import { createContext } from 'react'
import type { DOMElement } from '../dom.js'

export type CursorDeclaration = {
  /** Display column (terminal cell width) within the declared node */
  readonly relativeX: number
  /** Line number within the declared node */
  readonly relativeY: number
  /** The ink-box DOMElement whose yoga layout provides the absolute origin */
  readonly node: DOMElement
}

/**
 * Setter for the declared cursor position.
 *
 * The optional second argument makes `null` a conditional clear: the
 * declaration is only cleared if the currently-declared node matches
 * `clearIfNode`. This makes the hook safe for sibling components
 * (e.g. list items) that transfer focus among themselves — without the
 * node check, a newly-unfocused item's clear could clobber a
 * newly-focused sibling's set depending on layout-effect order.
 */
export type CursorDeclarationSetter = (
  declaration: CursorDeclaration | null,
  clearIfNode?: DOMElement | null,
) => void

const CursorDeclarationContext = createContext<CursorDeclarationSetter>(
  () => {},
)

export default CursorDeclarationContext