From 139027ac5f843c65aae5ad824d049aae6dae9f79 Mon Sep 17 00:00:00 2001
From: Ansh Nanda <anshnanda10@gmail.com>
Date: Tue, 16 May 2023 17:27:46 -0700
Subject: [PATCH] bad fix to the tab bar animation

---
 src/view/com/pager/FeedsTabBarMobile.tsx |   1 +
 src/view/com/pager/TabBar.tsx            | 154 ++++++++++++-----------
 2 files changed, 82 insertions(+), 73 deletions(-)

diff --git a/src/view/com/pager/FeedsTabBarMobile.tsx b/src/view/com/pager/FeedsTabBarMobile.tsx
index 0952cb14..0fcf19f1 100644
--- a/src/view/com/pager/FeedsTabBarMobile.tsx
+++ b/src/view/com/pager/FeedsTabBarMobile.tsx
@@ -53,6 +53,7 @@ export const FeedsTabBar = observer(
           <UserAvatar avatar={store.me.avatar} size={30} />
         </TouchableOpacity>
         <TabBar
+          key={store.me.savedFeeds.listOfPinnedFeedNames.join(',')}
           {...props}
           items={items}
           indicatorPosition="bottom"
diff --git a/src/view/com/pager/TabBar.tsx b/src/view/com/pager/TabBar.tsx
index 3a7a5583..6ef9d74e 100644
--- a/src/view/com/pager/TabBar.tsx
+++ b/src/view/com/pager/TabBar.tsx
@@ -1,10 +1,9 @@
 import React, {createRef, useState, useMemo, useRef} from 'react'
-import {Animated, StyleSheet, View} from 'react-native'
+import {Animated, StyleSheet, View, ScrollView} from 'react-native'
 import {Text} from '../util/text/Text'
 import {PressableWithHover} from '../util/PressableWithHover'
 import {usePalette} from 'lib/hooks/usePalette'
 import {isDesktopWeb} from 'platform/detection'
-import {ScrollView} from 'react-native-gesture-handler'
 
 interface Layout {
   x: number
@@ -35,59 +34,71 @@ export function TabBar({
   onPressSelected,
 }: TabBarProps) {
   const pal = usePalette('default')
-  // const [itemLayouts, setItemLayouts] = useState<Layout[]>(
-  //   items.map(() => ({x: 0, width: 0})),
-  // )
+  const [itemLayouts, setItemLayouts] = useState<Layout[]>(
+    items.map(() => ({x: 0, width: 0})),
+  )
   const itemRefs = useMemo(
     () => Array.from({length: items.length}).map(() => createRef<View>()),
     [items.length],
   )
-  // const panX = Animated.add(position, offset)
+  const panX = Animated.add(position, offset)
   const containerRef = useRef<View>(null)
+  const [scrollX, setScrollX] = useState(0)
 
-  // const indicatorStyle = {
-  //   backgroundColor: indicatorColor || pal.colors.link,
-  //   bottom:
-  //     indicatorPosition === 'bottom' ? (isDesktopWeb ? 0 : -1) : undefined,
-  //   top: indicatorPosition === 'top' ? (isDesktopWeb ? 0 : -1) : undefined,
-  //   transform: [
-  //     {
-  //       translateX: panX.interpolate({
-  //         inputRange: items.map((_item, i) => i),
-  //         outputRange: itemLayouts.map(l => l.x + l.width / 2),
-  //       }),
-  //     },
-  //     {
-  //       scaleX: panX.interpolate({
-  //         inputRange: items.map((_item, i) => i),
-  //         outputRange: itemLayouts.map(l => l.width),
-  //       }),
-  //     },
-  //   ],
-  // }
+  const indicatorStyle = useMemo(
+    () => ({
+      backgroundColor: indicatorColor || pal.colors.link,
+      bottom:
+        indicatorPosition === 'bottom' ? (isDesktopWeb ? 0 : -1) : undefined,
+      top: indicatorPosition === 'top' ? (isDesktopWeb ? 0 : -1) : undefined,
+      transform: [
+        {
+          translateX: panX.interpolate({
+            inputRange: items.map((_item, i) => i),
+            outputRange: itemLayouts.map(l => l.x + l.width / 2 - scrollX),
+          }),
+        },
+        {
+          scaleX: panX.interpolate({
+            inputRange: items.map((_item, i) => i),
+            outputRange: itemLayouts.map(l => l.width),
+          }),
+        },
+      ],
+    }),
+    [
+      indicatorColor,
+      indicatorPosition,
+      itemLayouts,
+      items,
+      panX,
+      pal.colors.link,
+      scrollX,
+    ],
+  )
 
