from multiprocessing import Process
from time import sleep

import psutil
from flask import Flask, redirect, session, url_for


app = Flask(__name__)
app.secret_key = 'fxa9x85xf0xe9x982xc4xf8xa0kx91xa7xefx12y'


@app.route('/')
def index():
    return (
        '<form action="/work/start" method="POST">'
            '<input type="submit" value="Start">'
        '</form>'
        '<form action="/work/stop" method="POST">'
        '<input type="submit" value="Stop">'
        '</form>'
    )


def work_it():
    while True:
        print('working...')
        sleep(1)

@app.route('/work/start', methods=['POST'])
def start_work():
    if 'work_process' not in session:
        process = Process(target=work_it)
        process.start()
        pid = process.pid
        parent_pid = psutil.Process(process.pid).parent().pid
        session['work_process'] = (parent_pid, pid)
     return redirect(url_for('index'))


@app.route('/work/stop', methods=['POST'])
def stop_work():
    if 'work_process' in session:
        parent_pid, pid = session['work_process']
        try:
            process = psutil.Process(pid)
            if process.parent().pid == parent_pid:
                process.terminate()
        except psutil.NoSuchProcess:
            pass
        session.pop('work_process')
    return redirect(url_for('index'))