'use client';

import { useEffect, useRef, useState, type ChangeEvent } from 'react';
import * as maplibregl from 'maplibre-gl';
import 'maplibre-gl/dist/maplibre-gl.css';
import pkg from '../package.json';
import { DEFAULT_STYLE_ID, STYLES, STYLE_STORAGE_KEY, isStyleId, localAssetsAvailable, styleUrlFor } from '../lib/mapStyles';
import type { GeoJsonFeatureCollection } from '../lib/airports';
import type { StateSnapshot } from '../lib/game/state';
import type { HoverTarget } from './hoverTypes';
import { hoverRouteGeoJson, hoverTraceGeoJson, planesGeoJson, queuedRoutesGeoJson, routesGeoJson, type AirportCoord, type PlaneFeatureProps } from '../lib/mapData';
import { weatherFor } from '../lib/weather';
import { approxLocalTime } from '../lib/localTime';

const EUROPE_CENTER: [number, number] = [10, 52];
const INITIAL_ZOOM = 4;
// Flat 2D view only. Max zoom ≈ ~100 km across a typical desktop viewport width at
// European latitudes (~47 m/px at z11, 52°N); street-level zoom has no gameplay value.
export const MIN_ZOOM = 3;
export const MAX_ZOOM = 11;

const AIRPORTS_SOURCE_ID = 'airports';
const AIRPORTS_LAYER_ID = 'airports-circles';
// Dynamic game-state layers (v0.11.0, package model v0.12.0): planes as circles,
// each FLYING plane's current leg (origin → dest_icao) as a line.
const PLANES_SOURCE_ID = 'planes';
const PLANES_GROUNDED_LAYER_ID = 'planes-grounded';
const PLANES_FLYING_LAYER_ID = 'planes-flying';
const ROUTES_SOURCE_ID = 'routes';
const ROUTES_LEGS_LAYER_ID = 'routes-legs';
// ISS-043 (v0.26.0): the dotted queue line — a flying plane's NOT-yet-started legs
// (dest → queue[0] → …) as their own source + layer, drawn under everything else dynamic.
const QUEUE_ROUTES_SOURCE_ID = 'queue-routes';
const QUEUE_ROUTES_LAYER_ID = 'queue-routes';
// ISS-098 (v0.50.0): amber/gold — planned legs read as "queued", visible on light and dark tiles alike.
export const QUEUE_ROUTE_LINE_COLOR = '#d4a017';
// ISS-002 (v0.15.0): top-most hover-highlight layers, added after the base layers so they
// render above them. Each starts filtered to match nothing; applyHoverRef drives the filters.
const PLANES_HIGHLIGHT_LAYER_ID = 'planes-highlight';
const ROUTES_HIGHLIGHT_LAYER_ID = 'routes-highlight';
const AIRPORTS_HIGHLIGHT_LAYER_ID = 'airports-highlight';
// ISS-022/025/027 (v0.22.0): the hover route trace — its OWN source + top-most dashed line,
// because the shared `routes` source only holds FLYING legs: an open package's or a grounded
// relocation's planned route is never in it. applyHoverRef pushes data into it on every hover.
const HOVER_ROUTES_SOURCE_ID = 'hover-routes';
const HOVER_ROUTE_LAYER_ID = 'hover-route';
// ISS-022 (v0.22.0): the DESTINATION airport's ring — a second, differently-colored circle over
// the same `airports` source so the target stands out from the origin's plain yellow ring.
// applyHoverRef filters it to the hovered target's destination icao only.
const AIRPORTS_TARGET_HIGHLIGHT_LAYER_ID = 'airports-target-highlight';

function escapeHtml(s: string): string {
  return s.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
}

interface MapProps {
  // The shell's polled /api/state snapshot (v0.11.0) — drives the plane markers and
  // route lines. Null until the first successful poll.
  state?: StateSnapshot | null;
  // ISS-002 (v0.15.0): the side panels' hover target — highlights the matching plane
  // (+ its route leg if flying) or a package's endpoint airports, and (ISS-022/025/027 v0.22.0)
  // draws the full great-circle trace between any hovered target's two endpoints. Null = nothing hovered.
  hovered?: HoverTarget | null;
  // ISS-010 (v0.18.0): push an action endpoint's full response snapshot into the shared
  // shell state — same callback RightPane receives, used by the airport popup's Relocate row.
  applySnapshot: (snapshot: StateSnapshot) => void;
}

