discourse/app/assets/javascripts/discourse/components/scrolling-post-stream.js.es6

342 lines
9.4 KiB
JavaScript

import DiscourseURL from "discourse/lib/url";
import MountWidget from "discourse/components/mount-widget";
import { cloak, uncloak } from "discourse/widgets/post-stream";
import { isWorkaroundActive } from "discourse/lib/safari-hacks";
import offsetCalculator from "discourse/lib/offset-calculator";
function findTopView($posts, viewportTop, postsWrapperTop, min, max) {
if (max < min) {
return min;
}
while (max > min) {
const mid = Math.floor((min + max) / 2);
const $post = $($posts[mid]);
const viewBottom = $post.offset().top - postsWrapperTop + $post.height();
if (viewBottom > viewportTop) {
max = mid - 1;
} else {
min = mid + 1;
}
}
return min;
}
export default MountWidget.extend({
widget: "post-stream",
_topVisible: null,
_bottomVisible: null,
_currentPost: null,
_currentVisible: null,
_currentPercent: null,
buildArgs() {
return this.getProperties(
"posts",
"canCreatePost",
"multiSelect",
"gaps",
"selectedQuery",
"selectedPostsCount",
"searchService"
);
},
beforePatch() {
const $body = $(document);
this.prevHeight = $body.height();
this.prevScrollTop = $body.scrollTop();
},
afterPatch() {
const $body = $(document);
const height = $body.height();
const scrollTop = $body.scrollTop();
// This hack is for when swapping out many cloaked views at once
// when using keyboard navigation. It could suddenly move the scroll
if (this.prevHeight === height && scrollTop !== this.prevScrollTop) {
$body.scrollTop(this.prevScrollTop);
}
},
scrolled() {
if (this.isDestroyed || this.isDestroying) {
return;
}
if (isWorkaroundActive()) {
return;
}
// We use this because watching videos fullscreen in Chrome was super buggy
// otherwise. Thanks to arrendek from q23 for the technique.
const topLeftCornerElement = document.elementFromPoint(0, 0);
if (
topLeftCornerElement &&
topLeftCornerElement.tagName.toUpperCase() === "IFRAME"
) {
return;
}
const $w = $(window);
const windowHeight = window.innerHeight ? window.innerHeight : $w.height();
const slack = Math.round(windowHeight * 5);
const onscreen = [];
const nearby = [];
const windowTop = $w.scrollTop();
const postsWrapperTop = $(".posts-wrapper").offset().top;
const $posts = $(
this.element.querySelectorAll(".onscreen-post, .cloaked-post")
);
const viewportTop = windowTop - slack;
const topView = findTopView(
$posts,
viewportTop,
postsWrapperTop,
0,
$posts.length - 1
);
let windowBottom = windowTop + windowHeight;
let viewportBottom = windowBottom + slack;
const bodyHeight = $("body").height();
if (windowBottom > bodyHeight) {
windowBottom = bodyHeight;
}
if (viewportBottom > bodyHeight) {
viewportBottom = bodyHeight;
}
let currentPost = null;
let percent = null;
const offset = offsetCalculator();
const topCheck = Math.ceil(windowTop + offset + 5);
// uncomment to debug the eyeline
/*
let $eyeline = $('.debug-eyeline');
if ($eyeline.length === 0) {
$('body').prepend('<div class="debug-eyeline"></div>');
$eyeline = $('.debug-eyeline');
}
$eyeline.css({ height: '5px', width: '100%', backgroundColor: 'blue', position: 'absolute', top: `${topCheck}px`, zIndex: 999999 });
*/
let allAbove = true;
let bottomView = topView;
let lastBottom = 0;
while (bottomView < $posts.length) {
const post = $posts[bottomView];
const $post = $(post);
if (!$post) {
break;
}
const viewTop = $post.offset().top;
const postHeight = $post.outerHeight(true);
const viewBottom = Math.ceil(viewTop + postHeight);
allAbove = allAbove && viewTop < topCheck;
if (viewTop > viewportBottom) {
break;
}
if (viewBottom >= windowTop && viewTop <= windowBottom) {
onscreen.push(bottomView);
}
if (
currentPost === null &&
((viewTop <= topCheck && viewBottom >= topCheck) ||
(lastBottom <= topCheck && viewTop >= topCheck))
) {
percent = (topCheck - viewTop) / postHeight;
currentPost = bottomView;
}
lastBottom = viewBottom;
nearby.push(bottomView);
bottomView++;
}
if (allAbove) {
if (percent === null) {
percent = 1.0;
}
if (currentPost === null) {
currentPost = bottomView - 1;
}
}
const posts = this.posts;
const refresh = cb => this.queueRerender(cb);
if (onscreen.length) {
const first = posts.objectAt(onscreen[0]);
if (this._topVisible !== first) {
this._topVisible = first;
const $body = $("body");
const elem = $posts[onscreen[0]];
const elemId = elem.id;
const $elem = $(elem);
const elemPos = $elem.position();
const distToElement = elemPos ? $body.scrollTop() - elemPos.top : 0;
const topRefresh = () => {
refresh(() => {
const $refreshedElem = $(`#${elemId}`);
// Quickly going back might mean the element is destroyed
const position = $refreshedElem.position();
if (position && position.top) {
let whereY = position.top + distToElement;
$("html, body").scrollTop(whereY);
// This seems weird, but somewhat infrequently a rerender
// will cause the browser to scroll to the top of the document
// in Chrome. This makes sure the scroll works correctly if that
// happens.
