fix: correct airport last visit date and add next visit

src/lib/components/airport-details/AirportStatsCard.svelte

@@ -1,18 +1,20 @@
 <script lang="ts">
-  import { PlaneLanding, PlaneTakeoff } from '@o7/icon/lucide';
   import NumberFlow from '@number-flow/svelte';
+  import { PlaneLanding, PlaneTakeoff } from '@o7/icon/lucide';
 
-  import type { FlightData } from '$lib/utils';
-  import { formatAsFlightDate } from '$lib/utils/datetime';
+  import { cn, type FlightData } from '$lib/utils';
+  import { getAirportVisitSummary } from '$lib/utils/data/airport-visits';
 
   let {
     flights,
     airportId,
     airlineCount,
+    now,
   }: {
     flights: FlightData[];
     airportId: number;
     airlineCount: number;
+    now: Date;
   } = $props();
 
   const departures = $derived(
@@ -32,28 +34,9 @@
     return set.size;
   });
 
-  const mostRecent = $derived.by(() => {
-    let best: FlightData | null = null;
-    let bestTs = -Infinity;
-    for (const f of flights) {
-      const ts = f.date?.getTime();
-      if (ts && ts > bestTs) {
-        bestTs = ts;
-        best = f;
-      }
-    }
-    return best;
-  });
-
-  const lastVisitLabel = $derived.by(() => {
-    if (!mostRecent?.date) return null;
-    return formatAsFlightDate(
-      mostRecent.date,
-      mostRecent.datePrecision ?? 'day',
-      false,
-      true,
-    );
-  });
+  const visits = $derived(getAirportVisitSummary(flights, airportId, now));
+  const lastVisitLabel = $derived(visits.last);
+  const nextVisitLabel = $derived(visits.next);
 </script>
 
 <section class="px-4 py-4">
@@ -86,27 +69,53 @@
     </div>
   </div>
 
+  {#if lastVisitLabel && nextVisitLabel}
+    <div
+      class="flex flex-wrap items-center gap-x-2 gap-y-1 mt-3 text-xs text-muted-foreground"
+    >
+      <span>
+        last visit <span class="text-foreground">{lastVisitLabel}</span>
+      </span>
+      <span class="inline-flex items-center gap-2">
+        <span aria-hidden="true">·</span>
+        <span>
+          next visit <span class="text-foreground">{nextVisitLabel}</span>
+        </span>
+      </span>
+    </div>
+  {/if}
+
   <div
-    class="flex flex-wrap items-center gap-x-2 gap-y-1 mt-3 text-xs text-muted-foreground"
+    class={cn(
+      'flex flex-wrap items-center gap-x-2 gap-y-1 text-xs text-muted-foreground',
+      lastVisitLabel && nextVisitLabel ? 'mt-1' : 'mt-3',
+    )}
   >
     <span>
       <span class="font-semibold text-foreground tabular-nums">
         {airlineCount}
       </span>
       airlines
     </span>
-    <span aria-hidden="true">·</span>
-    <span>
-      <span class="font-semibold text-foreground tabular-nums">
-        {distinctRoutes}
+    <span class="inline-flex items-center gap-2">
+      <span aria-hidden="true">·</span>
+      <span>
+        <span class="font-semibold text-foreground tabular-nums">
+          {distinctRoutes}
+        </span>
+        routes
       </span>
-      routes
     </span>
-    {#if lastVisitLabel}
-      <span aria-hidden="true">·</span>
-      <span
-        >last visit <span class="text-foreground">{lastVisitLabel}</span></span
-      >
+    {#if Boolean(lastVisitLabel) !== Boolean(nextVisitLabel)}
+      <span class="inline-flex items-center gap-2">
+        <span aria-hidden="true">·</span>
+        <span>
+          {lastVisitLabel ? 'last' : 'next'} visit
+          <span class="text-foreground">
+            {lastVisitLabel ?? nextVisitLabel}
+          </span>
+        </span>
+      </span>
     {/if}
   </div>
 </section>

src/lib/components/airport-details/AirportTimeCard.svelte

@@ -4,18 +4,10 @@
   import { page } from '$app/state';
   import { formatTime, getPreferences } from '$lib/utils/preferences';
 
