import { createContext, useContext } from "react";
import type { Page } from "../../lib/urlState";
import type { ChannelView } from "./navigationInit";

// The navigation contexts + their hooks, split out of NavigationProvider so that file exports only
// components (Fast Refresh can then hot-swap the provider without remounting the tree).
//
// TWO contexts on purpose: a STABLE actions context (setPage/openChannel/… never change reference)
// and a CHANGING state context (page/channelView/ytSearch). Context consumers re-render whenever the
// value changes, so deep memo'd leaves (VideoCard, PlayerModal) subscribe to actions ONLY and never
// re-render on a page/channel switch — preserving the memo that keeps feed appends from re-rendering
// every existing card.

export interface NavigationState {
  page: Page;
  /** The open channel page (null = none). Overlays `page`; rides in history.state._chan. */
  channelView: ChannelView | null;
  /** Live YouTube search term (null = normal feed). A feed sub-view; rides in history.state._yt. */
  ytSearch: string | null;
}

export interface NavigationActions {
  /** Switch modules. Closes every open overlay first and pushes only once their history entries are
   *  back (`lib/history.closeOverlaysThenNavigate`), so over an open player the push lands a moment
   *  after the call; with nothing open it is synchronous. The requested page being already current
   *  (with no channel page over it) pushes nothing — but the overlays still close.
   *
   *  `then` runs once the navigation has happened (the push made, or found unnecessary) — for a
   *  request that belongs to the NEW entry, which over an open player does not exist yet at the
   *  call (`lib/homeIntent`). */
  setPage: (next: Page, then?: () => void) => void;
  openChannel: (id: string, name?: string) => void;
  closeChannel: () => void;
  enterYtSearch: (q: string) => void;
  exitYtSearch: () => void;
}

export const NavigationStateContext = createContext<NavigationState>({
  page: "feed",
  channelView: null,
  ytSearch: null,
});
export const NavigationActionsContext = createContext<NavigationActions>({
  setPage: () => {},
  openChannel: () => {},
  closeChannel: () => {},
  enterYtSearch: () => {},
  exitYtSearch: () => {},
});

export function useNavigation(): NavigationState {
  return useContext(NavigationStateContext);
}
export function useNavigationActions(): NavigationActions {
  return useContext(NavigationActionsContext);
}