// Named FlightMap (not Map): a component called `Map` would shadow the global
// Map constructor inside its own body, breaking `new Map(...)` for the airport index.
export default function FlightMap({ state, hovered, applySnapshot }: MapProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const mapRef = useRef<maplibregl.Map | null>(null);
  // /api/airports is fetched at most once per page life: every styledata event
  // (initial load AND after each setStyle) reuses this promise.
  const airportsPromiseRef = useRef<Promise<GeoJsonFeatureCollection> | null>(null);
  // Latest snapshot + airport coordinate index, so the mount effect's styledata wiring
  // and the state-change effect can both push data without prop-drilling into closures.
  const stateRef = useRef<StateSnapshot | null>(null);
  // ISS-010 (v0.18.0): the shell's applySnapshot is stable (useCallback with no deps), but the
  // mount effect captures it once — keep a ref so the popup wiring always calls the latest one.
  const applySnapshotRef = useRef(applySnapshot);
  useEffect(() => {
    applySnapshotRef.current = applySnapshot;
  }, [applySnapshot]);
  const airportsIndexRef = useRef<Map<string, AirportCoord> | null>(null);
  const [airportCount, setAirportCount] = useState<number | null>(null);
  const [styleId, setStyleId] = useState<string>(DEFAULT_STYLE_ID);

  // Push the latest planes/routes GeoJSON into whatever sources currently exist.
  // No-op until the map (and for routes: the airport index) is ready — the mount
  // effect calls this again after every styledata re-establish and airports load.
  const applyDynamicRef = useRef<() => void>(() => {});
  applyDynamicRef.current = () => {
    const map = mapRef.current;
    const st = stateRef.current;
    if (!map || !st) return;
    const planesSource = map.getSource(PLANES_SOURCE_ID) as maplibregl.GeoJSONSource | undefined;
    // ISS-124 (v0.58.0): the airport index unwraps crossing markers — empty until it loads, so
    // planes draw at their wrapped position in the meantime (same as pre-v0.58.0).
    if (planesSource) void planesSource.setData(planesGeoJson(st, airportsIndexRef.current ?? new Map())); // v6 API (setGeoData was removed)
    const routesSource = map.getSource(ROUTES_SOURCE_ID) as maplibregl.GeoJSONSource | undefined;
    if (routesSource && airportsIndexRef.current) {
      void routesSource.setData(routesGeoJson(st, airportsIndexRef.current));
    }
    // ISS-043 (v0.26.0): the dotted queue line — same airport-index guard as the solid legs above.
    const queueRoutesSource = map.getSource(QUEUE_ROUTES_SOURCE_ID) as maplibregl.GeoJSONSource | undefined;
    if (queueRoutesSource && airportsIndexRef.current) {
      void queueRoutesSource.setData(queuedRoutesGeoJson(st.planes, airportsIndexRef.current));
    }
  };

  useEffect(() => {
    stateRef.current = state ?? null;
    applyDynamicRef.current();
    // ISS-040 (v0.23.2): re-apply the hover too, so an on-board package's trace follows a moving
    // carrier between polls while hovered — idempotent and cheap (one small setData + ring filters).
    applyHoverRef.current();
  }, [state]);

