src/llm/callLLM.js

import { getProviderConfig } from "./providers.js";

export async function callLLM({ provider, model, prompt }) {
  const cfg = getProviderConfig(provider, model);

  let body;

  switch (cfg.name) {
    case "gemini":
      body = {
        contents: [{ parts: [{ text: prompt }] }]
      };
      break;

    case "dashscope":
      body = {
        model: cfg.model,
        input: { prompt }
      };
      break;

    default:
      body = {
        model: cfg.model,
        messages: [
          { role: "system", content: "You are a market research analyst." },
          { role: "user", content: prompt }
        ],
        temperature: 0.4
      };
  }

  const res = await fetch(cfg.baseUrl, {
    method: "POST",
    headers: cfg.headers,
    body: JSON.stringify(body)
  });

  const text = await res.text();

  if (!res.ok) {
    throw new Error(`LLM error ${res.status}: ${text}`);
  }

  const json = JSON.parse(text);

  // Normalize output
  if (cfg.name === "gemini") {
    return json.candidates?.[0]?.content?.parts?.[0]?.text || "";
  }

  if (cfg.name === "dashscope") {
    return json.output?.text || "";
  }

  return json.choices?.[0]?.message?.content || "";
}