#!/usr/bin/env python3
from flask import Flask, request, jsonify, render_template

app = Flask(__name__)

def calculate_bmi(height, weight):
    return round(weight / (height ** 2), 2)

def user_input_check(height, weight):
    if height <= 0 or height > 3:
        return "Рост должен быть больше 0 и не превышать 3 метра."
    if weight <= 0 or weight > 200:
        return "Вес должен быть больше 0 и не превышать 200 кг."
    return None

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

@app.route('/calculate', methods=['POST'])
def calculate():
    data = request.get_json()
    height = float(data['height'])
    weight = float(data['weight'])

    error = user_input_check(height, weight)
    if error:
        return jsonify({'error': error}), 400

    bmi = calculate_bmi(height, weight)
    return jsonify({'bmi': bmi})

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