import time

from selenium.common.exceptions import (
    StaleElementReferenceException,
    TimeoutException)
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait

TIMEOUT_IN_S = 20

DEFAULT_IMPLICIT_WAIT_TIMEOUT_IN_S = 10


def wait_until_element_is_invisible_by_locator(context, locator_tuple,
                                               timeout=TIMEOUT_IN_S):
    wait = WebDriverWait(context.browser, timeout)
    wait.until(EC.invisibility_of_element_located(locator_tuple))


def wait_for_loading_to_finish(context, timeout=TIMEOUT_IN_S):
    wait_until_element_is_invisible_by_locator(
        context, (By.ID, 'loading'), timeout)


def wait_for_user_alert_to_disapear(context, timeout=TIMEOUT_IN_S):
    wait_until_element_is_invisible_by_locator(
        context, (By.ID, 'user-alerts'), timeout)


def _wait_until_elements_are_visible_by_locator(context, locator_tuple,
                                                timeout=TIMEOUT_IN_S):
    wait = WebDriverWait(context.browser, timeout)
    wait.until(EC.presence_of_all_elements_located(locator_tuple))
    return context.browser.find_elements(locator_tuple[0], locator_tuple[1])


def _wait_until_element_is_visible_by_locator(context, locator_tuple,
                                              timeout=TIMEOUT_IN_S):
    wait = WebDriverWait(context.browser, timeout)
    wait.until(EC.visibility_of_element_located(locator_tuple))
    return context.browser.find_element(locator_tuple[0], locator_tuple[1])


def wait_for_condition(context, predicate_func, timeout=TIMEOUT_IN_S,
                       poll_frequency=0.1):
    wait = WebDriverWait(context.browser, timeout,
                         poll_frequency=poll_frequency)
    wait.until(predicate_func)


def fill_by_xpath(context, xpath, text):
    field = context.browser.find_element_by_xpath(xpath)
    field.send_keys(text)


def fill_by_css_selector(context, css_selector, text, timeout=TIMEOUT_IN_S):
    field = find_element_by_css_selector(context, css_selector,
                                         timeout=timeout)
    field.send_keys(text)


def take_screenshot(context, filename):
    context.browser.save_screenshot(filename)


def page_has_css(context, css):
    try:
        find_element_by_css_selector(context, css)
        return True
    except TimeoutException:
        return False


def find_element_by_xpath(context, xpath):
    return _wait_until_element_is_visible_by_locator(
        context, (By.XPATH, xpath))


def find_element_by_id(context, id):
    return _wait_until_element_is_visible_by_locator(context, (By.ID, id))


def find_element_by_css_selector(context, css_selector, timeout=TIMEOUT_IN_S):
    return _wait_until_element_is_visible_by_locator(
        context, (By.CSS_SELECTOR, css_selector), timeout=timeout)


def find_element_by_class_name(context, class_name):
    return _wait_until_element_is_visible_by_locator(
        context, (By.CLASS_NAME, class_name))


def find_elements_by_css_selector(context, css_selector, timeout=TIMEOUT_IN_S):
    return _wait_until_elements_are_visible_by_locator(
        context, (By.CSS_SELECTOR, css_selector), timeout=timeout)


def find_elements_by_xpath(context, xpath, timeout=TIMEOUT_IN_S):
    return _wait_until_elements_are_visible_by_locator(
        context, (By.XPATH, xpath), timeout=timeout)


def find_element_containing_text(context, text, element_type='*'):
    return find_element_by_xpath(
        context, "//%s[contains(.,'%s')]" % (element_type, text))


def element_should_have_content(context, css_selector, content):
    e = find_element_by_css_selector(context, css_selector)
    assert e.text == content


def wait_until_button_is_visible(context, title, timeout=TIMEOUT_IN_S):
    wait = WebDriverWait(context.browser, timeout)
    locator_tuple = (By.XPATH, ("//%s[contains(.,'%s')]" % ('button', title)))
    wait.until(EC.visibility_of_element_located(locator_tuple))


def execute_ignoring_staleness(func, timeout=TIMEOUT_IN_S):
    end_time = time.time() + timeout
    while time.time() <= end_time:
        try:
            return func()
        except StaleElementReferenceException:
            pass
    raise TimeoutException(
        'did not solve stale state until timeout %f' % timeout)


def click_button(context, title, element='button'):
    button = find_element_containing_text(context, title, element_type=element)
    button.click()


def reply_subject(context):
    e = find_element_by_css_selector(context, '#reply-subject')
    return e.text