import { useState, useEffect, useMemo, useCallback, useRef } from 'react';
import { useOutletContext } from 'react-router-dom';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { useTranslation } from 'react-i18next';
import { Layers, Settings2, Package, Unlink, Link2, X } from 'lucide-react';
import type { SpoolBuddyOutletContext } from '../../components/spoolbuddy/SpoolBuddyLayout';
import { api } from '../../api/client';
import type { PrinterStatus, AMSTray, SpoolAssignment } from '../../api/client';
import { getGlobalTrayId, getFillBarColor, getSpoolmanFillLevel, getFallbackSpoolTag, formatSlotLabel, isBambuLabSpool } from '../../utils/amsHelpers';
import { AmsUnitCard, HumidityIndicator, TemperatureIndicator, NozzleBadge } from '../../components/spoolbuddy/AmsUnitCard';
import type { AmsThresholds } from '../../components/spoolbuddy/AmsUnitCard';
import { ConfigureAmsSlotModal } from '../../components/ConfigureAmsSlotModal';
import { AssignSpoolModal } from '../../components/AssignSpoolModal';
import { LinkSpoolModal } from '../../components/LinkSpoolModal';
import { useToast } from '../../contexts/ToastContext';

function getAmsName(amsId: number): string {
  if (amsId <= 3) return `AMS ${String.fromCharCode(65 + amsId)}`;
  if (amsId >= 128 && amsId <= 135) return `AMS HT ${String.fromCharCode(65 + amsId - 128)}`;
  return `AMS ${amsId}`;
}

function mapModelCode(ssdpModel: string | null): string {
  if (!ssdpModel) return '';
  const modelMap: Record<string, string> = {
    'O1D': 'H2D', 'O1E': 'H2D Pro', 'O2D': 'H2D Pro', 'O1C': 'H2C', 'O1C2': 'H2C', 'O1S': 'H2S',
    'BL-P001': 'X1C', 'BL-P002': 'X1', 'BL-P003': 'X1E',
    'N6': 'X2D',
    'C11': 'P1S', 'C12': 'P1P', 'C13': 'P2S',
    'N2S': 'A1', 'N1': 'A1 Mini',
    'X1C': 'X1C', 'X1': 'X1', 'X1E': 'X1E', 'X2D': 'X2D', 'P1S': 'P1S', 'P1P': 'P1P', 'P2S': 'P2S',
    'A1': 'A1', 'A1 Mini': 'A1 Mini', 'H2D': 'H2D', 'H2D Pro': 'H2D Pro', 'H2C': 'H2C', 'H2S': 'H2S',
  };
  return modelMap[ssdpModel] || ssdpModel;
}

function isTrayEmpty(tray: AMSTray): boolean {
  return !tray.tray_type || tray.tray_type === '';
}

function trayColorToCSS(color: string | null): string {
  if (!color) return '#808080';
  return `#${color.slice(0, 6)}`;
}

export function SpoolBuddyAmsPage() {
  const { selectedPrinterId, setAlert } = useOutletContext<SpoolBuddyOutletContext>();
  const { t } = useTranslation();
  const queryClient = useQueryClient();
  const { showToast } = useToast();

  const { data: status } = useQuery<PrinterStatus>({
    queryKey: ['printerStatus', selectedPrinterId],
    queryFn: () => api.getPrinterStatus(selectedPrinterId!),
    enabled: selectedPrinterId !== null,
    staleTime: 30 * 1000,
  });

  const { data: printer } = useQuery({
    queryKey: ['printer', selectedPrinterId],
    queryFn: () => api.getPrinter(selectedPrinterId!),
    enabled: selectedPrinterId !== null,
    staleTime: 60 * 1000,
  });

  const { data: slotPresets } = useQuery({
    queryKey: ['slotPresets', selectedPrinterId],
    queryFn: () => api.getSlotPresets(selectedPrinterId!),
    enabled: selectedPrinterId !== null,
    staleTime: 2 * 60 * 1000,
  });

  const { data: settings } = useQuery({
    queryKey: ['settings'],
    queryFn: () => api.getSettings(),
    staleTime: 5 * 60 * 1000,
  });

  // Fetch Spoolman status to enable fill-level chain
  const { data: spoolmanStatus } = useQuery({
    queryKey: ['spoolman-status'],
    queryFn: api.getSpoolmanStatus,
    staleTime: 60 * 1000,
  });
  const spoolmanEnabled = spoolmanStatus?.enabled && spoolmanStatus?.connected;

  // Fetch linked spools map (tag -> spool info) for Spoolman fill levels
  const { data: linkedSpoolsData } = useQuery({
    queryKey: ['linked-spools'],
    queryFn: api.getLinkedSpools,
    enabled: !!spoolmanEnabled,
    staleTime: 30 * 1000,
  });
  const linkedSpools = linkedSpoolsData?.linked;

  // Fetch all Spoolman slot assignments + spool metadata so the fill-bar
  // and the Link/Unlink button reflect slot-assigned-only Spoolman spools
  // (spools assigned to a slot via AssignToAmsModal but not tag-linked).
  // Without these, AmsUnitCard shows an empty fill bar and the Link button
  // stays active even though the slot is occupied.
  const { data: spoolmanSlotAssignmentsAll = [] } = useQuery({
    queryKey: ['spoolman-slot-assignments-all'],
    queryFn: () => api.getSpoolmanSlotAssignments(),
    enabled: !!spoolmanEnabled,
    staleTime: 30 * 1000,
  });
  const { data: spoolmanInventorySpoolsCache = [] } = useQuery({
    queryKey: ['spoolman-inventory-spools'],
    queryFn: () => api.getSpoolmanInventorySpools(false),
    enabled: !!spoolmanEnabled,
    staleTime: 30 * 1000,
  });

  const { data: assignments } = useQuery({
    queryKey: ['spool-assignments', selectedPrinterId],
    queryFn: () => api.getAssignments(selectedPrinterId!),
    enabled: selectedPrinterId !== null,
    staleTime: 30 * 1000,
  });

