discourse/plugins/lazy-yt/assets/javascripts/lib/lazyYT.js

/*!
 * lazyYT (lazy load YouTube videos)
 * v1.0.1 - 2014-12-30
 * (CC) This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
 * http://creativecommons.org/licenses/by-sa/4.0/
 * Contributors: https://github.com/tylerpearson/lazyYT/graphs/contributors || https://github.com/daugilas/lazyYT/graphs/contributors
 *
 * Usage: <div class="lazyYT" data-youtube-id="laknj093n" data-parameters="rel=0">loading...</div>
 *
 * Note: Discourse has forked this from the original, beware when updating the file.
 *
 */

import escape from "discourse-common/lib/escape";

export default function initLazyYt($) {
  "use strict";

  function setUp($el, settings) {
    let width = $el.data("width"),
      height = $el.data("height"),
      ratio = $el.data("ratio") ? $el.data("ratio") : settings.default_ratio,
      id = $el.data("youtube-id"),
      title = $el.data("youtube-title"),
      padding_bottom,
      innerHtml = [],
      $thumb,
      thumb_img,
      youtube_parameters = $el.data("parameters") || "";

    ratio = ratio.split(":");

    // width and height might override default_ratio value
    if (typeof width === "number" && typeof height === "number") {
      $el.width(width);
      padding_bottom = height + "px";
    } else if (typeof width === "number") {
      $el.width(width);
      padding_bottom = (width * ratio[1]) / ratio[0] + "px";
    } else {
      width = $el.width();

      // no width means that container is fluid and will be the size of its parent
      if (width === 0) {
        width = $el.parent().width();
      }

      padding_bottom = (ratio[1] / ratio[0]) * 100 + "%";
    }

    //
    // This HTML will be placed inside 'lazyYT' container

    innerHtml.push('<div class="ytp-thumbnail">');

    // Play button from YouTube (exactly as it is in YouTube)
    innerHtml.push('<div class="ytp-large-play-button"');
    if (width <= 640) {
      innerHtml.push(' style="transform: scale(0.563888888888889);"');
    }
    innerHtml.push(">");
    innerHtml.push("<svg>");
    innerHtml.push(
      '<path fill-rule="evenodd" clip-rule="evenodd" fill="#1F1F1F" class="ytp-large-play-button-svg" d="M84.15,26.4v6.35c0,2.833-0.15,5.967-0.45,9.4c-0.133,1.7-0.267,3.117-0.4,4.25l-0.15,0.95c-0.167,0.767-0.367,1.517-0.6,2.25c-0.667,2.367-1.533,4.083-2.6,5.15c-1.367,1.4-2.967,2.383-4.8,2.95c-0.633,0.2-1.316,0.333-2.05,0.4c-0.767,0.1-1.3,0.167-1.6,0.2c-4.9,0.367-11.283,0.617-19.15,0.75c-2.434,0.034-4.883,0.067-7.35,0.1h-2.95C38.417,59.117,34.5,59.067,30.3,59c-8.433-0.167-14.05-0.383-16.85-0.65c-0.067-0.033-0.667-0.117-1.8-0.25c-0.9-0.133-1.683-0.283-2.35-0.45c-2.066-0.533-3.783-1.5-5.15-2.9c-1.033-1.067-1.9-2.783-2.6-5.15C1.317,48.867,1.133,48.117,1,47.35L0.8,46.4c-0.133-1.133-0.267-2.55-0.4-4.25C0.133,38.717,0,35.583,0,32.75V26.4c0-2.833,0.133-5.95,0.4-9.35l0.4-4.25c0.167-0.966,0.417-2.05,0.75-3.25c0.7-2.333,1.567-4.033,2.6-5.1c1.367-1.434,2.967-2.434,4.8-3c0.633-0.167,1.333-0.3,2.1-0.4c0.4-0.066,0.917-0.133,1.55-0.2c4.9-0.333,11.283-0.567,19.15-0.7C35.65,0.05,39.083,0,42.05,0L45,0.05c2.467,0,4.933,0.034,7.4,0.1c7.833,0.133,14.2,0.367,19.1,0.7c0.3,0.033,0.833,0.1,1.6,0.2c0.733,0.1,1.417,0.233,2.05,0.4c1.833,0.566,3.434,1.566,4.8,3c1.066,1.066,1.933,2.767,2.6,5.1c0.367,1.2,0.617,2.284,0.75,3.25l0.4,4.25C84,20.45,84.15,23.567,84.15,26.4z M33.3,41.4L56,29.6L33.3,17.75V41.4z"></path>'
    );
    innerHtml.push(
      '<polygon fill-rule="evenodd" clip-rule="evenodd" fill="#FFFFFF" points="33.3,41.4 33.3,17.75 56,29.6"></polygon>'
    );
    innerHtml.push("</svg>");
    innerHtml.push("</div>"); // end of .ytp-large-play-button

