Files
opencode/packages/app/src/utils/aim.ts

139 lines
3.4 KiB
TypeScript

type Point = { x: number; y: number }
export function createAim(props: {
enabled: () => boolean
active: () => string | undefined
el: () => HTMLElement | undefined
onActivate: (id: string) => void
delay?: number
max?: number
tolerance?: number
edge?: number
}) {
const state = {
locs: [] as Point[],
timer: undefined as number | undefined,
pending: undefined as string | undefined,
over: undefined as string | undefined,
last: undefined as Point | undefined,
}
const delay = props.delay ?? 250
const max = props.max ?? 4
const tolerance = props.tolerance ?? 80
const edge = props.edge ?? 18
const cancel = () => {
if (state.timer !== undefined) clearTimeout(state.timer)
state.timer = undefined
state.pending = undefined
}
const reset = () => {
cancel()
state.over = undefined
state.last = undefined
state.locs.length = 0
}
const move = (event: MouseEvent) => {
if (!props.enabled()) return
const el = props.el()
if (!el) return
const rect = el.getBoundingClientRect()
const x = event.clientX
const y = event.clientY
if (x < rect.left || x > rect.right || y < rect.top || y > rect.bottom) return
state.locs.push({ x, y })
if (state.locs.length > max) state.locs.shift()
}
const wait = () => {
if (!props.enabled()) return 0
if (!props.active()) return 0
const el = props.el()
if (!el) return 0
if (state.locs.length < 2) return 0
const rect = el.getBoundingClientRect()
const loc = state.locs[state.locs.length - 1]
if (!loc) return 0
const prev = state.locs[0] ?? loc
if (prev.x < rect.left || prev.x > rect.right || prev.y < rect.top || prev.y > rect.bottom) return 0
if (state.last && loc.x === state.last.x && loc.y === state.last.y) return 0
if (rect.right - loc.x <= edge) {
state.last = loc
return delay
}
const upper = { x: rect.right, y: rect.top - tolerance }
const lower = { x: rect.right, y: rect.bottom + tolerance }
const slope = (a: Point, b: Point) => (b.y - a.y) / (b.x - a.x)
const decreasing = slope(loc, upper)
const increasing = slope(loc, lower)
const prevDecreasing = slope(prev, upper)
const prevIncreasing = slope(prev, lower)
if (decreasing < prevDecreasing && increasing > prevIncreasing) {
state.last = loc
return delay
}
state.last = undefined
return 0
}
const activate = (id: string) => {
cancel()
props.onActivate(id)
}
const request = (id: string) => {
if (!id) return
if (props.active() === id) return
if (!props.active()) {
activate(id)
return
}
const ms = wait()
if (ms === 0) {
activate(id)
return
}
cancel()
state.pending = id
state.timer = window.setTimeout(() => {
state.timer = undefined
if (state.pending !== id) return
state.pending = undefined
if (!props.enabled()) return
if (!props.active()) return
if (state.over !== id) return
props.onActivate(id)
}, ms)
}
const enter = (id: string, event: MouseEvent) => {
if (!props.enabled()) return
state.over = id
move(event)
request(id)
}
const leave = (id: string) => {
if (state.over === id) state.over = undefined
if (state.pending === id) cancel()
}
return { move, enter, leave, activate, request, cancel, reset }
}