fix: share chat exports instead of app-private path

lib/screens/assistant_screen.dart

@@ -13,6 +13,7 @@ import 'package:nova_assistant/models/model_info.dart';
 import 'package:nova_assistant/services/document_extractor.dart';
 import 'package:nova_assistant/services/chat_history_service.dart';
 import 'package:nova_assistant/services/conversation_summary_service.dart';
+import 'package:nova_assistant/services/export_service.dart';
 import 'package:nova_assistant/services/model_orchestrator.dart';
 import 'package:nova_assistant/services/model_release_policy.dart';
 import 'package:nova_assistant/services/tts_service.dart';
@@ -1544,15 +1545,27 @@ class _AssistantScreenState extends State<AssistantScreen>
                   PopupMenuButton<String>(
                     tooltip: 'Export conversation',
                     onSelected: (format) async {
-                      String? path;
-                      path = format == 'text'
+                      final content = format == 'text'
                           ? await ChatHistoryService.exportAsText()
                           : await ChatHistoryService.exportAsJson();
-                      if (path != null && mounted) {
+                      if (!mounted) return;
+                      if (content == null) {
                         ScaffoldMessenger.of(context).showSnackBar(
-                          SnackBar(
-                            content: Text('Exported to:\n$path'),
-                            duration: const Duration(seconds: 4),
+                          const SnackBar(content: Text('Nothing to export')),
+                        );
+
+                        return;
+                      }
+
+                      final fileName = format == 'text'
+                          ? 'nova_export.txt'
+                          : 'nova_export.json';
+                      await ExportService.instance.shareText(content, fileName);
+                      if (mounted) {
+                        ScaffoldMessenger.of(context).showSnackBar(
+                          const SnackBar(
+                            content: Text('Share sheet opened'),
+                            duration: Duration(seconds: 2),
                           ),
                         );
                       }
@@ -2109,11 +2122,20 @@ class _AssistantScreenState extends State<AssistantScreen>
                   ),
                   const SizedBox(width: 8),
                   VoiceInputButton(
+                    onPartial: (partial) {
+                      _inputController.text = partial;
+                      _inputController.selection = TextSelection.collapsed(
+                        offset: partial.length,
+                      );
+                    },
                     onTranscription: (transcript) {
-                      if (transcript.isNotEmpty) {
-                        _inputController.text = transcript;
-                        _sendMessage();
+                      if (transcript.isEmpty) return;
+                      _inputController.text = transcript;
+                      if (_isGenerating || ModelOrchestrator.instance.isBusy) {
+                        // Leave full text in the field for the user to send.
+                        return;
                       }
+                      _sendMessage();
                     },
                   ),
                   const SizedBox(width: 8),

lib/screens/assistant_screen_beginner.dart

@@ -489,11 +489,19 @@ class _AssistantScreenBeginnerState extends State<AssistantScreenBeginner> {
           ),
           const SizedBox(width: 12),
           VoiceInputButton(
+            onPartial: (partial) {
+              _inputController.text = partial;
+              _inputController.selection = TextSelection.collapsed(
+                offset: partial.length,
+              );
+            },
             onTranscription: (text) {
-              if (text.isNotEmpty) {
-                _inputController.text = text;
-                _sendMessage();
+              if (text.isEmpty) return;
+              _inputController.text = text;
+              if (_isGenerating || ModelOrchestrator.instance.isBusy) {
+                return;
               }
+              _sendMessage();
             },
           ),
           const SizedBox(width: 8),

lib/screens/chat_history_screen.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:nova_assistant/models/conversation.dart';
 import 'package:nova_assistant/screens/assistant_screen.dart';
 import 'package:nova_assistant/services/chat_history_service.dart';
+import 'package:nova_assistant/services/export_service.dart';
 
 class ChatHistoryScreen extends StatefulWidget {
   const ChatHistoryScreen({super.key});
@@ -196,17 +197,24 @@ class _ChatHistoryScreenState extends State<ChatHistoryScreen> {
   }
 
   Future<void> _exportConversation(Conversation conversation) async {
-    final path = await ChatHistoryService.exportConversationAsText(
+    final content = await ChatHistoryService.exportConversationAsText(
       conversation.id,
     );
+    if (!mounted) return;
+    if (content == null) {
+      ScaffoldMessenger.of(context)
+          .showSnackBar(const SnackBar(content: Text('Export failed')));
+
+      return;
+    }
+
+    await ExportService.instance.shareText(
+      content,
+      'nova_chat_${conversation.id}.txt',
+    );
     if (mounted) {
-      if (path != null) {
-        ScaffoldMessenger.of(context)
-            .showSnackBar(SnackBar(content: Text('Exported to:\n$path')));
-      } else {
-        ScaffoldMessenger.of(context)
-            .showSnackBar(const SnackBar(content: Text('Export failed')));
-      }
+      ScaffoldMessenger.of(context)
+          .showSnackBar(const SnackBar(content: Text('Share sheet opened')));
     }
   }
 

lib/services/chat_history_service.dart

@@ -1,8 +1,6 @@
 import 'dart:convert';
-import 'dart:io';
 
 import 'package:flutter/foundation.dart';
-import 'package:path_provider/path_provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:nova_assistant/models/chat_message.dart';
 import 'package:nova_assistant/models/conversation.dart';
@@ -187,6 +185,7 @@ class ChatHistoryService {
     await p.remove(_key);
   }
 