  // Build fill-level override map from inventory assignments
  // Key: "amsId-trayId", Value: fill percentage (0-100)
  const fillOverrides = useMemo(() => {
    const map: Record<string, number> = {};
    if (!assignments) return map;
    for (const a of assignments) {
      const sp = a.spool;
      if (sp && sp.label_weight > 0 && sp.weight_used != null) {
        const fill = Math.round(Math.max(0, sp.label_weight - sp.weight_used) / sp.label_weight * 100);
        map[`${a.ams_id}-${a.tray_id}`] = fill;
      }
    }
    return map;
  }, [assignments]);

  // Look up Spoolman fill level for a given tray
  const printerSerial = printer?.serial_number ?? '';
  const getSpoolmanFillForSlot = useCallback((amsId: number, trayId: number, tray: AMSTray | null): number | null => {
    // Stage 1: slot-assigned Spoolman spool. The user's explicit, recent
    // action — must outrank the tag-link to avoid #1457, where a non-RFID
    // slot's deterministic fallback tag stayed bound to the previous spool
    // in Spoolman's extra.tag and the fill bar reported the old (stale)
    // spool's remaining weight instead of the freshly assigned one.
    if (selectedPrinterId !== null && spoolmanSlotAssignmentsAll.length && spoolmanInventorySpoolsCache.length) {
      const slotAssign = spoolmanSlotAssignmentsAll.find(a =>
        a.printer_id === selectedPrinterId &&
        a.ams_id === amsId &&
        a.tray_id === trayId,
      );
      if (slotAssign) {
        const spool = spoolmanInventorySpoolsCache.find(s => s.id === slotAssign.spoolman_spool_id);
        if (spool && (spool.label_weight ?? 0) > 0) {
          return Math.round(Math.max(0, spool.label_weight - spool.weight_used) / spool.label_weight * 100);
        }
      }
    }
    // Stage 2: tag-linked spool (linkedSpools map keyed by tag/UUID).
    if (linkedSpools && printerSerial) {
      const tag = (tray?.tray_uuid || tray?.tag_uid || getFallbackSpoolTag(printerSerial, amsId, trayId))?.toUpperCase();
      const linkedSpool = tag ? linkedSpools[tag] : undefined;
      const tagFill = getSpoolmanFillLevel(linkedSpool);
      if (tagFill !== null) return tagFill;
    }
    return null;
  }, [linkedSpools, printerSerial, selectedPrinterId, spoolmanSlotAssignmentsAll, spoolmanInventorySpoolsCache]);

  const isConnected = status?.connected ?? false;

  // Cache AMS data per printer to prevent it disappearing on idle/offline printers
  const cachedAmsData = useRef<Record<number, PrinterStatus['ams']>>({});
  useEffect(() => {
    if (selectedPrinterId && status?.ams && status.ams.length > 0) {
      cachedAmsData.current[selectedPrinterId] = status.ams;
    }
  }, [status?.ams, selectedPrinterId]);
  const amsUnits = useMemo(() => {
    const live = status?.ams;
    if (live && live.length > 0) return live;
    return (selectedPrinterId ? cachedAmsData.current[selectedPrinterId] : null) ?? [];
  }, [status?.ams, selectedPrinterId]);
  const regularAms = useMemo(() => amsUnits.filter(u => !u.is_ams_ht), [amsUnits]);
  const htAms = useMemo(() => amsUnits.filter(u => u.is_ams_ht), [amsUnits]);

  // Build Spoolman fill-level override map for regular AMS cards
  const spoolmanFillOverrides = useMemo(() => {
    const map: Record<string, number> = {};
    if (!linkedSpools || !printerSerial) return map;
    for (const unit of regularAms) {
      for (let i = 0; i < (unit.tray?.length ?? 0); i++) {
        const tray = unit.tray![i];
        const fill = getSpoolmanFillForSlot(unit.id, i, isTrayEmpty(tray) ? null : tray);
        if (fill !== null) map[`${unit.id}-${i}`] = fill;
      }
    }
    return map;
  }, [linkedSpools, printerSerial, regularAms, getSpoolmanFillForSlot]);

  // Cache tray_now to prevent flickering when undefined values come in
  // Valid tray IDs: 0-253 for AMS, 254 for external spool
  // tray_now=255 means "no tray loaded" (Bambu protocol sentinel) — never active
  const cachedTrayNow = useRef<number | undefined>(undefined);
  const currentTrayNow = status?.tray_now;
  if (currentTrayNow !== undefined && currentTrayNow !== 255) {
    cachedTrayNow.current = currentTrayNow;
  } else if (currentTrayNow === 255) {
    cachedTrayNow.current = undefined;
  }
  const effectiveTrayNow = (currentTrayNow !== undefined && currentTrayNow !== 255)
    ? currentTrayNow
    : cachedTrayNow.current;
  const isDualNozzle = printer?.nozzle_count === 2 || status?.temperatures?.nozzle_2 !== undefined;
  const vtTrays = useMemo(() => [...(status?.vt_tray ?? [])].sort((a, b) => (a.id ?? 254) - (b.id ?? 254)), [status?.vt_tray]);

  const amsThresholds: AmsThresholds | undefined = settings ? {
    humidityGood: Number(settings.ams_humidity_good) || 40,
    humidityFair: Number(settings.ams_humidity_fair) || 60,
    tempGood: Number(settings.ams_temp_good) || 28,
    tempFair: Number(settings.ams_temp_fair) || 35,
  } : undefined;

