import { env } from "@/lib/config";

export type FetchOptions = {
  method?: "GET" | "POST" | "PUT" | "DELETE" | "PATCH";
  token?: string;
  body?: Record<string, unknown> | FormData;
  query?: Record<string, string | number | boolean | undefined | null>;
  signal?: AbortSignal;
};

export class ApiError extends Error {
  constructor(
    public readonly status: number,
    public readonly payload: unknown,
    message?: string,
  ) {
    super(message ?? `Erreur API (${status})`);
    this.name = "ApiError";
  }
}

export async function apiFetch<T>(
  path: string,
  opts: FetchOptions = {},
): Promise<T> {
  const base = env.apiBaseUrl;
  const target = path.startsWith("/") ? path : `/${path}`;
  const url = new URL(base + target);

  if (opts.query) {
    for (const [k, v] of Object.entries(opts.query)) {
      if (v !== undefined && v !== null) {
        url.searchParams.set(k, String(v));
      }
    }
  }

  const headers: Record<string, string> = { Accept: "application/json" };
  if (opts.token) {
    headers.Authorization = `Bearer ${opts.token}`;
  }

  let body: BodyInit | undefined;
  if (opts.body instanceof FormData) {
    body = opts.body;
  } else if (opts.body !== undefined) {
    headers["Content-Type"] = "application/json";
    body = JSON.stringify(opts.body);
  }

  const res = await fetch(url, {
    method: opts.method ?? "GET",
    headers,
    body,
    signal: opts.signal,
    cache: "no-store",
  });

  const text = await res.text();
  let payload: unknown = null;
  if (text) {
    try {
      payload = JSON.parse(text);
    } catch {
      payload = text;
    }
  }

  if (!res.ok) {
    const message =
      payload && typeof payload === "object" && "message" in payload
        ? String((payload as { message: unknown }).message)
        : undefined;
    throw new ApiError(res.status, payload, message);
  }

  return payload as T;
}