feat(liquid-gen): add liquid-gen app and workspace launch config

.vscode/launch.json

@@ -26,6 +26,27 @@
             "type": "dart",
             "flutterMode": "release"
         },
+        {
+            "name": "liquid-gen",
+            "cwd": "apps/liquid-gen",
+            "request": "launch",
+            "type": "dart"
+        },
+        {
+            "name": "liquid-gen (profile mode)",
+            "cwd": "apps/liquid-gen",
+            "request": "launch",
+            "type": "dart",
+            "flutterMode": "profile"
+        },
+        {
+            "name": "liquid-gen (release mode)",
+            "cwd": "apps/liquid-gen",
+            "request": "launch",
+            "type": "dart",
+            "flutterMode": "release"
+        },
+
         {
             "name": "Update goldens",
             "request": "launch",

apps/liquid-gen/.gitignore

@@ -0,0 +1,45 @@
+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

apps/liquid-gen/.metadata

@@ -0,0 +1,30 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "bd7a4a6b5576630823ca344e3e684c53aa1a0f46"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: bd7a4a6b5576630823ca344e3e684c53aa1a0f46
+      base_revision: bd7a4a6b5576630823ca344e3e684c53aa1a0f46
+    - platform: macos
+      create_revision: bd7a4a6b5576630823ca344e3e684c53aa1a0f46
+      base_revision: bd7a4a6b5576630823ca344e3e684c53aa1a0f46
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'

apps/liquid-gen/README.md

@@ -0,0 +1,3 @@
+# liquid_gen
+
+A new Flutter project.

apps/liquid-gen/analysis_options.yaml

@@ -0,0 +1 @@
+include: package:flutter_lints/flutter.yaml

apps/liquid-gen/lib/ai/genui_service.dart

@@ -0,0 +1,95 @@
+import 'package:flutter/foundation.dart';
+import 'package:genui/genui.dart' as genui;
+import 'package:genui_google_generative_ai/genui_google_generative_ai.dart';
+
+import '../catalog/liquid_catalog.dart';
+import '../services/api_key_service.dart';
+import 'system_instructions.dart';
+
+/// GenUI service that manages the conversation and content generation
+class GenUIService {
+  static final GenUIService instance = GenUIService._();
+  GenUIService._();
+
+  genui.GenUiConversation? _conversation;
+  genui.A2uiMessageProcessor? _messageProcessor;
+  GoogleGenerativeAiContentGenerator? _contentGenerator;
+  ValueChanged<genui.SurfaceAdded>? _onSurfaceAdded;
+  ValueChanged<genui.SurfaceRemoved>? _onSurfaceDeleted;
+
+  /// Set callbacks for surface events
+  void setCallbacks({
+    ValueChanged<genui.SurfaceAdded>? onSurfaceAdded,
+    ValueChanged<genui.SurfaceRemoved>? onSurfaceDeleted,
+  }) {
+    _onSurfaceAdded = onSurfaceAdded;
+    _onSurfaceDeleted = onSurfaceDeleted;
+  }
+
+  /// Initialize the GenUI conversation with Google Gemini
+  ///
+  /// Note: You may see a warning about "Unsupported keyword 'minItems'" when
+  /// GenUI adapts the catalog schema to function tool schemas. This is a known
+  /// GenUI limitation where `minItems` constraints are added to the `components`
+  /// property, which Gemini's function calling API doesn't support in that context.
+  /// The warning says "It will be ignored" and can be safely ignored - functionality
+  /// is not affected. See: https://github.com/flutter/genui/issues/428
+  Future<void> initialize() async {
+    // Get API key
+    final apiKey = await ApiKeyService.instance.getApiKey('gemini');
+    if (apiKey == null || apiKey.isEmpty) {
+      throw Exception('Gemini API key not found. Please set it in settings.');
+    }
+
+    // Create message processor with Liquid Flutter catalog
+    _messageProcessor = genui.A2uiMessageProcessor(
+      catalogs: [LiquidCatalog.catalog],
+    );
+
+    // Create content generator
+    _contentGenerator = GoogleGenerativeAiContentGenerator(
+      catalog: LiquidCatalog.catalog,
+      systemInstruction: systemInstructions,
+      modelName: 'models/gemini-2.5-flash',
+      apiKey: apiKey,
+    );
+
+    // Create conversation
+    _conversation = genui.GenUiConversation(
+      contentGenerator: _contentGenerator!,
+      a2uiMessageProcessor: _messageProcessor!,
+      onSurfaceAdded: _onSurfaceAdded,
+      onSurfaceDeleted: _onSurfaceDeleted,
+    );
+  }
+
+  /// Get the GenUI conversation instance
+  genui.GenUiConversation? get conversation => _conversation;
+
+  /// Get the message processor (host) for GenUiSurface
+  genui.A2uiMessageProcessor? get host => _messageProcessor;
+
+  /// Send a message to the AI
+  Future<void> sendMessage(String text) async {
+    if (_conversation == null) {
+      await initialize();
+    }
+    _conversation?.sendRequest(genui.UserMessage.text(text));
+  }
+
+  /// Dispose resources
+  void dispose() {
+    _conversation?.dispose();
+    _contentGenerator?.dispose();
+    _messageProcessor?.dispose();
+    _conversation = null;
+    _contentGenerator = null;
+    _messageProcessor = null;
+  }
+
+  /// Reinitialize with new API key if needed
+  Future<void> reinitialize() async {
+    dispose();
+    await initialize();
+  }
+}

apps/liquid-gen/lib/ai/system_instructions.dart

@@ -0,0 +1,35 @@
+/// System instructions for GenUI to guide AI in using Liquid Flutter widgets correctly
+const String systemInstructions = '''
+You are an expert UI generation assistant for Liquid Flutter. Your task is to generate Flutter widget trees using Liquid Flutter components.
+
+CRITICAL RULES:
+1. You MUST use ONLY the widgets available in the catalog. Do NOT use Column, Row, or basic Flutter Container widgets.
+2. Use LdAutoSpace instead of Column for arranging items vertically with automatic spacing.
+3. Use LdContainer (from the catalog) for theme-aware containers, not the basic Flutter Container widget.
+4. Use LdScaffold as the root widget for screens with LdAppBar and LdScaffoldBody.
+5. Use LdScaffoldBody with addContainer: true for automatic padding.
+6. Follow the Liquid Flutter design system patterns:
+   - Use LdText.h() for headlines
+   - Use LdText.p() for paragraphs
+   - Use LdText.l() for labels
+   - Use LdText.caption() for captions
+   - Use LdAutoSpace() for vertical layouts with automatic spacing
+   - Use LdCard with padding: EdgeInsets.zero when containing LdListItems
+   - Group related content in LdBundle or LdCard
+
+When generating UI:
+1. Always start with LdScaffold as the root
+2. Add LdAppBar in the appBars array if a title is needed
+3. Use LdScaffoldBody with addContainer: true for the main content
+4. Use LdAutoSpace for arranging widgets vertically
+5. Use appropriate Liquid Flutter components from the catalog
+6. Follow proper nesting and structure
+7. Include appropriate properties for each widget
+
+Example structure:
+- LdScaffold
+  - appBars: [LdAppBar with title]
+  - body: LdScaffoldBody
+    - addContainer: true
+    - children: [LdAutoSpace with content widgets]
+''';