  // Cache ams_extruder_map to prevent L/R indicators bouncing on updates
  const cachedAmsExtruderMap = useRef<Record<string, number>>({});
  useEffect(() => {
    if (status?.ams_extruder_map && Object.keys(status.ams_extruder_map).length > 0) {
      cachedAmsExtruderMap.current = status.ams_extruder_map;
    }
  }, [status?.ams_extruder_map]);
  const amsExtruderMap = (status?.ams_extruder_map && Object.keys(status.ams_extruder_map).length > 0)
    ? status.ams_extruder_map
    : cachedAmsExtruderMap.current;

  const getNozzleSide = useCallback((amsId: number): 'L' | 'R' | null => {
    if (!isDualNozzle) return null;
    const mappedExtruderId = amsExtruderMap[String(amsId)];
    const normalizedId = amsId >= 128 ? amsId - 128 : amsId;
    const extruderId = mappedExtruderId !== undefined ? mappedExtruderId : normalizedId;
    // extruder 0 = right, 1 = left
    return extruderId === 1 ? 'L' : 'R';
  }, [isDualNozzle, amsExtruderMap]);

  const [configureSlotModal, setConfigureSlotModal] = useState<{
    amsId: number;
    trayId: number;
    trayCount: number;
    trayType?: string;
    trayColor?: string;
    traySubBrands?: string;
    trayInfoIdx?: string;
    extruderId?: number;
    caliIdx?: number | null;
    savedPresetId?: string;
  } | null>(null);

  // Slot action picker: shown before opening configure or assign modal
  const [slotActionPicker, setSlotActionPicker] = useState<{
    amsId: number;
    trayId: number;
    trayCount: number;
    tray: AMSTray | null;
    trayType?: string;
    trayColor?: string;
    traySubBrands?: string;
    trayInfoIdx?: string;
    extruderId?: number;
    caliIdx?: number | null;
    savedPresetId?: string;
    location: string;
  } | null>(null);

  // Assign spool modal state (inventory)
  const [assignSpoolModal, setAssignSpoolModal] = useState<{
    printerId: number;
    amsId: number;
    trayId: number;
    trayInfo: { type: string; material?: string; profile?: string; color: string; location: string };
  } | null>(null);

  // Link spool modal state (Spoolman)
  const [linkSpoolModal, setLinkSpoolModal] = useState<{
    tagUid: string;
    trayUuid: string;
    printerId: number;
    amsId: number;
    trayId: number;
  } | null>(null);

  const getAssignment = useCallback((amsId: number, trayId: number): SpoolAssignment | undefined => {
    return assignments?.find(a => a.ams_id === Number(amsId) && a.tray_id === Number(trayId));
  }, [assignments]);

  const getLinkedSpool = useCallback((amsId: number, trayId: number, tray: AMSTray | null) => {
    if (!linkedSpools || !printerSerial) return undefined;
    const tag = (tray?.tray_uuid || tray?.tag_uid || getFallbackSpoolTag(printerSerial, amsId, trayId))?.toUpperCase();
    return tag ? linkedSpools[tag] : undefined;
  }, [linkedSpools, printerSerial]);

  const unassignMutation = useMutation({
    mutationFn: ({ printerId, amsId, trayId }: { printerId: number; amsId: number; trayId: number }) =>
      api.unassignSpool(printerId, amsId, trayId),
    onSuccess: () => {
      // Two cache-key shapes coexist for spool assignments: this page and a
      // few SpoolBuddy components key by printerId, while AssignSpoolModal
      // (and most of Bambuddy) keys without it. Both must be invalidated
      // here, otherwise after a SpoolBuddy unassign the modal opens with a
      // stale assignments list, sees the just-freed spool as still taken,
      // filters it out, and shows "no spools available" — even though it's
      // sitting in inventory ready to re-assign (#1133 follow-up).
      queryClient.invalidateQueries({ queryKey: ['spool-assignments', selectedPrinterId] });
      queryClient.invalidateQueries({ queryKey: ['spool-assignments'] });
      showToast(t('inventory.unassignSuccess', 'Spool unassigned'), 'success');
      setSlotActionPicker(null);
    },
  });

  const unlinkSpoolMutation = useMutation({
    mutationFn: (spoolId: number) => api.unlinkSpool(spoolId),
    onSuccess: (result) => {
      showToast(t('spoolman.unlinkSuccess') || result?.message, 'success');
      queryClient.invalidateQueries({ queryKey: ['linked-spools'] });
      queryClient.invalidateQueries({ queryKey: ['unlinked-spools'] });
      // Backend (spoolman.py:986) also deletes the SpoolmanSlotAssignment row,
      // so invalidate every cache that depends on slot assignments. Without
      // these PrintersPage / InventoryPage / SpoolBuddyDashboard keep showing
      // the spool as still assigned for ~30s until refetchInterval kicks in.
      queryClient.invalidateQueries({ queryKey: ['spoolman-slot-assignments'] });
      queryClient.invalidateQueries({ queryKey: ['spoolman-slot-assignments-all'] });
      queryClient.invalidateQueries({ queryKey: ['spoolman-inventory-spools'] });
      setSlotActionPicker(null);
    },
    onError: (error: Error) => {
      showToast(error.message || t('spoolman.unlinkFailed'), 'error');
    },
  });

