● Add prefer lowest remaining filament in auto-matching (#805)

When multiple AMS spools match the same type/color criteria, an optional
  setting now prefers the spool with the lowest remaining filament. This
  helps consume partial spools before starting new ones. Sorting applies
  to all matching paths: queue scheduler, print modal, and multi-printer
  mapping. Unknown remain values (-1) sort to end.

frontend/src/__tests__/components/PrinterSelector.test.ts

@@ -25,9 +25,12 @@ function makeFilament(overrides: Partial<LoadedFilament> & { globalTrayId: numbe
     colorName: 'White',
     amsId: 0,
     trayId: 0,
+    isHt: false,
+    isExternal: false,
     label: 'AMS1-T1',
     trayInfoIdx: '',
     extruderId: undefined,
+    remain: -1,
     ...overrides,
   };
 }
@@ -196,3 +199,51 @@ describe('autoMatchFilament', () => {
     expect(result!.globalTrayId).toBe(0);
   });
 });
+
+// -- autoMatchFilament with preferLowest ------------------------------------
+
+describe('autoMatchFilament preferLowest', () => {
+  it('picks spool with lowest remain when enabled', () => {
+    const filaments = [
+      makeFilament({ globalTrayId: 0, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 80 }),
+      makeFilament({ globalTrayId: 1, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 30 }),
+    ];
+    const req = makeReq({ type: 'PLA', color: '#FF0000' });
+    const result = autoMatchFilament(req, filaments, new Set(), true);
+    expect(result).toBeDefined();
+    expect(result!.globalTrayId).toBe(1); // 30% < 80%
+  });
+
+  it('picks first spool when disabled (default behavior)', () => {
+    const filaments = [
+      makeFilament({ globalTrayId: 0, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 80 }),
+      makeFilament({ globalTrayId: 1, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 30 }),
+    ];
+    const req = makeReq({ type: 'PLA', color: '#FF0000' });
+    const result = autoMatchFilament(req, filaments, new Set(), false);
+    expect(result).toBeDefined();
+    expect(result!.globalTrayId).toBe(0); // First match
+  });
+
+  it('sorts unknown remain (-1) to end', () => {
+    const filaments = [
+      makeFilament({ globalTrayId: 0, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: -1 }),
+      makeFilament({ globalTrayId: 1, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 50 }),
+    ];
+    const req = makeReq({ type: 'PLA', color: '#FF0000' });
+    const result = autoMatchFilament(req, filaments, new Set(), true);
+    expect(result).toBeDefined();
+    expect(result!.globalTrayId).toBe(1); // Known 50% over unknown
+  });
+
+  it('still respects nozzle constraint with preferLowest', () => {
+    const filaments = [
+      makeFilament({ globalTrayId: 0, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 10, extruderId: 1 }),
+      makeFilament({ globalTrayId: 1, type: 'PLA', color: '#FF0000', colorName: 'Red', remain: 80, extruderId: 0 }),
+    ];
+    const req = makeReq({ type: 'PLA', color: '#FF0000', nozzle_id: 0 });
+    const result = autoMatchFilament(req, filaments, new Set(), true);
+    expect(result).toBeDefined();
+    expect(result!.globalTrayId).toBe(1); // Only tray on correct nozzle
+  });
+});

frontend/src/__tests__/hooks/useFilamentMapping.test.ts

@@ -873,3 +873,59 @@ describe('X1C model tests (single nozzle, real data)', () => {
     });
   });
 });
+
+describe('computeAmsMapping preferLowest', () => {
+  it('picks spool with lowest remain when enabled', () => {
+    const reqs = {
+      filaments: [{ slot_id: 1, type: 'PLA', color: '#FF0000', used_grams: 10 }],
+    };
+    const status = createPrinterStatus([
+      {
+        id: 0,
+        tray: [
+          { id: 0, tray_type: 'PLA', tray_color: 'FF0000', remain: 80 },
+          { id: 1, tray_type: 'PLA', tray_color: 'FF0000', remain: 25 },
+        ],
+      },
+    ]);
+
+    const result = computeAmsMapping(reqs, status, true);
+    expect(result).toEqual([1]); // Tray 1 has 25% remain
+  });
+
+  it('picks first match when disabled', () => {
+    const reqs = {
+      filaments: [{ slot_id: 1, type: 'PLA', color: '#FF0000', used_grams: 10 }],
+    };
+    const status = createPrinterStatus([
+      {
+        id: 0,
+        tray: [
+          { id: 0, tray_type: 'PLA', tray_color: 'FF0000', remain: 80 },
+          { id: 1, tray_type: 'PLA', tray_color: 'FF0000', remain: 25 },
+        ],
+      },
+    ]);
+
+    const result = computeAmsMapping(reqs, status, false);
+    expect(result).toEqual([0]); // First match (default)
+  });
+
+  it('sorts unknown remain to end', () => {
+    const reqs = {
+      filaments: [{ slot_id: 1, type: 'PLA', color: '#FF0000', used_grams: 10 }],
+    };
+    const status = createPrinterStatus([
+      {
+        id: 0,
+        tray: [
+          { id: 0, tray_type: 'PLA', tray_color: 'FF0000' },  // No remain (defaults to -1)
+          { id: 1, tray_type: 'PLA', tray_color: 'FF0000', remain: 60 },
+        ],
+      },
+    ]);
+
+    const result = computeAmsMapping(reqs, status, true);
+    expect(result).toEqual([1]); // Known 60% over unknown
+  });
+});

