// ONE read of out/clips-raw, answering for every clip in a project.
//
// Its own module, and deliberately a LEAF: lib/projects/report.mjs reads it, and
// so does lib/report/serve.mjs, which report.mjs is itself imported by. Putting
// it in serve.mjs closed that circle and broke module initialisation outright
// (kinds.mjs reads a const of report.mjs at top level, and in the cycle that
// const is still in its temporal dead zone). Nothing here imports anything of
// ours but the predicate.
import path from "node:path";
import {
  listRawNames,
  tightestContaining,
  windowsFromNames,
} from "umtool-report-to-video/build-video";

/**
 * The cache. The directory is keyed by VIDEO and a page asks about it per clip
 * -- the bench page did two readdirs per clip, and a forty-clip cut paid eighty
 * of them for one screen. The listing is read once, the per-video parse is
 * memoised, and every question below is then arithmetic.
 *
 * `isFetched(clip)` is the walk's question and the one a follow-up importer
 * wants: is there a cached file holding this clip's OWN window, end to end.
 * Not the PADDED window the build would fetch (that is `containing()` with the
 * pad applied, and it calls three of four fixture clips unfetched), and not
 * mere overlap -- a half-covered clip cannot be watched through, so it is not
 * ready to judge.
 *
 * @param {string} projectDir
 * @param {{ extraWindows?: { video: string, windows: { name: string, path: string, from: number, to: number }[] }[] }} [opts]
 *   Windows OUTSIDE the project that also hold a given video -- the corpus's
 *   clip windows and a saved whole source, as `clipWindowDirs` lists them
 *   through the render's own sources.mjs, so the bench and the build agree on
 *   what is local. A whole container is the window [0, duration]: a full
 *   source contains every window of its video, which is exactly what the
 *   predicate needs to know.
 */
export async function rawCacheOf(projectDir, { extraWindows = [] } = {}) {
  const rawDir = path.join(projectDir, "out", "clips-raw");
  const names = await listRawNames(rawDir);
  const extra = new Map();
  for (const e of extraWindows) {
    if (!e?.video || !e?.windows?.length) continue;
    extra.set(e.video, [...(extra.get(e.video) ?? []), ...e.windows]);
  }
  const byVideo = new Map();
  const windows = (video) => {
    if (!byVideo.has(video)) {
      byVideo.set(video, [
        ...windowsFromNames(names, rawDir, video),
        ...(extra.get(video) ?? []),
      ]);
    }
    return byVideo.get(video);
  };
  return {
    rawDir,
    windows,
    containing: (video, from, to) => tightestContaining(windows(video), from, to),
    isFetched: (clip) => {
      const { start, end, video } = clip ?? {};
      if (!Number.isFinite(start) || !Number.isFinite(end)) return false;
      return !!tightestContaining(windows(video), start, end);
    },
  };
}