import time
from dataclasses import dataclass
from typing import Optional

from otppy import OTP
from selenium import webdriver
from selenium.common.exceptions import ElementClickInterceptedException
from selenium.common.exceptions import NoSuchElementException
from selenium.common.exceptions import StaleElementReferenceException
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.common.by import By
from selenium.webdriver.firefox.options import Options as FirefoxOptions
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait

USERNAME_INPUT_NAME = "loginfmt"
PASSWORD_INPUT_NAME = "passwd"
MFA_INPUT_ID = "otc"
CONTINUE_BUTTON_ID = "idSIButton9"
MFA_CONTINUE_BUTTON_ID = "idSubmit_SAOTCC_Continue"
MFA_ERROR_TEXT_ID = "idSpan_SAOTCC_Error_OTC"
VPN_INSTALL_PAGE_EXCLUSIVE_ELEMENT_ID = "provisioning_action_label"
MFA_MAX_RETRY_COUNT = 6
ELEMENT_CHECK_DELAY = 0.5


@dataclass
class VPNCookie:
    domain: str
    cookie: str


def login(
    username: str,
    password: str,
    mfa_secret: Optional[str] = None,
    vpn_site: str = "https://vpn.fhnw.ch",
    headless: bool = True,
) -> VPNCookie:
    options = FirefoxOptions()

    if headless:
        options.add_argument("--headless")

    driver = webdriver.Firefox(options=options)
    driver.get(vpn_site)

    _fill_login(driver, username, password)
    _fill_mfa(driver, mfa_secret)
    _confirm_stay_signed_in(driver)
    _is_on_install_page(driver)
    return _get_webvpn_cookie(driver)


def _fill_login(driver: webdriver.Firefox, username: str, password: str) -> None:
    if not _find_element(driver, By.NAME, USERNAME_INPUT_NAME):
        raise ValueError("Could not find login page!")

    driver.find_element(By.NAME, USERNAME_INPUT_NAME).send_keys(username)
    driver.find_element(By.NAME, PASSWORD_INPUT_NAME).send_keys(password)
    click_continue(driver)  # Confirm username
    click_continue(driver)  # Confirm password


def _fill_mfa(driver: webdriver.Firefox, mfa_secret: Optional[str]) -> None:
    # Check if we have to enter a MFA code
    if mfa_secret is None:
        return

    for _ in range(MFA_MAX_RETRY_COUNT):
        if not _find_element(driver, By.ID, MFA_INPUT_ID):
            time.sleep(ELEMENT_CHECK_DELAY)
            continue

        mfa_code = get_mfa_code(mfa_secret)
        driver.find_element(By.NAME, MFA_INPUT_ID).send_keys(mfa_code)
        click_continue(driver, MFA_CONTINUE_BUTTON_ID)  # Confirm otp

        # Check for any errors
        if _find_element(driver, By.ID, MFA_ERROR_TEXT_ID, 2):
            # Found an error
            break


def _confirm_stay_signed_in(driver: webdriver.Firefox) -> None:
    click_continue(driver)  # Confirm stay signed in


def _find_element(driver: webdriver.Firefox, by: str, item: str, wait: int = 8) -> bool:
    try:
        w = WebDriverWait(driver, wait)
        w.until(EC.presence_of_element_located((by, item)))
        return True

    except TimeoutException:
        return False


def _is_on_install_page(driver: webdriver.Firefox) -> None:
    if not _find_element(driver, By.ID, VPN_INSTALL_PAGE_EXCLUSIVE_ELEMENT_ID):
        raise ValueError("Could not find install page!")


def _get_webvpn_cookie(driver: webdriver.Firefox) -> VPNCookie:
    webvpn_cookie = driver.get_cookie("webvpn")
    driver.close()

    if webvpn_cookie is None:
        raise ValueError(
            "Failed to find the webvpn cookie. Maybe the authentication has failed?"
        )

    webvpn_domain = webvpn_cookie["domain"]
    webvpn_value = webvpn_cookie["value"]
    return VPNCookie(domain=webvpn_domain, cookie=webvpn_value)


def click_continue(driver: webdriver.Firefox, btn_id: str = CONTINUE_BUTTON_ID) -> bool:
    """Returns true if still on login page, false if not"""
    for _ in range(16):
        try:
            driver.find_element(By.ID, btn_id).click()
            return True

        except (ElementClickInterceptedException, StaleElementReferenceException):
            pass
        except NoSuchElementException:
            if ".fhnw.ch" in driver.current_url:
                return False

        time.sleep(ELEMENT_CHECK_DELAY)

    return ".fhnw.ch" not in driver.current_url


def get_mfa_code(secret: str) -> str:
    otp = OTP.fromb32(secret)
    code: str = otp.TOTP()[0]
    return code