  // Unassign a Spoolman spool from an AMS slot (slot-only assignment, no tag link).
  // Distinct from unlinkSpoolMutation, which also clears the tag binding via
  // /spoolman/spools/<id>/unlink. This one only deletes the SpoolmanSlotAssignment
  // row so the spool remains tag-linked (if it was) but is no longer bound to a slot.
  const unassignSpoolmanSlotMutation = useMutation({
    mutationFn: (spoolmanSpoolId: number) => api.unassignSpoolmanSlot(spoolmanSpoolId),
    onSuccess: () => {
      showToast(t('inventory.unassignSuccess', 'Spool unassigned'), 'success');
      // Invalidate every query that filters or counts spools by slot-assignment
      // state, otherwise re-opening LinkSpoolModal right after an unassign
      // shows a stale list that still treats the freed spool as taken.
      // unlinkSpoolMutation does the same set — keep them aligned so both
      // unbind paths refresh the same caches.
      queryClient.invalidateQueries({ queryKey: ['spoolman-slot-assignments'] });
      queryClient.invalidateQueries({ queryKey: ['spoolman-slot-assignments-all'] });
      queryClient.invalidateQueries({ queryKey: ['spoolman-inventory-spools'] });
      queryClient.invalidateQueries({ queryKey: ['unlinked-spools'] });
      queryClient.invalidateQueries({ queryKey: ['linked-spools'] });
      setSlotActionPicker(null);
    },
    onError: (error: Error) => {
      showToast(error.message || t('inventory.assignFailed', 'Failed to unassign spool'), 'error');
    },
  });

  const getActiveSlotForAms = useCallback((amsId: number): number | null => {
    if (effectiveTrayNow === undefined) return null;
    if (amsId <= 3) {
      const activeAmsId = Math.floor(effectiveTrayNow / 4);
      if (activeAmsId === amsId) return effectiveTrayNow % 4;
    }
    if (amsId >= 128 && amsId <= 135) {
      // AMS-HT: global tray ID equals the AMS unit ID itself (128, 129, ...)
      if (effectiveTrayNow === getGlobalTrayId(amsId, 0, false)) return 0;
    }
    return null;
  }, [effectiveTrayNow]);

  const handleAmsSlotClick = useCallback((amsId: number, trayId: number, tray: AMSTray | null) => {
    const globalTrayId = getGlobalTrayId(amsId, trayId, false);
    const slotPreset = slotPresets?.[globalTrayId];
    const mappedExtruderId = amsExtruderMap[String(amsId)];
    const normalizedId = amsId >= 128 ? amsId - 128 : amsId;
    const extruderId = mappedExtruderId !== undefined ? mappedExtruderId : normalizedId;
    const slotData = {
      amsId,
      trayId,
      trayCount: tray ? (amsId >= 128 ? 1 : 4) : 4,
      tray,
      trayType: tray?.tray_type || undefined,
      trayColor: tray?.tray_color || undefined,
      traySubBrands: tray?.tray_sub_brands || undefined,
      trayInfoIdx: tray?.tray_info_idx || undefined,
      extruderId: isDualNozzle ? extruderId : undefined,
      caliIdx: tray?.cali_idx,
      savedPresetId: slotPreset?.preset_id,
      location: `${getAmsName(amsId)} Slot ${trayId + 1}`,
    };

    setSlotActionPicker(slotData);
  }, [slotPresets, amsExtruderMap, isDualNozzle]);

  const handleExtSlotClick = useCallback((extTray: AMSTray) => {
    const extTrayId = extTray.id ?? 254;
    const slotTrayId = extTrayId - 254;
    const extSlotPreset = slotPresets?.[255 * 4 + slotTrayId];
    const slotData = {
      amsId: 255,
      trayId: slotTrayId,
      trayCount: 1,
      tray: isTrayEmpty(extTray) ? null : extTray,
      trayType: extTray.tray_type || undefined,
      trayColor: extTray.tray_color || undefined,
      traySubBrands: extTray.tray_sub_brands || undefined,
      trayInfoIdx: extTray.tray_info_idx || undefined,
      extruderId: isDualNozzle ? (extTrayId === 254 ? 1 : 0) : undefined,
      caliIdx: extTray.cali_idx,
      savedPresetId: extSlotPreset?.preset_id,
      location: isDualNozzle
        ? (extTrayId === 254 ? 'Ext-L' : 'Ext-R')
        : 'External',
    };

    setSlotActionPicker(slotData);
  }, [slotPresets, isDualNozzle]);

  const openConfigureFromPicker = useCallback(() => {
    if (!slotActionPicker) return;
    // eslint-disable-next-line @typescript-eslint/no-unused-vars
    const { tray, location, ...configData } = slotActionPicker;
    setSlotActionPicker(null);
    setConfigureSlotModal(configData);
  }, [slotActionPicker]);

  const openAssignFromPicker = useCallback(() => {
    if (!slotActionPicker || !selectedPrinterId) return;
    const { amsId, trayId, trayType, trayColor, location } = slotActionPicker;
    setSlotActionPicker(null);
    setAssignSpoolModal({
      printerId: selectedPrinterId,
      amsId,
      trayId,
      trayInfo: {
        type: trayType || '',
        material: trayType,
        color: trayColor?.slice(0, 6) || '',
        location,
      },
    });
  }, [slotActionPicker, selectedPrinterId]);

  const openLinkFromPicker = useCallback(() => {
    if (!slotActionPicker || !selectedPrinterId) return;
    const { amsId, trayId, tray } = slotActionPicker;
    const linkTag = (tray?.tray_uuid || tray?.tag_uid || getFallbackSpoolTag(printerSerial, amsId, trayId))?.toUpperCase() || '';
    setSlotActionPicker(null);
    setLinkSpoolModal({
      tagUid: tray?.tag_uid || linkTag,
      trayUuid: tray?.tray_uuid || '',
      printerId: selectedPrinterId,
      amsId,
      trayId,
    });
  }, [slotActionPicker, selectedPrinterId, printerSerial]);

  const handleUnassignFromPicker = useCallback(() => {
    if (!slotActionPicker || !selectedPrinterId) return;
    const { amsId, trayId } = slotActionPicker;
    unassignMutation.mutate({ printerId: selectedPrinterId, amsId, trayId });
  }, [slotActionPicker, selectedPrinterId, unassignMutation]);

