import type { JobRecord } from "./registry";

// THE CLIP-WINDOW JOB ALREADY ON ITS WAY (release 19, A5).
//
// A tool that asks for a window and does not get it at once asks again — umtool's
// fetch-via-editor after a timeout, an agent retrying, the same manifest sent
// twice — and every ask used to queue another job for the same seconds of the
// same video: the second waited behind the first, found nothing to fetch when
// it ran, and meanwhile both sat in the platform's queue in front of real work.
// The disk cache (`findContainingClipWindow`) only answers once a file exists;
// this answers the window that is still being fetched.
//
// A request is IN FLIGHT when a queued or running job will produce a file that
// covers it: a single `fetch-window` job for the same channel and video whose
// window CONTAINS the asked one (the cache accepts a wider file, so this does
// too), or a `fetch-windows` batch with such an item. The source height cap
// must match: a window capped at 480 is not an answer to a request for 720.
// Read off the job's replay spec — the request it was started with — so a
// record without one (an old job) is never a match.

export type WantedWindow = {
  slug: string;
  videoId: string;
  from: number;
  to: number;
  maxHeight?: number;
};

export type WindowInFlight = {
  jobId: string;
  kind: "fetch-window" | "fetch-windows";
  status: "queued" | "running";
  // The window the job will write, which contains the asked one.
  from: number;
  to: number;
};

const num = (v: unknown): number | undefined =>
  typeof v === "number" && Number.isFinite(v) ? v : undefined;

export function windowInFlight(
  records: readonly JobRecord[],
  want: WantedWindow,
): WindowInFlight | null {
  for (const r of records) {
    if (r.status !== "queued" && r.status !== "running") continue;
    const p = (r.spec?.params ?? {}) as Record<string, unknown>;
    if (num(p.maxHeight) !== want.maxHeight) continue;
    const covers = (from: number | undefined, to: number | undefined) =>
      from !== undefined && to !== undefined && from <= want.from && to >= want.to;
    if (r.kind === "fetch-window") {
      if (r.spec?.slug !== want.slug || p.videoId !== want.videoId) continue;
      const from = num(p.from);
      const to = num(p.to);
      if (covers(from, to)) {
        return { jobId: r.id, kind: "fetch-window", status: r.status, from: from!, to: to! };
      }
    } else if (r.kind === "fetch-windows" && Array.isArray(p.items)) {
      for (const raw of p.items) {
        const it = (raw ?? {}) as Record<string, unknown>;
        if (it.slug !== want.slug || it.id !== want.videoId) continue;
        const from = num(it.from);
        const to = num(it.to);
        if (covers(from, to)) {
          return { jobId: r.id, kind: "fetch-windows", status: r.status, from: from!, to: to! };
        }
      }
    }
  }
  return null;
}