import os

from flask import Flask, session, redirect, escape, request


# Configure the application name with the FLASK_APP environment variable.
app = Flask(__name__)


# Configure the secret_key with the SECRET_KEY environment variable.
app.secret_key = os.environ.get('SECRET_KEY', default=None)


@app.route('/')
def index():
    if 'username' in session:
        return 'Logged in as %s' % escape(session['username'])
    return 'You are not logged in'


@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        session['username'] = request.form['username']
        return redirect('/')
    return '''
        <form method="post">
        <p><input type=text name=username>
        <p><input type=submit value=Login>
        </form>
    '''


@app.route('/logout')
def logout():
    session.pop('username', None)
    return redirect('/')