const OPENROUTER_API_KEY = process.env.OPENROUTER_API_KEY;
const DEFAULT_MODEL = process.env.OPENROUTER_DEFAULT_MODEL || "openai/gpt-4o-mini";

export async function askOpenRouter(model, prompt) {
  if (!OPENROUTER_API_KEY) {
    throw new Error("OPENROUTER_API_KEY is not set");
  }

  const res = await fetch("https://openrouter.ai/api/v1/chat/completions", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${OPENROUTER_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      model: model || DEFAULT_MODEL,
      messages: [{ role: "user", content: prompt }],
      // Some models default max_tokens to their full context window (e.g. 65536),
      // which can exceed available credit balance before a single token is generated.
      // This is a quick chat reply, not a long-form task — cap it.
      max_tokens: 1024,
    }),
  });

  if (!res.ok) {
    throw new Error(`OpenRouter request failed: ${res.status} ${await res.text()}`);
  }

  const data = await res.json();
  const content = data.choices?.[0]?.message?.content;
  if (!content) {
    throw new Error(`OpenRouter returned no content: ${JSON.stringify(data)}`);
  }
  return content;
}

export { DEFAULT_MODEL };