import { createContext, type ReactNode } from "react";

// FrameContext is the runtime channel between Frame and its descendant
// MdxArea instances. Frame creates one of these on each render; MdxArea
// reads it to claim its slot of allocated content.
//
// "Claiming" is order-sensitive: the first <MdxArea chainId="X"> rendered
// inside a Frame takes areaIndex 0 for chain X, the next takes index 1,
// and so on. Empty Frames (no allocation) return null, which renders the
// MdxArea as a measurement placeholder.

export interface ConsumedMdxArea {
  indexInFrame: number;
  // Null when the frame has no allocation (measurement pass) or no blocks
  // for this chain at the claimed index.
  blocks: ReactNode | null;
}

export interface FrameContextValue {
  frameKey: string;
  objectId: string;
  pageId: string;
  consumeArea(chainId: string): ConsumedMdxArea;
}

export const FrameContext = createContext<FrameContextValue | null>(null);