  // Set alert for low filament in status bar
  useEffect(() => {
    if (!isConnected && selectedPrinterId) {
      setAlert({ type: 'warning', message: t('spoolbuddy.ams.printerDisconnected', 'Printer disconnected') });
      return;
    }
    for (const unit of amsUnits) {
      const trays = unit.tray || [];
      for (let i = 0; i < trays.length; i++) {
        const tray = trays[i];
        if (tray.remain !== null && tray.remain >= 0 && tray.remain < 15 && tray.tray_type) {
          const isExternal = unit.id === 254 || unit.id === 255;
          const isHt = !isExternal && unit.id >= 128;
          const slot = formatSlotLabel(unit.id, i, isHt, isExternal);
          setAlert({
            type: 'warning',
            message: `Low Filament: ${tray.tray_type} (${slot}) - ${tray.remain}% remaining`,
          });
          return;
        }
      }
    }
    setAlert(null);
  }, [amsUnits, isConnected, selectedPrinterId, setAlert, t]);

  // Build list of single-slot items (AMS-HT + External) for compact rendering
  const singleSlots = useMemo(() => {
    const items: {
      key: string; label: string; tray: AMSTray; isEmpty: boolean; isActive: boolean;
      temp?: number | null; humidity?: number | null; nozzleSide?: 'L' | 'R' | null;
      effectiveFill: number | null;
      onClick: () => void;
    }[] = [];

    for (const unit of htAms) {
      const tray = unit.tray?.[0] || {
        id: 0, tray_color: null, tray_type: '', tray_sub_brands: null,
        tray_id_name: null, tray_info_idx: null, remain: -1, k: null,
        cali_idx: null, tag_uid: null, tray_uuid: null, nozzle_temp_min: null, nozzle_temp_max: null,
      };
      // Fill level fallback chain: Spoolman → Inventory → AMS remain
      const spoolmanFill = getSpoolmanFillForSlot(unit.id, 0, isTrayEmpty(tray) ? null : tray);
      const invFill = fillOverrides[`${unit.id}-0`] ?? null;
      const amsFill = tray.remain != null && tray.remain >= 0 ? tray.remain : null;
      // If inventory says 0% but AMS reports positive remain, prefer AMS (#676)
      const resolvedInvFill = (invFill === 0 && amsFill !== null && amsFill > 0) ? null : invFill;
      items.push({
        key: `ht-${unit.id}`,
        label: getAmsName(unit.id),
        tray,
        isEmpty: isTrayEmpty(tray),
        isActive: getActiveSlotForAms(unit.id) === 0,
        temp: unit.temp,
        humidity: unit.humidity,
        nozzleSide: getNozzleSide(unit.id),
        effectiveFill: spoolmanFill ?? resolvedInvFill ?? amsFill,
        onClick: () => handleAmsSlotClick(unit.id, 0, isTrayEmpty(tray) ? null : tray),
      });
    }

    for (const extTray of vtTrays) {
      const extTrayId = extTray.id ?? 254;
      // On dual-nozzle (H2C/H2D), tray_now=254 means "external spool"
      // generically — use active_extruder to determine L vs R:
      // extruder 1=left → Ext-L (id=254), extruder 0=right → Ext-R (id=255)
      const isExtActive = isDualNozzle && effectiveTrayNow === 254
        ? (extTrayId === 254 && status?.active_extruder === 1) ||
          (extTrayId === 255 && status?.active_extruder === 0)
        : effectiveTrayNow === extTrayId;
      const extSlotTrayId = extTrayId - 254;
      // Fill level fallback chain: Spoolman → Inventory → AMS remain
      const extSpoolmanFill = getSpoolmanFillForSlot(255, extSlotTrayId, isTrayEmpty(extTray) ? null : extTray);
      const extInvFill = fillOverrides[`255-${extSlotTrayId}`] ?? null;
      const extAmsFill = extTray.remain != null && extTray.remain >= 0 ? extTray.remain : null;
      // If inventory says 0% but AMS reports positive remain, prefer AMS (#676)
      const extResolvedInvFill = (extInvFill === 0 && extAmsFill !== null && extAmsFill > 0) ? null : extInvFill;
      items.push({
        key: `ext-${extTrayId}`,
        label: isDualNozzle
          ? (extTrayId === 254 ? t('printers.extL', 'Ext-L') : t('printers.extR', 'Ext-R'))
          : t('printers.ext', 'Ext'),
        tray: extTray,
        isEmpty: isTrayEmpty(extTray),
        isActive: isExtActive,
        nozzleSide: null,
        effectiveFill: extSpoolmanFill ?? extResolvedInvFill ?? extAmsFill,
        onClick: () => handleExtSlotClick(extTray),
      });
    }

    return items;
  }, [htAms, vtTrays, isDualNozzle, effectiveTrayNow, status?.active_extruder, t, getActiveSlotForAms, getNozzleSide, handleAmsSlotClick, handleExtSlotClick, fillOverrides, getSpoolmanFillForSlot]);

