import { useState, useEffect, useCallback, useMemo, useRef } from 'react';
import { useExperimental } from '@/hooks/useExperimental';
import {
    Server, Cpu, MemoryStick, HardDrive, RefreshCw, ChevronDown, ChevronRight,
    Layers, Wifi, WifiOff, Search, AlertTriangle,
    RotateCcw, ExternalLink, Camera, Download, Loader2,
    Network, SlidersHorizontal,
    Send, KeyRound, ArrowLeftRight,
} from 'lucide-react';
import { FleetMasthead } from './fleet/FleetMasthead';
import { FleetTopology } from './fleet/FleetTopology';
import { ReconnectingOverlay } from './FleetView/ReconnectingOverlay';
import { NodeUpdatesSheet } from './FleetView/NodeUpdatesSheet';
import { LocalUpdateConfirmDialog } from './FleetView/LocalUpdateConfirmDialog';
import { UpdateStatusBadge } from './FleetView/UpdateStatusBadge';
import type { NodeUpdateStatus, ViewMode, FleetPreferences, FleetPaletteEntry } from './FleetView/types';
import { OverviewToolbar } from './FleetView/OverviewToolbar';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { Skeleton } from '@/components/ui/skeleton';
import { Tabs, TabsContent, TabsList, TabsTrigger, TabsHighlight, TabsHighlightItem } from '@/components/ui/tabs';
import { springs } from '@/lib/motion';
import { apiFetch, fetchForNode } from '@/lib/api';
import { useLicense } from '@/context/LicenseContext';
import { AdmiralGate } from './AdmiralGate';
import FleetSnapshots from './FleetSnapshots';
import { FleetConfiguration } from './fleet/FleetConfiguration';
import { FleetSoonPlaceholder, SoonBadge } from './fleet/FleetSoonPlaceholder';
import { RoutingTab } from './fleet/RoutingTab';
import { DeploymentsTab } from './blueprints/DeploymentsTab';
import { toast } from '@/components/ui/toast-store';
import { LabelDot } from './LabelPill';
import { type Label as StackLabel, type LabelColor } from './label-types';
import { formatVersion } from '@/lib/version';

function labelPaletteKey(name: string, color: LabelColor): string {
    return `${name.trim().toLowerCase()}|${color}`;
}

// --- Types ---

interface FleetNodeStats {
    active: number;
    managed: number;
    unmanaged: number;
    exited: number;
    total: number;
}

interface FleetNodeSystemStats {
    cpu: { usage: string; cores: number };
    memory: { total: number; used: number; free: number; usagePercent: string };
    disk: { total: number; used: number; free: number; usagePercent: string } | null;
}

interface FleetNode {
    id: number;
    name: string;
    type: 'local' | 'remote';
    status: 'online' | 'offline' | 'unknown';
    stats: FleetNodeStats | null;
    systemStats: FleetNodeSystemStats | null;
    stacks: string[] | null;
}

interface StackContainer {
    Id?: string;
    Names?: string[];
    Image?: string;
    State?: string;
    Status?: string;
}

const PREFS_KEY = 'sencho-fleet-preferences';

function loadPreferences(): FleetPreferences {
    try {
        const stored = localStorage.getItem(PREFS_KEY);
        if (stored) return JSON.parse(stored) as FleetPreferences;
    } catch { /* use defaults */ }
    return { sortBy: 'name', sortDir: 'asc', filterStatus: 'all', filterType: 'all', filterCritical: false };
}

function savePreferences(prefs: FleetPreferences) {
    localStorage.setItem(PREFS_KEY, JSON.stringify(prefs));
}

// --- Utilities ---

function formatBytes(bytes: number): string {
    if (bytes === 0) return '0 B';
    const k = 1024;
    const sizes = ['B', 'KB', 'MB', 'GB', 'TB'];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i];
}

function getNodeCpu(node: FleetNode): number {
    return node.systemStats ? parseFloat(node.systemStats.cpu.usage) : 0;
}

function getNodeMem(node: FleetNode): number {
    return node.systemStats ? parseFloat(node.systemStats.memory.usagePercent) : 0;
}

function getNodeDisk(node: FleetNode): number {
    return node.systemStats?.disk ? parseFloat(node.systemStats.disk.usagePercent) : 0;
}

function isCritical(node: FleetNode): boolean {
    return getNodeCpu(node) > 90 || getNodeDisk(node) > 90;
}

function containerName(c: StackContainer): string {
    if (c.Names && c.Names.length > 0) {
        return c.Names[0].replace(/^\//, '');
    }
    return c.Id?.slice(0, 12) ?? 'unknown';
}

// --- Sub-Components ---

function UsageBar({ percent, color }: { percent: number; color: string }) {
    return (
        <div className="h-1.5 w-full bg-muted rounded-full overflow-hidden">
            <div
                className={`h-full rounded-full transition-all duration-500 ${color}`}
                style={{ width: `${Math.min(100, percent)}%` }}
            />
        </div>
    );
}

function ContainerRow({ container, nodeId, onNavigate }: {
    container: StackContainer;
    nodeId: number;
    onNavigate: (nodeId: number) => void;
}) {
    const name = containerName(container);
    const state = container.State?.toLowerCase() ?? 'unknown';
    const image = container.Image;
    const status = container.Status ?? '';

    const stateColor = state === 'running' ? 'bg-success' :
        state === 'restarting' ? 'bg-warning' : 'bg-destructive';

