/** Three/Cesium 视口的输入焦点边界；只接管视口内部的浏览器菜单。 */
export function attachSceneFocus(element) {
    if (!element || typeof element.addEventListener !== 'function') return () => {}

    const tabIndex = element.getAttribute?.('tabindex') ?? null
    if (tabIndex === null) element.setAttribute?.('tabindex', '0')
    const editable = (target) => target?.closest?.('input, textarea, select, [contenteditable]')
    const focus = () => element.focus?.({ preventScroll: true })
    const onDown = (event) => {
        if (event.button !== 0 && event.button !== 2) return
        if (editable(event.target) || event.target?.closest?.('button, a, [role="button"]')) return
        focus()
    }
    const onMenu = (event) => {
        if (editable(event.target)) return
        event.preventDefault()
        event.stopPropagation()
        focus()
    }
    const onFocus = () => element.setAttribute?.('data-scene-focused', 'true')
    const onBlur = (event) => {
        if (!element.contains?.(event.relatedTarget)) element.removeAttribute?.('data-scene-focused')
    }

    // 捕获阶段覆盖 canvas、三维标签和覆盖层，即使后代停止冒泡也不会漏掉右键。
    const capture = { capture: true }
    element.addEventListener('pointerdown', onDown, capture)
    element.addEventListener('contextmenu', onMenu, capture)
    element.addEventListener('focusin', onFocus)
    element.addEventListener('focusout', onBlur)
    return () => {
        element.removeEventListener('pointerdown', onDown, capture)
        element.removeEventListener('contextmenu', onMenu, capture)
        element.removeEventListener('focusin', onFocus)
        element.removeEventListener('focusout', onBlur)
        element.removeAttribute?.('data-scene-focused')
        if (tabIndex === null) element.removeAttribute?.('tabindex')
    }
}