from flask import Flask, render_template, request, jsonify
import numpy as np
import matplotlib.pyplot as plt

app = Flask(__name__)

def calcular_vpn(n, r, cash_flow):
    descuento = 1 / ((1 + r) ** np.arange(1, n + 1))
    vpn = np.sum(cash_flow * descuento)
    return vpn

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/calcular', methods=['POST'])
def calcular():
    data = request.get_json()
    n = int(data['n'])
    r = float(data['r'])
    cash_flow = np.array(data['cash_flow'])
    
    vpn = calcular_vpn(n, r, cash_flow)
    
    plt.figure(figsize=(10, 6))
    plt.plot(np.arange(1, n + 1), cash_flow, marker='o')
    plt.xlabel('Años')
    plt.ylabel('Cash Flow')
    plt.title('Flujo de Efectivo')
    plt.grid(True)
    
    # Guardar el gráfico como imagen
    img_path = 'static/plot.png'
    plt.savefig(img_path)
    
    return jsonify({'vpn': vpn, 'plot_path': img_path})

if __name__ == '__main__':
    app.run(debug=True)