perf: run all searches on isolate

+ allow entering yt local search page before resources are prepared
ref: #61

lib/controller/search_ports_provider.dart

@@ -0,0 +1,57 @@
+import 'dart:async';
+import 'dart:isolate';
+
+import 'package:namida/core/enums.dart';
+import 'package:namida/core/extensions.dart';
+
+typedef _PortsComm = ({ReceivePort items, Completer<SendPort> search});
+
+class SearchPortsProvider {
+  static final SearchPortsProvider inst = SearchPortsProvider._internal();
+  SearchPortsProvider._internal();
+
+  final _ports = <MediaType, _PortsComm?>{};
+
+  Future<void> _disposePort(_PortsComm port) async {
+    port.items.close();
+    (await port.search.future).send('dispose');
+  }
+
+  void disposeAll() {
+    for (final p in _ports.values) {
+      if (p != null) _disposePort(p);
+    }
+    _ports.clear();
+  }
+
+  Future<void> closePorts(MediaType type) async {
+    final port = _ports[type];
+    if (port != null) {
+      await _disposePort(port);
+      _ports[type] = null;
+    }
+  }
+
+  Future<SendPort> preparePorts({
+    required MediaType type,
+    required void Function(dynamic result) onResult,
+    required Future<void> Function(SendPort itemsSendPort) isolateFunction,
+    bool force = false,
+  }) async {
+    final portC = _ports[type];
+    if (portC != null && !force) return await portC.search.future;
+
+    await closePorts(type);
+    _ports[type] = (items: ReceivePort(), search: Completer<SendPort>());
+    final port = _ports[type];
+    port!.items.listen((result) {
+      if (result is SendPort) {
+        port.search.completeIfWasnt(result);
+      } else {
+        onResult(result);
+      }
+    });
+    await isolateFunction(port.items.sendPort);
+    return await port.search.future;
+  }
+}