import { Color, DoubleSide, Fog } from "three";
import { MapControls } from "three/examples/jsm/controls/MapControls.js";
import { CSS2DObject } from "three/examples/jsm/renderers/CSS2DRenderer.js";

import XYZ from "ol/source/XYZ.js";

import Coordinates from "@giro3d/giro3d/core/geographic/Coordinates.js";
import Extent from "@giro3d/giro3d/core/geographic/Extent.js";
import Instance from "@giro3d/giro3d/core/Instance.js";
import Map from "@giro3d/giro3d/entities/Map.js";
import TiledImageSource from "@giro3d/giro3d/sources/TiledImageSource.js";
import MapboxTerrainFormat from "@giro3d/giro3d/formats/MapboxTerrainFormat.js";
import ColorLayer from "@giro3d/giro3d/core/layer/ColorLayer.js";
import ElevationLayer from "@giro3d/giro3d/core/layer/ElevationLayer.js";
import Inspector from "@giro3d/giro3d/gui/Inspector.js";

Instance.registerCRS(
  "EPSG:2154",
  "+proj=lcc +lat_0=46.5 +lon_0=3 +lat_1=49 +lat_2=44 +x_0=700000 +y_0=6600000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs +type=crs",
);

const SKY_COLOR = "#87CEEB";
const size = 200_000;
const extent = Extent.fromCenterAndSize(
  "EPSG:2154",
  { x: 1_051_908, y: 6_542_409 },
  size,
  size,
);

const instance = new Instance({
  target: "view",
  crs: extent.crs,
  backgroundColor: SKY_COLOR,
});

const map = new Map({
  extent,
  hillshading: {
    enabled: true,
    elevationLayersOnly: true,
  },
  side: DoubleSide,
  backgroundColor: "gray",
});

instance.add(map);

const key =
  "pk.eyJ1IjoidG11Z3VldCIsImEiOiJjbGJ4dTNkOW0wYWx4M25ybWZ5YnpicHV6In0.KhDJ7W5N3d1z3ArrsDjX_A";

// Adds a XYZ elevation layer with MapBox terrain RGB tileset
const elevationLayer = new ElevationLayer({
  name: "xyz_elevation",
  extent,
  resolutionFactor: 0.5,
  minmax: { min: 0, max: 5000 },
  source: new TiledImageSource({
    format: new MapboxTerrainFormat(),
    source: new XYZ({
      url: `https://api.mapbox.com/v4/mapbox.terrain-rgb/{z}/{x}/{y}.pngraw?access_token=${key}`,
      projection: "EPSG:3857",
      crossOrigin: "anonymous",
    }),
  }),
});
map.addLayer(elevationLayer);

// Adds a XYZ color layer with MapBox satellite tileset
const satelliteLayer = new ColorLayer({
  name: "xyz_color",
  extent,
  source: new TiledImageSource({
    source: new XYZ({
      url: `https://api.mapbox.com/v4/mapbox.satellite/{z}/{x}/{y}.webp?access_token=${key}`,
      projection: "EPSG:3857",
      crossOrigin: "anonymous",
    }),
  }),
});
map.addLayer(satelliteLayer);

const controls = new MapControls(instance.view.camera, instance.domElement);

instance.view.camera.position.set(994_410, 6_520_646, 5_520);
controls.target.set(1_011_954, 6_539_864, 1_000);

instance.view.setControls(controls);

