project-lyra/core/relay/server.js

import express from "express";
import dotenv from "dotenv";
import cors from "cors";

dotenv.config();

const app = express();
app.use(cors());
app.use(express.json());

const PORT = Number(process.env.PORT || 7078);

// core endpoints
const CORTEX_REASON = process.env.CORTEX_REASON_URL || "http://cortex:7081/reason";
const CORTEX_INGEST = process.env.CORTEX_INGEST_URL || "http://cortex:7081/ingest";

// -----------------------------------------------------
// Helper request wrapper
// -----------------------------------------------------
async function postJSON(url, data) {
  const resp = await fetch(url, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(data),
  });

  const raw = await resp.text();
  let json;

  // Try to parse JSON safely
  try {
    json = raw ? JSON.parse(raw) : null;
  } catch (e) {
    throw new Error(`Non-JSON from ${url}: ${raw}`);
  }

  if (!resp.ok) {
    throw new Error(json?.detail || json?.error || raw);
  }

  return json;
}

// -----------------------------------------------------
// Shared chat handler logic
// -----------------------------------------------------
async function handleChatRequest(session_id, user_msg) {
  // 1. → Cortex.reason: the main pipeline
  let reason;
  try {
    reason = await postJSON(CORTEX_REASON, {
      session_id,
      user_prompt: user_msg
    });
  } catch (e) {
    console.error("Relay → Cortex.reason error:", e.message);
    throw new Error(`cortex_reason_failed: ${e.message}`);
  }

  const persona = reason.final_output || reason.persona || "(no persona text)";

  // 2. → Cortex.ingest (async, non-blocking)
  // Cortex might still want this for separate ingestion pipeline.
  postJSON(CORTEX_INGEST, {
    session_id,
    user_msg,
    assistant_msg: persona
  }).catch(e =>
    console.warn("Relay → Cortex.ingest failed:", e.message)
  );

  // 3. Return corrected result
  return {
    session_id,
    reply: persona
  };
}

// -----------------------------------------------------
// HEALTHCHECK
// -----------------------------------------------------
app.get("/_health", (_, res) => {
  res.json({ ok: true });
});

// -----------------------------------------------------
// OPENAI-COMPATIBLE ENDPOINT (for UI & clients)
// -----------------------------------------------------
app.post("/v1/chat/completions", async (req, res) => {
  try {
    const session_id = req.body.session_id || req.body.user || "default";
    const messages = req.body.messages || [];
    const lastMessage = messages[messages.length - 1];
    const user_msg = lastMessage?.content || "";

    if (!user_msg) {
      return res.status(400).json({ error: "No message content provided" });
    }

    console.log(`Relay (v1) → received: "${user_msg}"`);

    const result = await handleChatRequest(session_id, user_msg);

    return res.json({
      id: `chatcmpl-${Date.now()}`,
      object: "chat.completion",
      created: Math.floor(Date.now() / 1000),
      model: "lyra",
      choices: [{
        index: 0,
        message: {
          role: "assistant",
          content: result.reply
        },
        finish_reason: "stop"
      }],
      usage: {
        prompt_tokens: 0,
        completion_tokens: 0,
        total_tokens: 0
      }
    });

  } catch (err) {
    console.error("Relay v1 fatal:", err);
    res.status(500).json({
      error: {
        message: err.message || String(err),
        type: "server_error",
        code: "relay_failed"
      }
    });
  }
});

// -----------------------------------------------------
// MAIN ENDPOINT (canonical Lyra UI entrance)
// -----------------------------------------------------
app.post("/chat", async (req, res) => {
  try {
    const session_id = req.body.session_id || "default";
    const user_msg   = req.body.message || "";

    console.log(`Relay → received: "${user_msg}"`);

    const result = await handleChatRequest(session_id, user_msg);
    return res.json(result);

  } catch (err) {
    console.error("Relay fatal:", err);
    res.status(500).json({
      error: "relay_failed",
      detail: err.message || String(err)
    });
  }
});

// -----------------------------------------------------
app.listen(PORT, () => {
  console.log(`Relay is online on port ${PORT}`);
});