import * as maplibregl from 'maplibre-gl';
import type { GeoJSONSource, Map as MLMap, StyleSpecification } from 'maplibre-gl';
import 'maplibre-gl/dist/maplibre-gl.css';
import { useEffect, useMemo, useRef, useState } from 'react';
import { useI18n, type Key } from '../lib/i18n';
import type { LatLon } from '../lib/geo';
import { HARD_FLAGS, type RouteResult } from '../lib/route';
import type { Place, Verdict } from '../lib/types';
import { VERDICT_STYLE } from './ui';

maplibregl.setWorkerUrl(new URL(`${import.meta.env.BASE_URL}maplibre/maplibre-gl-worker.mjs`, document.baseURI).href);

const STYLE: StyleSpecification = {
  version: 8,
  sources: {
    osm: {
      type: 'raster',
      tiles: ['https://tile.openstreetmap.org/{z}/{x}/{y}.png'],
      tileSize: 256,
      maxzoom: 19,
      attribution: '© <a href="https://www.openstreetmap.org/copyright" target="_blank" rel="noreferrer">OpenStreetMap</a>',
    },
  },
  layers: [{ id: 'osm', type: 'raster', source: 'osm' }],
};

const reduceMotion = () => window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const lngLat = (p: LatLon): [number, number] => [p[1], p[0]];
const SPRITE = `${import.meta.env.BASE_URL}uswds/sprite.svg`;

interface Props {
  places: { place: Place; verdict: Verdict }[];
  showPlaces: boolean;
  selectedId: string | null;
  onSelect: (id: string) => void;
  route: RouteResult | null;
  routeEnds: { from: LatLon; to: LatLon } | null;
  focus: { at: LatLon; n: number } | null;
  /** Re-measure when the pane becomes visible. */
  visible: boolean;
  bbox: [number, number, number, number];
  online: boolean;
}

export function MapView({ places, showPlaces, selectedId, onSelect, route, routeEnds, focus, visible, bbox, online }: Props) {
  const { t, lang } = useI18n();
  const ref = useRef<HTMLDivElement>(null);
  const mapRef = useRef<MLMap | null>(null);
  const markers = useRef<maplibregl.Marker[]>([]);
  const onSelectRef = useRef(onSelect);
  onSelectRef.current = onSelect;
  const [ready, setReady] = useState(false);

