idempotency.ts

export type IdempotencyRecord = {
  seq: number;
  at: string;
};

type State = { store: Map<string, IdempotencyRecord> };

const GLOBAL_KEY = Symbol.for('super.webhooks.idempotency');

type GlobalWithState = typeof globalThis & { [GLOBAL_KEY]?: State };

function getState(): State {
  const g = globalThis as GlobalWithState;
  let existing = g[GLOBAL_KEY];
  if (!existing) {
    existing = { store: new Map() };
    g[GLOBAL_KEY] = existing;
  }
  return existing;
}

export function compositeKey(partnerSlug: string, idempotencyKey: string): string {
  return `${partnerSlug}:${idempotencyKey}`;
}

export function checkIdempotency(key: string): IdempotencyRecord | null {
  return getState().store.get(key) ?? null;
}

export function markIdempotent(key: string, record: IdempotencyRecord): void {
  getState().store.set(key, record);
}

export function __resetIdempotencyStore(): void {
  getState().store = new Map();
}