import colormap from "colormap";

import * as FunctionCurveEditor from "function-curve-editor";

import { MathUtils, Vector3, Color } from "three";
import { MapControls } from "three/examples/jsm/controls/MapControls.js";
import { CSS2DObject } from "three/examples/jsm/renderers/CSS2DRenderer.js";

import Instance from "@giro3d/giro3d/core/Instance.js";
import Tiles3D from "@giro3d/giro3d/entities/Tiles3D.js";
import PointCloudMaterial, {
  MODE,
} from "@giro3d/giro3d/renderer/PointCloudMaterial.js";
import Tiles3DSource from "@giro3d/giro3d/sources/Tiles3DSource.js";
import Inspector from "@giro3d/giro3d/gui/Inspector.js";

function bindToggle(id, onChange) {
  const element = document.getElementById(id);
  if (!(element instanceof HTMLInputElement)) {
    throw new Error(
      "invalid binding element: expected HTMLButtonElement, got: " +
        element.constructor.name,
    );
  }

  element.oninput = function oninput() {
    onChange(element.checked);
  };

  const callback = (v) => {
    element.checked = v;
    onChange(element.checked);
  };

  return [callback, element.checked, element];
}

function bindDropDown(id, onChange) {
  const element = document.getElementById(id);
  if (!(element instanceof HTMLSelectElement)) {
    throw new Error(
      "invalid binding element: expected HTMLSelectElement, got: " +
        element.constructor.name,
    );
  }

  element.onchange = () => {
    onChange(element.value);
  };

  const callback = (v) => {
    element.value = v;
    onChange(element.value);
  };

  const setOptions = (options) => {
    const items = options.map(
      (opt) =>
        `<option value=${opt.id} ${opt.selected ? "selected" : ""}>${opt.name}</option>`,
    );
    element.innerHTML = items.join("\n");
  };

  return [callback, element.value, element, setOptions];
}

function bindButton(id, onClick) {
  const element = document.getElementById(id);
  if (!(element instanceof HTMLButtonElement)) {
    throw new Error(
      "invalid binding element: expected HTMLButtonElement, got: " +
        element.constructor.name,
    );
  }

  element.onclick = () => {
    onClick(element);
  };

  return element;
}

function makeColorRamp(
  preset,
  discrete = false,
  invert = false,
  mirror = false,
) {
  let nshades = discrete ? 10 : 256;

  const values = colormap({ colormap: preset, nshades });

  const colors = values.map((v) => new Color(v));

  if (invert) {
    colors.reverse();
  }

  if (mirror) {
    const mirrored = [...colors, ...colors.reverse()];
    return mirrored;
  }

  return colors;
}

function bindColorMapBounds(callback) {
  const min = document.getElementById("min");
  if (!(min instanceof HTMLInputElement)) {
    throw new Error(
      "invalid binding element: expected HTMLInputElement, got: " +
        min.constructor.name,
    );
  }

  const max = document.getElementById("max");
  if (!(max instanceof HTMLInputElement)) {
    throw new Error(
      "invalid binding element: expected HTMLInputElement, got: " +
        max.constructor.name,
    );
  }

  const lower = min;
  const upper = max;

  callback(lower.valueAsNumber, upper.valueAsNumber);

  function updateLabels() {
    document.getElementById("minLabel").innerText =
      `Lower bound: ${Math.round(lower.valueAsNumber)}m`;
    document.getElementById("maxLabel").innerText =
      `Upper bound: ${Math.round(upper.valueAsNumber)}m`;
  }

  lower.oninput = function oninput() {
    const rawValue = lower.valueAsNumber;
    const clampedValue = MathUtils.clamp(
      rawValue,
      Number.parseFloat(lower.min),
      upper.valueAsNumber - 1,
    );
    lower.valueAsNumber = clampedValue;
    callback(lower.valueAsNumber, upper.valueAsNumber);
    updateLabels();
  };

  upper.oninput = function oninput() {
    const rawValue = upper.valueAsNumber;
    const clampedValue = MathUtils.clamp(
      rawValue,
      lower.valueAsNumber + 1,
      Number.parseFloat(upper.max),
    );
    upper.valueAsNumber = clampedValue;
    callback(lower.valueAsNumber, upper.valueAsNumber);
    updateLabels();
  };

  const externalInput = (min, max) => {
    lower.min = min;
    lower.max = max;
    upper.min = min;
    upper.max = max;
    lower.valueAsNumber = min;
    upper.valueAsNumber = max;
    callback(lower.valueAsNumber, upper.valueAsNumber);
    updateLabels();
  };

  return externalInput;
}

Instance.registerCRS(
  "EPSG:3946",
  "+proj=lcc +lat_1=45.25 +lat_2=46.75 +lat_0=46 +lon_0=3 +x_0=1700000 " +
    "+y_0=5200000 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs",
);

const instance = new Instance({
  target: "view",
  crs: "EPSG:3946",
  backgroundColor: null, // To make canvas transparent
});

// Enable point cloud post processing effects
instance.renderingOptions.enableEDL = true;
// But not inpainting and occlusion because it would hinder the opacity filtering
instance.renderingOptions.enableInpainting = false;
instance.renderingOptions.enablePointCloudOcclusion = false;

