pleroma: add Status.VisibleTo

Pleroma/Models/Status.cs

@@ -154,6 +154,35 @@ public class Status : ASObject
         return ReplyToAccount == user.ID || Mentions.Any(m => m.ID == user.ID);
     }
 
+    /// <summary>
+    /// Returns true if the status is visible to a particular account.
+    /// </summary>
+    public bool VisibleTo(Account account)
+    {
+        if (Author.ID == account.ID)
+            return true;
+
+        switch (Visibility)
+        {
+            case StatusVisibility.Public:
+            case StatusVisibility.Unlisted:
+                return true;
+
+            case StatusVisibility.Local:
+                return Author.Instance == account.Instance;
+
+            case StatusVisibility.Private: //TODO: Not correctly implemented, but finding the correct answer would require fetching the relationship
+            case StatusVisibility.Direct:
+                return Mentions.Any(mention => mention.ID == account.ID);
+
+            case StatusVisibility.List:
+                return false;
+
+            default:
+                return false;
+        }
+    }
+
     public override string ToString() => $"{Author?.Username ?? "unknown"}: \"{Content}\"";
 }