import { getOfflineStore } from "./db";
import { getOfflineState, whenReady } from "./outbox";
import { ctxKeyOf } from "./types";

/**
 * Form drafts in IndexedDB (lane L7, Spec §22 "automatische Zwischenspeicherung"): note text,
 * report draft … Stored per tenant+user context, deleted with the local data on logout.
 * `key` is a stable form id, e.g. `note:<workOrderId>` or `report:<workOrderId>:daily`.
 */

const metaKey = (key: string) => `draft:${key}`;

export async function loadDraft<T>(key: string): Promise<T | null> {
  if (!(await whenReady())) return null;
  const ctx = getOfflineState().ctx;
  if (!ctx) return null;
  try {
    return await (await getOfflineStore()).getMeta<T>(ctxKeyOf(ctx), metaKey(key));
  } catch {
    return null;
  }
}

export async function saveDraft(key: string, value: unknown): Promise<void> {
  const ctx = getOfflineState().ctx;
  if (!ctx) return;
  try {
    await (await getOfflineStore()).setMeta(ctxKeyOf(ctx), metaKey(key), value);
  } catch {
    // quota / private mode — the form keeps working without a draft
  }
}

export async function clearDraft(key: string): Promise<void> {
  const ctx = getOfflineState().ctx;
  if (!ctx) return;
  try {
    await (await getOfflineStore()).deleteMeta(ctxKeyOf(ctx), metaKey(key));
  } catch {
    /* ignore */
  }
}