  // ---- init ----
  useEffect(() => {
    if (!ref.current) return;
    const [s, w, n, e] = bbox;
    const map = new maplibregl.Map({
      container: ref.current,
      style: STYLE,
      center: [(w + e) / 2, (s + n) / 2],
      zoom: 15,
      minZoom: 12,
      maxBounds: [[w - 0.04, s - 0.03], [e + 0.04, n + 0.03]],
      attributionControl: { compact: true },
      locale: {
        'NavigationControl.ZoomIn': t('map.zoomIn'),
        'NavigationControl.ZoomOut': t('map.zoomOut'),
        'AttributionControl.ToggleAttribution': t('map.attrToggle'),
      },
    });
    map.addControl(new maplibregl.NavigationControl({ showCompass: false }), 'top-right');
    map.on('load', () => {
      map.addSource('places', { type: 'geojson', data: { type: 'FeatureCollection', features: [] } });
      map.addSource('route', { type: 'geojson', data: { type: 'FeatureCollection', features: [] } });
      map.addLayer({
        id: 'route-casing', type: 'line', source: 'route',
        layout: { 'line-cap': 'round', 'line-join': 'round' }, paint: { 'line-color': '#ffffff', 'line-width': 9 },
      });
      const line = (id: string, status: string, color: string, width: number, dash?: number[]) =>
        map.addLayer({
          id, type: 'line', source: 'route', filter: ['==', ['get', 'status'], status],
          layout: { 'line-cap': dash ? 'butt' : 'round', 'line-join': 'round' },
          paint: { 'line-color': color, 'line-width': width, ...(dash ? { 'line-dasharray': dash } : {}) },
        });
      line('route-ok', 'ok', '#005ea2', 5);
      line('route-warn', 'warn', '#a2461c', 5, [2, 1.5]);
      line('route-blocked', 'blocked', '#b50909', 6, [0.4, 1.6]);
      map.addLayer({
        id: 'places', type: 'circle', source: 'places',
        paint: {
          'circle-radius': ['interpolate', ['linear'], ['zoom'], 13, 3.5, 17, 9],
          'circle-color': ['match', ['get', 'verdict'], 'match', VERDICT_STYLE.match.hex, 'partial', VERDICT_STYLE.partial.hex, 'conflict', VERDICT_STYLE.conflict.hex, 'fail', VERDICT_STYLE.fail.hex, '#ffffff'],
          'circle-stroke-color': ['match', ['get', 'verdict'], 'incomplete', '#565c65', '#1b1b1b'],
          'circle-stroke-width': ['match', ['get', 'verdict'], 'incomplete', 2.5, 1.5],
        },
      });
      map.addLayer({
        id: 'places-selected', type: 'circle', source: 'places', filter: ['==', ['get', 'id'], ''],
        paint: { 'circle-radius': ['interpolate', ['linear'], ['zoom'], 13, 8, 17, 15], 'circle-color': 'rgba(0,0,0,0)', 'circle-stroke-color': '#005ea2', 'circle-stroke-width': 4 },
      });
      map.on('click', 'places', (ev: maplibregl.MapMouseEvent & { features?: maplibregl.MapGeoJSONFeature[] }) => {
        const id = ev.features?.[0]?.properties?.id as string | undefined;
        if (id) onSelectRef.current(id);
      });
      map.on('mouseenter', 'places', () => { map.getCanvas().style.cursor = 'pointer'; });
      map.on('mouseleave', 'places', () => { map.getCanvas().style.cursor = ''; });
      setReady(true);
    });
    mapRef.current = map;
    const ro = new ResizeObserver(() => map.resize());
    ro.observe(ref.current);
    return () => { ro.disconnect(); markers.current.forEach((m) => m.remove()); map.remove(); mapRef.current = null; setReady(false); };
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  useEffect(() => { if (visible) mapRef.current?.resize(); }, [visible]);

  // ---- places ----
  const fc = useMemo(
    () => ({
      type: 'FeatureCollection' as const,
      features: places.map(({ place, verdict }) => ({
        type: 'Feature' as const,
        geometry: { type: 'Point' as const, coordinates: [place.lon, place.lat] },
        properties: { id: place.id, verdict },
      })),
    }),
    [places],
  );
  useEffect(() => {
    const map = mapRef.current;
    if (!ready || !map) return;
    (map.getSource('places') as GeoJSONSource).setData(showPlaces ? fc : { type: 'FeatureCollection', features: [] });
  }, [ready, fc, showPlaces]);

  useEffect(() => {
    const map = mapRef.current;
    if (!ready || !map) return;
    map.setFilter('places-selected', ['==', ['get', 'id'], showPlaces ? selectedId ?? '' : '']);
    const sel = selectedId ? places.find((p) => p.place.id === selectedId)?.place : undefined;
    if (sel && showPlaces) map.easeTo({ center: [sel.lon, sel.lat], zoom: Math.max(map.getZoom(), 17), duration: reduceMotion() ? 0 : 500 });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [ready, selectedId, showPlaces]);

