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import React, {createRef, useState, useMemo, useRef} from 'react'
import {Animated, Pressable, StyleSheet, View} from 'react-native'
import {Text} from './text/Text'
import {usePalette} from 'lib/hooks/usePalette'
interface Layout {
x: number
width: number
}
export function Selector({
selectedIndex,
items,
panX,
onSelect,
}: {
selectedIndex: number
items: string[]
panX: Animated.Value
onSelect?: (index: number) => void
}) {
const containerRef = useRef<View>(null)
const pal = usePalette('default')
const [itemLayouts, setItemLayouts] = useState<undefined | Layout[]>(
undefined,
)
const itemRefs = useMemo(
() => Array.from({length: items.length}).map(() => createRef<View>()),
[items.length],
)
const currentLayouts = useMemo(() => {
const left = itemLayouts?.[selectedIndex - 1] || {x: 0, width: 0}
const middle = itemLayouts?.[selectedIndex] || {x: 0, width: 0}
const right = itemLayouts?.[selectedIndex + 1] || {
x: middle.x + 20,
width: middle.width,
}
return [left, middle, right]
}, [selectedIndex, itemLayouts])
const underlineStyle = {
backgroundColor: pal.colors.text,
left: panX.interpolate({
inputRange: [-1, 0, 1],
outputRange: [
currentLayouts[0].x,
currentLayouts[1].x,
currentLayouts[2].x,
],
}),
width: panX.interpolate({
inputRange: [-1, 0, 1],
outputRange: [
currentLayouts[0].width,
currentLayouts[1].width,
currentLayouts[2].width,
],
}),
}
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)
})
}
const onPressItem = (index: number) => {
onSelect?.(index)
}
return (
<View
style={[pal.view, styles.outer]}
onLayout={onLayout}
ref={containerRef}>
<Animated.View style={[styles.underline, underlineStyle]} />
{items.map((item, i) => {
const selected = i === selectedIndex
return (
<Pressable key={item} onPress={() => onPressItem(i)}>
<View style={styles.item} ref={itemRefs[i]}>
<Text
style={
selected
? [styles.labelSelected, pal.text]
: [styles.label, pal.textLight]
}>
{item}
</Text>
</View>
</Pressable>
)
})}
</View>
)
}
const styles = StyleSheet.create({
outer: {
flexDirection: 'row',
paddingTop: 8,
paddingBottom: 12,
paddingHorizontal: 14,
},
item: {
marginRight: 14,
paddingHorizontal: 10,
},
label: {
fontWeight: '600',
},
labelSelected: {
fontWeight: '600',
},
underline: {
position: 'absolute',
height: 4,
bottom: 0,
},
})
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