+  /// Builds a plain-text export of all conversations (no file write).
   static Future<String?> exportAsText() async {
     try {
       final conversations = await loadConversations();
@@ -206,35 +205,18 @@ class ChatHistoryService {
         buffer.writeln('-' * 30);
 
         for (final msg in convo.messages) {
-          final time = msg.timestamp.toLocal();
-          final timeStr =
-              '${time.hour.toString().padLeft(2, '0')}:${time.minute.toString().padLeft(2, '0')}';
-          final sender = msg.isUser ? 'User' : 'Assistant';
-          buffer.writeln('[$timeStr] $sender:');
-          buffer.writeln(msg.text);
-          if (msg.imageData != null) buffer.writeln('[Image attached]');
-          if (msg.toolCalls != null && msg.toolCalls!.isNotEmpty) {
-            buffer.writeln('[Tool calls: ${msg.toolCalls}]');
-          }
-          if (msg.thinking != null && msg.thinking!.isNotEmpty) {
-            buffer.writeln('[Thinking: ${msg.thinking}]');
-          }
-          buffer.writeln();
+          _appendMessage(buffer, msg);
         }
         buffer.writeln('=' * 50);
       }
 
-      final dir = await getApplicationDocumentsDirectory();
-      final file = File(
-        '${dir.path}/nova_export_${DateTime.now().millisecondsSinceEpoch}.txt',
-      );
-      await file.writeAsString(buffer.toString());
-      return file.path;
+      return buffer.toString();
     } on Exception {
       return null;
     }
   }
 
+  /// Builds a plain-text export of one conversation (no file write).
   static Future<String?> exportConversationAsText(String conversationId) async {
     try {
       final convo = await getConversation(conversationId);
@@ -248,33 +230,16 @@ class ChatHistoryService {
       buffer.writeln('---');
 
       for (final msg in convo.messages) {
-        final time = msg.timestamp.toLocal();
-        final timeStr =
-            '${time.hour.toString().padLeft(2, '0')}:${time.minute.toString().padLeft(2, '0')}';
-        final sender = msg.isUser ? 'User' : 'Assistant';
-        buffer.writeln('[$timeStr] $sender:');
-        buffer.writeln(msg.text);
-        if (msg.imageData != null) buffer.writeln('[Image attached]');
-        if (msg.toolCalls != null && msg.toolCalls!.isNotEmpty) {
-          buffer.writeln('[Tool calls: ${msg.toolCalls}]');
-        }
-        if (msg.thinking != null && msg.thinking!.isNotEmpty) {
-          buffer.writeln('[Thinking: ${msg.thinking}]');
-        }
-        buffer.writeln();
+        _appendMessage(buffer, msg);
       }
 
-      final dir = await getApplicationDocumentsDirectory();
-      final file = File(
-        '${dir.path}/nova_export_${DateTime.now().millisecondsSinceEpoch}.txt',
-      );
-      await file.writeAsString(buffer.toString());
-      return file.path;
+      return buffer.toString();
     } on Exception {
       return null;
     }
   }
 
+  /// Builds a JSON export of all conversations (no file write).
   static Future<String?> exportAsJson() async {
     try {
       final conversations = await loadConversations();
@@ -286,14 +251,27 @@ class ChatHistoryService {
         'conversations': conversations.map((c) => c.toJson()).toList(),
       };
 
-      final dir = await getApplicationDocumentsDirectory();
-      final file = File(
-        '${dir.path}/nova_export_${DateTime.now().millisecondsSinceEpoch}.json',
-      );
-      await file.writeAsString(jsonEncode(export));
-      return file.path;
+      return const JsonEncoder.withIndent('  ').convert(export);
     } on Exception {
       return null;
     }
   }
+
+  static void _appendMessage(StringBuffer buffer, ChatMessage msg) {
+    final time = msg.timestamp.toLocal();
+    final timeStr =
+        '${time.hour.toString().padLeft(2, '0')}:'
+        '${time.minute.toString().padLeft(2, '0')}';
+    final sender = msg.isUser ? 'User' : 'Assistant';
+    buffer.writeln('[$timeStr] $sender:');
+    buffer.writeln(msg.text);
+    if (msg.imageData != null) buffer.writeln('[Image attached]');
+    if (msg.toolCalls != null && msg.toolCalls!.isNotEmpty) {
+      buffer.writeln('[Tool calls: ${msg.toolCalls}]');
+    }
+    if (msg.thinking != null && msg.thinking!.isNotEmpty) {
+      buffer.writeln('[Thinking: ${msg.thinking}]');
+    }
+    buffer.writeln();
+  }
 }

lib/services/model_orchestrator.dart

@@ -30,6 +30,7 @@ import 'package:nova_assistant/services/platform_adaptation_service.dart';
 import 'package:nova_assistant/utils/alarm_time_parser.dart';
 import 'package:nova_assistant/utils/agent_debug_log.dart';
 import 'package:nova_assistant/utils/message_limits.dart';
+import 'package:nova_assistant/utils/open_app_intent_parser.dart';
 import 'package:nova_assistant/services/memory_diagnostics_service.dart';
 import 'package:nova_assistant/services/session_history_reinjection.dart';
 
