/*!
 * (C) Ionic http://ionicframework.com - MIT License
 */
import { proxyCustomElement, HTMLElement, createEvent, h, Host } from '@stencil/core/internal/client';
import { b as getIonMode } from './ionic-global.js';
import { d as inheritAttributes } from './helpers.js';

const imgCss = ":host{display:block;-o-object-fit:contain;object-fit:contain}img{display:block;width:100%;height:100%;-o-object-fit:inherit;object-fit:inherit;-o-object-position:inherit;object-position:inherit}";

const Img = /*@__PURE__*/ proxyCustomElement(class extends HTMLElement {
  constructor() {
    super();
    this.__registerHost();
    this.__attachShadow();
    this.ionImgWillLoad = createEvent(this, "ionImgWillLoad", 7);
    this.ionImgDidLoad = createEvent(this, "ionImgDidLoad", 7);
    this.ionError = createEvent(this, "ionError", 7);
    this.inheritedAttributes = {};
    this.onLoad = () => {
      this.ionImgDidLoad.emit();
    };
    this.onError = () => {
      this.ionError.emit();
    };
  }
  srcChanged() {
    this.addIO();
  }
  componentWillLoad() {
    this.inheritedAttributes = inheritAttributes(this.el, ['draggable']);
  }
  componentDidLoad() {
    this.addIO();
  }
  addIO() {
    if (this.src === undefined) {
      return;
    }
    if (typeof window !== 'undefined' &&
      'IntersectionObserver' in window &&
      'IntersectionObserverEntry' in window &&
      'isIntersecting' in window.IntersectionObserverEntry.prototype) {
      this.removeIO();
      this.io = new IntersectionObserver((data) => {
        /**
         * On slower devices, it is possible for an intersection observer entry to contain multiple
         * objects in the array. This happens when quickly scrolling an image into view and then out of
         * view. In this case, the last object represents the current state of the component.
         */
        if (data[data.length - 1].isIntersecting) {
          this.load();
          this.removeIO();
        }
      });
      this.io.observe(this.el);
    }
    else {
      // fall back to setTimeout for Safari and IE
      setTimeout(() => this.load(), 200);
    }
  }
  load() {
    this.loadError = this.onError;
    this.loadSrc = this.src;
    this.ionImgWillLoad.emit();
  }
  removeIO() {
    if (this.io) {
      this.io.disconnect();
      this.io = undefined;
    }
  }
  render() {
    const { loadSrc, alt, onLoad, loadError, inheritedAttributes } = this;
    const { draggable } = inheritedAttributes;
    return (h(Host, { class: getIonMode(this) }, h("img", { decoding: "async", src: loadSrc, alt: alt, onLoad: onLoad, onError: loadError, part: "image", draggable: isDraggable(draggable) })));
  }
  get el() { return this; }
  static get watchers() { return {
    "src": ["srcChanged"]
  }; }
  static get style() { return imgCss; }
}, [1, "ion-img", {
    "alt": [1],
    "src": [1],
    "loadSrc": [32],
    "loadError": [32]
  }]);
/**
 * Enumerated strings must be set as booleans
 * as Stencil will not render 'false' in the DOM.
 * The need to explicitly render draggable="true"
 * as only certain elements are draggable by default.
 * https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/draggable.
 */
const isDraggable = (draggable) => {
  switch (draggable) {
    case 'true':
      return true;
    case 'false':
      return false;
    default:
      return undefined;
  }
};
function defineCustomElement$1() {
  if (typeof customElements === "undefined") {
    return;
  }
  const components = ["ion-img"];
  components.forEach(tagName => { switch (tagName) {
    case "ion-img":
      if (!customElements.get(tagName)) {
        customElements.define(tagName, Img);
      }
      break;
  } });
}

const IonImg = Img;
const defineCustomElement = defineCustomElement$1;

export { IonImg, defineCustomElement };