import { Request, Response } from 'express';

export type UpstreamFetch = typeof fetch;

/**
 * After zappier meters the call, forward Verae operations to middleware.
 * When ZAPPIER_UPSTREAM is unset, callers keep the local mock.
 */
export async function proxyVerae(
  req: Request,
  res: Response,
  pathname: string,
  fetchImpl: UpstreamFetch = fetch,
): Promise<boolean> {
  const base = (process.env.ZAPPIER_UPSTREAM || '').replace(/\/$/, '');
  if (!base) return false;
  const url = new URL(pathname, `${base}/`);
  for (const [k, v] of Object.entries(req.query)) {
    if (typeof v === 'string') url.searchParams.set(k, v);
  }
  const headers: Record<string, string> = { accept: 'application/json' };
  const key = req.header('x-api-key');
  if (key) headers['x-api-key'] = key;
  const auth = req.header('authorization');
  if (auth) headers.authorization = auth;
  const veraeUserId = req.customer?.veraeUserId;
  if (veraeUserId) headers['x-verae-user-id'] = veraeUserId;
  const method = req.method.toUpperCase();
  const init: RequestInit = { method, headers };
  if (method !== 'GET' && method !== 'HEAD') {
    headers['content-type'] = 'application/json';
    init.body = JSON.stringify(req.body ?? {});
  }
  const r = await fetchImpl(url.toString(), init);
  const text = await r.text();
  let body: unknown = text;
  try {
    body = text ? JSON.parse(text) : {};
  } catch {
    /* keep text */
  }
  if (body && typeof body === 'object' && !Array.isArray(body) && res.locals.quote) {
    (body as Record<string, unknown>).quote = res.locals.quote;
  }
  res.status(r.status).json(body);
  return true;
}