From 41fb0eb7c6c29180664925b30a9f231aa304558d Mon Sep 17 00:00:00 2001
From: Qstick <qstick@gmail.com>
Date: Sat, 6 May 2023 00:36:38 -0500
Subject: [PATCH] Virtualize movie select for manual import with react-window

---
 .../Movie/SelectMovieModalContent.tsx         | 125 ++++++++++++++++--
 1 file changed, 112 insertions(+), 13 deletions(-)

diff --git a/frontend/src/InteractiveImport/Movie/SelectMovieModalContent.tsx b/frontend/src/InteractiveImport/Movie/SelectMovieModalContent.tsx
index 05506fdcb..3208050cf 100644
--- a/frontend/src/InteractiveImport/Movie/SelectMovieModalContent.tsx
+++ b/frontend/src/InteractiveImport/Movie/SelectMovieModalContent.tsx
@@ -1,5 +1,13 @@
-import React, { useCallback, useMemo, useState } from 'react';
+import { throttle } from 'lodash';
+import React, {
+  useCallback,
+  useEffect,
+  useMemo,
+  useRef,
+  useState,
+} from 'react';
 import { useSelector } from 'react-redux';
+import { FixedSizeList as List, ListChildComponentProps } from 'react-window';
 import TextInput from 'Components/Form/TextInput';
 import Button from 'Components/Link/Button';
 import ModalBody from 'Components/Modal/ModalBody';
@@ -10,20 +18,100 @@ import Scroller from 'Components/Scroller/Scroller';
 import { scrollDirections } from 'Helpers/Props';
 import Movie from 'Movie/Movie';
 import createAllMoviesSelector from 'Store/Selectors/createAllMoviesSelector';
+import dimensions from 'Styles/Variables/dimensions';
 import SelectMovieRow from './SelectMovieRow';
 import styles from './SelectMovieModalContent.css';
 
+const bodyPadding = parseInt(dimensions.pageContentBodyPadding);
+
 interface SelectMovieModalContentProps {
   modalTitle: string;
   onMovieSelect(movie: Movie): void;
   onModalClose(): void;
 }
 
+interface RowItemData {
+  items: Movie[];
+  onMovieSelect(movieId: number): void;
+}
+
+const Row: React.FC<ListChildComponentProps<RowItemData>> = ({
+  index,
+  style,
+  data,
+}) => {
+  const { items, onMovieSelect } = data;
+
+  if (index >= items.length) {
+    return null;
+  }
+
+  const movie = items[index];
+
+  return (
+    <div
+      style={{
+        display: 'flex',
+        justifyContent: 'space-between',
+        ...style,
+      }}
+    >
+      <SelectMovieRow
+        id={movie.id}
+        title={movie.title}
+        year={movie.year}
+        onMovieSelect={onMovieSelect}
+      />
+    </div>
+  );
+};
+
 function SelectMovieModalContent(props: SelectMovieModalContentProps) {
   const { modalTitle, onMovieSelect, onModalClose } = props;
 
+  const listRef = useRef<List<RowItemData>>(null);
+  const scrollerRef = useRef<HTMLDivElement>(null);
   const allMovies: Movie[] = useSelector(createAllMoviesSelector());
   const [filter, setFilter] = useState('');
+  const [size, setSize] = useState({ width: 0, height: 0 });
+  const windowHeight = window.innerHeight;
+
+  useEffect(() => {
+    const current = scrollerRef?.current as HTMLElement;
+
+    if (current) {
+      const width = current.clientWidth;
+      const height = current.clientHeight;
+      const padding = bodyPadding - 5;
+
+      setSize({
+        width: width - padding * 2,
+        height: height + padding,
+      });
+    }
+  }, [windowHeight, scrollerRef]);
+
+  useEffect(() => {
+    const currentScrollerRef = scrollerRef.current as HTMLElement;
+    const currentScrollListener = currentScrollerRef;
+
+    const handleScroll = throttle(() => {
+      const { offsetTop = 0 } = currentScrollerRef;
+      const scrollTop = currentScrollerRef.scrollTop - offsetTop;
+
+      listRef.current?.scrollTo(scrollTop);
+    }, 10);
+
+    currentScrollListener.addEventListener('scroll', handleScroll);
+
+    return () => {
+      handleScroll.cancel();
+
+      if (currentScrollListener) {
+        currentScrollListener.removeEventListener('scroll', handleScroll);
+      }
+    };
+  }, [listRef, scrollerRef]);
 
   const onFilterChange = useCallback(
     ({ value }: { value: string }) => {
@@ -68,18 +156,29 @@ function SelectMovieModalContent(props: SelectMovieModalContentProps) {
           onChange={onFilterChange}
         />
 
-        <Scroller className={styles.scroller} autoFocus={false}>
-          {items.map((item) => {
-            return (
-              <SelectMovieRow
-                key={item.id}
-                id={item.id}
-                title={item.title}
-                year={item.year}
-                onMovieSelect={onMovieSelectWrapper}
-              />
-            );
-          })}
+        <Scroller
+          className={styles.scroller}
+          autoFocus={false}
+          ref={scrollerRef}
+        >
+          <List<RowItemData>
+            ref={listRef}
+            style={{
+              width: '100%',
+              height: '100%',
+              overflow: 'none',
+            }}
+            width={size.width}
+            height={size.height}
+            itemCount={items.length}
+            itemSize={38}
+            itemData={{
+              items,
+              onMovieSelect: onMovieSelectWrapper,
+            }}
+          >
+            {Row}
+          </List>
         </Scroller>
       </ModalBody>