import maplibregl, { type Map as MapLibreMap } from "maplibre-gl";
import {
  CITY_LAYERS,
  CITY_LIGHT,
  CITY_ROOT,
  cityManifestSchema,
  citySources,
  findCitySceneInsertionLayerId
} from "./city-scene-layers";
import { Protocol } from "pmtiles";

const cityTileProtocol = new Protocol();
maplibregl.addProtocol("pmtiles", cityTileProtocol.tile);

class CitySceneControl {
  private map?: MapLibreMap;
  private initialized = false;

  private attribution?: maplibregl.AttributionControl;

  attach(map: MapLibreMap) {
    this.map = map;
    map.on("pitchend", this.syncVisibility);
    this.syncVisibility();
  }

  private syncVisibility = () => {
    const map = this.map;
    if (!map) return;
    const enabled = map.getPitch() > 0;
    if (enabled && !this.initialized) this.addLayers();
    if (!this.initialized) return;
    CITY_LAYERS.forEach(({ id }) =>
      map.setLayoutProperty(id, "visibility", enabled ? "visible" : "none")
    );
  };

  private addLayers() {
    const map = this.map;
    if (!map) return;
    map.setLight(CITY_LIGHT);
    Object.entries(citySources()).forEach(([id, source]) => map.addSource(id, source));
    const firstHitLayer = findCitySceneInsertionLayerId(map.getStyle().layers);
    CITY_LAYERS.forEach((layer) => map.addLayer(layer, firstHitLayer));
    this.attribution = new maplibregl.AttributionControl({
      compact: true,
      customAttribution:
        '<a href="/city-model/ATTRIBUTION.md" target="_blank" rel="noopener noreferrer">Qian Shi et al. · 数据来源与许可</a>'
    });
    map.addControl(this.attribution, "bottom-left");
    this.initialized = true;
  }

  onRemove() {
    const map = this.map;
    map?.off("pitchend", this.syncVisibility);
    if (this.attribution && map?.hasControl(this.attribution)) map.removeControl(this.attribution);
    if (map && this.initialized) {
      [...CITY_LAYERS].reverse().forEach(({ id }) => {
        if (map.getLayer(id)) map.removeLayer(id);
      });
      Object.keys(citySources()).forEach((id) => {
        if (map.getSource(id)) map.removeSource(id);
      });
    }
    this.map = undefined;
  }
}

/** Scene is optional; absent local data must not break the operational map. */
export function installCityScene(map: MapLibreMap): () => void {
  const abort = new AbortController();
  let control: CitySceneControl | undefined;
  void fetch(`${CITY_ROOT}/manifest.json`, { signal: abort.signal })
    .then(async (response) => {
      if (!response.ok) return;
      const manifest = cityManifestSchema.safeParse(await response.json());
      if (!manifest.success || abort.signal.aborted) return;
      control = new CitySceneControl();
      control.attach(map);
    })
    .catch(() => {
      /* Optional scene is not deployed on every installation. */
    });
  return () => {
    abort.abort();
    control?.onRemove();
  };
}