import type { SubviewUrl } from "../lib/history";
import { parsePositiveIntId } from "../lib/parseId";

// The Plex module's sub-view union and its address-bar mirror, extracted from PlexBrowse so the
// encode/decode round-trip (and its guards) can be unit-tested without pulling the whole component
// (and its lazy hls.js player) into the test graph.
export type Sub =
  | { kind: "discover" }
  | { kind: "grid" }
  | { kind: "playlists" } // browse-all-playlists surface (header pill "Playlist" mode)
  | { kind: "collections" } // browse-all-collections surface (header pill "Collection" mode)
  | { kind: "show"; id: string }
  | { kind: "season"; showId: string; seasonId: string }
  | { kind: "player"; id: string; queue?: string[] }
  | { kind: "info"; id: string }
  | { kind: "person"; name: string }
  | { kind: "playlist"; id: number }
  | { kind: "collection"; id: string }; // the Collection info page (id = collection rating_key)

// Mirror the Plex sub-view to ?v=<kind>:<args> so a show / season / movie-info / person / playlist page
// — and the flat browse grid — are bookmarkable. Discover is the ROOT landing (E5 S4), so it (and the
// ephemeral player) is not mirrored (encode → null); the grid gets `?v=browse` so "Browse all" is a
// distinct, shareable URL. The person name is the whole tail after the first ":", so a name containing
// ":" round-trips.
export const PLEX_SUB_URL: SubviewUrl<Sub> = {
  key: "v",
  encode: (v) => {
    switch (v.kind) {
      case "grid":
        return "browse";
      case "playlists":
        return "playlists";
      case "collections":
        return "collections";
      case "show":
        return `show:${v.id}`;
      case "season":
        return `season:${v.showId}:${v.seasonId}`;
      case "info":
        return `info:${v.id}`;
      case "person":
        return `person:${v.name}`;
      case "playlist":
        return `playlist:${v.id}`;
      case "collection":
        return `collection:${v.id}`;
      default:
        return null; // discover (root) + the ephemeral player are not URL-mirrored
    }
  },
  decode: (raw) => {
    const i = raw.indexOf(":");
    const kind = i === -1 ? raw : raw.slice(0, i);
    const arg = i === -1 ? "" : raw.slice(i + 1);
    switch (kind) {
      case "browse":
        return { kind: "grid" };
      case "playlists":
        return { kind: "playlists" };
      case "collections":
        return { kind: "collections" };
      case "show":
        return arg ? { kind: "show", id: arg } : null;
      case "info":
        return arg ? { kind: "info", id: arg } : null;
      case "person":
        return arg ? { kind: "person", name: arg } : null;
      case "playlist": {
        // Positive-integer id only — a fractional/zero/negative ?v=playlist:<arg> would open a
        // sub-view for a non-existent id (shares parsePositiveIntId with readSelectedId's ?pl guard).
        const id = parsePositiveIntId(arg);
        return id != null ? { kind: "playlist", id } : null;
      }
      case "collection":
        return arg ? { kind: "collection", id: arg } : null;
      case "season": {
        const [showId, seasonId] = arg.split(":");
        return showId && seasonId ? { kind: "season", showId, seasonId } : null;
      }
      default:
        return null;
    }
  },
};