#!/usr/bin/python
#
# Copyright 2011 Software Freedom Conservancy.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import time
from selenium.common.exceptions import NoSuchElementException
from selenium.common.exceptions import TimeoutException

POLL_FREQUENCY = 0.5  # How long to sleep inbetween calls to the method

class WebDriverWait(object):

    def __init__(self, driver, timeout, poll_frequency=POLL_FREQUENCY):
        """Constructor, takes a WebDriver instance and timeout in seconds.
           
           :Args:
            - driver - Instance of WebDriver (Ie, Firefox, Chrome or Remote)
            - timeout - Number of seconds before timing out

           Example:
            from selenium.webdriver.support.ui import WebDriverWait \n
            element = WebDriverWait(driver, 10).until(lambda x: x.find_element_by_id("someId"))
        """
        self._driver = driver
        self._timeout = timeout
        self._poll = poll_frequency
        # avoid the divide by zero
        if self._poll == 0:
            self._poll = POLL_FREQUENCY

    def until(self, method, message=''):
        """Calls the method provided with the driver as an argument until the \
        return value is not False."""
        end_time = time.time() + self._timeout
        while(True):
            try:
                value = method(self._driver)
                if value:
                    return value
            except NoSuchElementException:
                pass
            time.sleep(self._poll)
            if(time.time() > end_time):
                break
        raise TimeoutException(message)

    def until_not(self, method, message=''):
          """Calls the method provided with the driver as an argument until the \
          return value is False."""
          end_time = time.time() + self._timeout
          while(True):
              try:
                  value = method(self._driver)
                  if not value:
                      return value
              except NoSuchElementException:
                  return True
              time.sleep(self._poll)
              if(time.time() > end_time):
                  break
          raise TimeoutException(message)