    return (
        <div className="flex items-center gap-3 px-3 py-2 rounded-lg hover:bg-muted/50 transition-colors group">
            <div className={`w-1.5 h-1.5 rounded-full shrink-0 ${stateColor}`} />
            <div className="min-w-0 flex-1">
                <div className="flex items-center gap-2">
                    <span className="text-xs font-medium truncate">{name}</span>
                    <Badge variant="outline" className="text-[9px] px-1 py-0 h-3.5 shrink-0">{state}</Badge>
                </div>
                {(image || status) && (
                    <div className="flex items-center gap-2 mt-0.5">
                        {image && <span className="text-[10px] text-muted-foreground truncate">{image}</span>}
                        {status && <span className="text-[10px] text-muted-foreground shrink-0">{image ? '· ' : ''}{status}</span>}
                    </div>
                )}
            </div>
            <Button
                variant="ghost"
                size="sm"
                className="h-6 w-6 p-0 opacity-0 group-hover:opacity-100 transition-opacity"
                onClick={() => onNavigate(nodeId)}
                title="Open in editor"
            >
                <ExternalLink className="w-3 h-3" strokeWidth={1.5} />
            </Button>
        </div>
    );
}

function StackSection({ stackName, nodeId, onNavigate, labelMap }: {
    stackName: string;
    nodeId: number;
    onNavigate: (nodeId: number, stackName: string) => void;
    labelMap?: Record<string, StackLabel[]>;
}) {
    const [expanded, setExpanded] = useState(false);
    const [containers, setContainers] = useState<StackContainer[] | null>(null);
    const [loading, setLoading] = useState(false);

    const handleExpand = async () => {
        if (loading) return;
        const next = !expanded;
        setExpanded(next);

        if (next) {
            setLoading(true);
            try {
                const res = await apiFetch(`/fleet/node/${nodeId}/stacks/${encodeURIComponent(stackName)}/containers`, { localOnly: true });
                if (res.ok) {
                    setContainers(await res.json());
                } else {
                    toast.error('Failed to load containers for ' + stackName);
                }
            } catch (error) {
                console.error('Failed to load containers for', stackName, error);
                toast.error('Failed to load containers for ' + stackName);
            } finally {
                setLoading(false);
            }
        }
    };

    const runningCount = containers?.filter(c => c.State?.toLowerCase() === 'running').length ?? 0;
    const totalCount = containers?.length ?? 0;

    return (
        <div>
            <button
                onClick={handleExpand}
                className="flex items-center gap-2 w-full px-3 py-1.5 rounded-md text-xs hover:bg-muted/50 transition-colors text-left group"
            >
                {expanded ? <ChevronDown className="w-3 h-3 shrink-0" /> : <ChevronRight className="w-3 h-3 shrink-0" />}
                <Layers className="w-3 h-3 text-muted-foreground shrink-0" />
                <span className="truncate flex-1">{stackName}</span>
                {labelMap?.[stackName]?.length ? (
                    <span className="flex items-center gap-0.5 shrink-0">
                        {labelMap[stackName].map(l => (
                            <LabelDot key={l.id} color={l.color} />
                        ))}
                    </span>
                ) : null}
                {containers !== null && (
                    <span className="text-[10px] text-muted-foreground shrink-0">
                        {runningCount}/{totalCount}
                    </span>
                )}
            </button>
            {expanded && (
                <div className="ml-4 mt-1 space-y-0.5">
                    {loading ? (
                        <div className="space-y-2 px-3 py-1">
                            <Skeleton className="h-5 w-full" />
                            <Skeleton className="h-5 w-3/4" />
                        </div>
                    ) : containers && containers.length > 0 ? (
                        containers.map(c => (
                            <ContainerRow
                                key={c.Id ?? containerName(c)}
                                container={c}
                                nodeId={nodeId}
                                onNavigate={(nid) => onNavigate(nid, stackName)}
                            />
                        ))
                    ) : (
                        <p className="text-[10px] text-muted-foreground px-3 py-1">No containers</p>
                    )}
                </div>
            )}
        </div>
    );
}

interface NodeCardProps {
    node: FleetNode;
    onNavigate: (nodeId: number, stackName: string) => void;
    labelMap?: Record<string, StackLabel[]>;
    updateStatus?: NodeUpdateStatus;
    onUpdate?: (nodeId: number) => void;
    updatingNodeId?: number | null;
    onRetryUpdate?: (nodeId: number) => void;
    onDismissUpdate?: (nodeId: number) => void;
}

function NodeCard({ node, onNavigate, labelMap, updateStatus, onUpdate, updatingNodeId, onRetryUpdate, onDismissUpdate }: NodeCardProps) {
    const { isPaid } = useLicense();
    const [expanded, setExpanded] = useState(false);
    const [stacks, setStacks] = useState<string[] | null>(node.stacks);
    const [loadingStacks, setLoadingStacks] = useState(false);

    const isOnline = node.status === 'online';
    const isLocal = node.type === 'local';
    const formattedVersion = formatVersion(updateStatus?.version);
    const formattedLatest = formatVersion(updateStatus?.latestVersion);
    const cpuPercent = getNodeCpu(node);
    const memPercent = getNodeMem(node);
    const diskPercent = getNodeDisk(node);

    const handleExpand = async () => {
        if (!isPaid) return;
        const next = !expanded;
        setExpanded(next);

        if (next && !stacks) {
            setLoadingStacks(true);
            try {
                const res = await apiFetch(`/fleet/node/${node.id}/stacks`, { localOnly: true });
                if (res.ok) {
                    setStacks(await res.json());
                } else {
                    toast.error('Failed to load stacks for ' + node.name);
                }
            } catch (error) {
                console.error('Failed to load stacks for', node.name, error);
                toast.error('Failed to load stacks for ' + node.name);
            } finally {
                setLoadingStacks(false);
            }
        }
    };

