app.py

import logging
import smtplib
import re
from email.mime.text import MIMEText
from flask import Flask, request, jsonify
from dotenv import load_dotenv
import os

# Load environment variables
load_dotenv()

# Configure logging
logging.basicConfig(level=logging.DEBUG, format="%(asctime)s - %(levelname)s - %(message)s")
logger = logging.getLogger("bot_brain")

# SMTP Server Configuration
SMTP_HOST = os.getenv("SMTP_HOST", "0.0.0.0")
SMTP_PORT = int(os.getenv("SMTP_PORT", "587"))
CLIENT_SMTP_HOST = os.getenv("CLIENT_SMTP_HOST", "localhost")
SMTP_USER = os.getenv("SMTP_USER", "noreply@yourdomain.com")
SMTP_PASSWORD = os.getenv("SMTP_PASSWORD", "password")

# Global conversation state: maps sender's WhatsApp number to conversation data.
conversations = {}

# Regex for validating email addresses
EMAIL_REGEX = re.compile(r"^[^@]+@[^@]+\.[^@]+$")

def validate_email(email: str) -> bool:
    """Validate an email address using regex."""
    return re.match(EMAIL_REGEX, email) is not None

def send_email(from_addr: str, to_addr: str, subject: str, body: str) -> bool:
    """
    Sends an email using the SMTP client.
    """
    msg = MIMEText(body)
    msg['Subject'] = subject
    msg['From'] = from_addr
    msg['To'] = to_addr

    logger.debug(f"Preparing to send email from {from_addr} to {to_addr} with subject '{subject}'")

    try:
        with smtplib.SMTP(CLIENT_SMTP_HOST, SMTP_PORT) as server:
            server.starttls()  # Upgrade to TLS
            server.login(SMTP_USER, SMTP_PASSWORD)
            server.sendmail(from_addr, [to_addr], msg.as_string())

        logger.info(f"Email sent successfully from {from_addr} to {to_addr}")
        return True
    except Exception as e:
        logger.error(f"Error sending email: {e}")
        return False

# Flask app acting as the Bot Brain API
app = Flask(__name__)

@app.route("/bot", methods=["POST"])
def bot():
    try:
        data = request.json
        logger.info("Received request from Node.js server: %s", data)
        sender_number = data.get("from", "unknown")
        message_body = data.get("message", {}).get("text", {}).get("body", "").strip()
        logger.info("Processing message from %s: %s", sender_number, message_body)
    except Exception as e:
        logger.error("Invalid JSON payload: %s", e)
        return jsonify({"status": "error", "message": "Invalid payload"}), 400

    state = conversations.get(sender_number, {})

    if not state:
        # Start a new conversation
        conversations[sender_number] = {"step": "from"}
        response_msg = "Welcome to SMTP Assistant! Please provide your 'From' email address."
    else:
        step = state.get("step")
        if step == "from":
            if validate_email(message_body):
                state["from"] = message_body
                state["step"] = "to"
                response_msg = "Thanks! Now, please provide the recipient's email address."
            else:
                response_msg = "Invalid email format. Please provide a valid 'From' email address."
        elif step == "to":
            if validate_email(message_body):
                state["to"] = message_body
                state["step"] = "subject"
                response_msg = "Great! Please provide the email subject."
            else:
                response_msg = "Invalid email format. Please provide a valid recipient email address."
        elif step == "subject":
            state["subject"] = message_body
            state["step"] = "body"
            response_msg = "Almost done! Please provide the email body."
        elif step == "body":
            state["body"] = message_body
            from_addr = state.get("from")
            to_addr = state.get("to")
            subject = state.get("subject")
            body = state.get("body")
            if send_email(from_addr, to_addr, subject, body):
                response_msg = f"Email sent successfully from {from_addr} to {to_addr}."
            else:
                response_msg = "Failed to send email. Please try again later."
            # Clear the conversation state after sending
            del conversations[sender_number]
        else:
            response_msg = "Unrecognized step. Let's start over. Please provide your 'From' email address."
            conversations[sender_number] = {"step": "from"}

    logger.info("Sending response to Node.js server: %s", response_msg)
    return jsonify({"status": "success", "message": response_msg})
    
if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)