mtf-nlp/src/server.js

// Import dotenv file if not in production
if (process.env.NODE_ENV !== "production") {
	require("dotenv").config();
}

const {env, pipeline} = require("@xenova/transformers");
const path = require("path");
env.allowRemoteModels = false;
env.localModelPath = path.resolve(__dirname, "./models/transformers").replace(/\\/g, "/");

const models = require("./models");
const db = models.db;
const redis = models.redis;
const {sequelize, Sequelize} = db;
const Intent = db.intent;

async function getIntents() {
  try {
    const intents = await Intent.findAll();

    console.log(intents);

    return intents;
  } catch (err) {
    console.error("getIntents error:", err);
  }
}

const config = require("./config");

/*const INTENTS = [
  {
    name: "play_music",
    examples: ["play music", "start music", "resume music", "play songs"],
  },
  {
    name: "stop_music",
    examples: ["stop music", "pause music", "halt music", "stop playback"],
  },
  {
    name: "set_volume",
    examples: ["set volume to 30", "volume 50", "turn volume up", "turn volume down"],
  },
];*/

let extractor;

function normalizeText(text) {
  return text
    .toLowerCase()
    .replace(/[^\w\s]/g, " ")
    .replace(/\s+/g, " ")
    .trim();
}

function cosineSimilarity(a, b) {
  let dot = 0;
  let magA = 0;
  let magB = 0;

  for (let i = 0; i < a.length; i++) {
    dot += a[i] * b[i];
    magA += a[i] * a[i];
    magB += b[i] * b[i];
  }

  return dot / (Math.sqrt(magA) * Math.sqrt(magB));
}

async function initModel() {
  extractor = await pipeline("feature-extraction", `${config.NLP_TRANSFORMER}`, {
    dtype: 'fp32',
    quantized: false,
    device: "cpu",
  });
  console.log("MiniLM model loaded");
}

async function embed(text) {
  const output = await extractor(normalizeText(text), {
    pooling: "mean",
    normalize: true,
  });

  return Array.from(output.data);
}

async function classifyIntent(text) {
  const inputEmbedding = await embed(text);

  let best = {
    name: "unknown",
    confidence: 0,
    matched: null,
  };

  for (const intent of INTENTS) {
    for (const example of intent.examples) {
      const exampleEmbedding = await embed(example);
      const score = cosineSimilarity(inputEmbedding, exampleEmbedding);

      if (score > best.confidence) {
        best = {
          name: intent.name,
          confidence: score,
          matched: example,
        };
      }
    }
  }

  return best;
}

async function handleIntent(streamKey, msg) {
	const text = msg.message?.text;
	const deviceId = msg.message?.device_id;

	if (!text) return;

	const intent = await classifyIntent(text);

	await redis.client.xAdd(streamKey, '*', {
		transcript_id: msg.id,
		command: intent.name,
		confidence: String(intent.confidence),
		matched: intent.matched || "",
		device_id: deviceId || "",
		text,
	});

	console.log("TODO: Handle Intents", intent);
}

async function processor(group, consumer, streamKey) {
	await redis.client.connect().catch(console.error);

	while (true) {
		const res = await redis.client.xReadGroup(
			group,
			consumer,
			[{key: streamKey, id: '>'}], // '>' means undelivered messages
			{COUNT: 5, BLOCK:3000}
		);

		if (!res) continue;

		for (const stream of res) {
			for (const msg of stream.messages) {
				try {
					console.log(`[${consumer}] Processing:`, msg);

					await handleIntent("commands", msg);

					await redis.client.xAck(streamKey, group, msg.id);
				} catch (err) {
					console.error("Failed to process message:", err);
				}
			}
		}
	}
}

const main = async () => {
	// Sync DB (not forced in production)
	const doForce = config.FORCE_DB_SYNC === "true" && config.NODE_ENV !== "production";
	await sequelize.authenticate();
	await sequelize.sync({force: doForce});

	if (doForce) console.info("Database dropped and resynced (force=true).");

  const INTENTS = getIntents();

	await initModel();
	
	await redis.ensureGroup("transcripts", 'nlp');
	await redis.ensureGroup("commands", 'nlp');

	processor('nlp', `${config.DEVICE_ID}`, "transcripts").catch(console.error);
}

main().catch(console.error);