import time
import pytest

def pytest_configure_node(node):
    node.slaveinput['all_nodes'] = {'a': True, 'b': True, 'c': True}
    node.slaveinput['used_nodes'] = {}

def _get_browser(request):
    def get_browser():
        class Browser(object):
            node = None
        browser = Browser()
        if hasattr(request.config, 'slaveinput'):
            all_nodes = request.config.slaveinput['all_nodes']
            used_nodes = request.config.slaveinput['used_nodes']
            free_nodes = set(all_nodes.keys()) - set(used_nodes.keys())
            node = free_nodes.pop()
            used_nodes[node] = all_nodes[node]
            request.config.slaveinput['used_nodes'] = used_nodes
            browser.node = node
        return browser
    return get_browser

def _close_browser(request):
    def close_browser(browser):
        if hasattr(request.config, 'slaveinput'):
            used_nodes = request.config.slaveinput['used_nodes']
            del used_nodes[browser.node]
            request.config.slaveinput['used_nodes'] = used_nodes
    return close_browser

def pytest_funcarg__browser(request):
    return request.cached_setup(
             setup=_get_browser(request),
             teardown=_close_browser(request),
             scope='function')