import { getCookie as serializeStoredCookies } from "@better-auth/expo/client";
import * as SecureStore from "expo-secure-store";
import type { createAuthClient } from "better-auth/react";

import { normalizeSecureStoreKey } from "@/lib/secure-store-keys";

type AuthClient = ReturnType<typeof createAuthClient>;

const CHUNK_MARKER = "\u0001ba-chunks:";

function readSecureStoreValueSync(key: string): string | null {
  const value = SecureStore.getItem(key);
  if (value == null) return null;
  if (!value.startsWith(CHUNK_MARKER)) return value;

  const count = Number(value.slice(CHUNK_MARKER.length));
  if (!Number.isInteger(count) || count < 1) return null;

  let assembled = "";
  for (let index = 0; index < count; index += 1) {
    const chunk = SecureStore.getItem(`${key}.${index}`);
    if (chunk == null) return null;
    assembled += chunk;
  }
  return assembled;
}

/** Read session cookie string for tRPC requests (Expo client plugin + SecureStore fallback). */
export function getAuthCookie(
  authClient: AuthClient,
  storagePrefix: string,
): string | null {
  const fromClient = (
    authClient as AuthClient & { getCookie?: () => string }
  ).getCookie?.();
  if (fromClient?.trim()) return fromClient.trim();

  const raw = readSecureStoreValueSync(
    normalizeSecureStoreKey(`${storagePrefix}_cookie`),
  );
  if (!raw || raw === "{}") return null;

  const cookie = serializeStoredCookies(raw);
  return cookie.trim() || null;
}

export function getAuthCookieHeaders(
  authClient: AuthClient,
  storagePrefix: string,
): Record<string, string> {
  const cookie = getAuthCookie(authClient, storagePrefix);
  return cookie
    ? { cookie, Cookie: cookie, "x-beenvoice-auth-cookie": cookie }
    : {};
}