    const localRailClasses = isLocal
        ? 'relative overflow-hidden ring-1 ring-brand/30 before:absolute before:inset-y-0 before:left-0 before:w-[2px] before:bg-brand before:rounded-l-xl after:pointer-events-none after:absolute after:inset-0 after:bg-gradient-to-r after:from-brand/[0.06] after:via-transparent after:to-transparent'
        : '';

    return (
        <div className={`rounded-xl border border-card-border border-t-card-border-top bg-card text-card-foreground shadow-card-bevel transition-colors hover:border-t-card-border-hover ${localRailClasses} ${isOnline ? '' : 'opacity-60'}`}>
            {/* Card Header */}
            <div className="relative p-4 pb-3">
                {isLocal && (
                    <span className="absolute top-3 right-3 font-mono text-[9px] uppercase tracking-[0.22em] text-brand">
                        ★ Local
                    </span>
                )}
                <div className="flex items-center justify-between mb-3">
                    <div className="flex items-center gap-2.5 min-w-0">
                        <div className={`flex items-center justify-center w-8 h-8 rounded-lg ${isOnline ? 'bg-success-muted' : 'bg-muted'}`}>
                            <Server className={`w-4 h-4 ${isOnline ? 'text-success' : 'text-muted-foreground'}`} />
                        </div>
                        <div className="min-w-0">
                            <h3 className="text-sm font-medium truncate">{node.name}</h3>
                            <div className="flex items-center gap-1.5 mt-0.5 flex-wrap">
                                <Badge variant={isOnline ? 'default' : 'secondary'} className="text-[10px] px-1.5 py-0 h-4 shrink-0">
                                    {isOnline ? (
                                        <><Wifi className="w-2.5 h-2.5 mr-0.5" /> Online</>
                                    ) : (
                                        <><WifiOff className="w-2.5 h-2.5 mr-0.5" /> Offline</>
                                    )}
                                </Badge>
                                <Badge variant="outline" className="text-[10px] px-1.5 py-0 h-4 shrink-0">
                                    {node.type}
                                </Badge>
                                {formattedVersion && (
                                    <Badge variant="outline" className="text-[10px] px-1.5 py-0 h-4 font-mono tabular-nums shrink-0">
                                        {formattedVersion}
                                    </Badge>
                                )}
                                {updateStatus?.updateStatus && (
                                    <UpdateStatusBadge
                                        status={updateStatus.updateStatus}
                                        error={updateStatus.error}
                                        onRetry={onRetryUpdate ? () => onRetryUpdate(node.id) : undefined}
                                        onDismiss={onDismissUpdate ? () => onDismissUpdate(node.id) : undefined}
                                    />
                                )}
                                {updateStatus?.updateAvailable && !updateStatus.updateStatus && (
                                    <Badge className="text-[10px] px-1.5 py-0 h-4 bg-warning/15 text-warning border-warning/30 shrink-0">
                                        Update available
                                    </Badge>
                                )}
                                {isOnline && isCritical(node) && (
                                    <Badge variant="destructive" className="text-[10px] px-1.5 py-0 h-4 shrink-0">
                                        <AlertTriangle className="w-2.5 h-2.5 mr-0.5" /> Critical
                                    </Badge>
                                )}
                            </div>
                        </div>
                    </div>
                </div>

                {/* Container Stats */}
                {isOnline && node.stats && (
                    <div className="grid grid-cols-3 mb-3 rounded-md border border-card-border overflow-hidden">
                        <div className="border-r border-card-border bg-card px-2.5 py-2 text-center">
                            <div className="text-lg font-medium leading-none tabular-nums text-stat-value">{node.stats.active}</div>
                            <div className="text-[10px] leading-3 font-mono uppercase tracking-[0.18em] text-stat-subtitle mt-1">Running</div>
                        </div>
                        <div className="border-r border-card-border bg-card px-2.5 py-2 text-center">
                            <div className="text-lg font-medium leading-none tabular-nums text-stat-value">{node.stats.exited}</div>
                            <div className="text-[10px] leading-3 font-mono uppercase tracking-[0.18em] text-stat-subtitle mt-1">Stopped</div>
                        </div>
                        <div className="bg-card px-2.5 py-2 text-center">
                            <div className="text-lg font-medium leading-none tabular-nums text-stat-value">{node.stacks?.length ?? '-'}</div>
                            <div className="text-[10px] leading-3 font-mono uppercase tracking-[0.18em] text-stat-subtitle mt-1">Stacks</div>
                        </div>
                    </div>
                )}

                {/* Resource Usage Bars */}
                {isOnline && node.systemStats && (
                    <div className="space-y-2">
                        <div>
                            <div className="flex items-center justify-between text-xs mb-1">
                                <span className="flex items-center gap-1 text-muted-foreground">
                                    <Cpu className="w-3 h-3" /> CPU
                                </span>
                                <span className="font-medium">{node.systemStats.cpu.usage}%</span>
                            </div>
                            <UsageBar percent={cpuPercent} color={cpuPercent > 80 ? 'bg-destructive/80' : cpuPercent > 60 ? 'bg-warning' : 'bg-success'} />
                        </div>
                        <div>
                            <div className="flex items-center justify-between text-xs mb-1">
                                <span className="flex items-center gap-1 text-muted-foreground">
                                    <MemoryStick className="w-3 h-3" /> RAM
                                </span>
                                <span className="font-medium">{formatBytes(node.systemStats.memory.used)} / {formatBytes(node.systemStats.memory.total)}</span>
                            </div>
                            <UsageBar percent={memPercent} color={memPercent > 80 ? 'bg-destructive/80' : memPercent > 60 ? 'bg-warning' : 'bg-brand/60'} />
                        </div>
                        {node.systemStats.disk && (
                            <div>
                                <div className="flex items-center justify-between text-xs mb-1">
                                    <span className="flex items-center gap-1 text-muted-foreground">
                                        <HardDrive className="w-3 h-3" /> Disk
                                    </span>
                                    <span className="font-medium">{formatBytes(node.systemStats.disk.used)} / {formatBytes(node.systemStats.disk.total)}</span>
                                </div>
                                <UsageBar percent={diskPercent} color={diskPercent > 90 ? 'bg-destructive/80' : diskPercent > 75 ? 'bg-warning' : 'bg-brand'} />
                            </div>
                        )}
                    </div>
                )}