  // ISS-002 (v0.15.0): hover highlight — same ref + effect pattern as the snapshot above.
  // No-op until the layers exist; ensureLayers re-applies the current filter after every
  // styledata re-establish, so a hover that outlives a style switch stays highlighted.
  const hoveredRef = useRef<HoverTarget | null>(null);
  const applyHoverRef = useRef<() => void>(() => {});
  applyHoverRef.current = () => {
    const map = mapRef.current;
    if (!map) return;
    const h = hoveredRef.current;
    // The empty-string sentinel matches nothing: no feature has id/icao ''. A package hover may
    // name its plane (ISS-025 on-board cargo rows), so that plane's halo stays lit too.
    let planeId = '';
    let fromIcao = '';
    let toIcao = '';
    if (h) {
      if (h.kind === 'plane') planeId = h.id;
      else if (h.kind === 'package') {
        planeId = h.planeId ?? '';
        fromIcao = h.originIcao;
        toIcao = h.destIcao;
      } else {
        // 'route' — the Relocate panel's planned flight: trace + target airport only.
        fromIcao = h.fromIcao;
        toIcao = h.toIcao;
      }
    }
    if (map.getLayer(PLANES_HIGHLIGHT_LAYER_ID)) {
      map.setFilter(PLANES_HIGHLIGHT_LAYER_ID, ['==', ['get', 'id'], planeId]);
    }
    if (map.getLayer(ROUTES_HIGHLIGHT_LAYER_ID)) {
      map.setFilter(ROUTES_HIGHLIGHT_LAYER_ID, ['==', ['get', 'planeId'], planeId]);
    }
    // ISS-022/025/027: the hover route trace — one great-circle line for any target carrying two
    // ICAOs (package origin→dest / relocate fromIcao→toIcao); empty when either endpoint is unknown.
    const hoverSource = map.getSource(HOVER_ROUTES_SOURCE_ID) as maplibregl.GeoJSONSource | undefined;
    if (hoverSource) {
      // ISS-040 (v0.23.2): an on-board package's trace starts from the carrier plane's LIVE position,
      // not its origin airport — identical to before while grounded at the pickup, different once it
      // has departed with cargo still loaded. No carrier in state yet → fall back to the ICAO trace.
      // ISS-077 (v0.41.0): a FLYING carrier's trace starts at its LANDING airport (destIcao), not the
      // live mid-flight position — the hover previews what happens AFTER this leg lands, and the solid
      // active-leg + dotted queue layers already show where it is now. Grounded / no active leg keeps
      // today's behavior exactly (live position = the plane's airport). destIcao missing from the
      // index → fall back to the live position rather than guessing.
      const idx = airportsIndexRef.current ?? new Map();
      const carrier = h?.kind === 'package' && h.planeId ? stateRef.current?.planes.find((p) => p.id === h.planeId) : undefined;
      const landing = carrier?.status === 'flying' && carrier.destIcao ? idx.get(carrier.destIcao) : undefined;
      void hoverSource.setData(
        landing
          ? hoverTraceGeoJson(landing, toIcao, idx)
          : carrier
            ? hoverTraceGeoJson({ lat: carrier.lat, lon: carrier.lon }, toIcao, idx)
            : hoverRouteGeoJson(fromIcao, toIcao, idx),
      );
    }
    // Package hovers ring BOTH endpoints (v0.15.0 behavior); 'route' hovers ring the TARGET only —
    // the relocation's destination is what ISS-027 asks to see. Plane hovers ring nothing.
    const originIcao = h?.kind === 'package' ? fromIcao : '';
    const destIcao = h?.kind === 'package' || h?.kind === 'route' ? toIcao : '';
    if (map.getLayer(AIRPORTS_HIGHLIGHT_LAYER_ID)) {
      map.setFilter(
        AIRPORTS_HIGHLIGHT_LAYER_ID,
        ['any', ['==', ['get', 'icao'], originIcao], ['==', ['get', 'icao'], destIcao]],
      );
    }
    // ISS-022: the destination gets its own distinct-colored ring on top (package AND route hovers).
    if (map.getLayer(AIRPORTS_TARGET_HIGHLIGHT_LAYER_ID)) {
      map.setFilter(AIRPORTS_TARGET_HIGHLIGHT_LAYER_ID, ['==', ['get', 'icao'], destIcao]);
    }
  };

  useEffect(() => {
    hoveredRef.current = hovered ?? null;
    applyHoverRef.current();
  }, [hovered]);

  useEffect(() => {
    if (!containerRef.current) return;

    // Bundlers (Turbopack) break MapLibre's derived worker URL, so point it at a
    // route that serves the worker script (and its relative imports) from node_modules.
    maplibregl.setWorkerUrl('/api/mlworker/maplibre-gl-worker.mjs');

    let cancelled = false;

