// The Home surface ("Mit nézzek most?", E24): one hero suggestion, a cross-source resume rail, and
// the comfort shelf. Types mirror `backend/app/discover/` — the card carries the NATIVE feed / Plex
// payload under `video` / `plex`, so the page renders through the existing VideoCard /
// PlexPosterCard instead of a third card component.
import { req } from "./core";
import type { Video } from "./feed";
import type { PlexCard } from "./plex";

// How much time the user says they have. The deterministic replacement for a mood question: the band
// also decides the source (ten minutes is a video, an evening is a film). Bands live server-side
// (`app/discover/budget.py`) — these are just the names on the wire.
export const DISCOVER_BUDGETS = ["short", "medium", "long", "any"] as const;
export type DiscoverBudget = (typeof DISCOVER_BUDGETS)[number];

// Where the hero came from. Travels with the card so the page can label it honestly instead of
// inferring "where you left off" over something the user has never opened.
export type HeroTier = "resume" | "comfort" | "surprise";
/** The server's tier order (`app/discover/hero.py::HERO_TIERS`): a reroll's press count `start`
 *  leads with `HERO_TIERS[start % 3]`, which is how a press can ASK for a tier. */
export const HERO_TIERS: readonly HeroTier[] = ["resume", "comfort", "surprise"];

export type DiscoverKind = "video" | "movie" | "show" | "episode" | "channel" | "playlist";

// What can go on the comfort shelf. `plex_item` covers a movie or a single episode; a show is pinned
// as `plex_show` because "put that show on" resolves to whichever episode is next.
export const PIN_KINDS = ["video", "channel", "plex_item", "plex_show", "playlist"] as const;
export type PinKind = (typeof PIN_KINDS)[number];

export interface DiscoverCard {
  source: "youtube" | "plex";
  kind: DiscoverKind;
  id: string;
  title: string;
  subtitle: string | null;
  thumb: string | null;
  // The ARTWORK's shape, not the module's: a Plex episode ships a landscape still exactly like a
  // YouTube video, while movies and shows ship posters. Lets a rail size its tiles without
  // branching on `source`.
  aspect: "wide" | "poster";
  duration_seconds: number | null;
  position_seconds: number;
  remaining_seconds: number | null;
  status: string;
  // Exactly one is set (both null for a channel / playlist tile, which are not themselves playable).
  video: Video | null;
  plex: PlexCard | null;
  // Shelf entries only.
  pin_id?: number;
  /** A comfort-tier hero only: the shelf entry it was resolved from — for a pinned SHOW, the show
   *  whose next episode this is. The hero's pin row acts on it rather than on the episode, which is
   *  not itself pinned (`app/discover/pins.py::playables`). */
  pinned_from?: Pick<DiscoverCard, "source" | "kind" | "id" | "title">;
  /** What actually plays when the tile is clicked: a show's next episode, a channel's newest
   * unwatched video, or a copy of the tile itself when it plays directly. Null when the pin has
   * nothing to offer right now (a fully-watched channel, an empty playlist). */
  next?: DiscoverCard | null;
  unwatched_count?: number;
  item_count?: number;
}

export interface DiscoverHero {
  tier: HeroTier;
  card: DiscoverCard;
}

export interface DiscoverPayload {
  budget: DiscoverBudget;
  hero: DiscoverHero | null;
  continue_watching: DiscoverCard[];
  comfort: DiscoverCard[];
}

export const discoverApi = {
  discover: (budget: DiscoverBudget, seed: number): Promise<DiscoverPayload> =>
    req(`/api/discover?budget=${budget}&seed=${seed}`),
  // The "Mást kérek" reroll: a new hero alone, so pressing it does not re-fetch the rails under the
  // user's cursor.
  // `exclude` is the rolling list of `<source>:<id>` keys already shown. Without it a reroll only
  // moves the surprise tier, so a user with something half-finished gets the same hero back.
  // `press` is which press this is; it rotates the tier the server answers from, so consecutive
  // presses offer a different KIND of answer instead of walking down the resume rail.
  discoverPick: (
    budget: DiscoverBudget,
    seed: number,
    exclude: string[] = [],
    press = 0,
  ): Promise<{ budget: DiscoverBudget; hero: DiscoverHero | null }> =>
    req(
      `/api/discover/pick?budget=${budget}&seed=${seed}&start=${press}` +
        (exclude.length ? `&exclude=${encodeURIComponent(exclude.join(","))}` : ""),
    ),
  comfortPins: (): Promise<{ items: DiscoverCard[] }> => req("/api/discover/pins"),
  addComfortPin: (
    kind: PinKind,
    ref: string,
  ): Promise<{ ok: boolean; id: number; created: boolean }> =>
    req("/api/discover/pins", { method: "POST", body: JSON.stringify({ kind, ref }) }),
  removeComfortPin: (pinId: number): Promise<{ deleted: number }> =>
    req(`/api/discover/pins/${pinId}`, { method: "DELETE" }),
  reorderComfortPins: (ids: number[]): Promise<{ ok: boolean }> =>
    req("/api/discover/pins/reorder", { method: "POST", body: JSON.stringify({ ids }) }),
};

/** A card's identity across sources — mirrors `app/discover/cards.py::key`. The reroll's exclusion
 * list and the "is this tile the hero?" check both speak it, so the two cannot drift. */
export function discoverCardKey(card: Pick<DiscoverCard, "source" | "id">): string {
  return `${card.source}:${card.id}`;
}