frontend/src/api/client.ts

@@ -838,6 +838,7 @@ export interface AppSettings {
   time_format: 'system' | '12h' | '24h';
   // Filament tracking
   disable_filament_warnings: boolean;  // Disable filament warnings (print insufficiency and assignment mismatch)
+  prefer_lowest_filament: boolean;  // When multiple spools match, prefer lowest remaining filament
   // Default printer
   default_printer_id: number | null;
   // Dark mode theme settings

frontend/src/components/PrintModal/PrinterSelector.tsx

@@ -107,7 +107,8 @@ function InlineMappingEditor({
       isManual = true;
     } else {
       const usedTrayIds = new Set<number>(Object.values(printerResult.config.manualMappings));
-      loaded = autoMatchFilament(req, printerResult.loadedFilaments, usedTrayIds) as LoadedFilament | undefined;
+      const cachedSettings = queryClient.getQueryData<{ prefer_lowest_filament?: boolean }>(['settings']);
+      loaded = autoMatchFilament(req, printerResult.loadedFilaments, usedTrayIds, cachedSettings?.prefer_lowest_filament) as LoadedFilament | undefined;
     }
 
     // Determine status

frontend/src/components/PrintModal/index.tsx

@@ -324,7 +324,7 @@ export function PrintModal({
   });
 
   // Get AMS mapping from hook (only when single printer selected)
-  const { amsMapping } = useFilamentMapping(effectiveFilamentReqs, printerStatus, manualMappings);
+  const { amsMapping } = useFilamentMapping(effectiveFilamentReqs, printerStatus, manualMappings, settings?.prefer_lowest_filament);
 
   // Multi-printer filament mapping (for per-printer configuration)
   const multiPrinterMapping = useMultiPrinterFilamentMapping(
@@ -333,7 +333,8 @@ export function PrintModal({
     effectiveFilamentReqs,
     manualMappings,
     perPrinterConfigs,
-    setPerPrinterConfigs
+    setPerPrinterConfigs,
+    settings?.prefer_lowest_filament,
   );
 
   // Auto-select first plate when plates load (single or multi-plate)

frontend/src/hooks/useFilamentMapping.ts

@@ -37,6 +37,7 @@ export function buildLoadedFilaments(printerStatus: PrinterStatus | undefined):
           trayInfoIdx: tray.tray_info_idx || '',
           traySubBrands: tray.tray_sub_brands || '',
           extruderId: amsExtruderMap?.[String(amsUnit.id)],
+          remain: tray.remain ?? -1,
         });
       }
     });
@@ -61,6 +62,7 @@ export function buildLoadedFilaments(printerStatus: PrinterStatus | undefined):
         trayInfoIdx: extTray.tray_info_idx || '',
         traySubBrands: extTray.tray_sub_brands || '',
         extruderId: hasDualNozzle ? (255 - trayId) : undefined,
+        remain: extTray.remain ?? -1,
       });
     }
   }
@@ -86,7 +88,8 @@ export function buildLoadedFilaments(printerStatus: PrinterStatus | undefined):
  */
 export function computeAmsMapping(
   filamentReqs: { filaments: FilamentRequirement[] } | undefined,
-  printerStatus: PrinterStatus | undefined
+  printerStatus: PrinterStatus | undefined,
+  preferLowest?: boolean,
 ): number[] | undefined {
   if (!filamentReqs?.filaments || filamentReqs.filaments.length === 0) return undefined;
 