  return (
    <div className="h-full flex flex-col p-4">
      <div className="flex-1 min-h-0">
        {!selectedPrinterId ? (
          <div className="flex-1 flex items-center justify-center h-full">
            <div className="text-center text-white/50">
              <p className="text-lg mb-2">{t('spoolbuddy.ams.noPrinter', 'No printer selected')}</p>
              <p className="text-sm">{t('spoolbuddy.ams.selectPrinter', 'Select a printer from the top bar')}</p>
            </div>
          </div>
        ) : !isConnected ? (
          <div className="flex-1 flex items-center justify-center h-full">
            <div className="text-center text-white/50">
              <p className="text-lg mb-2">{t('spoolbuddy.ams.printerDisconnected', 'Printer disconnected')}</p>
            </div>
          </div>
        ) : amsUnits.length === 0 && vtTrays.length === 0 ? (
          <div className="flex-1 flex items-center justify-center h-full">
            <div className="text-center text-white/50">
              <Layers className="w-12 h-12 mx-auto mb-3 opacity-50" />
              <p className="text-lg mb-2">{t('spoolbuddy.ams.noData', 'No AMS detected')}</p>
              <p className="text-sm">{t('spoolbuddy.ams.connectAms', 'Connect an AMS to see filament slots')}</p>
            </div>
          </div>
        ) : (
          <div className="flex flex-col gap-3 h-full">
            {/* Regular AMS cards — 4-slot, 2-col grid */}
            <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
              {regularAms.map((unit) => (
                <AmsUnitCard
                  key={unit.id}
                  unit={unit}
                  activeSlot={getActiveSlotForAms(unit.id)}
                  onConfigureSlot={handleAmsSlotClick}
                  isDualNozzle={isDualNozzle}
                  nozzleSide={getNozzleSide(unit.id)}
                  thresholds={amsThresholds}
                  fillOverrides={fillOverrides}
                  spoolmanFillOverrides={spoolmanFillOverrides}
                />
              ))}
            </div>

            {/* Third row: single-slot cards (AMS-HT + External) — half-width to align with AMS cards */}
            {singleSlots.length > 0 && (
              <div className="grid grid-cols-2 md:grid-cols-4 gap-3">
                {singleSlots.map(({ key, label, tray, isEmpty, isActive, temp, humidity, nozzleSide, effectiveFill, onClick }) => {
                  const color = trayColorToCSS(tray.tray_color);
                  return (
                    <div
                      key={key}
                      className={`bg-bambu-dark-secondary rounded-lg px-3 py-2 cursor-pointer hover:bg-bambu-dark-secondary/80 transition-all flex items-center gap-3 ${isActive ? 'ring-2 ring-bambu-green' : ''}`}
                      onClick={onClick}
                    >
                      {/* Spool */}
                      <div className="relative w-10 h-10 flex-shrink-0">
                        {isEmpty ? (
                          <div className="w-full h-full rounded-full border-2 border-dashed border-gray-500 flex items-center justify-center">
                            <div className="w-1.5 h-1.5 rounded-full bg-gray-600" />
                          </div>
                        ) : (
                          <svg viewBox="0 0 56 56" className="w-full h-full">
                            <circle cx="28" cy="28" r="26" fill={color} />
                            <circle cx="28" cy="28" r="20" fill={color} style={{ filter: 'brightness(0.85)' }} />
                            <ellipse cx="20" cy="20" rx="6" ry="4" fill="white" opacity="0.3" />
                            <circle cx="28" cy="28" r="8" fill="#2d2d2d" />
                            <circle cx="28" cy="28" r="5" fill="#1a1a1a" />
                          </svg>
                        )}
                        {isActive && (
                          <div className="absolute -bottom-0.5 left-1/2 -translate-x-1/2 w-1.5 h-1.5 bg-bambu-green rounded-full" />
                        )}
                      </div>
                      {/* Info */}
                      <div className="min-w-0">
                        <div className="flex items-center gap-1">
                          <span className="text-xs text-white/50 font-medium truncate">{label}</span>
                          {nozzleSide && <NozzleBadge side={nozzleSide} />}
                        </div>
                        <div className="text-sm text-white/80 truncate">
                          {isEmpty ? 'Empty' : tray.tray_type || '?'}
                        </div>
                        {(temp != null || humidity != null) && (
                          <div className="flex items-center gap-1.5">
                            {temp != null && (
                              <TemperatureIndicator
                                temp={temp}
                                goodThreshold={amsThresholds?.tempGood}
                                fairThreshold={amsThresholds?.tempFair}
                              />
                            )}
                            {humidity != null && (
                              <HumidityIndicator
                                humidity={humidity}
                                goodThreshold={amsThresholds?.humidityGood}
                                fairThreshold={amsThresholds?.humidityFair}
                              />
                            )}
                          </div>
                        )}
                      </div>
                      {/* Fill bar */}
                      {!isEmpty && effectiveFill != null && effectiveFill >= 0 && (
                        <div className="w-1.5 h-8 bg-bambu-dark-tertiary rounded-full overflow-hidden flex-shrink-0 flex flex-col-reverse">
                          <div
                            className="w-full rounded-full"
                            style={{
                              height: `${effectiveFill}%`,
                              backgroundColor: getFillBarColor(effectiveFill),
                            }}
                          />
                        </div>
                      )}
                    </div>
                  );
                })}
              </div>
            )}
          </div>
        )}
      </div>

