#!/usr/bin/env python3

# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at https://mozilla.org/MPL/2.0/.

from contextlib import contextmanager
import json
import os
from selenium import webdriver
from selenium.common.exceptions import TimeoutException
import sys


@contextmanager
def create_gecko_session():
    try:
        firefox_binary = os.environ['FIREFOX_BIN']
    except KeyError:
        print("+=============================================================+")
        print("| You must set the path to your firefox binary to FIREFOX_BIN |")
        print("+=============================================================+")
        sys.exit()

    driver = webdriver.Firefox(firefox_binary=firefox_binary)
    yield driver
    # driver.quit() gives an "'NoneType' object has no attribute 'path'" error.
    # Fixed in
    # https://github.com/SeleniumHQ/selenium/commit/9157c7071f9900c2608f5ca40ae4f518ed373b96
    driver.quit()


def generate_placeholder(testcase):
    # We need to still include the failed tests, otherwise Treeherder will
    # consider the result to be a new test series, and thus a new graph. So we
    # use a placeholder with values = -1 to make Treeherder happy, and still be
    # able to identify failed tests (successful tests have time >=0).

    timings = {
        "testcase": testcase,
        "title": ""
    }

    timing_names = [
        "navigationStart",
        "unloadEventStart",
        "domLoading",
        "fetchStart",
        "responseStart",
        "loadEventEnd",
        "connectStart",
        "domainLookupStart",
        "redirectStart",
        "domContentLoadedEventEnd",
        "requestStart",
        "secureConnectionStart",
        "connectEnd",
        "loadEventStart",
        "domInteractive",
        "domContentLoadedEventStart",
        "redirectEnd",
        "domainLookupEnd",
        "unloadEventEnd",
        "responseEnd",
        "domComplete",
    ]

    for name in timing_names:
        timings[name] = 0 if name == "navigationStart" else -1

    return [timings]


def run_gecko_test(testcase, url, date, timeout, is_async):
    with create_gecko_session() as driver:
        driver.set_page_load_timeout(timeout)
        try:
            driver.get(url)
        except TimeoutException:
            print("Timeout!")
            return generate_placeholder(testcase)

        try:
            timings = {
                "testcase": testcase,
                "title": driver.title.replace(",", ",")
            }

            timings.update(json.loads(
                driver.execute_script(
                    "return JSON.stringify(performance.timing)"
                )
            ))
        except Exception:
            # We need to return a timing object no matter what happened.
            # See the comment in generate_placeholder() for explanation
            print("Failed to get a valid timing measurement.")
            return generate_placeholder(testcase)

        if is_async:
            # TODO: the timeout is hardcoded
            driver.implicitly_wait(5)  # sec
            driver.find_element_by_id("GECKO_TEST_DONE")
            timings.update(json.loads(
                driver.execute_script(
                    "return JSON.stringify(window.customTimers)"
                )
            ))

    return [timings]


if __name__ == '__main__':
    # Just for manual testing
    from pprint import pprint
    url = "http://localhost:8000/page_load_test/tp5n/dailymail.co.uk/www.dailymail.co.uk/ushome/index.html"
    pprint(run_gecko_test(url, 15))