// Here we have a list of summits of the Alps and their geographic coordinates,
// but without any elevation information
const summits = [
  { latitude: 45.832866, longitude: 6.864824, name: "Mont Blanc" },
  { latitude: 45.976389, longitude: 7.658333, name: "Matterhorn" },
  { latitude: 45.8667, longitude: 6.98333, name: "Grandes Jorasses" },
  { latitude: 45.930835, longitude: 6.989466, name: "Les Droites" },
  { latitude: 45.95, longitude: 7.3, name: "Grand Combin" },
];
const summitMarkers = [];

function updateMarker(marker) {
  const { x, y } = marker.position;
  const coordinates = new Coordinates(instance.referenceCrs, x, y);
  const result = map.getElevation({ coordinates });
  if (result.samples.length > 0) {
    result.samples.sort((a, b) => a.resolution - b.resolution);
    const sample = result.samples[0];

    marker.position.setZ(sample.elevation);
    marker.updateMatrixWorld(true);
  }
}

function updateMarkers(extent) {
  for (const marker of summitMarkers) {
    const { x, y } = marker.position;
    const coordinates = new Coordinates(instance.referenceCrs, x, y);

    // Only update markers that are inside the updated area
    if (extent.isPointInside(coordinates)) {
      updateMarker(marker);
    }
  }
}

async function loadMarker(summit) {
  const { name, latitude, longitude } = summit;

  const markerHtmlElement = document.createElement("div");
  markerHtmlElement.style.paddingBottom = "4rem";
  const span = document.createElement("span");
  span.classList.value = "badge rounded-pill text-bg-dark";
  span.innerText = summit.name;
  markerHtmlElement.appendChild(span);

  const marker = new CSS2DObject(markerHtmlElement);
  marker.name = name;

  // Let's convert our summit coordinates from EPSG:4326 to EPSG:2154
  const coordinates = new Coordinates("EPSG:4326", longitude, latitude).as(
    instance.referenceCrs,
  );
  marker.position.set(coordinates.x, coordinates.y, 0);

  instance.add(marker);

  marker.updateMatrixWorld(true);
  summitMarkers.push(marker);

  updateMarker(marker);
}

for (const summit of summits) {
  loadMarker(summit);
}

// Let's update the markers' elevations whenever there is some new elevation data loaded on the map
map.addEventListener("elevation-changed", ({ extent }) =>
  updateMarkers(extent),
);

const fog = new Fog(new Color(SKY_COLOR), 1000, 200_000);
instance.scene.fog = fog;

Inspector.attach("inspector", instance);

<!doctype html>
<html lang="en">
  <head>
    <title>Query map elevations</title>
    <meta charset="UTF-8" />
    <meta name="name" content="query_map_elevation" />
    <meta
      name="description"
      content="Sample elevation at various points in the map."
    />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />

    <link rel="icon" href="https://giro3d.org/images/favicon.svg" />
    <link
      href="https://giro3d.org/assets/bootstrap-custom.css"
      rel="stylesheet"
    />
    <script src="https://giro3d.org/assets/bootstrap.bundle.min.js"></script>
    <link
      rel="stylesheet"
      type="text/css"
      href="https://giro3d.org/latest/examples/css/example.css"
    />
  </head>

  <body>
    <div id="view" class="m-0 p-0 w-100 h-100"></div>
    <div
      id="inspector"
      class="position-absolute top-0 start-0 mh-100 overflow-auto"
    ></div>

    <script type="module" src="index.js"></script>
    <script>
      /* activate popovers */
      const popoverTriggerList = [].slice.call(
        document.querySelectorAll('[data-bs-toggle="popover"]'),
      );
      popoverTriggerList.map(
        // bootstrap is used as script in the template, disable warning about undef
        // eslint-disable-next-line no-undef
        (popoverTriggerEl) =>
          new bootstrap.Popover(popoverTriggerEl, {
            trigger: "hover",
            placement: "left",
            content: document.getElementById(
              popoverTriggerEl.getAttribute("data-bs-content"),
            ).innerHTML,
            html: true,
          }),
      );
    </script>
  </body>
</html>

{
    "name": "query_map_elevation",
    "dependencies": {
        "@giro3d/giro3d": "0.41.0"
    },
    "devDependencies": {
        "vite": "^3.2.3"
    },
    "scripts": {
        "start": "vite",
        "build": "vite build"
    }
}