from flask import Flask, request, jsonify, render_template

app = Flask(__name__)

# SIP Calculation Function
def calculate_sip(P, i, n):
    M = P * (((1 + i) ** n - 1) / i) * (1 + i)
    return M

# REST API Endpoint for SIP Calculation
@app.route('/api/sip', methods=['POST'])
def sip_api():
    try:
        data = request.json  # Get JSON request data
        P = float(data.get("P", 5000))  # Default: 5000
        i = float(data.get("i", 12))  # Default: 12% annual
        n = int(data.get("n", 10))  # Default: 10 years

        # Convert annual interest rate to monthly and decimal
        monthly_rate = i / 12 / 100
        n_payments = n * 12

        M = calculate_sip(P, monthly_rate, n_payments)
        total_invested = P * n_payments
        estimated_returns = M - total_invested

        return jsonify({
            "monthly_investment": P,
            "annual_interest_rate": i,
            "years": n,
            "final_amount": M,
            "total_invested": total_invested,
            "estimated_returns": estimated_returns
        })

    except Exception as e:
        return jsonify({"error": str(e)}), 400  # Return error in JSON format

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000, debug=True)