FAILED,
+    NO_TEXT_EXTRACTED,
+
+    /// <summary>
+    /// The content does not match the file extension. This is a notice, not a failure: the file
+    /// was read according to its content.
+    /// </summary>
+    EXTENSION_MISMATCH,
+
+    /// <summary>
+    /// The file was read as text, but its bytes are not text.
+    /// </summary>
+    NOT_TEXT_CONTENT,
+
+    /// <summary>
+    /// The file is an executable, no matter what its extension claims.
+    /// </summary>
+    EXECUTABLE_REJECTED,
+    UNSUPPORTED,
+    INTERNAL,
+
+    //
+    // Codes reported by the app itself:
+    //
+
+    /// <summary>
+    /// Reading the file needs Pandoc, which is not available.
+    /// </summary>
+    PANDOC_UNAVAILABLE,
+
+    /// <summary>
+    /// The runtime answered with an unsuccessful HTTP status.
+    /// </summary>
+    REQUEST_FAILED,
+
+    /// <summary>
+    /// Reading the file took longer than the app is willing to wait.
+    /// </summary>
+    TIMEOUT,
+
+    /// <summary>
+    /// The runtime sent something the app could not deserialize.
+    /// </summary>
+    INVALID_RESPONSE,
+
+    /// <summary>
+    /// The extraction finished without reporting a failure, but produced no content at all.
+    /// </summary>
+    NO_CONTENT,
+}