@@ -109,6 +112,15 @@ export function computeAmsMapping(
       available = available.filter((f) => f.extruderId === req.nozzle_id);
     }
 
+    // Sort by remaining filament (ascending) so .find() picks the lowest-remain spool first
+    if (preferLowest) {
+      available = [...available].sort((a, b) => {
+        const ra = a.remain >= 0 ? a.remain : 101;
+        const rb = b.remain >= 0 ? b.remain : 101;
+        return ra - rb;
+      });
+    }
+
     let idxMatch: LoadedFilament | undefined;
     let exactMatch: LoadedFilament | undefined;
     let similarMatch: LoadedFilament | undefined;
@@ -122,6 +134,13 @@ export function computeAmsMapping(
         idxMatch = idxMatches[0];
       } else if (idxMatches.length > 1) {
         // Multiple trays with same tray_info_idx - use color matching among them
+        if (preferLowest) {
+          idxMatches.sort((a, b) => {
+            const ra = a.remain >= 0 ? a.remain : 101;
+            const rb = b.remain >= 0 ? b.remain : 101;
+            return ra - rb;
+          });
+        }
         exactMatch = idxMatches.find(
           (f) =>
             f.type?.toUpperCase() === req.type?.toUpperCase() &&
@@ -212,6 +231,8 @@ export interface LoadedFilament {
   traySubBrands?: string;
   /** Extruder ID for dual-nozzle printers (0=right, 1=left) */
   extruderId?: number;
+  /** Remaining filament percentage (0-100), -1 = unknown */
+  remain: number;
 }
 
 /**
@@ -285,7 +306,8 @@ export function useLoadedFilaments(
 export function useFilamentMapping(
   filamentReqs: FilamentRequirementsResponse | undefined,
   printerStatus: PrinterStatus | undefined,
-  manualMappings: Record<number, number>
+  manualMappings: Record<number, number>,
+  preferLowest?: boolean,
 ): UseFilamentMappingResult {
   const loadedFilaments = useLoadedFilaments(printerStatus);
 
@@ -345,6 +367,15 @@ export function useFilamentMapping(
         available = available.filter((f) => f.extruderId === req.nozzle_id);
       }
 
+      // Sort by remaining filament (ascending) so .find() picks the lowest-remain spool first
+      if (preferLowest) {
+        available = [...available].sort((a, b) => {
+          const ra = a.remain >= 0 ? a.remain : 101;
+          const rb = b.remain >= 0 ? b.remain : 101;
+          return ra - rb;
+        });
+      }
+
       let idxMatch: LoadedFilament | undefined;
       let exactMatch: LoadedFilament | undefined;
       let similarMatch: LoadedFilament | undefined;
@@ -358,6 +389,13 @@ export function useFilamentMapping(
           idxMatch = idxMatches[0];
         } else if (idxMatches.length > 1) {
           // Multiple trays with same tray_info_idx - use color matching among them
+          if (preferLowest) {
+            idxMatches.sort((a, b) => {
+              const ra = a.remain >= 0 ? a.remain : 101;
+              const rb = b.remain >= 0 ? b.remain : 101;
+              return ra - rb;
+            });
+          }
           exactMatch = idxMatches.find(
             (f) =>
               f.type?.toUpperCase() === req.type?.toUpperCase() &&
@@ -431,7 +469,7 @@ export function useFilamentMapping(
         isManual: false,
       };
     });
-  }, [filamentReqs, loadedFilaments, manualMappings]);
+  }, [filamentReqs, loadedFilaments, manualMappings, preferLowest]);
 
   // Build AMS mapping from matched filaments
   // Format: array matching 3MF filament slot structure

frontend/src/hooks/useMultiPrinterFilamentMapping.ts

@@ -88,7 +88,8 @@ export interface UseMultiPrinterFilamentMappingResult {
 function computeMatchDetails(
   filamentReqs: FilamentRequirement[] | undefined,
   loadedFilaments: LoadedFilament[],
-  manualMappings: Record<number, number>
+  manualMappings: Record<number, number>,
+  preferLowest?: boolean,
 ): { exactMatches: number; typeOnlyMatches: number; missingTypes: number; totalSlots: number; status: PrinterMatchStatus } {
   if (!filamentReqs || filamentReqs.length === 0) {
     return { exactMatches: 0, typeOnlyMatches: 0, missingTypes: 0, totalSlots: 0, status: 'full' };
@@ -133,6 +134,14 @@ function computeMatchDetails(
       }
     }
 