  // ---- route ----
  useEffect(() => {
    const map = mapRef.current;
    if (!ready || !map) return;
    markers.current.forEach((m) => m.remove());
    markers.current = [];
    const src = map.getSource('route') as GeoJSONSource;
    if (!route || route.status === 'none') {
      src.setData({ type: 'FeatureCollection', features: [] });
      return;
    }
    src.setData({
      type: 'FeatureCollection',
      features: route.segments.map((s) => {
        const hard = s.flags.some((f) => HARD_FLAGS.has(f));
        const warn = s.flags.some((f) => f !== 'surface-unknown' && f !== 'ramp-steps' && !HARD_FLAGS.has(f));
        return {
          type: 'Feature' as const,
          geometry: { type: 'LineString' as const, coordinates: s.coords.map(lngLat) },
          properties: { status: hard ? 'blocked' : warn ? 'warn' : 'ok' },
        };
      }),
    });

    const addMarker = (el: HTMLElement, at: LatLon, popupText?: string) => {
      const m = new maplibregl.Marker({ element: el }).setLngLat(lngLat(at));
      if (popupText) m.setPopup(new maplibregl.Popup({ offset: 16, closeButton: true }).setText(popupText));
      m.addTo(map);
      markers.current.push(m);
    };
    const pin = (label: string, aria: string, cls: string) => {
      const b = document.createElement('div');
      b.className = `kbb-pin ${cls}`;
      b.textContent = label;
      b.setAttribute('role', 'img');
      b.setAttribute('aria-label', aria);
      return b;
    };
    if (routeEnds) {
      addMarker(pin('A', t('route.start'), 'kbb-pin--start'), routeEnds.from);
      addMarker(pin('B', t('route.end'), 'kbb-pin--end'), routeEnds.to);
    }
    for (const b of route.barriers) {
      if (b.flag === 'surface-unknown' || b.flag === 'ramp-steps') continue;
      const hard = HARD_FLAGS.has(b.flag);
      const el = document.createElement('button');
      el.type = 'button';
      el.className = `kbb-pin kbb-pin--barrier ${hard ? 'kbb-pin--hard' : ''}`;
      const text = `${t(`flag.${b.flag}` as Key)}${b.name ? ` · ${b.name}` : ''}`;
      el.setAttribute('aria-label', text);
      el.innerHTML = `<svg class="usa-icon" aria-hidden="true" focusable="false"><use href="${SPRITE}#${hard ? 'error' : 'warning'}"></use></svg>`;
      addMarker(el, b.at, text);
    }
    const bounds = new maplibregl.LngLatBounds();
    route.coords.forEach((c) => bounds.extend(lngLat(c)));
    map.fitBounds(bounds, { padding: 70, duration: reduceMotion() ? 0 : 600, maxZoom: 17 });
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [ready, route, routeEnds, lang]);

  useEffect(() => {
    const map = mapRef.current;
    if (!ready || !map || !focus) return;
    map.easeTo({ center: lngLat(focus.at), zoom: Math.max(map.getZoom(), 18), duration: reduceMotion() ? 0 : 500 });
  }, [ready, focus]);

  return (
    <div className="kbb-map-wrap">
      <div ref={ref} className="kbb-map" role="region" aria-label={t('map.label')} aria-describedby="map-alt" />
      <p id="map-alt" className="usa-sr-only">{t('map.alt')}</p>
      {!online && <p className="kbb-map-note usa-alert usa-alert--warning usa-alert--slim margin-0"><span className="usa-alert__body"><span className="usa-alert__text">{t('map.offline')}</span></span></p>}
      {showPlaces && (
        <details className="kbb-legend">
          <summary>{t('map.legend')}</summary>
          <ul className="usa-list--unstyled margin-0 padding-0">
            {(['match', 'partial', 'conflict', 'incomplete', 'fail'] as Verdict[]).map((v) => (
              <li key={v} className="display-flex flex-align-center">
                <span className="kbb-swatch" style={{ background: VERDICT_STYLE[v].hex, borderColor: v === 'incomplete' ? '#565c65' : '#1b1b1b' }} aria-hidden="true" />
                {t(`verdict.${v}`)}{v === 'incomplete' ? ` (${t('map.hollow')})` : ''}
              </li>
            ))}
          </ul>
        </details>
      )}
    </div>
  );
}