Ember.run.next(() => $("html, body").scrollTop(whereY));
}
});
};
this.topVisibleChanged({
post: first,
refresh: topRefresh
});
}
const last = posts.objectAt(onscreen[onscreen.length - 1]);
if (this._bottomVisible !== last) {
this._bottomVisible = last;
this.bottomVisibleChanged({ post: last, refresh });
}
const changedPost = this._currentPost !== currentPost;
if (changedPost) {
this._currentPost = currentPost;
const post = posts.objectAt(currentPost);
this.currentPostChanged({ post });
}
if (percent !== null) {
percent = Math.max(0.0, Math.min(1.0, percent));
if (changedPost || this._currentPercent !== percent) {
this._currentPercent = percent;
this.currentPostScrolled({ percent });
}
}
} else {
this._topVisible = null;
this._bottomVisible = null;
this._currentPost = null;
this._currentPercent = null;
}
const onscreenPostNumbers = [];
const readPostNumbers = [];
const prev = this._previouslyNearby;
const newPrev = {};
nearby.forEach(idx => {
const post = posts.objectAt(idx);
const postNumber = post.post_number;
delete prev[postNumber];
if (onscreen.indexOf(idx) !== -1) {
onscreenPostNumbers.push(postNumber);
if (post.read) {
readPostNumbers.push(postNumber);
}
}
newPrev[postNumber] = post;
uncloak(post, this);
});
Object.values(prev).forEach(node => cloak(node, this));
this._previouslyNearby = newPrev;
this.screenTrack.setOnscreen(onscreenPostNumbers, readPostNumbers);
},
_scrollTriggered() {
Ember.run.scheduleOnce("afterRender", this, this.scrolled);
},
_posted(staged) {
this.queueRerender(() => {
if (staged) {
const postNumber = staged.get("post_number");
DiscourseURL.jumpToPost(postNumber, { skipIfOnScreen: true });
}
});
},
_refresh(args) {
if (args) {
if (args.id) {
this.dirtyKeys.keyDirty(`post-${args.id}`);
if (args.refreshLikes) {
this.dirtyKeys.keyDirty(`post-menu-${args.id}`, {
onRefresh: "refreshLikes"
});
}
} else if (args.force) {
this.dirtyKeys.forceAll();
}
}
this.queueRerender();
},
_debouncedScroll() {
Ember.run.debounce(this, this._scrollTriggered, 10);
},
didInsertElement() {
this._super(...arguments);
const debouncedScroll = () =>
Ember.run.debounce(this, this._scrollTriggered, 10);
this._previouslyNearby = {};
this.appEvents.on("post-stream:refresh", this, "_debouncedScroll");
$(document).bind("touchmove.post-stream", debouncedScroll);
$(window).bind("scroll.post-stream", debouncedScroll);
this._scrollTriggered();
this.appEvents.on("post-stream:posted", this, "_posted");
$(this.element).on("mouseenter.post-stream", "button.widget-button", e => {
$("button.widget-button").removeClass("d-hover");
$(e.target).addClass("d-hover");
});
$(this.element).on("mouseleave.post-stream", "button.widget-button", () => {
$("button.widget-button").removeClass("d-hover");
});
this.appEvents.on("post-stream:refresh", this, "_refresh");
},
willDestroyElement() {
this._super(...arguments);
$(document).unbind("touchmove.post-stream");
$(window).unbind("scroll.post-stream");
this.appEvents.off("post-stream:refresh", this, "_debouncedScroll");
$(this.element).off("mouseenter.post-stream");
$(this.element).off("mouseleave.post-stream");
this.appEvents.off("post-stream:refresh", this, "_refresh");
this.appEvents.off("post-stream:posted", this, "_posted");
}
});