+    if (preferLowest) {
+      candidates = [...candidates].sort((a, b) => {
+        const ra = a.remain >= 0 ? a.remain : 101;
+        const rb = b.remain >= 0 ? b.remain : 101;
+        return ra - rb;
+      });
+    }
+
     const exactMatch = candidates.find(
       (f) =>
         f.type?.toUpperCase() === req.type?.toUpperCase() &&
@@ -183,7 +192,8 @@ function computeMatchDetails(
 function computeMappingWithOverrides(
   filamentReqs: { filaments: FilamentRequirement[] } | undefined,
   printerStatus: PrinterStatus | undefined,
-  manualMappings: Record<number, number>
+  manualMappings: Record<number, number>,
+  preferLowest?: boolean,
 ): number[] | undefined {
   if (!filamentReqs?.filaments || filamentReqs.filaments.length === 0) return undefined;
 
@@ -211,6 +221,14 @@ function computeMappingWithOverrides(
       }
     }
 
+    if (preferLowest) {
+      candidates = [...candidates].sort((a, b) => {
+        const ra = a.remain >= 0 ? a.remain : 101;
+        const rb = b.remain >= 0 ? b.remain : 101;
+        return ra - rb;
+      });
+    }
+
     const exactMatch = candidates.find(
       (f) =>
         f.type?.toUpperCase() === req.type?.toUpperCase() &&
@@ -270,7 +288,8 @@ export function useMultiPrinterFilamentMapping(
   filamentReqs: { filaments: FilamentRequirement[] } | undefined,
   defaultMappings: Record<number, number>,
   perPrinterConfigs: Record<number, PerPrinterConfig>,
-  setPerPrinterConfigs: React.Dispatch<React.SetStateAction<Record<number, PerPrinterConfig>>>
+  setPerPrinterConfigs: React.Dispatch<React.SetStateAction<Record<number, PerPrinterConfig>>>,
+  preferLowest?: boolean,
 ): UseMultiPrinterFilamentMappingResult {
   // Fetch printer status for all selected printers in parallel
   const statusQueries = useQueries({
@@ -294,7 +313,7 @@ export function useMultiPrinterFilamentMapping(
       const config = perPrinterConfigs[printerId] || DEFAULT_PRINTER_CONFIG;
 
       // Compute auto mapping for this printer
-      const autoMapping = computeAmsMapping(filamentReqs, printerStatus);
+      const autoMapping = computeAmsMapping(filamentReqs, printerStatus, preferLowest);
 
       // Determine which mappings to use:
       // If printer has override (useDefault=false), use its custom mappings
@@ -304,13 +323,14 @@ export function useMultiPrinterFilamentMapping(
         : defaultMappings;
 
       // Compute final mapping with overrides
-      const finalMapping = computeMappingWithOverrides(filamentReqs, printerStatus, effectiveMappings);
+      const finalMapping = computeMappingWithOverrides(filamentReqs, printerStatus, effectiveMappings, preferLowest);
 
       // Compute match details
       const matchDetails = computeMatchDetails(
         filamentReqs?.filaments,
         loadedFilaments,
-        effectiveMappings
+        effectiveMappings,
+        preferLowest,
       );
 
       return {
@@ -329,7 +349,7 @@ export function useMultiPrinterFilamentMapping(
         config,
       };
     });
-  }, [selectedPrinterIds, statusQueries, printers, filamentReqs, perPrinterConfigs, defaultMappings]);
+  }, [selectedPrinterIds, statusQueries, printers, filamentReqs, perPrinterConfigs, defaultMappings, preferLowest]);
 
   const isLoading = statusQueries.some((q) => q.isLoading);
 
@@ -350,7 +370,7 @@ export function useMultiPrinterFilamentMapping(
     if (!result || !result.status || !filamentReqs?.filaments) return;
 
     // Compute optimal mapping for this printer
-    const autoMapping = computeAmsMapping(filamentReqs, result.status);
+    const autoMapping = computeAmsMapping(filamentReqs, result.status, preferLowest);
     if (!autoMapping) return;
 
