/**
 * [Gitea #120] What this device stores for Lotus, from the APIs that are cheap
 * to ask. `estimate()` is the total the browser accounts for; Chromium adds a
 * per-bucket breakdown (`usageDetails`), Firefox/Safari don't. Media files are
 * not in here at all: they live in the browser's own HTTP cache, which manages
 * and evicts them itself.
 */
export type StorageUsage = {
  usage: number;
  quota: number;
  /** Chromium only: IndexedDB (sync store, crypto store, search index) bytes. */
  indexedDB?: number;
  /** Chromium only: Cache Storage (offline app shell) bytes. */
  caches?: number;
  /** Whether the browser granted persistent storage (won't evict under pressure). */
  persisted: boolean | undefined;
};

type EstimateWithDetails = StorageEstimate & {
  usageDetails?: { indexedDB?: number; caches?: number; serviceWorkerRegistrations?: number };
};

export const storageUsageSupported = (): boolean =>
  typeof navigator !== 'undefined' && !!navigator.storage && !!navigator.storage.estimate;

export async function readStorageUsage(): Promise<StorageUsage | undefined> {
  if (!storageUsageSupported()) return undefined;
  const est = (await navigator.storage.estimate()) as EstimateWithDetails;
  let persisted: boolean | undefined;
  try {
    persisted = navigator.storage.persisted ? await navigator.storage.persisted() : undefined;
  } catch {
    persisted = undefined;
  }
  return {
    usage: est.usage ?? 0,
    quota: est.quota ?? 0,
    indexedDB: est.usageDetails?.indexedDB,
    caches: est.usageDetails?.caches,
    persisted,
  };
}

/** Ask the browser to keep this origin's storage; returns the new state. */
export async function requestPersistentStorage(): Promise<boolean | undefined> {
  if (!navigator.storage?.persist) return undefined;
  try {
    return await navigator.storage.persist();
  } catch {
    return undefined;
  }
}

export const percentOf = (usage: number, quota: number): number =>
  quota > 0 ? Math.min(100, Math.round((usage / quota) * 100)) : 0;