/**
 * Admin 后台管理系统 - 统一 API 客户端
 *
 * 写入型/高成本接口(采集、回测、结算)受 X-API-Key 保护:
 * 密钥在「系统配置」页设置,存于本机 localStorage,每次请求自动附带。
 */

const API_BASE = '/api/v1'
const TIMEOUT_MS = 30_000

const ADMIN_KEY_STORAGE = 'profeto_admin_key'

/** 读取本机保存的管理员密钥 */
export function getAdminKey(): string {
  try {
    return localStorage.getItem(ADMIN_KEY_STORAGE) ?? ''
  } catch {
    return ''
  }
}

/** 保存/清除管理员密钥(传空字符串即清除) */
export function setAdminKey(key: string): void {
  try {
    if (key) localStorage.setItem(ADMIN_KEY_STORAGE, key)
    else localStorage.removeItem(ADMIN_KEY_STORAGE)
  } catch {
    /* 隐私模式等场景下不可用,静默忽略 */
  }
}

export class ApiError extends Error {
  constructor(
    message: string,
    public status: number,
    public data?: unknown,
  ) {
    super(message)
    this.name = 'ApiError'
  }
}

async function request<T>(path: string, options: RequestInit = {}): Promise<T> {
  // 修复: 正确拼接 API_BASE
  const url = path.startsWith('http')
    ? path
    : path.startsWith('/')
      ? path  // 已经是绝对路径(如 /health)
      : `${API_BASE}${path}`

  const controller = new AbortController()
  const timer = setTimeout(() => controller.abort(), TIMEOUT_MS)

  try {
    const adminKey = getAdminKey()
    const res = await fetch(url, {
      ...options,
      signal: controller.signal,
      headers: {
        'Content-Type': 'application/json',
        ...(adminKey ? { 'X-API-Key': adminKey } : {}),
        ...options.headers,
      },
    })

    if (!res.ok) {
      let detail: unknown
      try {
        detail = await res.json()
      } catch {
        detail = await res.text()
      }
      let message =
        detail && typeof detail === 'object' && 'detail' in detail
          ? String((detail as { detail: unknown }).detail)
          : `HTTP ${res.status}: ${res.statusText}`
      if (res.status === 401) {
        message += '\n请在「系统配置」页填写管理员密钥后重试。'
      }
      throw new ApiError(message, res.status, detail)
    }

    // 修复: 正确判断 204 No Content
    if (res.status === 204) {
      return undefined as T
    }

    return res.json() as Promise<T>
  } catch (err) {
    if (err instanceof ApiError) throw err
    if (err instanceof DOMException && err.name === 'AbortError') {
      throw new ApiError('请求超时,请稍后重试', 0)
    }
    throw new ApiError(
      err instanceof Error ? err.message : '网络错误,请检查连接',
      0,
    )
  } finally {
    clearTimeout(timer)
  }
}

export const api = {
  get: <T>(path: string) => request<T>(path),
  post: <T>(path: string, body?: unknown) =>
    request<T>(path, { method: 'POST', body: body ? JSON.stringify(body) : undefined }),
  put: <T>(path: string, body?: unknown) =>
    request<T>(path, { method: 'PUT', body: body ? JSON.stringify(body) : undefined }),
  delete: <T>(path: string) => request<T>(path, { method: 'DELETE' }),
}

export { API_BASE }