      {configureSlotModal && selectedPrinterId && (
        <ConfigureAmsSlotModal
          isOpen={!!configureSlotModal}
          onClose={() => setConfigureSlotModal(null)}
          printerId={selectedPrinterId}
          slotInfo={configureSlotModal}
          printerModel={mapModelCode(printer?.model ?? null) || undefined}
          fullScreen
          onSuccess={() => {
            queryClient.invalidateQueries({ queryKey: ['slotPresets', selectedPrinterId] });
            queryClient.invalidateQueries({ queryKey: ['printerStatus', selectedPrinterId] });
          }}
        />
      )}

      {/* Slot action picker */}
      {slotActionPicker && selectedPrinterId && (() => {
        const assignment = getAssignment(slotActionPicker.amsId, slotActionPicker.trayId);
        const linked = getLinkedSpool(slotActionPicker.amsId, slotActionPicker.trayId, slotActionPicker.tray);
        // Slot-only Spoolman assignment (no tag link). Resolves the spool details
        // from spoolmanInventorySpoolsCache so we can show "Assigned spool: …"
        // and an Unassign button — without this branch, picking a slot that was
        // assigned via the dashboard's Assign-to-AMS flow showed only "Configure"
        // with no info about which spool was bound.
        const spoolmanAssign = spoolmanEnabled
          ? spoolmanSlotAssignmentsAll.find(a =>
              a.printer_id === selectedPrinterId &&
              a.ams_id === slotActionPicker.amsId &&
              a.tray_id === slotActionPicker.trayId,
            )
          : undefined;
        const spoolmanAssignedSpool = spoolmanAssign
          ? spoolmanInventorySpoolsCache.find(s => s.id === spoolmanAssign.spoolman_spool_id) ?? null
          : null;
        return (
          <div className="fixed inset-0 z-50 flex items-center justify-center">
            <div
              className="absolute inset-0 bg-black/60 backdrop-blur-sm"
              onClick={() => setSlotActionPicker(null)}
            />
            <div className="relative w-full max-w-sm mx-4 bg-bambu-dark-secondary border border-bambu-dark-tertiary rounded-xl shadow-2xl">
              <div className="flex items-center justify-between p-4 border-b border-bambu-dark-tertiary">
                <div className="flex items-center gap-2">
                  {slotActionPicker.trayColor && (
                    <span
                      className="w-4 h-4 rounded-full border border-black/20"
                      style={{ backgroundColor: `#${slotActionPicker.trayColor.slice(0, 6)}` }}
                    />
                  )}
                  <h2 className="text-lg font-semibold text-white">{slotActionPicker.location}</h2>
                  {slotActionPicker.traySubBrands && (
                    <span className="text-sm text-bambu-gray">({slotActionPicker.traySubBrands})</span>
                  )}
                </div>
                <button
                  onClick={() => setSlotActionPicker(null)}
                  className="p-1 text-bambu-gray hover:text-white rounded transition-colors"
                >
                  <X className="w-5 h-5" />
                </button>
              </div>
              <div className="p-4 space-y-2">
                {/* Currently assigned/linked spool info */}
                {!spoolmanEnabled && assignment?.spool && (
                  <div className="p-2.5 bg-bambu-dark rounded-lg border border-bambu-dark-tertiary mb-3">
                    <p className="text-xs text-bambu-gray mb-1">{t('inventory.assignedSpool', 'Assigned spool')}</p>
                    <div className="flex items-center gap-2">
                      {assignment.spool.rgba && (
                        <span
                          className="w-3 h-3 rounded-full border border-black/20 flex-shrink-0"
                          style={{ backgroundColor: `#${assignment.spool.rgba.substring(0, 6)}` }}
                        />
                      )}
                      <span className="text-sm text-white">
                        {assignment.spool.brand ? `${assignment.spool.brand} ` : ''}{assignment.spool.material}
                        {assignment.spool.color_name ? ` - ${assignment.spool.color_name}` : ''}
                      </span>
                      <span className="text-[10px] font-mono text-zinc-500 shrink-0 ml-auto">#{assignment.spool.id}</span>
                    </div>
                  </div>
                )}
                {/* #1457: Assigned-spool block is rendered FIRST when a slot
                    assignment exists, regardless of whether a (possibly stale)
                    tag-link also exists. The tag-link block is the fallback
                    for slots that have only a tag-link. */}
                {spoolmanEnabled && linked && !spoolmanAssignedSpool && (
                  <div className="p-2.5 bg-bambu-dark rounded-lg border border-bambu-dark-tertiary mb-3">
                    <p className="text-xs text-bambu-gray mb-1">{t('spoolman.linkedSpool', 'Linked spool')}</p>
                    <div className="flex items-center gap-2">
                      <span className="text-sm text-white">
                        Spoolman #{linked.id}
                        {linked.remaining_weight != null ? ` (${Math.round(linked.remaining_weight)}g)` : ''}
                      </span>
                    </div>
                  </div>
                )}
                {spoolmanEnabled && spoolmanAssignedSpool && (
                  <div className="p-2.5 bg-bambu-dark rounded-lg border border-bambu-dark-tertiary mb-3">
                    <p className="text-xs text-bambu-gray mb-1">{t('inventory.assignedSpool', 'Assigned spool')}</p>
                    <div className="flex items-center gap-2">
                      {spoolmanAssignedSpool.rgba && (
                        <span
                          className="w-3 h-3 rounded-full border border-black/20 flex-shrink-0"
                          style={{ backgroundColor: `#${spoolmanAssignedSpool.rgba.substring(0, 6)}` }}
                        />
                      )}
                      <span className="text-sm text-white">
                        {spoolmanAssignedSpool.brand ? `${spoolmanAssignedSpool.brand} ` : ''}{spoolmanAssignedSpool.material}
                        {spoolmanAssignedSpool.color_name ? ` - ${spoolmanAssignedSpool.color_name}` : ''}
                      </span>
                    </div>
                  </div>
                )}