    // Defer map creation until the asset-pack probe resolves — one cheap local
    // request decides between self-hosted styles (volume-mounted public/) and the
    // remote openfreemap.org fallback. The persisted style choice is read here,
    // post-mount: SSR hydration stays safe (server + first paint use the default),
    // and applying it at creation time avoids a fiord→saved-style flash.
    void localAssetsAvailable().then((available) => {
      if (cancelled || !containerRef.current) return;

      const saved = window.localStorage.getItem(STYLE_STORAGE_KEY);
      const initialId = saved && isStyleId(saved) ? saved : DEFAULT_STYLE_ID;
      setStyleId(initialId);

      const map = new maplibregl.Map({
        container: containerRef.current,
        style: styleUrlFor(initialId, available), // local pack or remote OFM fallback
        center: EUROPE_CENTER,
        zoom: INITIAL_ZOOM,
        minZoom: MIN_ZOOM,
        maxZoom: MAX_ZOOM,
      });
      mapRef.current = map;
      // Dev/e2e hook so tests can project coordinates to screen space.
      (window as unknown as Record<string, unknown>).__flightMap = map;

      const onAirportClick = (e: maplibregl.MapLayerMouseEvent) => {
        const f = e.features?.[0];
        if (!f) return;
        const p = f.properties as { name: string; icao: string; lat: number; lon: number };
        // Display-only extras (v0.11.0): approximate local time from longitude and a
        // deterministic generated weather — no gameplay effects per PLAN.md.
        const w = weatherFor(p.icao);
        const localTime = approxLocalTime(p.lon, Date.now());
        // ISS-010 (v0.18.0): Relocate row — every plane from the latest snapshot can be sent to
        // this airport: grounded ones fly immediately (POST /api/planes/{id}/fly), flying/repairing
        // ones get the leg appended to their queue (POST /api/planes/{id}/queue, ISS-096 v0.49.0).
        const st = stateRef.current;
        const planes = st ? st.planes : [];
        const planeLabel = (model: string) => st?.catalog.find((c) => c.model === model)?.label ?? model;
        const relocateHtml =
          planes.length > 0
            ? `<select data-testid="airport-popup-plane" aria-label="Plane to relocate here">` +
              `<option value="">Select a plane\u2026</option>` +
              planes.map(
                (pl) =>
                  `<option value="${escapeHtml(pl.id)}">${escapeHtml(planeLabel(pl.model))} \u2014 ${escapeHtml(pl.locationIcao)}</option>`,
              ).join('') +
              `</select><button type="button" data-testid="airport-popup-relocate" disabled>Relocate here</button>`
            : `<span data-testid="airport-popup-no-planes">No planes to relocate.</span>`;
        const popup = new maplibregl.Popup({ offset: 10 })
          .setLngLat(f.geometry.coordinates as [number, number])
          .setHTML(
            `<div data-testid="airport-popup">` +
              `<strong>${escapeHtml(p.name)}</strong><br/>${escapeHtml(p.icao)}<br/>` +
              `<span data-testid="airport-local-time">${localTime} local (approx)</span><br/>` +
              `<span data-testid="airport-weather">${w.condition}, wind ${w.windDirDeg}\u00B0 / ${w.windKt} kt, vis ${w.visibilityM} m</span>` +
              `<div class="popup-relocate">` + relocateHtml + `<span data-testid="airport-popup-relocate-status"></span></div>` +
            `</div>`,
          )
          .addTo(map);

        // Popups are plain HTML, not React — the element only exists after addTo, so wire the
        // controls via querySelector (the select enables the button once a plane is picked).
        const el = popup.getElement();
        const select = el?.querySelector<HTMLSelectElement>('[data-testid="airport-popup-plane"]');
        const button = el?.querySelector<HTMLButtonElement>('[data-testid="airport-popup-relocate"]');
        // The status span is always in the popup HTML (even with no planes), so it
        // exists whenever the select/button do.
        const statusEl = el?.querySelector<HTMLElement>('[data-testid="airport-popup-relocate-status"]');
        if (select && button && statusEl) {
          select.addEventListener('change', () => {
            button.disabled = select.value === '';
          });
          button.addEventListener('click', async () => {
            const planeId = select.value;
            if (!planeId || button.disabled) return;
            button.disabled = true;
            statusEl.textContent = 'Relocating\u2026';
            try {
              // ISS-096 (v0.49.0): endpoint follows the SELECTED plane's current status — grounded
              // planes fly now, flying/repairing ones get the leg queued for after landing.
              const planeStatus = stateRef.current?.planes.find((pl) => pl.id === planeId)?.status ?? 'available';
              const action = planeStatus === 'available' ? 'fly' : 'queue';
              const res = await fetch(`/api/planes/${planeId}/${action}`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ destIcao: p.icao }),
                cache: 'no-store',
              });
              const data = (await res.json()) as StateSnapshot & { error?: string };
              if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`);
              applySnapshotRef.current(data); // shared shell state updates immediately, like the panes' runAction
              statusEl.textContent = action === 'fly' ? 'Relocation started.' : 'Added to queue.';
            } catch (err) {
              statusEl.textContent = err instanceof Error ? err.message : String(err);
              button.disabled = false; // allow retry / picking another plane
            }
          });
        }
      };

