lotteryFront/src/lib/lottery-http.ts

import axios, {
  AxiosHeaders,
  isAxiosError,
  type AxiosRequestConfig,
  type AxiosResponse,
} from "axios";

/** 后端 `{ code, msg, data }`；约定 `code === 0` 表示成功 */
export type ApiEnvelope<T = unknown> = {
  code: number;
  msg: string;
  data: T;
};

/** HTTP 状态非 2xx（或 Axios 报错）但其 body 仍是业务信封且 `code !== 0` 时抛出 */
export class LotteryApiBizError extends Error {
  readonly code: number;
  readonly data: unknown;

  constructor(message: string, code: number, data: unknown) {
    super(message);
    this.name = "LotteryApiBizError";
    this.code = code;
    this.data = data;
  }
}

/** body 不是约定的信封结构 */
export class LotteryApiEnvelopeError extends Error {
  constructor(message = "响应不是约定的 { code, msg, data }") {
    super(message);
    this.name = "LotteryApiEnvelopeError";
  }
}

export function setLotteryRequestLocale(locale: string | null): void {
  if (locale === null) {
    overrideLocale = null;
    return;
  }
  const p = locale.trim().toLowerCase().split("-")[0] ?? "";
  overrideLocale =
    p === "zh" || p === "en" || p === "ne" ? (p as "zh" | "en" | "ne") : null;
}

let overrideLocale: "zh" | "en" | "ne" | null = null;

function requestLocale(): "zh" | "en" | "ne" {
  if (overrideLocale) {
    return overrideLocale;
  }
  if (typeof document !== "undefined") {
    const tag = document.documentElement.lang.trim().toLowerCase();
    const primary = tag.split("-")[0] ?? tag;
    if (primary === "zh" || primary === "en" || primary === "ne") {
      return primary;
    }
  }
  return "en";
}

function acceptLanguage(loc: ReturnType<typeof requestLocale>): string {
  if (loc === "zh") {
    return "zh-CN,zh;q=0.9,en;q=0.8";
  }
  if (loc === "ne") {
    return "ne,ne-NP;q=0.9,en;q=0.8";
  }
  return "en-US,en;q=0.9";
}

function isEnvelope(v: unknown): v is ApiEnvelope {
  if (v === null || typeof v !== "object") {
    return false;
  }
  const o = v as Record<string, unknown>;
  return (
    typeof o.code === "number" &&
    typeof o.msg === "string" &&
    "data" in o
  );
}

const baseURL = process.env.NEXT_PUBLIC_LOTTERY_API_BASE_URL?.trim();

/**
 * **第一层**：只挂 `baseURL` / `timeout` / 默认 `Accept`。业务解析、toast 都不在这里。
 */
export const lotteryHttp = axios.create({
  baseURL: baseURL && baseURL !== "" ? baseURL : undefined,
  timeout: 30_000,
  headers: { Accept: "application/json" },
});

function mergeLocaleHeaders(
  config: AxiosRequestConfig,
): AxiosRequestConfig {
  const loc = requestLocale();
  const merged: AxiosRequestConfig = { ...config };
  // Axios 的 RequestConfig.headers 类型比 concat 能接受的头对象更窄
  const headers = AxiosHeaders.concat(
    merged.headers as Parameters<typeof AxiosHeaders.concat>[0],
  );
  headers.set("X-Locale", loc);
  headers.set("Accept-Language", acceptLanguage(loc));
  merged.headers = headers;
  return merged;
}

/**
 * 对 **payload**（通常是 `response.data`）校验信封并成功时返回 `data`；
 * `code !== 0` 抛 {@link LotteryApiBizError}。
 */
export function unwrapData<T>(payload: unknown): T {
  if (!isEnvelope(payload)) {
    throw new LotteryApiEnvelopeError();
  }
  if (payload.code !== 0) {
    throw new LotteryApiBizError(payload.msg, payload.code, payload.data);
  }
  return payload.data as T;
}

/** 对已拿到的 `AxiosResponse` 解一层 `unwrapData(response.data)` */
export function unwrapResponse<T>(res: AxiosResponse<unknown>): T {
  return unwrapData<T>(res.data);
}

/**
 * **第二层**：自动带语言头，用 `lotteryHttp` 发请求，再 `unwrapResponse`。
 * 是否提示用户由各页面/特性自己 `catch` 决定。
 */
export async function request<T>(config: AxiosRequestConfig): Promise<T> {
  const merged = mergeLocaleHeaders(config);
  try {
    const res = await lotteryHttp.request<unknown>(merged);
    return unwrapResponse<T>(res);
  } catch (err: unknown) {
    if (isAxiosError(err) && err.response?.data !== undefined) {
      const body = err.response.data;
      if (isEnvelope(body) && body.code !== 0) {
        throw new LotteryApiBizError(body.msg, body.code, body.data);
      }
    }
    throw err;
  }
}

/** 第二层常用动词（内部都是 `request`） */
export const lotteryRequest = {
  request,

  get: <T>(url: string, config?: Omit<AxiosRequestConfig, "url" | "method">) =>
    request<T>({ ...config, url, method: "GET" }),

  delete: <T>(url: string, config?: Omit<AxiosRequestConfig, "url" | "method">) =>
    request<T>({ ...config, url, method: "DELETE" }),

  post: <T>(
    url: string,
    data?: unknown,
    config?: Omit<AxiosRequestConfig, "url" | "method" | "data">,
  ) => request<T>({ ...config, url, method: "POST", data }),

  put: <T>(
    url: string,
    data?: unknown,
    config?: Omit<AxiosRequestConfig, "url" | "method" | "data">,
  ) => request<T>({ ...config, url, method: "PUT", data }),

  patch: <T>(
    url: string,
    data?: unknown,
    config?: Omit<AxiosRequestConfig, "url" | "method" | "data">,
  ) => request<T>({ ...config, url, method: "PATCH", data }),
};