const EPOCH_MS = Date.parse("2025-04-25T16:00:00.000Z");
const DAY_MS = 86_400_000;

export function livingTime(nowMs = Date.now()) {
  if (!Number.isInteger(nowMs) || nowMs < EPOCH_MS) throw new Error("time_before_guanghu_epoch");
  const elapsed = nowMs - EPOCH_MS;
  return {
    schema: "guanghu.era-living-time-snapshot/v1",
    state: "LIVE_REALITY_TIME_DERIVED",
    observed_at_unix_ms: nowMs,
    world: {
      id: "SYS-GLW-0001",
      era_id: "GUANGHU-ERA-0001",
      visible_birth_date_beijing: "2025-04-26",
      birth_fact_precision: "DATE",
      exact_birth_instant: null,
      calendar_epoch_boundary: "2025-04-26T00:00:00+08:00",
      calendar_epoch_boundary_kind: "DETERMINISTIC_COMPUTATION_CONVENTION_NOT_CLAIMED_BIRTH_INSTANT",
      era_day: Math.floor(elapsed / DAY_MS) + 1,
      elapsed_days_completed: Math.floor(elapsed / DAY_MS),
      elapsed_milliseconds: elapsed,
    },
    time_control_channel: { id: "CH-GLW-TIME-0001", path: "glw://time/control" },
    clock: { source: "REALITY_SYSTEM_CLOCK_UTC", stored_tick_counter: false, persona_wake_required: false, scheduler_required: false },
  };
}