                {/* Update button */}
                {isOnline && updateStatus?.updateAvailable && !updateStatus.updateStatus && onUpdate && (
                    <div className="mt-3 pt-3 border-t border-border/50">
                        <Button
                            variant="outline"
                            size="sm"
                            className="w-full h-7 text-xs"
                            onClick={() => onUpdate(node.id)}
                            disabled={updatingNodeId === node.id}
                        >
                            {updatingNodeId === node.id ? (
                                <><Loader2 className="w-3 h-3 mr-1.5 animate-spin" />Triggering...</>
                            ) : (
                                <><Download className="w-3 h-3 mr-1.5" strokeWidth={1.5} />{formattedLatest ? `Update to ${formattedLatest}` : 'Update'}</>
                            )}
                        </Button>
                    </div>
                )}

                {/* Offline placeholder */}
                {!isOnline && (
                    <div className="flex items-center justify-center py-6 text-muted-foreground text-sm">
                        Node unreachable
                    </div>
                )}
            </div>

            {/* Paid: Expandable Stack List with Container Drill-Down */}
            {isOnline && isPaid && (
                <div className="border-t">
                    <button
                        onClick={handleExpand}
                        className="flex items-center gap-2 w-full px-4 py-2.5 text-xs text-muted-foreground hover:bg-muted/50 transition-colors"
                    >
                        {expanded ? <ChevronDown className="w-3.5 h-3.5" /> : <ChevronRight className="w-3.5 h-3.5" />}
                        <Layers className="w-3.5 h-3.5" />
                        Stack details
                        {stacks !== null && (
                            <span className="ml-auto text-[10px]">{stacks.length} stacks</span>
                        )}
                    </button>
                    {expanded && (
                        <div className="px-2 pb-3">
                            {loadingStacks ? (
                                <div className="space-y-2 px-2">
                                    <Skeleton className="h-6 w-full" />
                                    <Skeleton className="h-6 w-3/4" />
                                </div>
                            ) : stacks && stacks.length > 0 ? (
                                <div className="space-y-0.5">
                                    {stacks.map(stack => (
                                        <StackSection
                                            key={stack}
                                            stackName={stack}
                                            nodeId={node.id}
                                            onNavigate={onNavigate}
                                            labelMap={labelMap}
                                        />
                                    ))}
                                </div>
                            ) : (
                                <p className="text-xs text-muted-foreground py-1 px-2">No stacks found</p>
                            )}
                        </div>
                    )}
                </div>
            )}
        </div>
    );
}

// --- Main Component ---

interface FleetViewProps {
    onNavigateToNode: (nodeId: number, stackName: string) => void;
}

export function FleetView({ onNavigateToNode }: FleetViewProps) {
    const [nodes, setNodes] = useState<FleetNode[]>([]);
    const [loading, setLoading] = useState(true);
    const [refreshing, setRefreshing] = useState(false);
    const [searchQuery, setSearchQuery] = useState('');
    const [lastSyncAt, setLastSyncAt] = useState<number | null>(null);
    const [viewMode, setViewMode] = useState<ViewMode>('grid');
    const [prefs, setPrefs] = useState<FleetPreferences>(loadPreferences);
    const [fleetPalette, setFleetPalette] = useState<FleetPaletteEntry[]>([]);
    const [fleetStackLabelMap, setFleetStackLabelMap] = useState<Record<number, Record<string, StackLabel[]>>>({});
    const [labelFilters, setLabelFilters] = useState<Set<string>>(new Set());
    const { isPaid, license } = useLicense();
    const isAdmiral = isPaid && license?.variant === 'admiral';
    const experimental = useExperimental();
    const [updateStatuses, setUpdateStatuses] = useState<NodeUpdateStatus[]>([]);
    const [updatingNodeId, setUpdatingNodeId] = useState<number | null>(null);
    const [reconnecting, setReconnecting] = useState(false);
    const [preUpdateStartedAt, setPreUpdateStartedAt] = useState<number | null>(null);
    const [localUpdateConfirm, setLocalUpdateConfirm] = useState<number | null>(null);
    const [showUpdateModal, setShowUpdateModal] = useState(false);
    const [checkingUpdates, setCheckingUpdates] = useState(false);
    const updateStatusesRef = useRef(updateStatuses);
    updateStatusesRef.current = updateStatuses;

    const updatePrefs = useCallback((update: Partial<FleetPreferences>) => {
        setPrefs(prev => {
            const next = { ...prev, ...update };
            savePreferences(next);
            return next;
        });
    }, []);

    const fetchOverview = useCallback(async (showRefresh = false) => {
        if (showRefresh) setRefreshing(true);
        try {
            const res = await apiFetch('/fleet/overview', { localOnly: true });
            if (res.ok) {
                setNodes(await res.json());
                setLastSyncAt(Date.now());
            }
        } catch (error) {
            console.error('Failed to fetch fleet overview:', error);
        } finally {
            setLoading(false);
            setRefreshing(false);
        }
    }, []);

