14_human_approval.js

import { ChatGroq } from "@langchain/groq";
import { MemorySaver } from "@langchain/langgraph";
import { StateGraph, START, END, Annotation } from "@langchain/langgraph";
import * as readline from "readline";
import nodeMailer from "nodemailer";
import "dotenv/config";

//terminal input setup
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});

const askQuestion = (query) => new Promise((resolve) => rl.question(query, resolve));

//1. setup llm
const llm = new ChatGroq({
    apiKey: process.env.GROQ_API_KEY,
    model: "openai/gpt-oss-120b",
    temperature: 0.2
});

//2. Email transporter setup(nodemailer)
const transporter = nodeMailer.createTransport({
    service: 'gmail',
    auth: {
        user: process.env.EMAIL_USER,
        pass: process.env.EMAIL_PASS,
    }
});

//3. define graph state
const GraphState = Annotation.Root({
    recipient_email: Annotation(), //target email address
    topic: Annotation(), // topic of the email
    drafted_email: Annotation(), //email content generated by AI
});

//4. Nodes (worker)

//node A: ai email drafter
async function drafterNode(state) {

    console.log("\n [Ai drafter]: Writing professtional email for -> ", state.topic, "\n");
    const prompt = `Write a short , professtional email body (no subject line ) about this topic :${state.topic}`;
    const response = await llm.invoke(prompt);

    return { drafted_email: response.content };

}

//node B: email sender
async function senderNode(state) {

    console.log("Sending email...\n");
    try {
        const mailOptions = {
            from: process.env.EMAIL_USER,
            to: state.recipient_email,
            subject: "AI Automated Message", //mail subject
            text: state.drafted_email,
        };

        const info = await transporter.sendMail(mailOptions);
        console.log(`[Success] email officially send to : ${state.recipient_email}...\n `);
        console.log(`Message ID: ${info.messageId}`);


    } catch (error) {
        console.log("Error: ", error.message);

    }
    return {};

}

//build the graph
const memory = new MemorySaver();

const workflow = new StateGraph(GraphState)
    .addNode("drafter", drafterNode)
    .addNode("sender", senderNode)
    .addEdge(START, "drafter")
    .addEdge("drafter", "sender")
    .addEdge("sender", END)



//interrupt before send 
const app = workflow.compile({
    checkpointer: memory,
    interruptBefore: ["sender"]
});



async function main() {

    const config = { configurable: { thread_id: "email_01" } };

    const initialInput = {
        recipient_email: "manikkori697@gmail.com",
        topic: "Say good morning. "
    }

    //1. run graph(interrupt before sender) 
    await app.invoke(initialInput, config);

    //2. get current state
    const currentState = await app.getState(config);
    const nextNode = currentState.next[0];

    if (nextNode === "sender") {
        console.log("\n==================================================");
        console.log("⚠️  [SECURITY ALERT - APPROVAL REQUIRED] ⚠️");
        console.log("==================================================");
        console.log(`📤 To: ${currentState.values.recipient_email}`);
        console.log(`✉️  AI Draft:\n\n${currentState.values.drafted_email}`);
        console.log("==================================================\n");

        // 3: Ask for real permission
        const answer = await askQuestion(`Do you want to actually send this email? (Y/N): `);

        if (answer.toLowerCase() === 'y') {
            console.log("\n✅ Approved! Handing over to Nodemailer...");
            // resume the graph(rerun))
            await app.invoke(null, config);
        } else {
            console.log("\n❌ Cancelled! The email was safely destroyed.");
        }
    }
    rl.close()

}
main().catch(console.error)