// Use the same undici package for Agent + fetch. Global fetch on Node 18 is a
// different undici build, so a custom Agent only applies when fetch comes from
// this module too. undici is pinned to v6 for the node:18 Docker image.
const { Agent, fetch: undiciFetch } = require('undici');

/**
 * The dispatcher every LLM call must use.
 *
 * Node's global `fetch` is undici, whose `headersTimeout` defaults to 300 s.
 * Ollama is called with `stream: false`, so it sends NO response headers until
 * the whole answer is generated — an end-cycle report takes longer than that.
 * The connection was therefore being torn down at almost exactly 301 s with a
 * bare `TypeError: fetch failed`, and every such run was quietly demoted to the
 * local fallback generator.
 *
 * The `AbortSignal.timeout(...)` on those calls was never the effective limit:
 * undici gave up first, so raising the signal to 20 minutes changed nothing.
 * Both numbers have to be long for either to matter.
 */
const LLM_REQUEST_TIMEOUT_MS = 1_800_000; // 30 minutes

const llmDispatcher = new Agent({
  headersTimeout: LLM_REQUEST_TIMEOUT_MS,
  bodyTimeout: LLM_REQUEST_TIMEOUT_MS,
});

module.exports = { llmDispatcher, llmFetch: undiciFetch, LLM_REQUEST_TIMEOUT_MS };