gemini-compat-endpoint

// Module-level in-memory dedup cache for vision promotion.
// Prevents both title-gen and main-response from injecting the same attachment set
// within the same logical user turn.
// Source pattern: draw-things-chat/src/orchestrator.ts (recentlyInjected Map)

const DEDUP_TTL_MS = 10_000;
const recentlyInjected = new Map<string, number>(); // key → timestamp

/**
 * Returns true if this key was NOT recently injected (→ should proceed with injection).
 * Returns false if injection happened within the TTL (→ should skip).
 * Always marks the key as injected on first call.
 */
export function checkAndMarkInjected(key: string): boolean {
  const now = Date.now();
  // Prune stale entries
  for (const [k, ts] of recentlyInjected) {
    if (now - ts > DEDUP_TTL_MS) recentlyInjected.delete(k);
  }
  if (recentlyInjected.has(key)) return false; // already injected this turn
  recentlyInjected.set(key, now);
  return true;
}

export function makeDedupKey(chatWd: string, attachmentNs: number[]): string {
  return `${chatWd}:${[...attachmentNs].sort((a, b) => a - b).join(",")}`;
}