import { apiBase } from './api';

export const PROMO_STORAGE_KEY = 'dukang_promo_code';

function readPromoFromSearch(search: string): string | null {
  const params = new URLSearchParams(search.startsWith('?') ? search.slice(1) : search);
  const code = params.get('promo')?.trim();
  return code ? code.toUpperCase() : null;
}

/** 解析 URL 中的 ?promo= 并写入 sessionStorage */
export function capturePromoFromUrl(): string | null {
  if (typeof window === 'undefined') return null;
  let code = readPromoFromSearch(window.location.search);
  if (!code && window.location.hash.includes('?')) {
    const hashQuery = window.location.hash.slice(window.location.hash.indexOf('?'));
    code = readPromoFromSearch(hashQuery);
  }
  if (code) {
    sessionStorage.setItem(PROMO_STORAGE_KEY, code);
  }
  return code ?? sessionStorage.getItem(PROMO_STORAGE_KEY);
}

export function getStoredPromoCode(): string | null {
  if (typeof window === 'undefined') return null;
  return sessionStorage.getItem(PROMO_STORAGE_KEY);
}

/** 调用 /promo/touch 完成扫码归因（OptionalJwt：未登录也累加 scan_count） */
export async function touchPromoIfNeeded(): Promise<void> {
  const promoCode = getStoredPromoCode();
  if (!promoCode) return;

  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    'X-Client-App': 'USER_H5',
  };
  const token = localStorage.getItem('accessToken');
  if (token) headers.Authorization = `Bearer ${token}`;

  try {
    const res = await fetch(`${apiBase}/promo/touch`, {
      method: 'POST',
      headers,
      body: JSON.stringify({ promoCode }),
    });
    const json = await res.json();
    if (json.code !== 0) return;
  } catch {
    /* 静默失败，不阻断用户流程 */
  }
}