-  // const onLayout = () => {
-  //   const promises = []
-  //   for (let i = 0; i < items.length; i++) {
-  //     promises.push(
-  //       new Promise<Layout>(resolve => {
-  //         if (!containerRef.current || !itemRefs[i].current) {
-  //           return resolve({x: 0, width: 0})
-  //         }
+  const onLayout = () => {
+    const promises = []
+    for (let i = 0; i < items.length; i++) {
+      promises.push(
+        new Promise<Layout>(resolve => {
+          if (!containerRef.current || !itemRefs[i].current) {
+            return resolve({x: 0, width: 0})
+          }
 
-  //         itemRefs[i].current?.measureLayout(
-  //           containerRef.current,
-  //           (x: number, _y: number, width: number) => {
-  //             resolve({x, width})
-  //           },
-  //         )
-  //       }),
-  //     )
-  //   }
-  //   Promise.all(promises).then((layouts: Layout[]) => {
-  //     setItemLayouts(layouts)
-  //   })
-  // }
+          itemRefs[i].current?.measureLayout(
+            containerRef.current,
+            (x: number, _y: number, width: number) => {
+              resolve({x, width})
+            },
+          )
+        }),
+      )
+    }
+    Promise.all(promises).then((layouts: Layout[]) => {
+      setItemLayouts(layouts)
+    })
+  }
 
   const onPressItem = (index: number) => {
     onSelect?.(index)
@@ -100,31 +111,33 @@ export function TabBar({
     <View
       testID={testID}
       style={[pal.view, styles.outer]}
-      // onLayout={onLayout}
+      onLayout={onLayout}
       ref={containerRef}>
-      <Animated.View style={[styles.indicator]} />
-      <ScrollView horizontal={true} showsHorizontalScrollIndicator={false}>
+      <Animated.View style={[styles.indicator, indicatorStyle]} />
+      <ScrollView
+        horizontal={true}
+        showsHorizontalScrollIndicator={false}
+        onScroll={({nativeEvent}) => {
+          setScrollX(nativeEvent.contentOffset.x)
+        }}>
         {items.map((item, i) => {
           const selected = i === selectedPage
           return (
-            <Animated.View key={item} style={selected ? styles.active : []}>
-              <PressableWithHover
-                ref={itemRefs[i]}
-                style={[
-                  indicatorPosition === 'top'
-                    ? styles.itemTop
-                    : styles.itemBottom,
-                ]}
-                hoverStyle={pal.viewLight}
-                onPress={() => onPressItem(i)}>
-                <Text
-                  type="xl-bold"
-                  testID={testID ? `${testID}-${item}` : undefined}
-                  style={selected ? pal.text : pal.textLight}>
-                  {item}
-                </Text>
-              </PressableWithHover>
-            </Animated.View>
+            <PressableWithHover
+              ref={itemRefs[i]}
+              key={item}
+              style={
+                indicatorPosition === 'top' ? styles.itemTop : styles.itemBottom
+              }
+              hoverStyle={pal.viewLight}
+              onPress={() => onPressItem(i)}>
+              <Text
+                type="xl-bold"
+                testID={testID ? `${testID}-${item}` : undefined}
+                style={selected ? pal.text : pal.textLight}>
+                {item}
+              </Text>
+            </PressableWithHover>
           )
         })}
       </ScrollView>
@@ -155,7 +168,6 @@ const styles = isDesktopWeb
         height: 3,
         zIndex: 1,
       },
-      active: {},
     })
   : StyleSheet.create({
       outer: {
@@ -178,8 +190,4 @@ const styles = isDesktopWeb
         width: 1,
         height: 3,
       },
-      active: {
-        borderBottomColor: 'blue',
-        borderBottomWidth: 3,
-      },
     })