From 8cf0a6ecb27f63477babe20d129848bd76708ad4 Mon Sep 17 00:00:00 2001
From: Jackson Harper <jacksonh@gmail.com>
Date: Fri, 10 Mar 2023 16:47:02 +0800
Subject: [PATCH] Simplify top positioning

---
 .../components/templates/article/Article.tsx  |  4 +
 .../templates/article/ArticleContainer.tsx    |  1 +
 .../lib/hooks/useReadingProgressAnchor.tsx    | 85 ++-----------------
 .../networking/fragments/articleFragment.ts   |  2 +
 .../web/lib/networking/queries/search.tsx     |  7 +-
 .../networking/queries/useGetArticleQuery.tsx |  1 +
 .../queries/useGetLibraryItemsQuery.tsx       |  1 +
 7 files changed, 20 insertions(+), 81 deletions(-)

diff --git a/packages/web/components/templates/article/Article.tsx b/packages/web/components/templates/article/Article.tsx
index e54402b18..5e672dc39 100644
--- a/packages/web/components/templates/article/Article.tsx
+++ b/packages/web/components/templates/article/Article.tsx
@@ -1,6 +1,7 @@
 import { Box } from '../../elements/LayoutPrimitives'
 import {
   getTopOmnivoreAnchorElement,
+  parseDomTree,
   useReadingProgressAnchor,
 } from '../../../lib/hooks/useReadingProgressAnchor'
 import {
@@ -18,6 +19,7 @@ export type ArticleProps = {
   content: string
   initialAnchorIndex: number
   initialReadingProgress?: number
+  initialReadingProgressTop?: number
   highlightHref: MutableRefObject<string | null>
   articleMutations: ArticleMutations
 }
@@ -93,6 +95,8 @@ export function Article(props: ArticleProps): JSX.Element {
 
     setShouldScrollToInitialPosition(false)
 
+    parseDomTree(articleContentRef.current)
+
     // If we are scrolling to a highlight, dont scroll to read position
     if (props.highlightHref.current) {
       return
diff --git a/packages/web/components/templates/article/ArticleContainer.tsx b/packages/web/components/templates/article/ArticleContainer.tsx
index ee10a0f34..d4e425542 100644
--- a/packages/web/components/templates/article/ArticleContainer.tsx
+++ b/packages/web/components/templates/article/ArticleContainer.tsx
@@ -366,6 +366,7 @@ export function ArticleContainer(props: ArticleContainerProps): JSX.Element {
           content={props.article.content}
           highlightHref={highlightHref}
           initialAnchorIndex={props.article.readingProgressAnchorIndex}
+          initialReadingProgressTop={props.article.readingProgressTopPercent}
           articleMutations={props.articleMutations}
         />
         <Button
diff --git a/packages/web/lib/hooks/useReadingProgressAnchor.tsx b/packages/web/lib/hooks/useReadingProgressAnchor.tsx
index 3165f5cb3..4950f3470 100644
--- a/packages/web/lib/hooks/useReadingProgressAnchor.tsx
+++ b/packages/web/lib/hooks/useReadingProgressAnchor.tsx
@@ -13,7 +13,7 @@ export const getTopOmnivoreAnchorElement = (
 ): string | undefined => {
   let lastVisibleAnchor: Element | undefined = undefined
   const anchors = Array.from(
-    articleContentElement.querySelectorAll(`[data-omnivore-anchor-idx]`)
+    document.querySelectorAll(`[data-omnivore-anchor-idx]`)
   ).reverse()
 
   for (const anchor of anchors) {
@@ -35,87 +35,16 @@ export const getTopOmnivoreAnchorElement = (
 }
 
 export const useReadingProgressAnchor = (
-  articleContentRef: React.MutableRefObject<HTMLDivElement | null>,
-  setReadingAnchorIndex: React.Dispatch<React.SetStateAction<number>>
+  articleContentRef: React.MutableRefObject<HTMLDivElement | null>
 ): void => {
   useEffect(() => {
-    const visitedNodeList = parseDomTree(articleContentRef.current)
-    const observerOptions = {
-      root: null,
-      rootMargin: '0px',
-      // we only track elements on becoming completely visible.
-      threshold: [1],
-    }
-
-    function intersectionCallback(entries: IntersectionObserverEntry[]): void {
-      let topIntersectingElemId = 0
-      let minTopElem = 100000
-      entries.forEach(function (entry: IntersectionObserverEntry) {
-        const elem = entry.target
-        const elemId = elem.getAttribute('data-omnivore-anchor-idx') || '0'
-
-        if (entry.isIntersecting && entry.intersectionRatio === 1) {
-          // Among all intersecting elements, find the topmost element.
-          if (entry.boundingClientRect.top < minTopElem) {
-            minTopElem = entry.boundingClientRect.top
-            topIntersectingElemId = parseInt(elemId)
-          }
-        }
-      })
-
-      if (topIntersectingElemId > 0) {
-        /*
-         * Intersection observer is great in finding us the last element on the
-         * page that becomes visible on scroll. But for better user experience
-         * we are interested in the topmost element visible on the page that we
-         * can scroll to at the top on the next article page reader view. We
-         * iterate in reverse over anchor elements here us to find the topmost
-         * visible element.
-         */
-        let topVisibleElemId = topIntersectingElemId
-        while (topVisibleElemId - 1 > 0) {
-          const elem = document.querySelector(
-            `[data-omnivore-anchor-idx='${(topVisibleElemId - 1).toString()}']`
-          )
-          if (elem) {
-            const rect = elem.getBoundingClientRect()
-            if (
-              rect.top >= 0 &&
-              rect.left >= 0 &&
-              rect.bottom <=
-                (window.innerHeight || document.documentElement.clientHeight) &&
-              rect.right <=
-                (window.innerWidth || document.documentElement.clientWidth)
-            ) {
-              /* Is Visible */
-              topVisibleElemId = topVisibleElemId - 1
-            } else {
-              break
-            }
-          } else {
-            // Prevents the Event loop from the eternal blocking
-            throw new Error('Unable to find previous intersection element!')
-          }
-        }
-        setReadingAnchorIndex(topVisibleElemId)
-      }
-    }
-
-    const nodeObserver = new IntersectionObserver(
-      intersectionCallback,
-      observerOptions
-    )
-    visitedNodeList?.forEach((elem) => {
-      nodeObserver.observe(elem)
-    })
-
-    return () => {
-      nodeObserver.disconnect()
-    }
-  }, [articleContentRef, setReadingAnchorIndex])
+    parseDomTree(articleContentRef.current)
+  }, [articleContentRef])
 }
 
