feat: extension support (#78)

ui/flutter/lib/app/modules/extension/controllers/extension_controller.dart

@@ -0,0 +1,46 @@
+import 'package:get/get.dart';
+import 'package:gopeed/api/api.dart';
+
+import '../../../../api/model/extension.dart';
+
+class ExtensionController extends GetxController {
+  final extensions = <Extension>[].obs;
+  final updateFlags = <String, String>{}.obs;
+  final devMode = false.obs;
+  var _devModeCount = 0;
+
+  @override
+  void onInit() async {
+    super.onInit();
+    await load();
+    checkUpdate();
+  }
+
+  Future<void> load() async {
+    extensions.value = await getExtensions();
+  }
+
+  Future<void> checkUpdate() async {
+    for (final ext in extensions) {
+      final resp = await upgradeCheckExtension(ext.identity);
+      if (resp.newVersion.isNotEmpty) {
+        updateFlags[ext.identity] = resp.newVersion;
+      }
+    }
+  }
+
+  // Try to open dev mode when install button is clicked 5 times in 2 seconds
+  void tryOpenDevMode() {
+    if (_devModeCount == 0) {
+      Future.delayed(const Duration(seconds: 2), () {
+        if (devMode.value) return;
+        devMode.value = false;
+        _devModeCount = 0;
+      });
+    }
+    _devModeCount++;
+    if (_devModeCount >= 5) {
+      devMode.value = true;
+    }
+  }
+}