      const onPlaneClick = (e: maplibregl.MapLayerMouseEvent) => {
        const f = e.features?.[0];
        if (!f) return;
        const p = f.properties as PlaneFeatureProps;
        const routeLine = p.routeText ? `<br/><span data-testid="plane-route">${escapeHtml(p.routeText)}</span>` : '';
        new maplibregl.Popup({ offset: 12 })
          .setLngLat(f.geometry.coordinates as [number, number])
          .setHTML(
            `<div data-testid="plane-popup">` +
              `<strong>${escapeHtml(p.modelLabel)}</strong><br/>` +
              `<span data-testid="plane-status">${p.status}</span><br/>` +
              `fuel <span data-testid="plane-fuel">${p.fuelText}</span>` +
              routeLine +
            `</div>`,
          )
          .addTo(map);
      };

      const loadAirports = () => {
        if (!airportsPromiseRef.current) {
          airportsPromiseRef.current = fetch('/api/airports')
            .then((res) => {
              if (!res.ok) throw new Error(`GET /api/airports → HTTP ${res.status}`);
              return res.json() as Promise<GeoJsonFeatureCollection>;
            })
            .then((data) => {
              setAirportCount(data.features.length); // exactly once per page life
              airportsIndexRef.current = new Map(
                data.features.map((f) => [f.properties.icao, { lat: f.properties.lat, lon: f.properties.lon }]),
              );
              return data;
            });
        }
        return airportsPromiseRef.current;
      };

