added "Log Analisis" tab

Author: ievdokdm

dashboard/lib/service/data_seeder.dart

@@ -501,6 +501,13 @@ class DataSeeder {
       },
       startTime: creationTime + 30000,
       endTime: creationTime + 60000,
+      logAnalysis: switch (status) {
+        .failed =>
+          'Based on my analysis of the provided LUCI logs and the context of the changes in this PR, here is the breakdown of the build failure:\n\n ### 1. Identify the specific test or command that failed for $jobName \n...',
+        .infraFailure =>
+          'Based on my analysis of the provided LUCI logs and the context of the changes in this PR, here is the breakdown of the build failure:\n\n ### 1. Identify the specific infra issue for $jobName \n...',
+        _ => null,
+      },
     );
   }
 

dashboard/lib/views/presubmit_view.dart

@@ -328,18 +328,26 @@ class _JobDetailsViewerPane extends StatefulWidget {
 
 class _JobDetailsViewerPaneState extends State<_JobDetailsViewerPane> {
   int _selectedAttemptIndex = 0;
+  int _selectedDetailTabIndex = 0;
+  String? _lastJobName;
 
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
     final isDark = theme.brightness == Brightness.dark;
     final presubmitState = Provider.of<PresubmitState>(context);
+    final jobName = presubmitState.selectedJob;
+
+    if (_lastJobName != jobName) {
+      _lastJobName = jobName;
+      _selectedAttemptIndex = 0;
+      _selectedDetailTabIndex = 0;
+    }
 
     return AnimatedBuilder(
       animation: presubmitState,
       builder: (context, _) {
         final repo = presubmitState.repo;
-        final jobName = presubmitState.selectedJob;
         final jobs = presubmitState.jobs;
         final isLoading = presubmitState.isLoading;
 
@@ -360,6 +368,7 @@ class _JobDetailsViewerPaneState extends State<_JobDetailsViewerPane> {
         }
 
         final selectedJob = jobs[_selectedAttemptIndex];
+        final hasLogAnalysis = selectedJob.logAnalysis != null && selectedJob.logAnalysis!.isNotEmpty;
 
         return Column(
           crossAxisAlignment: CrossAxisAlignment.start,
@@ -448,22 +457,33 @@ class _JobDetailsViewerPaneState extends State<_JobDetailsViewerPane> {
                 ],
               ),
             ),
-            const Padding(
-              padding: EdgeInsets.symmetric(horizontal: 24, vertical: 12),
+
+            Container(
+              height: 40,
+              padding: const EdgeInsets.symmetric(horizontal: 24),
+              decoration: BoxDecoration(
+                color: theme.scaffoldBackgroundColor,
+                border: Border(bottom: BorderSide(color: borderColor)),
+              ),
               child: Row(
                 children: [
-                  Text(
-                    'Execution Details',
-                    style: TextStyle(fontWeight: FontWeight.w600),
-                  ),
-                  Spacer(),
-                  Text(
+                  if (hasLogAnalysis) ...[
+                    _buildDetailTab('Log Analysis', 0, isDark),
+                    _buildDetailTab('Execution Details', 1, isDark),
+                  ] else
+                    const Text(
+                      'Execution Details',
+                      style: TextStyle(fontWeight: FontWeight.w600),
+                    ),
+                  const Spacer(),
+                  const Text(
                     'Raw output',
                     style: TextStyle(fontSize: 12, color: Colors.grey),
                   ),
                 ],
               ),
             ),
+            const SizedBox(height: 12),
             Expanded(
               child: Container(
                 margin: const EdgeInsets.symmetric(horizontal: 24),
@@ -476,9 +496,11 @@ class _JobDetailsViewerPaneState extends State<_JobDetailsViewerPane> {
                 width: double.infinity,
                 child: SingleChildScrollView(
                   child: Text(
-                    selectedJob.summary?.trim().isEmpty ?? true
-                        ? _getDefaultJobDetails(selectedJob)
-                        : selectedJob.summary!,
+                    hasLogAnalysis && _selectedDetailTabIndex == 0
+                        ? selectedJob.logAnalysis!
+                        : (selectedJob.summary?.trim().isEmpty ?? true
+                            ? _getDefaultJobDetails(selectedJob)
+                            : selectedJob.summary!),
                     style: const TextStyle(
                       fontFamily: 'monospace',
                       fontSize: 13,
@@ -534,6 +556,35 @@ class _JobDetailsViewerPaneState extends State<_JobDetailsViewerPane> {
     );
   }
 
