// Shared helpers for OpenRouter probes. Key comes from process.env.OPENROUTER_API_KEY (never logged).
import { mkdirSync, writeFileSync } from "node:fs";
import OpenAI from "openai";

export const BASE = "https://openrouter.ai/api/v1";
export const KEY = process.env.OPENROUTER_API_KEY ?? "";
if (!KEY) {
  console.error("OPENROUTER_API_KEY missing (run: set -a; . ./.env; set +a)");
  process.exit(1);
}

export const OUT = new URL("./out/", import.meta.url).pathname;
mkdirSync(OUT, { recursive: true });

export const APP_HEADERS = { "HTTP-Referer": "https://www.polyllm.io", "X-Title": "PolyLLM research" };

export const client = new OpenAI({
  apiKey: KEY,
  baseURL: BASE,
  timeout: 120_000,
  maxRetries: 0,
  defaultHeaders: APP_HEADERS,
});

export function save(name: string, data: unknown) {
  writeFileSync(`${OUT}${name}`, JSON.stringify(data, null, 2));
  console.log(`saved out/${name}`);
}

const HEADER_RE = /ratelimit|request-id|x-request|retry-after|content-type|server|date|cf-ray|x-openrouter|x-or-/i;

/** Raw request; returns status, selected headers, and parsed body (never echoes the key). */
export async function raw(path: string, init: RequestInit & { key?: string } = {}) {
  const { key, ...rest } = init;
  const res = await fetch(`${BASE}${path}`, {
    ...rest,
    headers: {
      "Content-Type": "application/json",
      Authorization: `Bearer ${key ?? KEY}`,
      ...APP_HEADERS,
      ...(rest.headers ?? {}),
    },
  });
  const text = await res.text();
  let body: unknown = text;
  try {
    body = JSON.parse(text);
  } catch {}
  const headers: Record<string, string> = {};
  res.headers.forEach((v, k) => {
    if (HEADER_RE.test(k)) headers[k] = v;
  });
  return { status: res.status, headers, body };
}

/** Raw SSE POST; returns parsed data events plus every comment line (": OPENROUTER PROCESSING"). */
export async function rawSSE(path: string, payload: unknown, key?: string) {
  const res = await fetch(`${BASE}${path}`, {
    method: "POST",
    headers: { "Content-Type": "application/json", Authorization: `Bearer ${key ?? KEY}`, ...APP_HEADERS },
    body: JSON.stringify(payload),
  });
  const headers: Record<string, string> = {};
  res.headers.forEach((v, k) => {
    if (HEADER_RE.test(k)) headers[k] = v;
  });
  if (!res.ok || !res.body) {
    const text = await res.text();
    let body: unknown = text;
    try {
      body = JSON.parse(text);
    } catch {}
    return { status: res.status, headers, error: body, events: [] as any[], comments: [] as string[] };
  }
  const reader = res.body.getReader();
  const dec = new TextDecoder();
  let buf = "";
  const events: { event?: string; data: any; raw?: string }[] = [];
  const comments: string[] = [];
  for (;;) {
    const { value, done } = await reader.read();
    if (done) break;
    buf += dec.decode(value, { stream: true });
    let idx;
    while ((idx = buf.indexOf("\n\n")) >= 0) {
      const block = buf.slice(0, idx);
      buf = buf.slice(idx + 2);
      let ev: string | undefined;
      const datas: string[] = [];
      for (const line of block.split("\n")) {
        if (line.startsWith(":")) comments.push(line);
        else if (line.startsWith("event:")) ev = line.slice(6).trim();
        else if (line.startsWith("data:")) datas.push(line.slice(5).trim());
      }
      if (!datas.length) continue;
      const d = datas.join("\n");
      if (d === "[DONE]") {
        events.push({ event: ev, data: "[DONE]" });
        continue;
      }
      try {
        events.push({ event: ev, data: JSON.parse(d) });
      } catch {
        events.push({ event: ev, data: null, raw: d });
      }
    }
  }
  return { status: res.status, headers, events, comments };
}

export function short(s: unknown, n = 300) {
  const t = typeof s === "string" ? s : JSON.stringify(s) ?? String(s);
  return t.length > n ? t.slice(0, n) + "…" : t;
}