Add some utils

lib/util/regex.dart

@@ -0,0 +1,7 @@
+final postUrlRegex = RegExp(
+  r'https:\/\/bsky\.app\/profile\/[a-z0-9A-Z\-\.:]+\/post\/[a-z0-9A-Z\-\_\~]+',
+);
+
+final feedUrlRegex = RegExp(
+  r'https:\/\/bsky\.app\/profile\/[a-z0-9A-Z\-\.:]+\/feed\/[a-z0-9A-Z\-\_\~]+',
+);

lib/util/render_timestamp.dart

@@ -0,0 +1,16 @@
+String renderTimestamp(DateTime ts) {
+  final dur = DateTime.now().difference(ts);
+  if (dur < Duration.zero) {
+    return 'in ${dur.inHours.abs()}h';
+  } else if (dur < const Duration(minutes: 1)) {
+    return '${dur.inSeconds}s';
+  } else if (dur < const Duration(hours: 1)) {
+    return '${dur.inMinutes}m';
+  } else if (dur < const Duration(hours: 24)) {
+    return '${dur.inHours}h';
+  } else if (dur < const Duration(days: 30)) {
+    return '${dur.inDays}d';
+  } else {
+    return '${(dur.inDays / 30).round()}mon';
+  }
+}

lib/util/show_popup.dart

@@ -0,0 +1,15 @@
+import 'package:skyfeed/app.dart';
+
+void showPopup(BuildContext context, Function buildItems) {
+  final RenderBox renderBox = context.findRenderObject() as RenderBox;
+
+  final offset = renderBox.localToGlobal(Offset.zero);
+  final left = offset.dx;
+  final top = offset.dy + renderBox.size.height;
+  final right = left + renderBox.size.width;
+  showMenu(
+    context: context,
+    position: RelativeRect.fromLTRB(left, top, right, 0.0),
+    items: buildItems(context),
+  );
+}