-  let { tz }: { tz?: string | null } = $props();
+  let { tz, now }: { tz?: string | null; now: Date } = $props();
 
   const prefs = $derived(getPreferences(page.data.user));
 
-  let now = $state(new Date());
-  $effect(() => {
-    const id = setInterval(() => {
-      now = new Date();
-    }, 30_000);
-    return () => clearInterval(id);
-  });
-
   const resolvedTz = $derived(tz ?? 'UTC');
 
   const localTime = $derived(formatTime(now, prefs, resolvedTz));

src/lib/components/map-details/AirportDetailsBody.svelte

@@ -18,14 +18,21 @@
     onShowDepartures: (flightId?: number) => void;
     onShowArrivals: (flightId?: number) => void;
   } = $props();
+
+  let now = $state(new Date());
+  $effect(() => {
+    const id = setInterval(() => (now = new Date()), 30_000);
+    return () => clearInterval(id);
+  });
 </script>
 
 <AirportStatsCard
   flights={relatedFlights}
   airportId={airport.id}
   airlineCount={airport.airlines.length}
+  {now}
 />
-<AirportTimeCard tz={airport.tz} />
+<AirportTimeCard tz={airport.tz} {now} />
 <AirportWeatherCard icao={airport.icao} tz={airport.tz} lon={airport.lon} />
 <AirportFlightsCard
   flights={relatedFlights}

src/lib/utils/data/airport-visits.test.ts

@@ -0,0 +1,67 @@
+import { describe, expect, it } from 'vitest';
+
+import {
+  getAirportVisitSummary,
+  type AirportVisitFlight,
+} from './airport-visits';
+
+const baseFlight = (): AirportVisitFlight => ({
+  from: { id: 1, tz: 'America/Los_Angeles' },
+  to: { id: 2, tz: 'America/New_York' },
+  datePrecision: 'day',
+  duration: 14_400,
+  departure: null,
+  arrival: null,
+  departureScheduled: null,
+  arrivalScheduled: null,
+  takeoffScheduled: null,
+  takeoffActual: null,
+  landingScheduled: null,
+  landingActual: null,
+  raw: { date: '2024-06-14' },
+});
+
+describe('airport visit summary', () => {
+  it('uses day precision for an exact timestamp on a coarse flight date', () => {
+    const flight = {
+      ...baseFlight(),
+      datePrecision: 'month',
+      arrivalScheduled: '2024-06-14T09:45:00.000Z',
+    } satisfies AirportVisitFlight;
+
+    expect(
+      getAirportVisitSummary([flight], 2, new Date('2024-07-01T00:00:00Z'))
+        .last,
+    ).toContain('14');
+  });
+
+  it('derives an untimed arrival from departure and duration', () => {
+    const flight = {
+      ...baseFlight(),
+      departureScheduled: '2024-06-15T06:00:00.000Z',
+    } satisfies AirportVisitFlight;
+
+    expect(
+      getAirportVisitSummary([flight], 2, new Date('2024-07-01T00:00:00Z'))
+        .last,
+    ).toContain('15');
+  });
+
+  it('omits an arrival that cannot be placed on a calendar day', () => {
+    const flight = { ...baseFlight(), duration: null };
+
+    expect(
+      getAirportVisitSummary([flight], 2, new Date('2024-07-01T00:00:00Z')),
+    ).toEqual({ last: null, next: null });
+  });
+
+  it('does not classify an imprecise range that contains now', () => {
+    expect(
+      getAirportVisitSummary(
+        [baseFlight()],
+        1,
+        new Date('2024-06-14T12:00:00Z'),
+      ),
+    ).toEqual({ last: null, next: null });
+  });
+});

