backend/chat/chatChain.js

import { config } from "../src/config/index.js";
import { chatCompletion } from "../src/services/ollamaClient.js";
import { searchDocs } from "../chat/searchChat.js";
import fs from "node:fs";

function buildContextBlock(hits) {
  const lines = [];
  hits.forEach((h, i) => {
    const header = `# Fonte ${i + 1}${h.source ? ` (${h.source})` : ""}`;
    lines.push(header);
    lines.push(h.text);
    lines.push("");
  });
  return lines.join("\n").trim();
}

export async function answerWithContext({ message, sessionId }) {
  const hits = await searchDocs({ query: message, topK: config.rag.topK });
  const context = buildContextBlock(hits);
  // #region debug-point D:image-rag-context
  (() => {
    let u = "http://127.0.0.1:7777/event";
    let s = "image-rag-miss";
    try {
      const e = fs.readFileSync(".dbg/image-rag-miss.env", "utf8");
      u = e.match(/DEBUG_SERVER_URL=(.+)/)?.[1] || u;
      s = e.match(/DEBUG_SESSION_ID=(.+)/)?.[1] || s;
    } catch {}
    fetch(u, {
      method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({
        sessionId: s,
        runId: "post",
        hypothesisId: "D",
        location: "api/chat/chatChain.js",
        msg: "[DEBUG] answerWithContext context built",
        data: {
          questionHead: String(message ?? "").slice(0, 140),
          hits: Array.isArray(hits) ? hits.length : null,
          contextChars: context.length,
          topScore: hits?.[0]?.score ?? null,
          topSource: hits?.[0]?.source ?? null
        },
        ts: Date.now()
      })
    }).catch(() => {});
  })();
  // #endregion

  const system = [
    "Você é um assistente de atendimento interno de uma empresa.",
    "Responda apenas com base no CONTEXTO quando ele estiver disponível.",
    "Se o CONTEXTO não tiver a informação, diga que não encontrou na base da empresa e sugira o que solicitar ao time responsável.",
    "Seja direto e em português."
  ].join("\n");

  const messages = [
    { role: "system", content: system },
    ...(context ? [{ role: "system", content: `CONTEXTO:\n${context}` }] : []),
    ...(sessionId ? [{ role: "system", content: `session_id:${sessionId}` }] : []),
    { role: "user", content: message }
  ];

  const completion = await chatCompletion({ messages });

  return {
    answer: completion.content,
    sources: hits.map((h) => ({
      id: h.id,
      source: h.source,
      score: h.score,
      chunkIndex: h.chunkIndex,
      metadata: h.metadata
    }))
  };
}