import * as THREE from "three";

import {
  clearCountryBoundaryHover,
  getShowCountryBoundaries,
  updateCountryBoundaryHover,
} from "./country-boundaries.js";
import { screenToEarthCoords, vector3ToLatLon } from "./utils.js";

const UPDATE_INTERVAL_MS = 120;
const MIN_COORD_DELTA_DEGREES = 0.05;
const BLOCKING_BODY_CLASSES = [
  "earth-mobile-drawer-open",
  "earth-search-open",
  "earth-settings-open",
  "earth-media-open",
  "earth-info-open",
];

const centerRaycaster = new THREE.Raycaster();
const centerMouse = new THREE.Vector2();

let ownsHighlight = false;
let lastUpdateAt = 0;
let lastLat = null;
let lastLon = null;

function isMobileLayout() {
  return document.body.classList.contains("layout-mode-mobile");
}

function hasBlockingForegroundUi() {
  return BLOCKING_BODY_CLASSES.some((className) =>
    document.body.classList.contains(className),
  );
}

function resetCachedCenter() {
  lastUpdateAt = 0;
  lastLat = null;
  lastLon = null;
}

export function clearMobileCenterCountryHighlight() {
  if (ownsHighlight) {
    clearCountryBoundaryHover();
  }
  ownsHighlight = false;
  resetCachedCenter();
}

function clearAnyMobileCountryHighlight() {
  clearCountryBoundaryHover();
  ownsHighlight = false;
  resetCachedCenter();
}

function shouldSkipForSmallMovement(coords) {
  if (lastLat === null || lastLon === null) return false;
  return (
    Math.abs(coords.lat - lastLat) < MIN_COORD_DELTA_DEGREES &&
    Math.abs(coords.lon - lastLon) < MIN_COORD_DELTA_DEGREES
  );
}

export function updateMobileCenterCountryHighlight({
  camera,
  earth,
  renderer,
  now = performance.now(),
  isBlocked = false,
} = {}) {
  const mobile = isMobileLayout();

  if (!mobile) {
    clearMobileCenterCountryHighlight();
    return null;
  }

  if (
    !camera ||
    !earth ||
    !renderer?.domElement ||
    isBlocked ||
    hasBlockingForegroundUi() ||
    !getShowCountryBoundaries()
  ) {
    clearAnyMobileCountryHighlight();
    return null;
  }

  if (now - lastUpdateAt < UPDATE_INTERVAL_MS) {
    return null;
  }

  const rect = renderer.domElement.getBoundingClientRect();
  if (rect.width <= 0 || rect.height <= 0) {
    clearMobileCenterCountryHighlight();
    return null;
  }

  const earthPoint = screenToEarthCoords(
    rect.left + rect.width / 2,
    rect.top + rect.height / 2,
    camera,
    earth,
    renderer.domElement,
    centerRaycaster,
    centerMouse,
  );

  lastUpdateAt = now;

  if (!earthPoint) {
    clearMobileCenterCountryHighlight();
    return null;
  }

  const coords = vector3ToLatLon(earthPoint);
  if (shouldSkipForSmallMovement(coords)) {
    return null;
  }

  lastLat = coords.lat;
  lastLon = coords.lon;
  ownsHighlight = true;
  return updateCountryBoundaryHover(coords);
}