/**
 * 서버에 없는 전략 ID — 세션 간 404 반복 방지 (sessionStorage)
 */
const STORAGE_KEY = 'gc_strategy_missing_ids_v1';
const MAX_STORED = 64;

const strategyMissingIds = new Set<number>();

function persistStrategyMissingCache(): void {
  try {
    const arr = [...strategyMissingIds].filter(id => id > 0).slice(-MAX_STORED);
    if (arr.length === 0) sessionStorage.removeItem(STORAGE_KEY);
    else sessionStorage.setItem(STORAGE_KEY, JSON.stringify(arr));
  } catch {
    /* private mode · 용량 */
  }
}

/** 앱 기동 시 이전 탭에서 기록한 missing ID 복원 */
export function hydrateStrategyMissingCache(): void {
  try {
    const raw = sessionStorage.getItem(STORAGE_KEY);
    if (!raw) return;
    const parsed = JSON.parse(raw) as unknown;
    if (!Array.isArray(parsed)) return;
    for (const n of parsed) {
      const id = Number(n);
      if (id > 0) strategyMissingIds.add(id);
    }
  } catch {
    try { sessionStorage.removeItem(STORAGE_KEY); } catch { /* ok */ }
  }
}

export function isStrategyMissingOnServer(strategyId: number): boolean {
  return strategyId > 0 && strategyMissingIds.has(strategyId);
}

export function markStrategyMissingOnServer(strategyId: number): void {
  if (strategyId <= 0) return;
  strategyMissingIds.add(strategyId);
  persistStrategyMissingCache();
}

export function unmarkStrategyMissingOnServer(strategyId: number): void {
  if (strategyId <= 0) return;
  if (strategyMissingIds.delete(strategyId)) persistStrategyMissingCache();
}

/** 전략 목록에 다시 나타난 ID 는 missing 에서 제거 */
export function reconcileStrategyMissingWithValidIds(validIds: Iterable<number>): void {
  const valid = new Set(validIds);
  let changed = false;
  for (const id of strategyMissingIds) {
    if (valid.has(id)) {
      strategyMissingIds.delete(id);
      changed = true;
    }
  }
  if (changed) persistStrategyMissingCache();
}

export function markStrategyMissingFromPath(pathOnly: string): void {
  const m = pathOnly.match(/^\/strategies\/(\d+)(?:\/|$)/);
  if (m) markStrategyMissingOnServer(Number(m[1]));
}

/** 목록에 없는 참조 ID를 missing 으로 기록 — 삭제된 전략 404 반복 방지 */
export function markStrategyIdsMissingUnlessValid(
  validIds: Iterable<number>,
  referencedIds: Iterable<number | null | undefined>,
): void {
  const valid = new Set(
    [...validIds].map(id => Math.trunc(id)).filter(id => id > 0),
  );
  for (const raw of referencedIds) {
    if (raw == null) continue;
    const id = Math.trunc(raw);
    if (id > 0 && !valid.has(id)) markStrategyMissingOnServer(id);
  }
}

hydrateStrategyMissingCache();