                <button
                  onClick={openConfigureFromPicker}
                  className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-bambu-blue transition-colors text-left"
                >
                  <Settings2 className="w-5 h-5 text-bambu-blue flex-shrink-0" />
                  <div>
                    <p className="text-white font-medium">{t('configureAmsSlot.title')}</p>
                    <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.configureDesc', 'Set filament preset, K-profile, and color')}</p>
                  </div>
                </button>

                {/* Inventory: Assign or Unassign in local mode.
                    BL-RFID-detected slots are owned by the printer firmware —
                    suppress assign/unassign there to keep parity with the
                    Spoolman branch (Phase 14 A3). Manual changes would be
                    overwritten on the next RFID re-read. */}
                {!spoolmanEnabled && (() => {
                  if (isBambuLabSpool(slotActionPicker?.tray)) return null;
                  if (assignment) {
                    return (
                      <button
                        onClick={handleUnassignFromPicker}
                        disabled={unassignMutation.isPending}
                        className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-amber-500 transition-colors text-left"
                      >
                        <Unlink className="w-5 h-5 text-amber-400 flex-shrink-0" />
                        <div>
                          <p className="text-amber-400 font-medium">{t('inventory.unassignSpool', 'Unassign')}</p>
                          <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.unassignDesc', 'Remove inventory spool from this slot')}</p>
                        </div>
                      </button>
                    );
                  }
                  return (
                    <button
                      onClick={openAssignFromPicker}
                      className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-bambu-green transition-colors text-left"
                    >
                      <Package className="w-5 h-5 text-bambu-green flex-shrink-0" />
                      <div>
                        <p className="text-white font-medium">{t('inventory.assignSpool')}</p>
                        <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.assignDesc', 'Track a spool from your inventory')}</p>
                      </div>
                    </button>
                  );
                })()}

                {/* Spoolman: Link / Unlink (tag-linked) or Unassign (slot-only) */}
                {spoolmanEnabled && (() => {
                  if (linked?.id) {
                    return (
                      <button
                        onClick={() => unlinkSpoolMutation.mutate(linked.id)}
                        disabled={unlinkSpoolMutation.isPending}
                        className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-amber-500 transition-colors text-left active:opacity-50"
                      >
                        <Unlink className="w-5 h-5 text-amber-400 flex-shrink-0" />
                        <div>
                          <p className="text-amber-400 font-medium">{t('inventory.unassignSpool')}</p>
                          <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.unlinkDesc', 'Remove Spoolman link from this slot')}</p>
                        </div>
                      </button>
                    );
                  }
                  // Slot-only assignment (no tag link): show Unassign so the
                  // user can clear it. Previously this branch returned null
                  // and only the Configure button remained, hiding the fact
                  // that a spool was bound to the slot at all.
                  if (spoolmanAssignedSpool) {
                    return (
                      <button
                        onClick={() => unassignSpoolmanSlotMutation.mutate(spoolmanAssignedSpool.id)}
                        disabled={unassignSpoolmanSlotMutation.isPending}
                        className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-amber-500 transition-colors text-left active:opacity-50"
                      >
                        <Unlink className="w-5 h-5 text-amber-400 flex-shrink-0" />
                        <div>
                          <p className="text-amber-400 font-medium">{t('inventory.unassignSpool')}</p>
                          <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.unassignDesc', 'Remove inventory spool from this slot')}</p>
                        </div>
                      </button>
                    );
                  }
                  return (
                    <button
                      onClick={openLinkFromPicker}
                      className="w-full flex items-center gap-3 p-3 rounded-lg bg-bambu-dark border border-bambu-dark-tertiary hover:border-bambu-green transition-colors text-left"
                    >
                      <Link2 className="w-5 h-5 text-bambu-green flex-shrink-0" />
                      <div>
                        <p className="text-white font-medium">{t('inventory.assignSpool')}</p>
                        <p className="text-xs text-bambu-gray">{t('spoolbuddy.ams.linkDesc', 'Link a Spoolman spool to this slot')}</p>
                      </div>
                    </button>
                  );
                })()}
              </div>
            </div>
          </div>
        );
      })()}

      {/* Assign spool modal (inventory) */}
      {assignSpoolModal && (
        <AssignSpoolModal
          isOpen={!!assignSpoolModal}
          onClose={() => {
            setAssignSpoolModal(null);
            // Same dual-key invalidation as the unassign path — the AMS
            // status panel reads the printerId-keyed query while the
            // shared AssignSpoolModal reads the unkeyed one.
            queryClient.invalidateQueries({ queryKey: ['spool-assignments', selectedPrinterId] });
            queryClient.invalidateQueries({ queryKey: ['spool-assignments'] });
          }}
          printerId={assignSpoolModal.printerId}
          amsId={assignSpoolModal.amsId}
          trayId={assignSpoolModal.trayId}
          trayInfo={assignSpoolModal.trayInfo}
          spoolmanEnabled={!!spoolmanEnabled}
        />
      )}

      {/* Link spool modal (Spoolman) */}
      {linkSpoolModal && (
        <LinkSpoolModal
          isOpen={!!linkSpoolModal}
          onClose={() => setLinkSpoolModal(null)}
          tagUid={linkSpoolModal.tagUid}
          trayUuid={linkSpoolModal.trayUuid}
          printerId={linkSpoolModal.printerId}
          amsId={linkSpoolModal.amsId}
          trayId={linkSpoolModal.trayId}
        />
      )}
    </div>
  );
}