/**
 * 后端 API 客户端。
 *
 * 默认走同源代理：页面请求相对路径 /api/*，由 next.config.ts 的 rewrites 转发到后端
 * （默认 http://127.0.0.1:8000，可用环境变量 BACKEND_API_URL 覆盖）。
 * 需要直连（不走代理）时可用 NEXT_PUBLIC_API_BASE 显式指定后端地址（含 /api）。
 */
const explicitBase = process.env.NEXT_PUBLIC_API_BASE?.replace(/\/$/, "");
const BASE = explicitBase ?? "/api";

export async function apiGet<T>(path: string): Promise<T> {
  const resp = await fetch(`${BASE}${path}`);
  if (!resp.ok) throw new Error(`GET ${path} → ${resp.status}: ${await resp.text()}`);
  return (await resp.json()) as T;
}

export async function apiPost<T>(path: string, body: unknown): Promise<T> {
  const resp = await fetch(`${BASE}${path}`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body),
  });
  if (!resp.ok) {
    const text = await resp.text();
    throw new Error(`POST ${path} → ${resp.status}: ${text.slice(0, 300)}`);
  }
  return (await resp.json()) as T;
}

export interface ApiError {
  status: number;
  message: string;
}