@@ -1578,6 +1579,29 @@ class ModelOrchestrator {
         return;
       }
 
+      // Deterministic open-app shortcut (YouTube, Settings, etc.).
+      final openPackage = OpenAppIntentParser.tryParsePackage(query);
+      if (openPackage != null) {
+        _statusController.add('Opening app...');
+        final result = await ToolExecutorService.instance.openApp(openPackage);
+        final ok = result['success'] == true;
+        yield InferenceResult(
+          text: ok
+              ? 'Opened $openPackage.'
+              : 'Could not open the app: ${result['error'] ?? 'unknown error'}',
+          model: selector.primaryHeavy,
+          isStreaming: false,
+          toolCalls: [
+            {
+              'name': 'open_app',
+              'args': {'package': openPackage},
+              'result': result,
+            },
+          ],
+        );
+        return;
+      }
+
       // Check if there are image attachments that need vision processing
       final hasImageAttachments = attachments.any((att) {
         if (att.type != AttachedDataType.file) return false;
@@ -1702,6 +1726,7 @@ class ModelOrchestrator {
       }
 
       final chatTools = _toolsForCreateChat(model, tools);
+      final textToolPrompt = chatTools.isEmpty && tools.isNotEmpty;
       final wasNull = _activeChat == null;
       if (wasNull) {
         _isLoadingModel = true;
@@ -1713,6 +1738,7 @@ class ModelOrchestrator {
             model,
             ragContext,
             _capContextInjection(attachmentContext),
+            textToolPrompt ? tools : null,
           ),
           tools: chatTools,
           supportImage: model.hasVision && _activeModelSupportsImage,
@@ -2283,6 +2309,7 @@ class ModelOrchestrator {
     NovaModel model, [
     String? ragContext,
     String? attachmentContext,
+    List<Tool>? textTools,
   ]) async {
     final compact =
         !kIsWeb &&
@@ -2312,6 +2339,15 @@ class ModelOrchestrator {
       buffer.write('\n\n${await _languageInstruction()}');
     }
 
+    // Compact Android prompts drop the role's tool list — restore capability
+    // so the model does not claim it cannot open apps / set alarms.
+    // Gate to Android only: web FC-off must not get "Android device" wording.
+    final isAndroid =
+        !kIsWeb && defaultTargetPlatform == TargetPlatform.android;
+    if (isAndroid && (compact || (textTools != null && textTools.isNotEmpty))) {
+      buffer.write(_deviceToolsCapabilitySuffix(textTools));
+    }
+
     if (_adultModeEnabled) {
       buffer.write(AdultModePolicy.systemPromptSuffix(compact: compact));
     }
@@ -2342,6 +2378,27 @@ class ModelOrchestrator {
     return buffer.toString();
   }
 
+  /// Short capability block for on-device tools (and text-JSON FC when native FC
+  /// is unavailable on Android Gemma 4).
+  String _deviceToolsCapabilitySuffix(List<Tool>? textTools) {
+    final names = (textTools ?? const <Tool>[])
+        .map((t) => t.name)
+        .where((n) => n.isNotEmpty)
+        .toList();
+    final listed = names.isEmpty
+        ? 'get_time, set_alarm, cancel_alarm, open_app, open_settings, search_web'
+        : names.join(', ');
+
+    return ' You control this Android device via tools: $listed. '
+        'When the user asks to open an app, set/cancel an alarm, open settings, '
+        'or search the web, call the tool immediately — do not say you lack '
+        'device access. '
+        'open_app packages: com.google.android.youtube, com.android.settings, '
+        'com.android.chrome. '
+        'If native function calling is unavailable, reply with only JSON like '
+        '{"name":"open_app","arguments":{"package":"com.google.android.youtube"}}.';
+  }
+
   static AgentIdentity? _cachedIdentity;
 
   static AgentIdentity? _getCachedIdentity() => _cachedIdentity;

lib/tools/tool_definitions.dart

@@ -88,14 +88,18 @@ class NovaTools {
     name: 'open_app',
     description:
         'Open an application on the device. '
-        'Use this ONLY when the user explicitly asks to open '
-        'or launch a specific application.',
+        'Use when the user asks to open/launch an app (English or German: '
+        'open, launch, öffne, starte). '
+        'Common packages: YouTube=com.google.android.youtube, '
+        'Settings=com.android.settings, Chrome=com.android.chrome, '
+        'Spotify=com.spotify.music, Maps=com.google.android.apps.maps.',
     parameters: {
       'type': 'object',
       'properties': {
         'package': {
           'type': 'string',
-          'description': 'App package name (e.g. com.twitter.android)',
+          'description':
+              'Android package name, e.g. com.google.android.youtube',
         },
       },
       'required': ['package'],