src/lib/utils/data/airport-visits.ts

@@ -0,0 +1,125 @@
+import { TZDate } from '@date-fns/tz';
+
+import type { FlightDatePrecision } from '$lib/db/types';
+import {
+  formatAsFlightDate,
+  getFlightDateRange,
+  parseLocalizeISO,
+} from '$lib/utils/datetime';
+
+type AirportRef = { id: number; tz: string };
+
+export type AirportVisitFlight = {
+  from: AirportRef | null;
+  to: AirportRef | null;
+  datePrecision: FlightDatePrecision;
+  duration: number | null;
+  departure: TZDate | null;
+  arrival: TZDate | null;
+  departureScheduled: string | null;
+  arrivalScheduled: string | null;
+  takeoffScheduled: string | null;
+  takeoffActual: string | null;
+  landingScheduled: string | null;
+  landingActual: string | null;
+  raw: { date: string };
+};
+
+type VisitWindow = {
+  start: TZDate;
+  end: TZDate;
+  precision: FlightDatePrecision;
+};
+
+const parseTime = (value: string | null, tz: string) =>
+  value ? parseLocalizeISO(value, tz) : null;
+
+const exactWindow = (date: TZDate): VisitWindow => ({
+  start: date,
+  end: date,
+  precision: 'day',
+});
+
+const departureTime = (flight: AirportVisitFlight) => {
+  const tz = flight.from?.tz ?? 'UTC';
+  return (
+    flight.departure ??
+    parseTime(flight.takeoffActual, tz) ??
+    parseTime(flight.departureScheduled, tz) ??
+    parseTime(flight.takeoffScheduled, tz)
+  );
+};
+
+const arrivalTime = (flight: AirportVisitFlight, departure: TZDate | null) => {
+  const tz = flight.to?.tz ?? 'UTC';
+  const recorded =
+    flight.arrival ??
+    parseTime(flight.landingActual, tz) ??
+    parseTime(flight.arrivalScheduled, tz) ??
+    parseTime(flight.landingScheduled, tz);
+
+  if (recorded || !departure || flight.duration === null) return recorded;
+  return new TZDate(departure.getTime() + flight.duration * 1_000, tz);
+};
+
+const visitWindow = (
+  flight: AirportVisitFlight,
+  direction: 'departure' | 'arrival',
+): VisitWindow | null => {
+  const departure = departureTime(flight);
+  const exact =
+    direction === 'departure' ? departure : arrivalTime(flight, departure);
+  if (exact) return exactWindow(exact);
+  if (direction === 'arrival') return null;
+
+  const range = getFlightDateRange(
+    flight.raw.date,
+    flight.datePrecision,
+    flight.from?.tz ?? 'UTC',
+  );
+  if (!range.start || !range.end) return null;
+  return {
+    start: range.start,
+    end: range.end,
+    precision: flight.datePrecision,
+  };
+};
+
+type Visit = { label: string; time: number };
+
+export const getAirportVisitSummary = (
+  flights: AirportVisitFlight[],
+  airportId: number,
+  now: Date,
+) => {
+  let last: Visit | null = null;
+  let next: Visit | null = null;
+
+  for (const flight of flights) {
+    const windows = [
+      flight.from?.id === airportId ? visitWindow(flight, 'departure') : null,
+      flight.to?.id === airportId ? visitWindow(flight, 'arrival') : null,
+    ];
+
+    for (const window of windows) {
+      if (!window) continue;
+      const label = formatAsFlightDate(
+        window.start,
+        window.precision,
+        false,
+        true,
+      );
+
+      if (window.end < now && (!last || window.end.getTime() > last.time)) {
+        last = { label, time: window.end.getTime() };
+      } else if (
+        window.start > now &&
+        (!next || window.start.getTime() < next.time)
+      ) {
+        next = { label, time: window.start.getTime() };
+      }
+    }
+  }
+
+  return { last: last?.label ?? null, next: next?.label ?? null };
+};