Move reshareable logic to extension method w/network prohibitions hardcoded

lib/controls/timeline/interactions_bar_control.dart

@@ -1,16 +1,16 @@
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
 import 'package:logging/logging.dart';
-import 'package:relatica/models/exec_error.dart';
 import 'package:result_monad/result_monad.dart';
 
 import '../../globals.dart';
+import '../../models/exec_error.dart';
 import '../../models/timeline_entry.dart';
-import '../../models/visibility.dart' as v;
 import '../../services/feature_version_checker.dart';
 import '../../services/fediverse_server_validator.dart';
 import '../../services/timeline_manager.dart';
 import '../../utils/active_profile_selector.dart';
+import '../../utils/interaction_availability_util.dart';
 import '../../utils/snackbar_builder.dart';
 
 class InteractionsBarControl extends StatefulWidget {
@@ -181,19 +181,13 @@ class _InteractionsBarControlState extends State<InteractionsBarControl> {
   }
 
   Widget buildReshareButton() {
-    final canReshare = !widget.isMine &&
-        widget.entry.visibility.type == v.VisibilityType.public;
+    final reshareable = widget.entry.getIsReshareable(widget.isMine);
+    final canReshare = reshareable.isReshareable == Reshareable.yes;
     late final String tooltip;
     if (canReshare) {
       tooltip = youReshared ? 'Press to undo reshare' : 'Press to reshare';
     } else {
-      if (widget.isMine) {
-        tooltip = "Can't reshare your own post";
-      } else if (widget.entry.visibility.type != v.VisibilityType.public) {
-        tooltip = "Can't reshare a private post";
-      } else {
-        tooltip = "Can't reshare at this time";
-      }
+      tooltip = reshareable.reason;
     }
     return buildButton(
       youReshared ? Icons.repeat_on_outlined : Icons.repeat,

lib/utils/interaction_availability_util.dart

@@ -0,0 +1,55 @@
+import 'package:relatica/models/timeline_entry.dart';
+import 'package:relatica/models/timeline_network_info.dart';
+
+import '../models/visibility.dart';
+
+enum Reshareable {
+  no,
+  yes,
+}
+
+class ReshareableResult {
+  final Reshareable isReshareable;
+  final String reason;
+
+  const ReshareableResult({required this.isReshareable, required this.reason});
+}
+
+extension InteractionAvailabilityExtension on TimelineEntry {
+  ReshareableResult getIsReshareable(bool isMine) {
+    if (isMine) {
+      return const ReshareableResult(
+        isReshareable: Reshareable.no,
+        reason: "Can't reshare your own post",
+      );
+    }
+
+    if (networkInfo.network == KnownNetworks.threads) {
+      return const ReshareableResult(
+        isReshareable: Reshareable.no,
+        reason: "You have requested to not allow resharing of Threads posts.",
+      );
+    }
+
+    if (networkInfo.network == KnownNetworks.bluesky) {
+      return const ReshareableResult(
+        isReshareable: Reshareable.no,
+        reason:
+            "Resharing of Bluesky posts through the API isn't supported by Friendica.",
+      );
+    }
+
+    if (visibility.type == VisibilityType.public ||
+        visibility.type == VisibilityType.unlisted) {
+      return const ReshareableResult(
+        isReshareable: Reshareable.yes,
+        reason: "Can reshare post",
+      );
+    }
+
+    return const ReshareableResult(
+      isReshareable: Reshareable.no,
+      reason: "Can't reshare private posts",
+    );
+  }
+}