/**
 * # @devos/api-client
 * 浏览器端 API 客户端：统一的 fetch 封装，自动附带 JWT 与工作区头，
 * 归一化错误结构（与后端 error contract 对齐）。
 */

import type { ApiErrorBody } from "@devos/types";

/** # 客户端配置 **/
export interface ApiClientOptions {
  /** # API 基础地址，默认同源 /api/v1 **/
  baseUrl?: string;
  /** # 令牌提供器（返回当前 JWT 或 null） **/
  getToken: () => string | null;
  /** # 工作区 ID 提供器（返回当前工作区或 null） **/
  getWorkspaceId?: () => string | null;
  /** # 401 时的回调（例如跳转登录） **/
  onUnauthorized?: () => void;
}

/** # API 错误（客户端侧归一化） **/
export class ApiError extends Error {
  /** # 错误码 **/
  code: string;
  /** # HTTP 状态码 **/
  status: number;
  /** # 请求 ID **/
  requestId: string;
  constructor(status: number, code: string, message: string, requestId: string) {
    super(message);
    this.status = status;
    this.code = code;
    this.requestId = requestId;
  }
}

/** # API 客户端 **/
export class ApiClient {
  /** # 基础地址 **/
  private baseUrl: string;
  private getToken: () => string | null;
  private getWorkspaceId?: () => string | null;
  private onUnauthorized?: () => void;

  constructor(options: ApiClientOptions) {
    this.baseUrl = (options.baseUrl ?? "/api/v1").replace(/\/$/, "");
    this.getToken = options.getToken;
    this.getWorkspaceId = options.getWorkspaceId;
    this.onUnauthorized = options.onUnauthorized;
  }

  /** # 发起请求
   * @param method HTTP 方法
   * @param path 相对路径（不含 /api/v1）
   * @param body 请求体（自动 JSON 序列化）
   * @param query 查询参数
   * @returns 解析后的 JSON 响应
   */
  async request<T>(
    method: string,
    path: string,
    body?: unknown,
    query?: Record<string, string | number | boolean | undefined | null>,
  ): Promise<T> {
    const url = new URL(this.baseUrl + path, window.location.origin);
    if (query) {
      for (const [k, v] of Object.entries(query)) {
        if (v !== undefined && v !== null) url.searchParams.set(k, String(v));
      }
    }
    const headers: Record<string, string> = {};
    const token = this.getToken();
    if (token) headers["Authorization"] = `Bearer ${token}`;
    const wid = this.getWorkspaceId?.();
    if (wid) headers["X-Workspace-Id"] = wid;
    if (body !== undefined) headers["Content-Type"] = "application/json";

    const res = await fetch(url.toString(), {
      method,
      headers,
      body: body !== undefined ? JSON.stringify(body) : undefined,
    });

    if (!res.ok) {
      let code = "INTERNAL_ERROR";
      let message = res.statusText;
      let requestId = "";
      let parsed: ApiErrorBody | null = null;
      try {
        parsed = (await res.json()) as ApiErrorBody;
      } catch {
        /* 非 JSON 错误体 */
      }
      if (parsed?.error) {
        code = parsed.error.code;
        message = parsed.error.message;
        requestId = parsed.error.requestId;
      }
      if (res.status === 401) this.onUnauthorized?.();
      throw new ApiError(res.status, code, message, requestId);
    }
    if (res.status === 204) return undefined as T;
    return (await res.json()) as T;
  }

  get<T>(path: string, query?: Record<string, string | number | boolean | undefined | null>) {
    return this.request<T>("GET", path, undefined, query);
  }
  post<T>(path: string, body?: unknown) {
    return this.request<T>("POST", path, body);
  }
  patch<T>(path: string, body?: unknown) {
    return this.request<T>("PATCH", path, body);
  }
  delete<T>(path: string) {
    return this.request<T>("DELETE", path);
  }
}