import type { IControl, Map } from "maplibre-gl";

import type { Level, MapGLWithIndoor } from "./Types";

import IndoorLayer from "./IndoorLayer";
import IndoorMap from "./IndoorMap";

/**
 * Creates a indoor control with floors buttons

 * @implements {IControl}
 */
class IndoorControl implements IControl {
  _container?: HTMLElement;
  _indoor?: IndoorLayer;
  _indoorMap: IndoorMap | null;

  _levelsButtons: Array<HTMLElement>;
  _map?: MapGLWithIndoor;
  _selectedButton: HTMLElement | null;

  constructor() {
    this._levelsButtons = [];
    this._selectedButton = null;
    this._indoorMap = null;
  }

  _createLevelButton(container: HTMLElement, level: Level) {
    const a = document.createElement("button");
    a.innerHTML = level.toString();
    a.classList.add("maplibregl-ctrl-icon");
    container.appendChild(a);
    a.addEventListener("click", () => {
      this._map?.fire("indoor.control.clicked", { level });
      if (this._indoor!.getLevel() === level) return;
      this._indoor!.setLevel(level);
    });
    return a;
  }

  _onContextMenu(e: Event) {
    e.preventDefault();
  }

  _onLevelChanged = ({ level }: { level: Level | null }): void =>
    this._setSelected(level);

  _onMapLoaded = ({ indoorMap }: { indoorMap: IndoorMap }): void => {
    this._indoorMap = indoorMap;
    this._updateNavigationBar();
    this._setSelected(this._indoor!.getLevel());
  };

  _onMapUnLoaded = (): void => {
    this._indoorMap = null;
    this._updateNavigationBar();
  };

  _setSelected(level: Level | null) {
    if (this._levelsButtons.length === 0) {
      return;
    }

    if (this._selectedButton) {
      this._selectedButton.style.fontWeight = "normal";
    }
    if (level !== null && this._levelsButtons[level]) {
      this._levelsButtons[level].style.fontWeight = "bold";
      this._selectedButton = this._levelsButtons[level];
    }
  }

  _updateNavigationBar() {
    if (!this._container) {
      return;
    }

    if (this._indoorMap === null) {
      this._container.style.display = "none";
      return;
    }

    this._container.style.display = "block";

    this._levelsButtons = [];
    while (this._container.firstChild) {
      this._container.removeChild(this._container.firstChild);
    }

    const range = this._indoorMap.levelsRange;
    for (let i = range.max; i >= range.min; i--) {
      this._levelsButtons[i] = this._createLevelButton(this._container, i);
    }
  }

  onAdd(map: Map | MapGLWithIndoor) {
    if ((map as MapGLWithIndoor).indoor === undefined) {
      throw Error("call addIndoorTo(map) before creating the IndoorControl");
    }

    this._map = map as MapGLWithIndoor;
    this._indoor = this._map.indoor;

    // Create container
    const container = (this._container = document.createElement("div"));
    container.classList.add("maplibregl-ctrl");
    container.classList.add("maplibregl-ctrl-group");
    container.style.display = "none";
    container.addEventListener("contextmenu", this._onContextMenu);

    // If indoor layer is already loaded, update levels
    this._indoorMap = this._indoor.getSelectedMap();
    if (this._indoor.getSelectedMap() !== null) {
      this._updateNavigationBar();
      this._setSelected(this._indoor.getLevel());
    }

    // Register to indoor events
    this._map.on("indoor.map.loaded", this._onMapLoaded);
    this._map.on("indoor.map.unloaded", this._onMapUnLoaded);
    this._map.on("indoor.level.changed", this._onLevelChanged);

    return container;
  }

  onRemove() {
    this._container?.removeEventListener("contextmenu", this._onContextMenu);
    this._container?.remove();
    delete this._container;

    this._map?.off("indoor.map.loaded", this._onMapLoaded);
    this._map?.off("indoor.map.unloaded", this._onMapUnLoaded);
    this._map?.off("indoor.level.changed", this._onLevelChanged);
    delete this._map;
  }
}

export default IndoorControl;