     // Convert autoMapping array to manualMappings record

frontend/src/i18n/locales/de.ts

@@ -1419,6 +1419,8 @@ export default {
     filamentChecks: 'Filament-Prüfungen',
     disableFilamentWarnings: 'Filament-Warnungen deaktivieren',
     disableFilamentWarningsDesc: 'Keine Warnungen über unzureichendes Filament beim Drucken oder Einreihen anzeigen',
+    preferLowestFilament: 'Niedrigsten Filamentrest bevorzugen',
+    preferLowestFilamentDesc: 'Bei mehreren passenden Spulen die mit dem geringsten Restfilament verwenden',
     trackingModeBuiltIn: 'Integriertes Inventar',
     trackingModeBuiltInDesc: 'RFID-Erkennung und Verbrauchserfassung inklusive',
     trackingModeSpoolmanDesc: 'Externer Filament-Management-Server',

frontend/src/i18n/locales/en.ts

@@ -1420,6 +1420,8 @@ export default {
     filamentChecks: 'Filament checks',
     disableFilamentWarnings: 'Disable filament warnings',
     disableFilamentWarningsDesc: 'Don\'t show warnings about insufficient filament when printing or queueing',
+    preferLowestFilament: 'Prefer lowest remaining filament',
+    preferLowestFilamentDesc: 'When multiple spools match, use the one with the least filament remaining',
     trackingModeBuiltIn: 'Built-in Inventory',
     trackingModeBuiltInDesc: 'RFID auto-matching and usage tracking included',
     trackingModeSpoolmanDesc: 'External filament management server',

frontend/src/i18n/locales/fr.ts

@@ -1419,6 +1419,8 @@ export default {
     filamentChecks: 'Vérifications du filament',
     disableFilamentWarnings: 'Désactiver les avertissements de filament',
     disableFilamentWarningsDesc: 'Ne pas afficher les avertissements de filament insuffisant lors de l\'impression ou de la mise en file d\'attente',
+    preferLowestFilament: 'Préférer le filament le plus bas',
+    preferLowestFilamentDesc: 'Lorsque plusieurs bobines correspondent, utiliser celle avec le moins de filament restant',
     trackingModeBuiltIn: 'Inventaire Intégré',
     trackingModeBuiltInDesc: 'Correspondance RFID et suivi de consommation inclus',
     trackingModeSpoolmanDesc: 'Serveur de gestion externe',

frontend/src/i18n/locales/it.ts

@@ -1419,6 +1419,8 @@ export default {
     filamentChecks: 'Controlli filamento',
     disableFilamentWarnings: 'Disabilita avvisi filamento',
     disableFilamentWarningsDesc: 'Non mostrare avvisi per filamento insufficiente durante la stampa o l\'accodamento',
+    preferLowestFilament: 'Preferisci il filamento con meno residuo',
+    preferLowestFilamentDesc: 'Quando più bobine corrispondono, usa quella con meno filamento rimanente',
     trackingModeBuiltIn: 'Inventario integrato',
     trackingModeBuiltInDesc: 'Riconoscimento RFID automatico e tracciamento dell\'uso inclusi',
     trackingModeSpoolmanDesc: 'Server esterno per la gestione del filamento',

frontend/src/i18n/locales/ja.ts

@@ -1418,6 +1418,8 @@ export default {
     filamentChecks: 'フィラメントチェック',
     disableFilamentWarnings: 'フィラメント警告を無効化',
     disableFilamentWarningsDesc: '印刷またはキュー追加時にフィラメント不足の警告を表示しない',
+    preferLowestFilament: '残量が少ないフィラメントを優先',
+    preferLowestFilamentDesc: '複数のスプールが一致する場合、残量が最も少ないものを使用します',
     trackingModeBuiltIn: '内蔵インベントリ',
     trackingModeBuiltInDesc: 'RFID自動検出と使用量追跡を含む',
     trackingModeSpoolmanDesc: '外部フィラメント管理サーバー',

frontend/src/i18n/locales/pt-BR.ts

@@ -1419,6 +1419,8 @@ export default {
     filamentChecks: 'Verificações de filamento',
     disableFilamentWarnings: 'Desativar avisos de filamento',
     disableFilamentWarningsDesc: 'Não mostrar avisos sobre filamento insuficiente ao imprimir ou adicionar à fila',
+    preferLowestFilament: 'Preferir filamento com menor resto',
+    preferLowestFilamentDesc: 'Quando vários carretéis correspondem, usar o com menos filamento restante',
     trackingModeBuiltIn: 'Inventário Interno',
     trackingModeBuiltInDesc: 'Correspondência automática de RFID e rastreamento de uso incluídos',
     trackingModeSpoolmanDesc: 'Servidor de gerenciamento de filamento externo',