    const fetchLabelsForNodes = useCallback(async (fleetNodes: FleetNode[]) => {
        if (!isPaid || fleetNodes.length === 0) return;

        const paletteMap = new Map<string, FleetPaletteEntry>();
        const stackLabelMap: Record<number, Record<string, StackLabel[]>> = {};

        await Promise.allSettled(fleetNodes.map(async (node) => {
            if (node.status !== 'online') return;
            try {
                const [labelsRes, assignmentsRes] = await Promise.all([
                    fetchForNode('/labels', node.id, { signal: AbortSignal.timeout(5000) }),
                    fetchForNode('/labels/assignments', node.id, { signal: AbortSignal.timeout(5000) }),
                ]);
                if (labelsRes.ok) {
                    const labels = await labelsRes.json() as StackLabel[];
                    for (const l of labels) {
                        const key = labelPaletteKey(l.name, l.color);
                        if (!paletteMap.has(key)) {
                            paletteMap.set(key, { key, name: l.name, color: l.color });
                        }
                    }
                }
                if (assignmentsRes.ok) {
                    stackLabelMap[node.id] = await assignmentsRes.json() as Record<string, StackLabel[]>;
                }
            } catch {
                // Node unreachable or slow: skip, other nodes still contribute.
            }
        }));

        setFleetPalette(Array.from(paletteMap.values()).sort((a, b) => a.name.localeCompare(b.name)));
        setFleetStackLabelMap(stackLabelMap);
    }, [isPaid]);

    const fetchUpdateStatus = useCallback(async () => {
        if (!isPaid) return;
        try {
            const res = await apiFetch('/fleet/update-status', { localOnly: true });
            if (res.ok) {
                const data = await res.json();
                const next: NodeUpdateStatus[] = data.nodes ?? [];
                setUpdateStatuses(prev =>
                    JSON.stringify(prev) === JSON.stringify(next) ? prev : next
                );
            }
        } catch { /* non-critical */ }
    }, [isPaid]);

    const triggerNodeUpdate = useCallback(async (nodeId: number) => {
        const status = updateStatusesRef.current.find(s => s.nodeId === nodeId);
        if (status?.type === 'local') {
            setLocalUpdateConfirm(nodeId);
            return;
        }

        setUpdatingNodeId(nodeId);
        try {
            const res = await apiFetch(`/fleet/nodes/${nodeId}/update`, { method: 'POST', localOnly: true });
            if (res.ok) {
                toast.success(`Update initiated on ${status?.name ?? 'node'}.`);
                fetchUpdateStatus();
            } else {
                const err = await res.json().catch(() => ({}));
                toast.error(err?.message || err?.error || err?.data?.error || 'Failed to trigger update.');
            }
        } catch (e: unknown) {
            toast.error((e as Error)?.message || 'Something went wrong.');
        } finally {
            setUpdatingNodeId(null);
        }
    }, [fetchUpdateStatus]);

    const confirmLocalUpdate = useCallback(async () => {
        const nodeId = localUpdateConfirm;
        setLocalUpdateConfirm(null);
        if (!nodeId) return;

        setUpdatingNodeId(nodeId);
        try {
            // Capture pre-update boot timestamp so the overlay can detect a real restart
            // vs a false "online" response from the still-running old process mid-pull.
            let bootBefore: number | null = null;
            try {
                const healthRes = await fetch('/api/health');
                if (healthRes.ok) {
                    const data = await healthRes.json();
                    if (typeof data?.startedAt === 'number') bootBefore = data.startedAt;
                }
            } catch { /* fall back to offline-then-online detection */ }

            const res = await apiFetch(`/fleet/nodes/${nodeId}/update`, { method: 'POST', localOnly: true });
            if (res.ok) {
                setPreUpdateStartedAt(bootBefore);
                setReconnecting(true);
            } else {
                const err = await res.json().catch(() => ({}));
                toast.error(err?.message || err?.error || err?.data?.error || 'Failed to trigger local update.');
            }
        } catch (e: unknown) {
            toast.error((e as Error)?.message || 'Something went wrong.');
        } finally {
            setUpdatingNodeId(null);
        }
    }, [localUpdateConfirm]);

    const triggerUpdateAll = useCallback(async () => {
        try {
            const res = await apiFetch('/fleet/update-all', { method: 'POST', localOnly: true });
            if (res.ok) {
                const data = await res.json();
                if (data.updating?.length > 0) {
                    toast.success(`Update initiated on ${data.updating.length} node${data.updating.length > 1 ? 's' : ''}.`);
                } else {
                    toast.success('All nodes are up to date.');
                }
                fetchUpdateStatus();
            } else {
                const err = await res.json().catch(() => ({}));
                toast.error(err?.message || err?.error || err?.data?.error || 'Failed to trigger fleet update.');
            }
        } catch (e: unknown) {
            toast.error((e as Error)?.message || 'Something went wrong.');
        }
    }, [fetchUpdateStatus]);

    const dismissNodeUpdate = useCallback(async (nodeId: number) => {
        try {
            await apiFetch(`/fleet/nodes/${nodeId}/update-status`, { method: 'DELETE', localOnly: true });
            fetchUpdateStatus();
        } catch (error) {
            console.error('[Fleet] Failed to dismiss update status:', error);
        }
    }, [fetchUpdateStatus]);

    const retryNodeUpdate = useCallback(async (nodeId: number) => {
        triggerNodeUpdate(nodeId);
    }, [triggerNodeUpdate]);

    useEffect(() => {
        fetchOverview();
        fetchUpdateStatus();
    }, [fetchOverview, fetchUpdateStatus]);

