src/account/plausibility.ts

import type { DecodedState, DecodedView } from './decode.js';
export function viewContradictsState(
  first: DecodedState,
  second: DecodedState,
  view: DecodedView | null,
): string | null {
  if (!view || view.slot === null) return null;
  if (view.slot < first.slot || view.slot > second.slot) return null;
  const viewSet = new Set<string>();
  for (const [symbol, vp] of view.positions) {
    if (vp.sizeNonZero === null) return null;
    if (vp.sizeNonZero) viewSet.add(symbol);
  }
  const stateSet = new Set(
    second.positions.filter((p) => p.subaccountIndex === 0 && p.lots !== 0n).map((p) => p.symbol),
  );
  const onlyView = [...viewSet].filter((s) => !stateSet.has(s)).sort();
  const onlyState = [...stateSet].filter((s) => !viewSet.has(s)).sort();
  if (!onlyView.length && !onlyState.length) return null;
  return (
    `State slots ${first.slot}–${second.slot} contradict equity view slot ${view.slot}: ` +
    `${onlyView.length ? `view reports positions absent from state: ${onlyView.join(', ')}` : ''}` +
    `${onlyView.length && onlyState.length ? '; ' : ''}` +
    `${onlyState.length ? `state reports positions absent from view: ${onlyState.join(', ')}` : ''}`
  );
}