frontend/src/i18n/locales/zh-CN.ts

@@ -1419,6 +1419,8 @@ export default {
     filamentChecks: '耗材检查',
     disableFilamentWarnings: '禁用耗材警告',
     disableFilamentWarningsDesc: '在打印或加入队列时不显示耗材不足警告',
+    preferLowestFilament: '优先使用剩余最少的耗材',
+    preferLowestFilamentDesc: '当多个料盘匹配时，使用剩余耗材最少的那个',
     trackingModeBuiltIn: '内置库存',
     trackingModeBuiltInDesc: '包含 RFID 自动匹配和用量追踪',
     trackingModeSpoolmanDesc: '外部耗材管理服务器',

frontend/src/pages/SettingsPage.tsx

@@ -741,6 +741,7 @@ export function SettingsPage() {
       settings.ams_temp_fair !== localSettings.ams_temp_fair ||
       settings.ams_history_retention_days !== localSettings.ams_history_retention_days ||
       settings.disable_filament_warnings !== localSettings.disable_filament_warnings ||
+      settings.prefer_lowest_filament !== localSettings.prefer_lowest_filament ||
       (settings.queue_drying_enabled ?? false) !== (localSettings.queue_drying_enabled ?? false) ||
       (settings.queue_drying_block ?? false) !== (localSettings.queue_drying_block ?? false) ||
       (settings.ambient_drying_enabled ?? false) !== (localSettings.ambient_drying_enabled ?? false) ||
@@ -816,6 +817,7 @@ export function SettingsPage() {
         ams_temp_fair: localSettings.ams_temp_fair,
         ams_history_retention_days: localSettings.ams_history_retention_days,
         disable_filament_warnings: localSettings.disable_filament_warnings,
+        prefer_lowest_filament: localSettings.prefer_lowest_filament,
         queue_drying_enabled: localSettings.queue_drying_enabled,
         queue_drying_block: localSettings.queue_drying_block,
         ambient_drying_enabled: localSettings.ambient_drying_enabled,
@@ -3610,6 +3612,23 @@ export function SettingsPage() {
                     <div className="w-11 h-6 bg-bambu-dark-tertiary peer-focus:outline-none rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:rounded-full after:h-5 after:w-5 after:transition-all peer-checked:bg-bambu-green"></div>
                   </label>
                 </div>
+                <div className="flex items-center justify-between">
+                  <div>
+                    <p className="text-white">{t('settings.preferLowestFilament')}</p>
+                    <p className="text-sm text-bambu-gray">
+                      {t('settings.preferLowestFilamentDesc')}
+                    </p>
+                  </div>
+                  <label className="relative inline-flex items-center cursor-pointer">
+                    <input
+                      type="checkbox"
+                      checked={localSettings.prefer_lowest_filament}
+                      onChange={(e) => updateSetting('prefer_lowest_filament', e.target.checked)}
+                      className="sr-only peer"
+                    />
+                    <div className="w-11 h-6 bg-bambu-dark-tertiary peer-focus:outline-none rounded-full peer peer-checked:after:translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:rounded-full after:h-5 after:w-5 after:transition-all peer-checked:bg-bambu-green"></div>
+                  </label>
+                </div>
               </CardContent>
             </Card>
 

frontend/src/utils/amsHelpers.ts

@@ -203,10 +203,19 @@ export function isPlaceholderDate(scheduledTime: string | null | undefined): boo
  */
 export function autoMatchFilament(
   req: { type?: string; color?: string; nozzle_id?: number | null },
-  loadedFilaments: { globalTrayId: number; type?: string; color?: string; extruderId?: number }[],
+  loadedFilaments: { globalTrayId: number; type?: string; color?: string; extruderId?: number; remain?: number }[],
   usedTrayIds: Set<number>,
+  preferLowest?: boolean,
 ): typeof loadedFilaments[number] | undefined {
-  const nozzleFilaments = filterFilamentsByNozzle(loadedFilaments, req.nozzle_id);
+  let nozzleFilaments = filterFilamentsByNozzle(loadedFilaments, req.nozzle_id);
+
+  if (preferLowest) {
+    nozzleFilaments = [...nozzleFilaments].sort((a, b) => {
+      const ra = (a.remain ?? -1) >= 0 ? (a.remain ?? -1) : 101;
+      const rb = (b.remain ?? -1) >= 0 ? (b.remain ?? -1) : 101;
+      return ra - rb;
+    });
+  }
 
   const exactMatch = nozzleFilaments.find(
     (f) =>