Files
portfolio/src/hooks/useActiveSection.ts
T

86 lines
2.6 KiB
TypeScript

import { useState, useEffect, useCallback, useRef } from 'react'
const sectionTileMap: Record<string, string> = {
'patient-summary': 'overview',
'section-experience': 'experience',
'section-skills': 'skills',
}
const SCROLL_BOTTOM_THRESHOLD = 40
/**
* Hook to track which section is currently visible using IntersectionObserver.
* Observes tiles by their data-tile-id attribute inside main scroll content.
* Includes a scroll-position safety net: when scrolled to the very top,
* activates 'overview'; when scrolled to the very bottom, activates the
* last mapped section ('skills').
*
* @returns The currently active section ID
*/
export function useActiveSection(): string {
const [activeSection, setActiveSection] = useState<string>('overview')
const scrollOverrideRef = useRef<string | null>(null)
const updateFromScroll = useCallback((root: HTMLElement) => {
const { scrollTop, scrollHeight, clientHeight } = root
const atBottom = scrollHeight - scrollTop - clientHeight <= SCROLL_BOTTOM_THRESHOLD
const atTop = scrollTop <= SCROLL_BOTTOM_THRESHOLD
if (atTop) {
scrollOverrideRef.current = 'overview'
setActiveSection('overview')
} else if (atBottom) {
scrollOverrideRef.current = 'skills'
setActiveSection('skills')
} else {
scrollOverrideRef.current = null
}
}, [])
useEffect(() => {
const tiles = Array.from(
document.querySelectorAll('[data-tile-id]')
) as HTMLElement[]
const root = document.getElementById('main-content')
if (tiles.length === 0 || !root) return
const observer = new IntersectionObserver(
(entries) => {
if (scrollOverrideRef.current) return
const visibleEntries = entries.filter((entry) => entry.isIntersecting)
if (visibleEntries.length === 0) return
const mostVisible = visibleEntries.reduce((prev, current) =>
current.intersectionRatio > prev.intersectionRatio ? current : prev
)
const tileId = mostVisible.target.getAttribute('data-tile-id')
if (tileId && sectionTileMap[tileId]) {
setActiveSection(sectionTileMap[tileId])
}
},
{
threshold: [0, 0.25, 0.5, 0.75, 1],
root,
rootMargin: '-12% 0px -60% 0px',
}
)
tiles.forEach((tile) => observer.observe(tile))
const handleScroll = () => updateFromScroll(root)
root.addEventListener('scroll', handleScroll, { passive: true })
handleScroll()
return () => {
tiles.forEach((tile) => observer.unobserve(tile))
observer.disconnect()
root.removeEventListener('scroll', handleScroll)
}
}, [updateFromScroll])
return activeSection
}