'use client';

/**
 * LeafletMap — the Leaflet core shared by the /map page and journal map
 * blocks: tiles, markers from props, an optional line through them, fit to
 * bounds. It knows nothing about /api/map; MapView fetches and hands over.
 *
 * The Leaflet stylesheet is imported here rather than by each page, so a map
 * anywhere brings its own CSS. It comes from the npm package, bundled, not
 * from a CDN: no visitor request leaves this origin for it (#699). Marker
 * and popup styling lives in app/leaflet.css, loaded globally.
 */

import { useEffect, useRef } from 'react';
import 'leaflet/dist/leaflet.css';
import { useDictionary } from './I18nProvider';
import { escapeHtml } from '@/lib/escapeHtml';

export interface LeafletMarker {
  lat: number;
  lng: number;
  /** Inner HTML of the marker icon — already escaped by the caller. */
  html: string;
  /**
   * The marker's accessible name and hover title (plain text, not HTML).
   * Without it a screen reader announces only what the icon shows — for the
   * location map, a bare photo count like "12".
   */
  label?: string;
  popupHtml?: string;
}

interface LeafletMapProps {
  markers: LeafletMarker[];
  /** Draw a dashed line through the markers in the order given. */
  line?: boolean;
  className?: string;
  /** Cap the zoom fitBounds may pick — a single pin otherwise zooms to the rooftop. */
  fitMaxZoom?: number;
  onReady?: () => void;
  onError?: (err: unknown) => void;
}

export { escapeHtml } from '@/lib/escapeHtml';

/**
 * Leaflet's attribution prefix with its English link title swapped for
 * `title`. The rest — link, flag, name — is Leaflet's own markup, kept as is.
 */
export function localizedLeafletPrefix(prefix: string, title: string): string {
  return prefix.replace(/title="[^"]*"/, `title="${escapeHtml(title)}"`);
}

export function LeafletMap({
  markers,
  line = false,
  className = 'map-container',
  fitMaxZoom,
  onReady,
  onError,
}: LeafletMapProps) {
  const containerRef = useRef<HTMLDivElement>(null);
  const mapRef = useRef<L.Map | null>(null);
  // Read inside the effect through a ref: the locale never changes on a
  // mounted page, and a new dictionary object must not rebuild the map.
  const t = useDictionary();
  const labelsRef = useRef(t.map);
  labelsRef.current = t.map;

  // Callers rebuild the markers array on every render; the map is only
  // rebuilt when its content changes.
  const markersKey = JSON.stringify(markers);
  const markersRef = useRef(markers);
  markersRef.current = markers;
  const onReadyRef = useRef(onReady);
  onReadyRef.current = onReady;
  const onErrorRef = useRef(onError);
  onErrorRef.current = onError;

  useEffect(() => {
    let cancelled = false;

    async function init() {
      const L = (await import('leaflet')).default;
      if (cancelled || !containerRef.current || mapRef.current) return;

      // The zoom buttons' titles (which Leaflet also uses as their aria-label)
      // and the credit's link title are English in Leaflet; the site's
      // dictionary supplies them instead.
      const labels = labelsRef.current;
      const map = L.map(containerRef.current, { zoomControl: false, attributionControl: true });
      mapRef.current = map;
      L.control.zoom({ zoomInTitle: labels.zoomIn, zoomOutTitle: labels.zoomOut }).addTo(map);
      const prefix = map.attributionControl.options.prefix;
      if (typeof prefix === 'string') {
        map.attributionControl.setPrefix(localizedLeafletPrefix(prefix, labels.leafletTitle));
      }

      // OpenStreetMap's own tiles: free to use with attribution and a Referer,
      // which the Referrer-Policy sends. CARTO's Dark Matter, used before,
      // started answering every tile with "API KEY REQUIRED". The dark look
      // comes from a filter in app/leaflet.css, so it follows the colour mode.
      L.tileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}.png', {
        attribution:
          '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors',
        maxZoom: 19,
      }).addTo(map);

      const current = markersRef.current;
      if (current.length === 0) {
        // Nothing to place — world view
        map.setView([20, 0], 2);
      } else {
        const group = L.featureGroup(
          current.map((m) => {
            const marker = L.marker([m.lat, m.lng], {
              icon: L.divIcon({
                className: '',
                html: m.html,
                iconSize: [32, 32],
                iconAnchor: [16, 16],
                popupAnchor: [0, -20],
              }),
              ...(m.label ? { title: m.label } : {}),
            });
            // Leaflet makes the icon a focusable role="button"; the label
            // becomes its name once the element exists.
            if (m.label) {
              const label = m.label;
              marker.on('add', () => marker.getElement()?.setAttribute('aria-label', label));
            }
            if (m.popupHtml) marker.bindPopup(m.popupHtml, { maxWidth: 260, minWidth: 200 });
            return marker;
          }),
        ).addTo(map);

        if (line && current.length > 1) {
          const accent =
            getComputedStyle(document.documentElement).getPropertyValue('--accent').trim() ||
            '#e60012';
          L.polyline(
            current.map((m) => [m.lat, m.lng] as [number, number]),
            { color: accent, weight: 2, opacity: 0.75, dashArray: '4 6' },
          ).addTo(map);
        }

        map.fitBounds(group.getBounds().pad(0.15), fitMaxZoom ? { maxZoom: fitMaxZoom } : {});
      }

      // Force Leaflet to recalculate the tile grid once laid out
      setTimeout(() => map.invalidateSize(), 100);
      onReadyRef.current?.();
    }

    init().catch((err) => {
      console.error('[Map] Init error:', err);
      if (!cancelled) onErrorRef.current?.(err);
    });

    return () => {
      cancelled = true;
      if (mapRef.current) {
        mapRef.current.remove();
        mapRef.current = null;
      }
    };
  }, [markersKey, line, fitMaxZoom]);

  return <div ref={containerRef} className={className} />;
}