      // Idempotent, so it can run on EVERY styledata event: map.setStyle() removes all
      // sources/layers not in the new style, which wipes our GeoJSON layers after each
      // switch — this re-establishes them (and the initial load goes through here too).
      const ensureLayers = async () => {
        let data: GeoJsonFeatureCollection;
        try {
          data = await loadAirports();
        } catch (err) {
          console.error('failed to load airports', err);
          return;
        }
        if (!map.getSource(AIRPORTS_SOURCE_ID)) {
          map.addSource(AIRPORTS_SOURCE_ID, { type: 'geojson', data });
        }
        if (!map.getLayer(AIRPORTS_LAYER_ID)) {
          map.addLayer({
            id: AIRPORTS_LAYER_ID,
            type: 'circle',
            source: AIRPORTS_SOURCE_ID,
            paint: {
              'circle-radius': 5, // ISS-010 (v0.18.0): bigger — the r=3 dots were hard to click
              'circle-color': '#e11d48',
              'circle-stroke-width': 1.5,
              'circle-stroke-color': '#ffffff',
            },
          });
        }
        // Routes first so the lines render under the plane circles. Empty collections
        // until the shell's first snapshot lands — applyDynamicRef fills them in.
        if (!map.getSource(ROUTES_SOURCE_ID)) {
          map.addSource(ROUTES_SOURCE_ID, {
            type: 'geojson',
            data: routesGeoJson(stateRef.current, airportsIndexRef.current ?? new Map()),
          });
        }
        if (!map.getLayer(ROUTES_LEGS_LAYER_ID)) {
          map.addLayer({
            id: ROUTES_LEGS_LAYER_ID,
            type: 'line',
            source: ROUTES_SOURCE_ID,
            paint: {
              'line-color': '#f59e0b', // bright amber — actively flying the leg
              'line-width': 3,
            },
          });
        }
        // ISS-043 (v0.26.0): dotted queue line — added after routes-legs but BEFORE the hover
        // layers so a hovered trace still draws on top of it. Amber/gold + fine dots reads as
        // "planned/future", distinct from the solid bright-amber active leg and the [2,2] yellow hover dash.
        if (!map.getSource(QUEUE_ROUTES_SOURCE_ID)) {
          map.addSource(QUEUE_ROUTES_SOURCE_ID, {
            type: 'geojson',
            data: queuedRoutesGeoJson(stateRef.current?.planes ?? [], airportsIndexRef.current ?? new Map()),
          });
        }
        if (!map.getLayer(QUEUE_ROUTES_LAYER_ID)) {
          map.addLayer({
            id: QUEUE_ROUTES_LAYER_ID,
            type: 'line',
            source: QUEUE_ROUTES_SOURCE_ID,
            paint: {
              'line-color': QUEUE_ROUTE_LINE_COLOR, // amber/gold — planned legs, not actively flying (ISS-098)
              'line-width': 3,
              'line-dasharray': [0.1, 1.5], // dotted — distinct from solid legs and the [2,2] hover dash
            },
          });
        }
        if (!map.getSource(PLANES_SOURCE_ID)) {
          // ISS-124 (v0.58.0): same airport-index unwrap as applyDynamic above.
          map.addSource(PLANES_SOURCE_ID, { type: 'geojson', data: planesGeoJson(stateRef.current, airportsIndexRef.current ?? new Map()) });
        }
        if (!map.getLayer(PLANES_GROUNDED_LAYER_ID)) {
          map.addLayer({
            id: PLANES_GROUNDED_LAYER_ID,
            type: 'circle',
            source: PLANES_SOURCE_ID,
            filter: ['==', ['get', 'flying'], false],
            paint: {
              'circle-radius': 3,
              'circle-color': '#38bdf8', // sky blue at the home airport
              'circle-stroke-width': 1,
              'circle-stroke-color': '#ffffff',
            },
          });
        }
        if (!map.getLayer(PLANES_FLYING_LAYER_ID)) {
          map.addLayer({
            id: PLANES_FLYING_LAYER_ID,
            type: 'circle',
            source: PLANES_SOURCE_ID,
            filter: ['==', ['get', 'flying'], true],
            paint: {
              'circle-radius': 6, // bigger + distinct so a moving plane stands out
              'circle-color': '#22c55e',
              'circle-stroke-width': 1.5,
              'circle-stroke-color': '#ffffff',
            },
          });
        }
        // ISS-002 (v0.15.0): hover-highlight layers — added last so they sit top-most over
        // both plane layers / the route line / the airport circles. Each starts filtered to
        // match nothing; applyHoverRef sets the real filter on hover and re-applies it here.
        if (!map.getLayer(PLANES_HIGHLIGHT_LAYER_ID)) {
          map.addLayer({
            id: PLANES_HIGHLIGHT_LAYER_ID,
            type: 'circle',
            source: PLANES_SOURCE_ID,
            filter: ['==', ['get', 'id'], ''],
            paint: {
              'circle-radius': 10, // halo well above the base circles (3 grounded / 6 flying)
              'circle-color': '#38bdf8',
              'circle-stroke-width': 2.5,
              'circle-stroke-color': '#ffffff',
            },
          });
        }
        if (!map.getLayer(ROUTES_HIGHLIGHT_LAYER_ID)) {
          map.addLayer({
            id: ROUTES_HIGHLIGHT_LAYER_ID,
            type: 'line',
            source: ROUTES_SOURCE_ID,
            filter: ['==', ['get', 'planeId'], ''],
            paint: {
              'line-color': '#ef4444', // red — distinct from the amber routes-legs line
              'line-width': 6,
            },
          });
        }
        if (!map.getLayer(AIRPORTS_HIGHLIGHT_LAYER_ID)) {
          map.addLayer({
            id: AIRPORTS_HIGHLIGHT_LAYER_ID,
            type: 'circle',
            source: AIRPORTS_SOURCE_ID,
            filter: ['any', ['==', ['get', 'icao'], ''], ['==', ['get', 'icao'], '']],
            paint: {
              'circle-radius': 9, // ring around the base airport circles (r=5)
              'circle-color': 'rgba(0, 0, 0, 0)', // transparent fill — stroke-only ring
              'circle-stroke-width': 2.5,
              'circle-stroke-color': '#facc15',
            },
          });
        }
        // ISS-022/025/027 (v0.22.0): the hover route trace — added LAST so it sits above every
        // other layer, including the highlight rings at its endpoints. Own source: the shared
        // `routes` source only holds flying legs, never a planned one. Empty until a hover sets data.
        if (!map.getSource(HOVER_ROUTES_SOURCE_ID)) {
          map.addSource(HOVER_ROUTES_SOURCE_ID, { type: 'geojson', data: { type: 'FeatureCollection', features: [] } });
        }
        if (!map.getLayer(HOVER_ROUTE_LAYER_ID)) {
          map.addLayer({
            id: HOVER_ROUTE_LAYER_ID,
            type: 'line',
            source: HOVER_ROUTES_SOURCE_ID,
            paint: {
              'line-color': '#facc15', // matches the airports-highlight ring — one "trace" color
              'line-width': 4,
              'line-dasharray': [2, 2], // dashed = planned route, distinct from solid flying legs
            },
          });
        }
        // ISS-022 (v0.22.0): the destination's ring — same geometry as airports-highlight but a
        // DIFFERENT color so the target stands out over the origin's yellow ring; added last so it
        // also sits above the hover-route line at its endpoint. Starts filtered to match nothing.
        if (!map.getLayer(AIRPORTS_TARGET_HIGHLIGHT_LAYER_ID)) {
          map.addLayer({
            id: AIRPORTS_TARGET_HIGHLIGHT_LAYER_ID,
            type: 'circle',
            source: AIRPORTS_SOURCE_ID,
            filter: ['==', ['get', 'icao'], ''],
            paint: {
              'circle-radius': 9, // same ring size as airports-highlight (r=5 base circles)
              'circle-color': 'rgba(0, 0, 0, 0)', // transparent fill — stroke-only ring
              'circle-stroke-width': 3,
              'circle-stroke-color': '#4ade80', // green — distinct from the yellow endpoint rings
            },
          });
        }
        // Layer-scoped listeners survive setStyle (they filter by layer id at event
        // time), so off+on with the same reference re-wires without duplicating.
        map.off('click', AIRPORTS_LAYER_ID, onAirportClick);
        map.on('click', AIRPORTS_LAYER_ID, onAirportClick);
        map.off('click', PLANES_GROUNDED_LAYER_ID, onPlaneClick);
        map.on('click', PLANES_GROUNDED_LAYER_ID, onPlaneClick);
        map.off('click', PLANES_FLYING_LAYER_ID, onPlaneClick);
        map.on('click', PLANES_FLYING_LAYER_ID, onPlaneClick);
        // Sources were (re)created above — push the latest game state into them, and re-apply
        // the current hover filter to the (re-created) highlight layers.
        applyDynamicRef.current();
        applyHoverRef.current();
      };

