import { authorizedFetch } from './authHeaders';
import type {
  SystemConfigValue,
  SystemFeature,
  SystemKbInfo,
  SystemOverview,
  SystemSetting,
} from '../types/systemAdmin';

const BASE = '/api/v1/admin/system';

async function readError(resp: Response, fallback: string): Promise<Error> {
  let err: Error;
  try {
    const text = await resp.text();
    err = text ? new Error(text.slice(0, 200)) : new Error(`${fallback} (HTTP ${resp.status})`);
  } catch {
    err = new Error(`${fallback} (HTTP ${resp.status})`);
  }
  (err as Error & { status?: number }).status = resp.status;
  return err;
}

async function getJson<T>(path: string, fallback: string): Promise<T> {
  const resp = await authorizedFetch(path);
  if (!resp.ok) throw await readError(resp, fallback);
  return resp.json() as Promise<T>;
}

export async function fetchSystemOverview(): Promise<SystemOverview> {
  return getJson<SystemOverview>(`${BASE}/overview`, '获取系统总览失败');
}

export async function fetchSystemKb(): Promise<SystemKbInfo> {
  return getJson<SystemKbInfo>(`${BASE}/kb`, '获取知识库连接信息失败');
}

export async function fetchSystemFeatures(): Promise<SystemFeature[]> {
  const data = await getJson<{ features?: SystemFeature[] }>(`${BASE}/features`, '获取特性开关失败');
  return data.features ?? [];
}

export async function fetchSystemSettings(): Promise<SystemSetting[]> {
  const data = await getJson<{ settings?: SystemSetting[] }>(`${BASE}/settings`, '获取系统设置失败');
  return data.settings ?? [];
}

export async function updateSystemSetting(
  key: string,
  value: SystemConfigValue,
): Promise<SystemSetting> {
  const resp = await authorizedFetch(`${BASE}/settings/${encodeURIComponent(key)}`, {
    method: 'PUT',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ value }),
  });
  if (!resp.ok) throw await readError(resp, '保存设置失败');
  const data = (await resp.json()) as { setting?: SystemSetting } & SystemSetting;
  return data.setting ?? data;
}