External File Storage: Allow to suggest a filename in SaveFile (#3273)

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#### Summary <!-- Provide a general summary of your changes -->
Allows to predefine the FileName:
```
trigger OnAction()
var
    ExternalFileStorage: Codeunit "External File Storage";
    Path: Text;
begin
    ExternalFileStorage.Initialize("File Scenario"::Default);
    Path := ExternalFileStorage.SaveFile('2023', 'Invoice_1234', 'pdf', 'Save invoice...');
end;
```


![image](https://github.com/user-attachments/assets/4835956d-5287-49df-b3f1-5bb45375b27d)

#### Work Item(s) <!-- Add the issue number here after the #. The issue
needs to be open and approved. Submitting PRs with no linked issues or
unapproved issues is highly discouraged. -->
Fixes #3272

Fixes
[AB#571521](https://dynamicssmb2.visualstudio.com/1fcb79e7-ab07-432a-a3c6-6cf5a88ba4a5/_workitems/edit/571521)

Co-authored-by: Thomas Williamson <[email protected]>

Author: IceOnly

src/System Application/App/External File Storage/src/FileStorage/ExternalFileStorage.Codeunit.al

@@ -224,7 +224,7 @@ codeunit 9454 "External File Storage"
     var
         DefaultSaveFileTitleLbl: Label 'Save as';
     begin
-        exit(SaveFile(Path, FileExtension, DefaultSaveFileTitleLbl));
+        exit(SaveFile(Path, '', FileExtension, DefaultSaveFileTitleLbl));
     end;
 
     /// <summary>
@@ -236,7 +236,20 @@ codeunit 9454 "External File Storage"
     /// <returns>Returns the selected file path.</returns>
     procedure SaveFile(Path: Text; FileExtension: Text; DialogTitle: Text): Text
     begin
-        exit(ExternalFileStorageImpl.SaveFile(Path, FileExtension, DialogTitle));
+        exit(SaveFile(Path, '', FileExtension, DialogTitle));
+    end;
+
+    /// <summary>
+    /// Opens a save to dialog.
+    /// </summary>
+    /// <param name="Path">Start path of the dialog.</param>
+    /// <param name="FileNameSuggestion">Suggested file name for the dialog.</param>
+    /// <param name="FileExtension">The file extension without dot (like pdf or txt).</param>
+    ///  <param name="DialogTitle">Title of the selection dialog.</param>
+    /// <returns>Returns the selected file path.</returns>
+    procedure SaveFile(Path: Text; FileNameSuggestion: Text; FileExtension: Text; DialogTitle: Text): Text
+    begin
+        exit(ExternalFileStorageImpl.SaveFile(Path, FileNameSuggestion, FileExtension, DialogTitle));
     end;
 
     /// <summary>
@@ -246,4 +259,4 @@ codeunit 9454 "External File Storage"
     begin
         ExternalFileStorageImpl.BrowseAccount();
     end;
-}
+}

src/System Application/App/External File Storage/src/FileStorage/ExternalFileStorageImpl.Codeunit.al

@@ -184,7 +184,7 @@ codeunit 9455 "External File Storage Impl."
         exit(CombinePath(TempFileAccountContent."Parent Directory", TempFileAccountContent.Name));
     end;
 
-    procedure SaveFile(Path: Text; FileExtension: Text; DialogTitle: Text): Text
+    procedure SaveFile(Path: Text; FileNameSuggestion: Text; FileExtension: Text; DialogTitle: Text): Text
     var
         StorageBrowser: Page "Storage Browser";
         FileName, FileNameWithExtension : Text;
@@ -199,7 +199,7 @@ codeunit 9455 "External File Storage Impl."
 
         StorageBrowser.SetPageCaption(DialogTitle);
         StorageBrowser.SetFileAccount(TempCurrFileAccount);
-        StorageBrowser.EnableSaveFileLookupMode(Path, FileExtension);
+        StorageBrowser.EnableSaveFileLookupMode(Path, FileNameSuggestion, FileExtension);
         if StorageBrowser.RunModal() <> Action::LookupOK then
             exit('');
 

src/System Application/App/External File Storage/src/Lookup/StorageBrowser.Page.al

@@ -161,12 +161,13 @@ page 9455 "Storage Browser"
         BrowseFolder(Path);
     end;
 
-    internal procedure EnableSaveFileLookupMode(Path: Text; FileExtension: Text)
+    internal procedure EnableSaveFileLookupMode(Path: Text; FileNameSuggestion: Text; FileExtension: Text)
     var
         FileFilterTok: Label '*.%1', Locked = true;
     begin
         ShowFileName := true;
         FileFilter := StrSubstNo(FileFilterTok, FileExtension);
+        SaveFileName := FileNameSuggestion;
         EnableLookupMode();
         BrowseFolder(Path);
     end;
@@ -204,4 +205,4 @@ page 9455 "Storage Browser"
     begin
         FileAccountBrowserMgt.BrowseFolder(Rec, Path, CurrentPath, DoNotLoadFiles, FileFilter);
     end;
-}
+}