      if (map.isStyleLoaded()) void ensureLayers();
      else map.on('styledata', () => void ensureLayers());
    });

    return () => {
      cancelled = true;
      delete (window as unknown as Record<string, unknown>).__flightMap;
      const map = mapRef.current; // may be null if the probe hasn't resolved yet
      mapRef.current = null;
      if (map) map.remove();
    };
  }, []);

  const onStyleChange = (e: ChangeEvent<HTMLSelectElement>) => {
    const id = e.target.value;
    if (!isStyleId(id)) return;
    setStyleId(id);
    window.localStorage.setItem(STYLE_STORAGE_KEY, id);
    // The probe promise is cached module-wide and has resolved by the time a user
    // interacts — this just picks local vs remote for the new style.
    void localAssetsAvailable().then((available) => mapRef.current?.setStyle(styleUrlFor(id, available)));
  };

  return (
    <div className="map-wrap">
      <header data-testid="app-header" className="app-header">
        <h1>Flight Ops</h1>
        <a data-testid="app-version" href="https://git.kkhost.pl/OpenCode/Flight-Ops/src/branch/master/CHANGELOG.md" target="_blank" rel="noreferrer">
          <small>v{pkg.version}</small>
        </a>
        <select
          data-testid="style-switch"
          className="style-switch"
          aria-label="Map style"
          value={styleId}
          onChange={onStyleChange}
        >
          {STYLES.map((s) => (
            <option key={s.id} value={s.id}>
              {s.label}
            </option>
          ))}
        </select>
        <span data-testid="airport-count">
          {airportCount === null ? 'loading airports…' : `${airportCount} world airports`}
        </span>
      </header>
      <div ref={containerRef} data-testid="map" className="map-container" />
    </div>
  );
}