    // Refetch labels only when the set of online nodes actually changes,
    // not on every `fetchOverview` tick (which mints a new `nodes` ref).
    const onlineNodeKey = nodes
        .filter(n => n.status === 'online')
        .map(n => n.id)
        .sort((a, b) => a - b)
        .join(',');
    useEffect(() => {
        if (!isPaid || nodes.length === 0) return;
        fetchLabelsForNodes(nodes);
        // eslint-disable-next-line react-hooks/exhaustive-deps
    }, [isPaid, onlineNodeKey, fetchLabelsForNodes]);

    // Paid tier: auto-refresh every 30s
    useEffect(() => {
        if (!isPaid) return;
        const overviewInterval = setInterval(fetchOverview, 30000);
        const updateInterval = setInterval(fetchUpdateStatus, 120000);
        return () => { clearInterval(overviewInterval); clearInterval(updateInterval); };
    }, [isPaid, fetchOverview, fetchUpdateStatus]);

    // Fast poll (5s) when any node is actively updating. Uses ref to avoid interval thrashing.
    const hasUpdatingRef = useRef(false);
    useEffect(() => {
        hasUpdatingRef.current = updateStatuses.some(s => s.updateStatus === 'updating');
    }, [updateStatuses]);

    useEffect(() => {
        const id = setInterval(() => {
            if (hasUpdatingRef.current) {
                fetchUpdateStatus();
                fetchOverview();
            }
        }, 5000);
        return () => clearInterval(id);
    }, [fetchUpdateStatus, fetchOverview]);

    // --- Computed values ---

    const onlineNodes = useMemo(() => nodes.filter(n => n.status === 'online'), [nodes]);
    const onlineCount = onlineNodes.length;
    const totalContainers = nodes.reduce((sum, n) => sum + (n.stats?.active ?? 0), 0);
    const totalContainersAll = nodes.reduce((sum, n) => sum + (n.stats?.total ?? 0), 0);
    const criticalCount = onlineNodes.filter(isCritical).length;

    const avgCpuNum = onlineNodes.length > 0
        ? onlineNodes.reduce((sum, n) => sum + getNodeCpu(n), 0) / onlineNodes.length
        : 0;
    const worstCpuNode = onlineNodes.length > 0
        ? onlineNodes.reduce((worst, n) => getNodeCpu(n) > getNodeCpu(worst) ? n : worst, onlineNodes[0])
        : null;
    const worstCpu = worstCpuNode
        ? { name: worstCpuNode.name, percent: getNodeCpu(worstCpuNode) }
        : null;

    const totalMemUsed = onlineNodes.reduce((sum, n) => sum + (n.systemStats?.memory.used ?? 0), 0);
    const totalMemTotal = onlineNodes.reduce((sum, n) => sum + (n.systemStats?.memory.total ?? 0), 0);

    const updateStatusMap = useMemo(
        () => new Map(updateStatuses.map(s => [s.nodeId, s])),
        [updateStatuses]
    );

    // --- Filtering & Sorting (Skipper+) ---

    const processedNodes = useMemo(() => {
        let filtered = [...nodes];

        // Search (paid only, but harmless if applied - free users won't see the search bar)
        if (searchQuery.trim()) {
            const q = searchQuery.toLowerCase();
            filtered = filtered.filter(n =>
                n.name.toLowerCase().includes(q) ||
                n.stacks?.some(s => s.toLowerCase().includes(q))
            );
        }

        if (isPaid) {
            // Status filter
            if (prefs.filterStatus === 'online') filtered = filtered.filter(n => n.status === 'online');
            if (prefs.filterStatus === 'offline') filtered = filtered.filter(n => n.status !== 'online');

            // Type filter
            if (prefs.filterType === 'local') filtered = filtered.filter(n => n.type === 'local');
            if (prefs.filterType === 'remote') filtered = filtered.filter(n => n.type === 'remote');

            // Critical filter
            if (prefs.filterCritical) filtered = filtered.filter(isCritical);

            // Label filter: match by (name, color) palette key so equivalent
            // labels across nodes behave as one filter.
            if (labelFilters.size > 0) {
                filtered = filtered.filter(n => {
                    const nodeStackLabels = fleetStackLabelMap[n.id] ?? {};
                    return n.stacks?.some(s => {
                        const sLabels = nodeStackLabels[s] ?? [];
                        return sLabels.some(l => labelFilters.has(labelPaletteKey(l.name, l.color)));
                    });
                });
            }

            // Sort
            filtered.sort((a, b) => {
                let cmp = 0;
                switch (prefs.sortBy) {
                    case 'name':
                        cmp = a.name.localeCompare(b.name);
                        break;
                    case 'cpu':
                        cmp = getNodeCpu(b) - getNodeCpu(a);
                        break;
                    case 'memory':
                        cmp = getNodeMem(b) - getNodeMem(a);
                        break;
                    case 'containers':
                        cmp = (b.stats?.active ?? 0) - (a.stats?.active ?? 0);
                        break;
                    case 'status':
                        cmp = (a.status === 'online' ? 0 : 1) - (b.status === 'online' ? 0 : 1);
                        break;
                }
                return prefs.sortDir === 'desc' ? -cmp : cmp;
            });
        }

        return filtered;
    }, [nodes, searchQuery, isPaid, prefs, labelFilters, fleetStackLabelMap]);

