import "server-only";
import { notFound } from "next/navigation";
import type { Envelope } from "./types";

export const API_URL = (process.env.API_URL ?? "http://127.0.0.1:8391").replace(/\/$/, "");

export class ApiRequestError extends Error {
  constructor(
    public status: number,
    public code: string,
    message: string,
  ) {
    super(message);
  }
}

/** Server-side fetch of an API envelope. 404 → Next `notFound()`; other failures throw (caught by error.tsx). */
export async function apiEnvelope<T>(path: string, init: { revalidate?: number; timeoutMs?: number } = {}): Promise<Envelope<T>> {
  const ctrl = new AbortController();
  const timer = setTimeout(() => ctrl.abort(), init.timeoutMs ?? 12_000);
  try {
    const res = await fetch(`${API_URL}${path}`, {
      signal: ctrl.signal,
      headers: { accept: "application/json" },
      ...(init.revalidate === undefined ? { cache: "no-store" } : { next: { revalidate: init.revalidate } }),
    });
    if (res.status === 404) notFound();
    if (!res.ok) {
      let code = "API_ERROR";
      let message = `API ${res.status}`;
      try {
        const body = (await res.json()) as { error?: { code?: string; message?: string } };
        code = body.error?.code ?? code;
        message = body.error?.message ?? message;
      } catch {
        /* ignore */
      }
      throw new ApiRequestError(res.status, code, message);
    }
    return (await res.json()) as Envelope<T>;
  } finally {
    clearTimeout(timer);
  }
}

export async function api<T>(path: string, init?: { revalidate?: number; timeoutMs?: number }): Promise<T> {
  return (await apiEnvelope<T>(path, init)).data;
}

/** Best-effort variant for non-critical widgets: returns null instead of throwing. */
export async function apiOptional<T>(path: string, init?: { revalidate?: number; timeoutMs?: number }): Promise<T | null> {
  try {
    return await api<T>(path, init);
  } catch (err) {
    if (err && typeof err === "object" && "digest" in err && String((err as { digest: unknown }).digest).startsWith("NEXT_HTTP_ERROR_FALLBACK")) return null;
    return null;
  }
}