web/src/lib/freight-benchmarks.ts

import { apiFetch } from '@szl-holdings/shared-ui/api-fetch';
import { useQuery } from '@tanstack/react-query';

// Vessel-class keys exposed by the live freight benchmark feed.
export type VesselClassKey =
  | 'VLCC'
  | 'Suezmax'
  | 'Aframax'
  | 'Capesize'
  | 'Panamax'
  | 'Supramax'
  | 'Handysize'
  | 'LNG Carrier';

export interface FreightBenchmark {
  key: string;
  label: string;
  dwt: string;
  color: string;
  tce: number;
  change: number;
  changePct: number;
  fleetAvg: number;
  topQuartile: number;
  bottomQuartile: number;
  routes: string[];
  forward: number[];
  pnlAlias: string[];
}

export interface FreightRouteRate {
  route: string;
  classKey: string;
  rate: number;
  change: number;
  unit: string;
}

export interface FreightHistoryPoint {
  date: string;
  index: number;
}

export interface FreightBenchmarkSnapshot {
  asOf: string;
  source: string;
  sourceUrl?: string;
  methodology: string;
  refreshIntervalSeconds: number;
  nextRefreshAt: string;
  upstreamStatus?: 'live' | 'stale' | 'unavailable';
  upstreamLatestIndex?: number | null;
  upstreamPriorIndex?: number | null;
  upstreamYearAgoIndex?: number | null;
  upstreamObservationDate?: string | null;
  history?: FreightHistoryPoint[];
  benchmarks: FreightBenchmark[];
  benchmarksByLabel: Record<string, FreightBenchmark>;
  routes: FreightRouteRate[];
}

export function useFreightBenchmarks() {
  return useQuery<FreightBenchmarkSnapshot>({
    queryKey: ['vessels', 'freight', 'benchmarks'],
    queryFn: () => apiFetch<FreightBenchmarkSnapshot>('/vessels/freight/benchmarks'),
    staleTime: 60_000,
    refetchInterval: 5 * 60_000,
    refetchOnWindowFocus: false,
  });
}

export function formatAsOf(iso: string | undefined): string {
  if (!iso) return '—';
  try {
    const d = new Date(iso);
    return d.toLocaleString(undefined, {
      month: 'short',
      day: 'numeric',
      hour: '2-digit',
      minute: '2-digit',
      timeZoneName: 'short',
    });
  } catch {
    return iso;
  }
}

export interface BenchmarkComparison {
  classKey: VesselClassKey;
  benchmark: FreightBenchmark;
  voyageTce: number;
  delta: number;
  deltaPct: number;
  aboveMarket: boolean;
}

// Compare a voyage TCE against the live benchmark for the given class.
// Pass the snapshot from `useFreightBenchmarks()`.
export function compareVoyageToBenchmark(
  snapshot: FreightBenchmarkSnapshot | undefined,
  classKey: VesselClassKey | null,
  voyageTce: number,
): BenchmarkComparison | null {
  if (!snapshot || !classKey) return null;
  const benchmark = snapshot.benchmarksByLabel[classKey];
  if (!benchmark || benchmark.tce === 0) return null;
  const delta = voyageTce - benchmark.tce;
  const deltaPct = (delta / benchmark.tce) * 100;
  return {
    classKey,
    benchmark,
    voyageTce,
    delta,
    deltaPct,
    aboveMarket: delta >= 0,
  };
}

// Best-effort mapping from a free-text cargo description to the closest
// vessel class. Returns null when nothing reasonable matches. Preserved
// from the previous static benchmark module so callers that need to
// guess a class from a cargo string can still do so.
export function inferVesselClassFromCargo(
  cargoType: string | null | undefined,
): VesselClassKey | null {
  if (!cargoType) return null;
  const c = cargoType.toLowerCase();

  if (c.includes('lng') || c.includes('liquefied natural gas')) return 'LNG Carrier';
  if (c.includes('crude')) return 'VLCC';
  if (
    c.includes('fuel oil') ||
    c.includes('refined') ||
    c.includes('gasoline') ||
    c.includes('diesel') ||
    c.includes('naphtha') ||
    c.includes('jet')
  )
    return 'Aframax';
  if (c.includes('iron ore') || c.includes('coal')) return 'Capesize';
  if (
    c.includes('grain') ||
    c.includes('wheat') ||
    c.includes('corn') ||
    c.includes('soy') ||
    c.includes('bauxite') ||
    c.includes('cement')
  )
    return 'Panamax';
  if (c.includes('steel') || c.includes('scrap') || c.includes('fertilizer') || c.includes('sugar'))
    return 'Supramax';
  if (c.includes('bulk') || c.includes('aggregate') || c.includes('salt')) return 'Handysize';

  return null;
}