// Create a custom material for our point cloud.
const material = new PointCloudMaterial({ mode: MODE.INTENSITY });

material.colorMap.min = 0;
material.colorMap.max = 30;
material.colorMap.colors = makeColorRamp("greys");

let parameters = {
  ramp: "greys",
  discrete: false,
  invert: false,
  colors: makeColorRamp("greys", false, false),
  opacity: new Array(256).fill(1),
  min: 0,
  max: 30,
};

const url =
  "https://3d.oslandia.com/giro3d/3d-tiles/lidarhd_intensity/tileset.json";

// Create the 3D tiles entity
const pointcloud = new Tiles3D(new Tiles3DSource(url), {
  material,
});

function placeCamera(position, lookAt) {
  instance.view.camera.position.set(position.x, position.y, position.z);
  instance.view.camera.lookAt(lookAt);
  // create controls
  const controls = new MapControls(instance.view.camera, instance.domElement);
  controls.target.copy(lookAt);
  controls.enableDamping = true;
  controls.dampingFactor = 0.25;

  instance.view.setControls(controls);

  instance.notifyChange(instance.view.camera);
}

const tmpVec3 = new Vector3();

// add pointcloud to scene
function initializeCamera() {
  const bbox = pointcloud.root.boundingVolume.box
    .clone()
    .applyMatrix4(pointcloud.root.matrixWorld);

  instance.view.camera.far = 2.0 * bbox.getSize(tmpVec3).length();

  const lookAt = bbox.getCenter(tmpVec3);
  lookAt.z = bbox.min.z;

  placeCamera(new Vector3(221965, 6873398, 1951), lookAt);
}

instance.add(pointcloud).then(initializeCamera);

Inspector.attach("inspector", instance);

function updatePreview(colors) {
  const canvas = document.getElementById("gradient");
  const ctx = canvas.getContext("2d");

  canvas.width = colors.length;
  canvas.height = 32;

  for (let i = 0; i < colors.length; i++) {
    const color = colors[i];
    ctx.fillStyle = `#${color.getHexString()}`;
    ctx.fillRect(i, 0, 1, canvas.height);
  }
}

updatePreview(parameters.colors);

function updateColorRamp() {
  parameters.colors = makeColorRamp(
    parameters.ramp,
    parameters.discrete,
    parameters.invert,
  );
  material.colorMap.colors = parameters.colors;
  material.colorMap.min = parameters.min;
  material.colorMap.max = parameters.max;
  material.colorMap.mode = parameters.mode;

  updateTransparency();

  updatePreview(parameters.colors);

  instance.notifyChange(pointcloud);
}

const [setDiscrete] = bindToggle("discrete", (v) => {
  parameters.discrete = v;
  updateColorRamp();
});
const [setInvert] = bindToggle("invert", (v) => {
  parameters.invert = v;
  updateColorRamp();
});
const [setRamp] = bindDropDown("ramp", (v) => {
  parameters.ramp = v;
  updateColorRamp();
  instance.notifyChange(pointcloud);
});
const updateBounds = bindColorMapBounds((min, max) => {
  material.colorMap.min = min;
  material.colorMap.max = max;
  instance.notifyChange(pointcloud);
});

const canvas = document.getElementById("curve");

const widget = new FunctionCurveEditor.Widget(canvas);

function updateTransparency() {
  const length = parameters.colors.length;
  const f = widget.getFunction();
  const opacities = new Array(length);
  for (let i = 0; i < length; i++) {
    const t = i / length;
    opacities[i] = f(t);
  }
  parameters.opacity = opacities;
  material.colorMap.opacity = opacities;
}

function setupCurveEditor() {
  // Curve editor
  const initialKnots = [
    { x: 0, y: 1 },
    { x: 1, y: 1 },
  ];

  widget.setEditorState({
    knots: initialKnots,
    xMin: -0.2,
    xMax: 1.2,
    yMin: -0.2,
    yMax: 1.2,
    interpolationMethod: "linear",
    extendedDomain: true,
    relevantXMin: 0,
    relevantXMax: 1,
    gridEnabled: true,
  });

  widget.addEventListener("change", () => {
    updateColorRamp();
  });
}

setupCurveEditor();

function resetToDefaults() {
  setupCurveEditor();

  setRamp("greys");
  setDiscrete(false);
  setInvert(false);
  updateBounds(0, 30);

  parameters = {
    ramp: "greys",
    discrete: false,
    invert: false,
    colors: makeColorRamp("greys", false, false),
    opacity: new Array(256).fill(1),
    min: 0,
    max: 30,
  };

  material.colorMap.active = true;

  updateColorRamp();

  instance.notifyChange(pointcloud);
}

bindButton("reset", resetToDefaults);

const labelElement = document.createElement("div");
labelElement.classList.value = "badge rounded-pill text-bg-light";
labelElement.style.marginTop = "2rem";

const intensityValue = document.createElement("span");
intensityValue.style.marginLeft = "0.5rem";

const intensityColor = document.createElement("span");
intensityColor.classList.value = "badge rounded-pill";
intensityColor.style.color = "white";
intensityColor.style.background = "red";
intensityColor.style.width = "1rem";
intensityColor.innerText = " ";

labelElement.appendChild(intensityColor);
labelElement.appendChild(intensityValue);

const label = new CSS2DObject(labelElement);

instance.add(label);

