ussd.py

from flask import Flask, request, Response
from dotenv import load_dotenv
import os
import google.generativeai as genai
import logging
import re

#simple logging for debugging
logging.basicConfig(level=logging.INFO)

# Load environment variables
load_dotenv()

app = Flask(__name__)

# Configure Gemini
genai.configure(api_key=os.getenv("GOOGLE_API_KEY"))
model = genai.GenerativeModel("gemini-flash-1.5")

api_key = os.getenv("GOOGLE_API_KEY")
if not api_key:
    raise ValueError("GOOGLE_API_KEY not found in .env file.")
genai.configure(api_key=api_key)

#Define helper function outsdie the route
def clean_response(text):
    """Remove markdown and extra formatting for USSD"""
    return re.sub(r'[\*\#\_\`\~]', '', text.replace('\n', ' '))[:1600]

@app.before_request
def log_request():
    logging.info(f"Request from {request.form.get('phoneNumber')}: {request.form.get('text')}")

@app.route('/ussd', methods=['POST'])
def ussd():
    text = request.values.get('text', '')
    session_id = request.values.get('sessionId', '')
    phone_number = request.values.get('phoneNumber', '')
    service_code = request.values.get('serviceCode', "")

    logging.info(f"Incoming USSD request: {text}")

    # Split user input (USSD uses * to separate steps)
    steps = text.split('*')
    response = ""

    # main menu
    if text == "":
        response = "CON Welcome to Bitcoin Academy\n"
        response += "1. What is Bitcoin?\n"
        response += "2. How Bitcoin Works\n"
        response += "3. Bitcoin vs Traditional Currencies\n"
        response += "4. Ask AI Assistant"
    # Step 1: What is bitcoin
    elif text == '1':
        response = (
            "CON Bitcoin is digital money that anyone can send or receive without a bank.\n\n"
            "1. Next\n"
            "0. Back"
        )
    elif text == "1*0":
        response = (
            "CON Welcome to Bitcoin Academy\n"
            "1. What is Bitcoin?\n"
            "2. How Bitcoin Works\n"
            "3. Bitcoin vs Traditional Currencies\n"
            "4. Ask AI Assistant"
        )
    elif text == "1*1": # if user selects Next
        response = (
            "CON Bitcoin is secure, borderless and limited to 21 million coins.\n"
            "People preferit because it gives controlover their own money.\n"
            "0. Back"
        )
        
    elif text == "1*0": # if user selects Back
        response = (
            "CON Welcome to Bitcoin Academy\n"
            "1. What is Bitcoin?\n"
            "2. How Bitcoin Works\n"
            "3. Bitcoin vs Traditional Currencies\n"
            "4.Ask AI Assistant"
        )
    # step2: How Bitcoin Works
    elif text == "2":
        response = (
            "CON Bitcoin works on a network of computers that share one record - called the blockchain.\n\n"
            "1. Next\n"
            "0. Back"
        )
    elif text == "2*1": # user selects Next
        response = (
            "END When you send Bitcoin, computers confirm the transaction and add it to the blockchain. "
            "No bank controls it - the system runs through people all over the world."
        )
    elif text == "2*0": # user selects Back
        response = (
            "CON Welcome to Bitcoin Academy\n"
            "1. What is Bitcoin?\n"
            "2. Bitcoin vs Traditional Currencies\n"
            "3. Bitcoin Myths"
            "4.Ask AI Assistant"
        )
    # step3: Bitcoin vs Traditional Currencies
    elif text == "3":
        response = (
            "CON Traditional money is controlled by banks.\n"
            "Bitcoin is controlled by no one, it is open to everyone.\n\n"
            "Key Differences:\n"
            "Bitcoin is limited - no inflation.\n"
            "You control your money - no permission needed.\n\n"
            "0. Back"
        )
    elif response == "0":
        response = (
            "CON Welcome to Bitcoin Academy\n"
            "1. What is Bitcoin?\n"
            "2. How Bitcoin Works\n"
            "3. Bitcoin vs Traditional Currencies\n"
            "4.Ask AI Assistant"
        )
    elif steps[0] == "4":
        if len(steps) == 1:
            response = "CON Ask me any Bitcoin question:"
        else:
            user_question = " ".join(steps[1:])
            prompt = f"Explain this simply to a beginner in Bitcoin and new to technology make it short and easy to relate to: {user_question}"
            try:
                result = model.generate_content(prompt)
                ai_response = clean_response(result.text)
                response = f"END {ai_response[:1600]}"  # Limit length for USSD
            except Exception as e:
                response = f"END Sorry, something went wrong: {str(e)}"
    else:
        response = "END Invalid choice. Please try again."

    return Response(response, mimetype="text/plain")

if __name__ == '__main__':
    port = int(os.getenv("PORT", 5000))
    app.run(host='0.0.0.0', port=port, debug=True)