import axios from "axios";
import type { AxiosInstance, AxiosRequestConfig, AxiosResponse } from "axios";
import Cookies from "js-cookie";
import { AUTH_USER_ID, CLAIM_NAME } from "./env";
import { errorInterceptor } from "./error-interceptor";

interface ClientConfig {
  baseURL: string;
  siteId: string;
}

class Client {
  private static instance: Client;
  private axiosInstance: AxiosInstance;

  private constructor(config: ClientConfig) {
    this.axiosInstance = axios.create({
      baseURL: config.baseURL,
      headers: {
        "Content-Type": "application/json",
        "X-Site-Id": config.siteId,
      },
      withCredentials: true,
    });

    this.axiosInstance.interceptors.request.use((config) => {
      // X-Device-Id 자동 주입 로직 (기기에 고유한 UUID 세팅 및 쿠키/로컬스토리지 보관)
      let deviceId = Cookies.get("device-id");
      if (!deviceId && typeof window !== "undefined") {
        deviceId = localStorage.getItem("device-id") || undefined;
        if (!deviceId) {
          deviceId = generateUUID();
          localStorage.setItem("device-id", deviceId);
        }
        Cookies.set("device-id", deviceId, { expires: 365, path: "/" });
      }

      if (deviceId) {
        config.headers["X-Device-Id"] = deviceId;
      }

      const token = Cookies.get(CLAIM_NAME);
      const userId = Cookies.get(AUTH_USER_ID);

      if (!token || !userId) {
        return config;
      }

      config.headers[CLAIM_NAME] = token;
      config.headers[AUTH_USER_ID] = userId;

      return config;
    });

    this.axiosInstance.interceptors.response.use(
      (response) => response,
      (error) => errorInterceptor(error),
    );
  }

  public static getInstance(config: ClientConfig): Client {
    if (!Client.instance) {
      Client.instance = new Client(config);
    }
    return Client.instance;
  }

  public async get<T = unknown, R = AxiosResponse<T>>(
    url: string,
    config?: AxiosRequestConfig,
  ): Promise<R> {
    const response = await this.axiosInstance.get<T, R>(url, config);
    return response;
  }

  public async post<T = unknown, R = AxiosResponse<T>, D = unknown>(
    url: string,
    data?: D,
    config?: AxiosRequestConfig<D>,
  ): Promise<R> {
    const response = await this.axiosInstance.post<T, R>(url, data, config);
    return response;
  }

  public async put<T = unknown, R = AxiosResponse<T>, D = unknown>(
    url: string,
    data?: D,
    config?: AxiosRequestConfig<D>,
  ): Promise<R> {
    const response = await this.axiosInstance.put<T, R>(url, data, config);
    return response;
  }

  public async delete<T = unknown, R = AxiosResponse<T>>(
    url: string,
    config?: AxiosRequestConfig,
  ): Promise<R> {
    const response = await this.axiosInstance.delete<T, R>(url, config);
    return response;
  }
}

export type { ClientConfig };
export { Client };

// 기기 식별을 위한 안전한 v4 UUID 생성 폴백 헬퍼 함수
function generateUUID(): string {
  if (typeof crypto !== "undefined" && typeof crypto.randomUUID === "function") {
    return crypto.randomUUID();
  }
  return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, function (c) {
    const r = (Math.random() * 16) | 0;
    const v = c === "x" ? r : (r & 0x3) | 0x8;
    return v.toString(16);
  });
}