    const localNode = useMemo(() => processedNodes.find(n => n.type === 'local') ?? null, [processedNodes]);
    const remoteNodes = useMemo(() => processedNodes.filter(n => n.type !== 'local'), [processedNodes]);
    const topologyNodes = useMemo(() => processedNodes.map(n => ({
        id: n.id,
        name: n.name,
        type: n.type,
        status: n.status,
        cpuPercent: getNodeCpu(n),
        memPercent: getNodeMem(n),
        diskPercent: getNodeDisk(n),
        stackCount: n.stacks?.length ?? 0,
        runningCount: n.stats?.active ?? 0,
        critical: n.status === 'online' && isCritical(n),
    })), [processedNodes]);

    const clearFilters = useCallback(() => {
        updatePrefs({ filterStatus: 'all', filterType: 'all', filterCritical: false });
        setLabelFilters(new Set());
    }, [updatePrefs]);
    const allNodes = localNode ? [localNode, ...remoteNodes] : remoteNodes;

    return (
        <div className="h-full overflow-auto p-6">
            <FleetMasthead
                nodeCount={nodes.length}
                onlineCount={onlineCount}
                criticalCount={criticalCount}
                totalCpuPercent={avgCpuNum}
                worstCpu={worstCpu}
                totalMemUsed={totalMemUsed}
                totalMemTotal={totalMemTotal}
                activeContainers={totalContainers}
                totalContainers={totalContainersAll}
                lastSyncAt={lastSyncAt}
                loading={loading}
            />

            <Tabs defaultValue="overview">
                <div className="flex items-center justify-between gap-3 mb-4 flex-wrap">
                    <TabsList>
                        <TabsHighlight className="rounded-md bg-glass-highlight" transition={springs.snappy}>
                            <TabsHighlightItem value="overview">
                                <TabsTrigger value="overview">Overview</TabsTrigger>
                            </TabsHighlightItem>
                            {isPaid && (
                                <TabsHighlightItem value="snapshots">
                                    <TabsTrigger value="snapshots">
                                        <Camera className="w-4 h-4 mr-1.5" />Snapshots
                                    </TabsTrigger>
                                </TabsHighlightItem>
                            )}
                            {isAdmiral && experimental && (
                                <TabsHighlightItem value="routing">
                                    <TabsTrigger value="routing">
                                        <ArrowLeftRight className="w-4 h-4 mr-1.5" />Traffic · Routing
                                    </TabsTrigger>
                                </TabsHighlightItem>
                            )}
                            <TabsHighlightItem value="configuration">
                                <TabsTrigger value="configuration">
                                    <SlidersHorizontal className="w-4 h-4 mr-1.5" />Status
                                </TabsTrigger>
                            </TabsHighlightItem>
                            {experimental && (
                                <>
                                    <span aria-hidden className="self-center mx-1 h-4 w-px bg-border" />
                                    <TabsHighlightItem value="deployments">
                                        <TabsTrigger value="deployments">
                                            <Send className="w-4 h-4 mr-1.5" />Deployments
                                            {!isPaid && <SoonBadge />}
                                        </TabsTrigger>
                                    </TabsHighlightItem>
                                    <TabsHighlightItem value="federation">
                                        <TabsTrigger value="federation">
                                            <Network className="w-4 h-4 mr-1.5" />Federation
                                            <SoonBadge />
                                        </TabsTrigger>
                                    </TabsHighlightItem>
                                    <TabsHighlightItem value="secrets">
                                        <TabsTrigger value="secrets">
                                            <KeyRound className="w-4 h-4 mr-1.5" />Secrets
                                            <SoonBadge />
                                        </TabsTrigger>
                                    </TabsHighlightItem>
                                </>
                            )}
                        </TabsHighlight>
                    </TabsList>
                    <div className="flex items-center gap-2">
                        {isPaid && (
                            <Button
                                variant="outline"
                                size="sm"
                                onClick={async () => {
                                    setShowUpdateModal(true);
                                    setCheckingUpdates(true);
                                    await fetchUpdateStatus();
                                    setCheckingUpdates(false);
                                }}
                                className="gap-2"
                            >
                                <Search className="w-4 h-4" />
                                Check Updates
                            </Button>
                        )}
                        <Button
                            variant="outline"
                            size="sm"
                            onClick={() => fetchOverview(true)}
                            disabled={refreshing}
                            className="gap-2"
                        >
                            <RefreshCw className={`w-4 h-4 ${refreshing ? 'animate-spin' : ''}`} />
                            Refresh
                        </Button>
                    </div>
                </div>

                <TabsContent value="overview">
                    {/* Loading State */}
                    {loading && (
                        <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4">
                            {Array.from({ length: 3 }).map((_, i) => (
                                <div key={i} className="rounded-xl border bg-card p-4 space-y-3">
                                    <Skeleton className="h-8 w-32" />
                                    <div className="grid grid-cols-3 gap-2">
                                        <Skeleton className="h-14 rounded-lg" />
                                        <Skeleton className="h-14 rounded-lg" />
                                        <Skeleton className="h-14 rounded-lg" />
                                    </div>
                                    <Skeleton className="h-4 w-full" />
                                    <Skeleton className="h-4 w-full" />
                                    <Skeleton className="h-4 w-3/4" />
                                </div>
                            ))}
                        </div>
                    )}

                    {/* Empty State */}
                    {!loading && nodes.length === 0 && (
                        <div className="flex flex-col items-center justify-center py-20 text-center">
                            <Server className="w-12 h-12 text-muted-foreground/50 mb-4" />
                            <h3 className="text-lg font-medium mb-1">No nodes configured</h3>
                            <p className="text-sm text-muted-foreground">Add nodes in Settings to see your fleet here.</p>
                        </div>
                    )}

