// Pending sync alerts — audit fix HV-1b.
//
// When a sync round accepts a remote entry that REPLACES an existing local
// password, or soft-deletes a local entry via a remote tombstone, the user
// gets no signal today. This queue records those remote mutations so the
// popup can display them on next open (non-blocking — the sync itself is
// not interrupted).
//
// Persistence: chrome.storage.local under a dedicated key so alerts survive
// MV3 worker eviction between the sync round and the next popup open. The
// queue is cleared after the popup acknowledges display (GET_SYNC_ALERTS
// with `consume: true`).

export interface SyncAlert {
  type: "REMOTE_PASSWORD_CHANGE" | "REMOTE_DELETE" | "DEVICE_KEY_ROTATED";
  /** VaultEntry.id — a UUID string in this codebase (spec deviation: the
   *  fix spec typed this `number`, but entry ids are `crypto.randomUUID()`).
   *  Empty string for DEVICE_KEY_ROTATED (not entry-scoped). */
  entryId: string;
  entryTitle: string;
  /** Peer device name when known; "paired device" when the merge layer
   *  had no device context. */
  deviceName: string;
  timestamp: number;
}

const SYNC_ALERTS_KEY = "peach_pending_sync_alerts_v1";
/** Bound the queue so a hostile peer cannot grow storage without limit. */
const MAX_PENDING_ALERTS = 200;

export async function recordSyncAlerts(alerts: SyncAlert[]): Promise<void> {
  if (alerts.length === 0) return;
  const existing = await readAlerts();
  const merged = [...existing, ...alerts].slice(-MAX_PENDING_ALERTS);
  try {
    await chrome.storage.local.set({ [SYNC_ALERTS_KEY]: merged });
  } catch {
    // Alert persistence must never block or fail a sync merge.
  }
}

export async function getPendingSyncAlerts(): Promise<SyncAlert[]> {
  return readAlerts();
}

export async function clearPendingSyncAlerts(): Promise<void> {
  try {
    await chrome.storage.local.remove(SYNC_ALERTS_KEY);
  } catch {
    /* non-fatal */
  }
}

async function readAlerts(): Promise<SyncAlert[]> {
  try {
    const result = await chrome.storage.local.get(SYNC_ALERTS_KEY);
    const value = (result as Record<string, unknown>)[SYNC_ALERTS_KEY];
    if (!Array.isArray(value)) return [];
    return value.filter(isSyncAlert);
  } catch {
    return [];
  }
}

function isSyncAlert(x: unknown): x is SyncAlert {
  if (typeof x !== "object" || x === null) return false;
  const r = x as Record<string, unknown>;
  return (
    (r.type === "REMOTE_PASSWORD_CHANGE" ||
      r.type === "REMOTE_DELETE" ||
      r.type === "DEVICE_KEY_ROTATED") &&
    typeof r.entryId === "string" &&
    typeof r.entryTitle === "string" &&
    typeof r.deviceName === "string" &&
    typeof r.timestamp === "number"
  );
}