import {
  autoPauseReasonOf,
  autoPausedSlugs,
  type ChannelPriority,
  type StoredChannelTier,
} from "../lib/channelPriority";

// THE /review PAYLOAD'S THIRD SECTION: what the MACHINE decided on its own.
//
// /review is "findings a human decides, not work a lane runs", and an
// auto-pause is exactly that shape from the other direction: the storage watch
// took a decision while nobody was looking, and it stands until either the
// drive comes back or a person overrides it. Until now the only place that
// decision surfaced was a chip beside one channel's tier on /channels — so an
// operator whose platter went away found out by noticing that a channel had
// quietly stopped doing anything.
//
// PURE, like everything in this directory: the model arrives as an argument.
//
// ONE WORDING. The sentence is `autoPauseReasonOf`'s, the same one the rack and
// the channel page say, because three surfaces wording the same machine
// decision three ways is how an operator ends up unsure whether they are three
// different problems.

export type AutoPausedRow = {
  slug: string;
  // Which machine decided. One value today; a union so a second reason has
  // somewhere to go and a row can say which rather than "automatic".
  reason: "storage";
  // ISO, as stored. The renderer decides how much of it to show.
  since: string;
  // WHERE RESUME PUTS IT BACK. Carried because it is not derivable from
  // anything once the tier was overwritten with `paused` — that is the whole
  // content of the record — and because the Resume control has to post it.
  previousTier: StoredChannelTier;
  // The one sentence, already assembled.
  detail: string;
};

export function autoPausedRows(model: ChannelPriority): AutoPausedRow[] {
  const rows: AutoPausedRow[] = [];
  // `autoPausedSlugs` sorts, so the list is stable across renders — a section
  // that reorders itself under an auto-refresh is one an operator cannot click.
  for (const slug of autoPausedSlugs(model)) {
    const auto = model.channels[slug]?.autoPaused;
    if (!auto) continue;
    rows.push({
      slug,
      reason: auto.reason,
      since: auto.since,
      previousTier: auto.previousTier,
      // Never null here — the entry carries a record, which is exactly the
      // condition `autoPauseReasonOf` returns a sentence for.
      detail: autoPauseReasonOf(model, slug) ?? "",
    });
  }
  return rows;
}