export type CombatClock = () => number;

let activeCombatClock: CombatClock = () => Date.now();

/** Shared simulation time. Production uses wall time; deterministic tools inject a fixed-step clock. */
export function combatNow(): number {
  return activeCombatClock();
}

/**
 * Replaces the combat clock and returns a disposer that restores the previous
 * source. Benchmark callers must run sequentially because combat stores are
 * process-wide singletons.
 */
export function installCombatClock(clock: CombatClock): () => void {
  const previous = activeCombatClock;
  activeCombatClock = clock;
  return () => {
    activeCombatClock = previous;
  };
}