                    {/* Fleet Content */}
                    {!loading && nodes.length > 0 && (
                        <>
                            <OverviewToolbar
                                isPaid={isPaid}
                                viewMode={viewMode}
                                onViewModeChange={setViewMode}
                                searchQuery={searchQuery}
                                onSearchQueryChange={setSearchQuery}
                                prefs={prefs}
                                onPrefsChange={updatePrefs}
                                fleetPalette={fleetPalette}
                                labelFilters={labelFilters}
                                onLabelFiltersChange={setLabelFilters}
                                onClearFilters={clearFilters}
                            />

                            {viewMode === 'topology' && processedNodes.length > 0 ? (
                                <FleetTopology
                                    nodes={topologyNodes}
                                    onNodeClick={(id) => onNavigateToNode(id, '')}
                                />
                            ) : processedNodes.length > 0 ? (
                                <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4 items-start">
                                    {allNodes.map(node => (
                                        <NodeCard
                                            key={node.id}
                                            node={node}
                                            onNavigate={onNavigateToNode}
                                            labelMap={fleetStackLabelMap[node.id] ?? {}}
                                            updateStatus={updateStatusMap.get(node.id)}
                                            onUpdate={isPaid ? triggerNodeUpdate : undefined}
                                            updatingNodeId={updatingNodeId}
                                            onRetryUpdate={isPaid ? retryNodeUpdate : undefined}
                                            onDismissUpdate={isPaid ? dismissNodeUpdate : undefined}
                                        />
                                    ))}
                                </div>
                            ) : (
                                <div className="flex flex-col items-center justify-center py-16 text-center">
                                    <Search className="w-10 h-10 text-muted-foreground/50 mb-3" />
                                    <h3 className="text-sm font-medium mb-1">No nodes match your filters</h3>
                                    <p className="text-xs text-muted-foreground">Try adjusting your search or filter criteria.</p>
                                    <Button
                                        variant="outline"
                                        size="sm"
                                        className="mt-3"
                                        onClick={() => {
                                            setSearchQuery('');
                                            clearFilters();
                                        }}
                                    >
                                        <RotateCcw className="w-3.5 h-3.5 mr-1.5" />
                                        Clear filters
                                    </Button>
                                </div>
                            )}

                            {/* Paid tier auto-refresh indicator */}
                            {isPaid && (
                                <p className="text-xs text-muted-foreground text-center mt-6">
                                    Auto-refreshing every 30 seconds
                                </p>
                            )}

                        </>
                    )}
                </TabsContent>

                {isPaid && (
                    <TabsContent value="snapshots">
                        <FleetSnapshots />
                    </TabsContent>
                )}
                {isAdmiral && experimental && (
                    <TabsContent value="routing">
                        <AdmiralGate>
                            <RoutingTab />
                        </AdmiralGate>
                    </TabsContent>
                )}
                <TabsContent value="configuration">
                    <FleetConfiguration />
                </TabsContent>
                {experimental && (
                    <>
                        <TabsContent value="deployments">
                            {isPaid ? (
                                <DeploymentsTab />
                            ) : (
                                <FleetSoonPlaceholder
                                    icon={<Send className="h-4 w-4" />}
                                    kicker="Deployments · Blueprints"
                                    title="Declare once. Distribute everywhere."
                                    description="Pick nodes by label, drop in a docker-compose, and Sencho keeps the matching nodes in sync. Drift detection always on; auto-fix optional."
                                    plannedActions={['Author', 'Target', 'Reconcile', 'Snapshot+evict']}
                                />
                            )}
                        </TabsContent>
                        <TabsContent value="federation">
                            <FleetSoonPlaceholder
                                icon={<Network className="h-4 w-4" />}
                                kicker="Federation · Coming soon"
                                title="The fleet as one logical surface"
                                description="Pin policies, drain a node for maintenance, weight-aware scheduling. This stack runs on whichever node has capacity."
                                plannedActions={['Pin policy', 'Drain node', 'Cordon', 'Capacity plan']}
                            />
                        </TabsContent>
                        <TabsContent value="secrets">
                            <FleetSoonPlaceholder
                                icon={<KeyRound className="h-4 w-4" />}
                                kicker="Secrets · Coming soon"
                                title="One source of truth for env, creds and certs"
                                description="Push to selected nodes, rotate centrally, audit who-saw-what. Solves silent drift across copies."
                                plannedActions={['Sync env', 'Rotate', 'Audit', 'Pin to nodes']}
                            />
                        </TabsContent>
                    </>
                )}
            </Tabs>

            {/* Reconnecting overlay shown when local node is updating */}
            {reconnecting && <ReconnectingOverlay preUpdateStartedAt={preUpdateStartedAt} />}

            {/* Node Updates sheet */}
            <NodeUpdatesSheet
                open={showUpdateModal}
                onOpenChange={setShowUpdateModal}
                checkingUpdates={checkingUpdates}
                updateStatuses={updateStatuses}
                updatingNodeId={updatingNodeId}
                fetchUpdateStatus={fetchUpdateStatus}
                triggerNodeUpdate={triggerNodeUpdate}
                retryNodeUpdate={retryNodeUpdate}
                dismissNodeUpdate={dismissNodeUpdate}
                triggerUpdateAll={triggerUpdateAll}
            />

            {/* Confirm dialog for local node update */}
            <LocalUpdateConfirmDialog
                open={localUpdateConfirm !== null}
                onOpenChange={(open) => { if (!open) setLocalUpdateConfirm(null); }}
                onConfirm={confirmLocalUpdate}
            />
        </div>
    );
}