+  Widget _buildDetailTab(String label, int index, bool isDark) {
+    final isSelected = _selectedDetailTabIndex == index;
+    return InkWell(
+      onTap: () => setState(() => _selectedDetailTabIndex = index),
+      child: Container(
+        padding: const EdgeInsets.symmetric(horizontal: 16),
+        alignment: Alignment.center,
+        decoration: BoxDecoration(
+          border: Border(
+            bottom: BorderSide(
+              color: isSelected ? const Color(0xFF3B82F6) : Colors.transparent,
+              width: 2,
+            ),
+          ),
+        ),
+        child: Text(
+          label,
+          style: TextStyle(
+            fontSize: 13,
+            fontWeight: isSelected ? FontWeight.w600 : FontWeight.normal,
+            color: isSelected
+                ? (isDark ? Colors.white : Colors.black)
+                : (isDark ? const Color(0xFF8B949E) : const Color(0xFF6B7280)),
+          ),
+        ),
+      ),
+    );
+  }
+
   String _getDefaultJobDetails(PresubmitJobResponse job) {
     return switch (job.status) {
       .succeeded =>

dashboard/test/views/presubmit_view_test.dart

@@ -370,6 +370,93 @@ void main() {
     },
   );
 
+  testWidgets('PreSubmitView displays Log Analysis tab when present', (
+    WidgetTester tester,
+  ) async {
+    tester.view.physicalSize = const Size(2000, 1080);
+    tester.view.devicePixelRatio = 1.0;
+    addTearDown(tester.view.resetPhysicalSize);
+    addTearDown(tester.view.resetDevicePixelRatio);
+
+    const mockSha = 'decaf_3_real_sha';
+    const guardResponse = PresubmitGuardResponse(
+      prNum: 123,
+      author: 'dash',
+      guardStatus: GuardStatus.failed,
+      checkRunId: 456,
+      stages: [
+        PresubmitGuardStage(
+          name: 'Engine',
+          createdAt: 0,
+          builds: {'Mac mac_host_engine 1': TaskStatus.failed},
+        ),
+      ],
+    );
+
+    when(
+      mockCocoonService.fetchPresubmitGuard(
+        repo: anyNamed('repo'),
+        sha: mockSha,
+      ),
+    ).thenAnswer((_) async => const CocoonResponse.data(guardResponse));
+
+    when(
+      mockCocoonService.fetchPresubmitJobDetails(
+        checkRunId: anyNamed('checkRunId'),
+        jobName: argThat(contains('mac_host_engine'), named: 'jobName'),
+      ),
+    ).thenAnswer(
+      (_) async => CocoonResponse.data([
+        PresubmitJobResponse(
+          attemptNumber: 1,
+          jobName: 'Mac mac_host_engine 1',
+          creationTime: 0,
+          status: TaskStatus.failed,
+          summary: 'Test failed: Unit Tests',
+          logAnalysis: 'Found 2 flakiness candidates',
+        ),
+      ]),
+    );
+
+    await tester.runAsync(() async {
+      await tester.pumpWidget(
+        createPreSubmitView({'repo': 'flutter', 'pr': '123'}),
+      );
+      for (var i = 0; i < 50; i++) {
+        await tester.pump();
+        await Future<void>.delayed(const Duration(milliseconds: 50));
+        if (find.textContaining('by dash').evaluate().isNotEmpty) break;
+      }
+    });
+    await tester.pumpAndSettle();
+
+    expect(find.textContaining('PR #123'), findsOneWidget);
+
+    await tester.tap(find.textContaining('mac_host_engine').first);
+    await tester.runAsync(() async {
+      for (var i = 0; i < 50; i++) {
+        await tester.pump();
+        await Future<void>.delayed(const Duration(milliseconds: 50));
+        if (find.textContaining('Found 2 flakiness candidates').evaluate().isNotEmpty) {
+          break;
+        }
+      }
+    });
+    await tester.pumpAndSettle();
+
+    // Verify Log Analysis content is shown by default
+    expect(find.textContaining('Found 2 flakiness candidates'), findsOneWidget);
+    expect(find.text('Log Analysis'), findsOneWidget);
+    expect(find.text('Execution Details'), findsOneWidget);
+
+    // Switch to Execution Details tab
+    await tester.tap(find.text('Execution Details'));
+    await tester.pumpAndSettle();
+
+    // Verify Execution Details content is shown
+    expect(find.textContaining('Test failed: Unit Tests'), findsOneWidget);
+  });
+
   testWidgets(
     'PreSubmitView automatically selects latest SHA and updates sidebar when opened with PR only',
     (WidgetTester tester) async {