Przebudowanie aplikacji, usprawnione AI, dodanie combo buildera

lib/presentation/settings/ai_model_settings_controller.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:io';
 
 import 'package:archive/archive_io.dart';
@@ -27,12 +28,24 @@ Future<String> _llamaArchiveUrl() async {
   throw UnsupportedError('Unsupported platform: ${Platform.operatingSystem}');
 }
 
-@riverpod
+// keepAlive: a download must survive navigating away from the settings /
+// welcome screen — otherwise leaving the page silently drops its progress.
+@Riverpod(keepAlive: true)
 class AiModelSettingsController extends _$AiModelSettingsController {
   final _dio = Dio();
 
   @override
-  AiModelSettingsState build() => const AiModelSettingsState();
+  AiModelSettingsState build() {
+    // Check installed files right away so every screen (settings, welcome,
+    // chat) sees the real state without a manual "Validate" click.
+    Future.microtask(validateModels);
+    return const AiModelSettingsState();
+  }
+
+  /// A file that exists but is suspiciously small is a leftover from an
+  /// interrupted download — treat it as missing.
+  static bool _isComplete(File file, int minBytes) =>
+      file.existsSync() && file.lengthSync() >= minBytes;
 
   Future<void> validateModels() async {
     state = state.copyWith(
@@ -42,13 +55,19 @@ class AiModelSettingsController extends _$AiModelSettingsController {
     try {
       final dir = await getApplicationDocumentsDirectory();
       final base = dir.path;
-      final serverBin = File(p.join(base, AiConstants.serverBinaryName));
-      final nomicModel = File(p.join(base, AiConstants.nomicModelFile));
-      final qwenModel = File(p.join(base, AiConstants.qwenModelFile));
       final validated =
-          serverBin.existsSync() &&
-          nomicModel.existsSync() &&
-          qwenModel.existsSync();
+          _isComplete(
+            File(p.join(base, AiConstants.serverBinaryName)),
+            AiConstants.serverBinaryMinBytes,
+          ) &&
+          _isComplete(
+            File(p.join(base, AiConstants.nomicModelFile)),
+            AiConstants.nomicModelMinBytes,
+          ) &&
+          _isComplete(
+            File(p.join(base, AiConstants.qwenModelFile)),
+            AiConstants.qwenModelMinBytes,
+          );
       state = state.copyWith(
         areModelsValidated: validated,
         currentTask: validated ? 'All files present.' : 'Files missing.',
@@ -97,14 +116,16 @@ class AiModelSettingsController extends _$AiModelSettingsController {
         savePath: p.join(dir.path, AiConstants.nomicModelFile),
         taskLabel: 'Downloading Nomic embedding model…',
         overallStart: 0.2,
-        overallEnd: 0.55,
+        overallEnd: 0.35,
+        minBytes: AiConstants.nomicModelMinBytes,
       );
       await _downloadFile(
         url: AiConstants.qwenModelUrl,
         savePath: p.join(dir.path, AiConstants.qwenModelFile),
-        taskLabel: 'Downloading Qwen 2.5 7B model…',
-        overallStart: 0.55,
+        taskLabel: 'Downloading Qwen3 4B model…',
+        overallStart: 0.35,
         overallEnd: 1.0,
+        minBytes: AiConstants.qwenModelMinBytes,
       );
       state = state.copyWith(
         isDownloading: false,
@@ -112,6 +133,11 @@ class AiModelSettingsController extends _$AiModelSettingsController {
         currentTask: 'Download complete.',
       );
       await validateModels();
+      // Bring the AI online immediately — the user shouldn't have to visit
+      // the chat page or click anything for the servers to start loading.
+      if (state.areModelsValidated) {
+        unawaited(di.getIt<AiProcessManager>().startServers());
+      }
     } on DioException catch (e) {
       state = state.copyWith(
         isDownloading: false,
@@ -133,11 +159,23 @@ class AiModelSettingsController extends _$AiModelSettingsController {
     required String taskLabel,
     required double overallStart,
     required double overallEnd,
+    int minBytes = 0,
   }) async {
+    // Already downloaded (e.g. a retry after a failure further down the
+    // list) — don't pull gigabytes again.
+    if (_isComplete(File(savePath), minBytes) && minBytes > 0) {
+      state = state.copyWith(progress: overallEnd);
+      return;
+    }
+
     state = state.copyWith(currentTask: taskLabel, progress: overallStart);
+
+    // Download to a temp file and rename at the end, so an interrupted
+    // download can never masquerade as a complete model file.
+    final partPath = '$savePath.part';
     await _dio.download(
       url,
-      savePath,
+      partPath,
       onReceiveProgress: (received, total) {
         if (total <= 0) return;
         final fileProgress = received / total;
@@ -151,6 +189,10 @@ class AiModelSettingsController extends _$AiModelSettingsController {
         receiveTimeout: const Duration(hours: 2),
       ),
     );
+
+    final target = File(savePath);
+    if (target.existsSync()) target.deleteSync();
+    File(partPath).renameSync(savePath);
   }
 
   Future<void> _extractBinary(String archivePath, String destDir) async {