// Let's query the intensity of the picked point and display it in the label.
function updateLabel(mouseEvent) {
  const results = instance.pickObjectsAt(mouseEvent, { radius: 6 });

  // Reset label visibility
  label.visible = false;

  if (results && results.length > 0) {
    for (const result of results) {
      const { object, point, index } = result;

      if (object.isPointCloud) {
        const intensity = object.getIntensity(index);

        if (intensity) {
          const color = material.colorMap.sample(intensity);
          const opacity = material.colorMap.sampleOpacity(intensity);

          if (opacity > 0.5) {
            const hex = color.getHexString();
            intensityColor.style.background = `#${hex}`;

            intensityValue.innerText = `${intensity.toFixed(2)}`;

            label.visible = true;
            label.position.copy(point);
            label.updateMatrixWorld(true);

            break;
          }
        }
      }
    }
  }

  instance.notifyChange();
}

instance.domElement.addEventListener("mousemove", updateLabel);

// For some reason we have to wait a bit in order to the curve editor to display properly on Firefox.
setTimeout(resetToDefaults, 100);

<!doctype html>
<html lang="en">
  <head>
    <title>Point cloud intensity</title>
    <meta charset="UTF-8" />
    <meta name="name" content="point_cloud_intensity" />
    <meta
      name="description"
      content="Visualize point cloud intensity with a colormap."
    />
    <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/next/examples/css/example.css"
    />

    <style>
      #view canvas {
        background: rgb(132, 170, 182);
        background: radial-gradient(
          circle,
          rgba(132, 170, 182, 1) 0%,
          rgba(37, 44, 48, 1) 100%
        );
      }
    </style>
  </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>

    <div class="side-pane-with-status-bar" style="width: 20rem">
      <!--Parameters -->
      <div class="card">
        <div class="card-header">
          Parameters
          <button
            type="button"
            id="reset"
            class="btn btn-sm btn-primary rounded float-end"
          >
            reset
          </button>
        </div>

        <div class="card-body" id="top-options">
          <!-- Reverse color map -->
          <div class="form-check form-switch mb-1">
            <input
              class="form-check-input"
              type="checkbox"
              role="switch"
              id="invert"
              autocomplete="off"
            />
            <label class="form-check-label" for="invert"
              >Invert color map</label
            >
          </div>

          <!-- Discrete color map -->
          <div class="form-check form-switch mb-3">
            <input
              class="form-check-input"
              type="checkbox"
              role="switch"
              id="discrete"
              autocomplete="off"
            />
            <label class="form-check-label" for="discrete"
              >Discrete color map</label
            >
          </div>

          <!-- Color ramp selector -->
          <div class="input-group mb-3">
            <label class="input-group-text" for="ramp">Colors</label>
            <select class="form-select" id="ramp" autocomplete="off">
              <option value="greys" selected>Greys</option>
              <option value="viridis">Viridis</option>
              <option value="jet">Jet</option>
              <option value="blackbody">Blackbody</option>
              <option value="earth">Earth</option>
              <option value="bathymetry">Bathymetry</option>
              <option value="magma">Magma</option>
              <option value="par">Par</option>
              <option value="rdbu">RdBu</option>
            </select>
          </div>

          <!-- Gradient preview -->
          <div class="mb-3 w-100">
            <canvas
              id="gradient"
              height="32"
              class="w-100 border rounded"
              style="height: 32px; image-rendering: pixelated"
            ></canvas>
          </div>

          <!-- Opacity curve -->
          <div class="mb-3 w-100">
            <label for="curve" class="mb-2">Opacity curve</label>
            <canvas
              id="curve"
              height="128"
              class="w-100"
              style="height: 128px"
            ></canvas>
          </div>

          <!-- Bound sliders -->
          <div class="input-group border rounded p-2">
            <label for="min" id="minLabel" class="form-label"
              >Lower bound</label
            >
            <div class="input-group">
              <input
                type="range"
                min="0"
                max="30"
                value="0"
                class="form-range"
                id="min"
                autocomplete="off"
              />
            </div>

            <label for="max" id="maxLabel" class="form-label"
              >Upper bound</label
            >
            <div class="input-group">
              <input
                type="range"
                min="0"
                max="30"
                value="30"
                class="form-range"
                id="max"
                autocomplete="off"
              />
            </div>
          </div>
        </div>
      </div>
    </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": "point_cloud_intensity",
    "dependencies": {
        "colormap": "^2.3.2",
        "function-curve-editor": "^1.0.16",
        "@giro3d/giro3d": "git+https://gitlab.com/giro3d/giro3d.git"
    },
    "devDependencies": {
        "vite": "^3.2.3"
    },
    "scripts": {
        "start": "vite",
        "build": "vite build"
    }
}