fix: Data validation for scheduled maintenance

frontend/src/features/maintenance/components/MaintenanceScheduleReviewScreen.test.tsx

@@ -75,7 +75,7 @@ const sampleItems: MaintenanceScheduleItem[] = [
   },
 ];
 
-const sampleItemsWithEmpty: MaintenanceScheduleItem[] = [
+const sampleItemsWithEmptySubtypes: MaintenanceScheduleItem[] = [
   ...sampleItems,
   {
     service: 'Brake Fluid',
@@ -87,6 +87,18 @@ const sampleItemsWithEmpty: MaintenanceScheduleItem[] = [
   },
 ];
 
+const sampleItemsWithMissingIntervals: MaintenanceScheduleItem[] = [
+  ...sampleItems,
+  {
+    service: 'Coolant Flush',
+    intervalMiles: null,
+    intervalMonths: null,
+    details: null,
+    confidence: 0.55,
+    subtypes: ['Coolant'],
+  },
+];
+
 describe('MaintenanceScheduleReviewScreen', () => {
   const defaultProps = {
     open: true,
@@ -306,7 +318,7 @@ describe('MaintenanceScheduleReviewScreen', () => {
 
   describe('Subtype validation', () => {
     it('should disable create button when selected item has empty subtypes', () => {
-      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmpty} />);
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmptySubtypes} />);
 
       // All 4 items selected, but Brake Fluid has no subtypes
       const createButton = screen.getByRole('button', { name: /create/i });
@@ -314,7 +326,7 @@ describe('MaintenanceScheduleReviewScreen', () => {
     });
 
     it('should enable create button after deselecting item with empty subtypes', () => {
-      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmpty} />);
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmptySubtypes} />);
 
       // Deselect the 4th item (Brake Fluid with empty subtypes)
       const checkboxes = screen.getAllByRole('checkbox');
@@ -325,13 +337,13 @@ describe('MaintenanceScheduleReviewScreen', () => {
     });
 
     it('should show warning alert for items missing subtypes', () => {
-      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmpty} />);
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmptySubtypes} />);
 
       expect(screen.getByText(/missing subtypes/)).toBeInTheDocument();
     });
 
     it('should hide warning alert after deselecting items with empty subtypes', () => {
-      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmpty} />);
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithEmptySubtypes} />);
 
       // Deselect the Brake Fluid item
       const checkboxes = screen.getAllByRole('checkbox');
@@ -341,6 +353,50 @@ describe('MaintenanceScheduleReviewScreen', () => {
     });
   });
 
+  describe('Interval validation', () => {
+    it('should disable create button when selected item has no intervals', () => {
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithMissingIntervals} />);
+
+      const createButton = screen.getByRole('button', { name: /create/i });
+      expect(createButton).toBeDisabled();
+    });
+
+    it('should enable create button after deselecting item with missing intervals', () => {
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithMissingIntervals} />);
+
+      // Deselect the 4th item (Coolant Flush with null intervals)
+      const checkboxes = screen.getAllByRole('checkbox');
+      fireEvent.click(checkboxes[3]);
+
+      const createButton = screen.getByRole('button', { name: /create 3 schedules/i });
+      expect(createButton).not.toBeDisabled();
+    });
+
+    it('should show warning alert for items missing intervals', () => {
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithMissingIntervals} />);
+
+      expect(screen.getByText(/missing intervals/)).toBeInTheDocument();
+    });
+
+    it('should enable create button after editing interval on item', () => {
+      render(<MaintenanceScheduleReviewScreen {...defaultProps} items={sampleItemsWithMissingIntervals} />);
+
+      // The Coolant Flush item shows '-' for both intervals. Click the Miles '-' to edit.
+      // There are multiple '-' on screen, so find all and pick the right one.
+      const dashTexts = screen.getAllByText('-');
+      // Click the first dash (Miles field of the Coolant Flush item - last item's first dash)
+      fireEvent.click(dashTexts[dashTexts.length - 2]);
+
+      // Type a value and save
+      const input = screen.getByDisplayValue('');
+      fireEvent.change(input, { target: { value: '50000' } });
+      fireEvent.keyDown(input, { key: 'Enter' });
+
+      const createButton = screen.getByRole('button', { name: /create 4 schedules/i });
+      expect(createButton).not.toBeDisabled();
+    });
+  });
+
   describe('Responsive layout', () => {
     afterEach(() => {
       // Reset matchMedia after each test

frontend/src/features/maintenance/components/MaintenanceScheduleReviewScreen.tsx

@@ -191,6 +191,9 @@ export const MaintenanceScheduleReviewScreen: React.FC<MaintenanceScheduleReview
 
   const selectedCount = editableItems.filter((i) => i.selected).length;
   const hasInvalidSubtypes = editableItems.some((i) => i.selected && i.subtypes.length === 0);
+  const hasInvalidIntervals = editableItems.some(
+    (i) => i.selected && i.intervalMiles === null && i.intervalMonths === null
+  );
 
   const handleToggle = useCallback((index: number) => {
     setEditableItems((prev) =>
@@ -326,6 +329,7 @@ export const MaintenanceScheduleReviewScreen: React.FC<MaintenanceScheduleReview
                       display: 'flex',
                       flexDirection: isMobile ? 'column' : 'row',
                       gap: isMobile ? 0.5 : 2,
+                      alignItems: 'center',
                     }}>
                       <InlineField
                         label="Miles"
@@ -341,6 +345,11 @@ export const MaintenanceScheduleReviewScreen: React.FC<MaintenanceScheduleReview
                         onSave={(v) => handleFieldUpdate(index, 'intervalMonths', v)}
                         suffix="mo"
                       />
+                      {item.selected && item.intervalMiles === null && item.intervalMonths === null && (
+                        <Tooltip title="At least one interval (miles or months) is required">
+                          <WarningAmberIcon color="warning" sx={{ fontSize: 18 }} />
+                        </Tooltip>
+                      )}
                     </Box>
 
                     {item.details && (
@@ -377,6 +386,12 @@ export const MaintenanceScheduleReviewScreen: React.FC<MaintenanceScheduleReview
               </Alert>
             )}
 
+            {hasInvalidIntervals && (
+              <Alert severity="warning" sx={{ mt: 2 }}>
+                Some selected items are missing intervals. Please set at least one interval (miles or months) for each selected item.
+              </Alert>
+            )}
+
             <Typography variant="body2" color="text.secondary" sx={{ mt: 2, textAlign: 'center' }}>
               Tap any field to edit before creating schedules.
             </Typography>
@@ -409,7 +424,7 @@ export const MaintenanceScheduleReviewScreen: React.FC<MaintenanceScheduleReview
             <Button
               variant="contained"
               onClick={handleCreate}
-              disabled={selectedCount === 0 || hasInvalidSubtypes || createMutation.isPending}
+              disabled={selectedCount === 0 || hasInvalidSubtypes || hasInvalidIntervals || createMutation.isPending}
               startIcon={createMutation.isPending ? <CircularProgress size={16} /> : <CheckIcon />}
               sx={{ minHeight: 44, order: isMobile ? 1 : 2, width: isMobile ? '100%' : 'auto' }}
             >

frontend/src/features/maintenance/hooks/useCreateSchedulesFromExtraction.ts

@@ -21,6 +21,7 @@ export function useCreateSchedulesFromExtraction() {
       const results: MaintenanceScheduleResponse[] = [];
       for (const item of items) {
         if (item.subtypes.length === 0) continue;
+        if (item.intervalMiles === null && item.intervalMonths === null) continue;
         const request: CreateScheduleRequest = {
           vehicleId,
           category: 'routine_maintenance',