    innerHtml.push("</div>"); // end of .ytp-thumbnail

    // Video title (info bar)
    innerHtml.push('<div class="html5-info-bar">');
    innerHtml.push('<div class="html5-title">');
    innerHtml.push('<div class="html5-title-text-wrapper">');
    innerHtml.push(
      '<a class="html5-title-text" target="_blank" tabindex="3100" href="https://www.youtube.com/watch?v=',
      escape(id),
      '">'
    );
    if (title === undefined || title === null || title === "") {
      innerHtml.push("youtube.com/watch?v=" + escape(id));
    } else {
      innerHtml.push(escape(title));
    }
    innerHtml.push("</a>");
    innerHtml.push("</div>"); // .html5-title
    innerHtml.push("</div>"); // .html5-title-text-wrapper
    innerHtml.push("</div>"); // end of Video title .html5-info-bar

    let prefetchedThumbnail = $el[0].querySelector(".ytp-thumbnail-image");

    $el
      .css({
        "padding-bottom": padding_bottom,
      })
      .html(innerHtml.join(""));

    if (width > 640) {
      thumb_img = "maxresdefault.jpg";
    } else if (width > 480) {
      thumb_img = "sddefault.jpg";
    } else if (width > 320) {
      thumb_img = "hqdefault.jpg";
    } else if (width > 120) {
      thumb_img = "mqdefault.jpg";
    } else if (width === 0) {
      // sometimes it fails on fluid layout
      thumb_img = "hqdefault.jpg";
    } else {
      thumb_img = "default.jpg";
    }

    if (prefetchedThumbnail) {
      $el.find(".ytp-thumbnail").append(prefetchedThumbnail);
    } else {
      // Fallback for old posts which were baked before the lazy-yt onebox prefetched a thumbnail
      $el
        .find(".ytp-thumbnail")
        .append(
          $(
            [
              '<img class="ytp-thumbnail-image" src="https://img.youtube.com/vi/',
              escape(id),
              "/",
              thumb_img,
              '">',
            ].join("")
          )
        );
    }

    $thumb = $el
      .find(".ytp-thumbnail")
      .addClass("lazyYT-image-loaded")
      .on("click", function (e) {
        e.preventDefault();

        if (
          !$el.hasClass("lazyYT-video-loaded") &&
          $thumb.hasClass("lazyYT-image-loaded")
        ) {
          $el
            .html(
              '<iframe src="//www.youtube.com/embed/' +
                escape(id) +
                "?autoplay=1&" +
                youtube_parameters +
                '" frameborder="0" allowfullscreen></iframe>'
            )
            .addClass("lazyYT-video-loaded");
        }

        if (settings.onPlay) {
          settings.onPlay(e, $el);
        }
      });
  }

  $.fn.lazyYT = function (newSettings) {
    let defaultSettings = {
      default_ratio: "16:9",
      callback: null, // TODO: execute callback if given
      container_class: "lazyYT-container",
    };
    let settings = Object.assign(defaultSettings, newSettings);

    return this.each(function () {
      let $el = $(this).addClass(settings.container_class);
      setUp($el, settings);
    });
  };
}