-function parseDomTree(pageNode: HTMLDivElement | null): HTMLDivElement[] {
+export function parseDomTree(
+  pageNode: HTMLDivElement | null
+): HTMLDivElement[] {
   if (!pageNode || pageNode.childNodes.length == 0) {
     return []
   }
diff --git a/packages/web/lib/networking/fragments/articleFragment.ts b/packages/web/lib/networking/fragments/articleFragment.ts
index a8cc4636a..3511cfbaf 100644
--- a/packages/web/lib/networking/fragments/articleFragment.ts
+++ b/packages/web/lib/networking/fragments/articleFragment.ts
@@ -13,6 +13,7 @@ export const articleFragment = gql`
     contentReader
     originalArticleUrl
     readingProgressPercent
+    readingProgressTopPercent
     readingProgressAnchorIndex
     slug
     isArchived
@@ -52,6 +53,7 @@ export type ArticleFragmentData = {
   contentReader?: ContentReader
   originalArticleUrl: string
   readingProgressPercent: number
+  readingProgressTopPercent?: number
   readingProgressAnchorIndex: number
   slug: string
   isArchived: boolean
diff --git a/packages/web/lib/networking/queries/search.tsx b/packages/web/lib/networking/queries/search.tsx
index 7d3a780e3..fa6ec85d5 100644
--- a/packages/web/lib/networking/queries/search.tsx
+++ b/packages/web/lib/networking/queries/search.tsx
@@ -11,7 +11,7 @@ export async function searchQuery({
   limit = 10,
   searchQuery,
 }: LibraryItemsQueryInput): Promise<LibraryItemsData | undefined> {
-    const query = gql`
+  const query = gql`
     query Search($after: String, $first: Int, $query: String) {
       search(first: $first, after: $after, query: $query) {
         ... on SearchSuccess {
@@ -27,6 +27,7 @@ export async function searchQuery({
               createdAt
               isArchived
               readingProgressPercent
+              readingProgressTopPercent
               readingProgressAnchorIndex
               author
               image
@@ -71,8 +72,8 @@ export async function searchQuery({
   }
 
   try {
-    const data = (await gqlFetcher(query, {...variables}))
-    return data as LibraryItemsData || undefined;
+    const data = await gqlFetcher(query, { ...variables })
+    return (data as LibraryItemsData) || undefined
   } catch (error) {
     console.log('search error', error)
     return undefined
diff --git a/packages/web/lib/networking/queries/useGetArticleQuery.tsx b/packages/web/lib/networking/queries/useGetArticleQuery.tsx
index 6f76b05c6..df8bc08cc 100644
--- a/packages/web/lib/networking/queries/useGetArticleQuery.tsx
+++ b/packages/web/lib/networking/queries/useGetArticleQuery.tsx
@@ -50,6 +50,7 @@ export type ArticleAttributes = {
   description?: string
   contentReader: ContentReader
   readingProgressPercent: number
+  readingProgressTopPercent?: number
   readingProgressAnchorIndex: number
   slug: string
   savedByViewer?: boolean
diff --git a/packages/web/lib/networking/queries/useGetLibraryItemsQuery.tsx b/packages/web/lib/networking/queries/useGetLibraryItemsQuery.tsx
index 0d4d7d686..99294f701 100644
--- a/packages/web/lib/networking/queries/useGetLibraryItemsQuery.tsx
+++ b/packages/web/lib/networking/queries/useGetLibraryItemsQuery.tsx
@@ -67,6 +67,7 @@ export type LibraryItemNode = {
   contentReader?: ContentReader
   originalArticleUrl: string
   readingProgressPercent: number
+  readingProgressTopPercent?: number
   readingProgressAnchorIndex: number
   slug: string
   isArchived: boolean