// The one-word answer to "what does this video know about who is speaking?",
// client-safe so a badge, a snapshot bucket and a stage card can all read it
// without pulling a server module in.
//
// FOUR STATES, and the two middle ones are deliberately not collapsed into a
// single "attributed". The lanes are not interchangeable: "diarized" names
// acoustic clusters and costs about one model call per video, while "text-only"
// reconstructs speaker changes from the transcript at ~30 calls and has to
// re-establish identity at every chunk seam. A UI that showed one word for both
// would be claiming a confidence the text-only lane has not earned — and PLAN.md
// is explicit that this misfires on rapid back-and-forth and has nothing to work
// with on auto-caption channels. The filtering that eventually consumes this is
// supposed to be able to say "diarized only", which it cannot do against a
// status that has already thrown the distinction away.

import {
  isAttributionFresh,
  type AttributionFreshnessTarget,
  type AttributionRecord,
} from "./attribution";

export type AttributionStatus = "none" | "text-only" | "diarized" | "stale";

// `target` is OPTIONAL, and the two cases are genuinely different questions.
//
// With a target — a server-side caller that has settings — "stale" is reachable
// and means the record exists but is not what we would produce now. Without one
// — an exported viewer, which has no settings and no engine — staleness is
// unknowable, so the honest answer is the method that IS recorded. Returning
// "stale" there would be a guess, and returning "none" would hide real work.
export function attributionStatus(
  record: AttributionRecord | null,
  target?: AttributionFreshnessTarget,
): AttributionStatus {
  if (!record) return "none";
  const method = record.provenance?.method;
  if (method !== "text-only" && method !== "diarized") return "none";
  if (target && !isAttributionFresh(record, target)) return "stale";
  return method;
}

// UI copy, kept beside the type so a second surface cannot invent its own
// wording for the same state.
export function attributionStatusLabel(status: AttributionStatus): string {
  switch (status) {
    case "diarized":
      return "Speakers named from audio";
    case "text-only":
      // Hedged on purpose. See the header.
      return "Speakers guessed from the transcript";
    case "stale":
      return "Speaker names are out of date";
    default:
      return "No speaker names";
  }
}