import logging
import time
from dataclasses import dataclass
from typing import Optional
from urllib.parse import urlparse

from otppy import OTP
from selenium import webdriver
from selenium.common.exceptions import ElementClickInterceptedException
from selenium.common.exceptions import ElementNotInteractableException
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_NAME = "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"
MAX_RETRY_DOMAIN_CHECK = 16
MFA_MAX_RETRY_COUNT = 3
ELEMENT_CHECK_DELAY = 0.5
DOMAIN_CHECK_DELAY = 0.5

LOGGER = logging.getLogger("OCMA")
LOGGER.setLevel(logging.INFO)


@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,
    log_messages: bool = False,
) -> VPNCookie:
    if log_messages:
        formatter = logging.Formatter(
            "%(asctime)s: %(levelname)s - %(name)s - %(message)s"
        )
        fh_s = logging.StreamHandler()
        fh_s.setLevel(logging.INFO)
        fh_s.setFormatter(formatter)
        LOGGER.addHandler(fh_s)

    LOGGER.info("Starting")

    options = FirefoxOptions()
    if headless:
        LOGGER.info("Running in headless mode")
        options.add_argument("--headless")

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

    retries = MAX_RETRY_DOMAIN_CHECK
    while not _is_on_ms_login_page(driver) and retries > 0:
        retries -= 1
        time.sleep(DOMAIN_CHECK_DELAY)

    if retries < 0:
        raise ValueError(
            f"We never reached the MS login page! Currently on {driver.current_url}"
        )

    _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:
    LOGGER.info("Filling in login information")

    _check_on_ms_login_page(driver)

    if not _find_element(driver, By.NAME, USERNAME_INPUT_NAME):
        raise ValueError("Could not find login page!")

    if not _element_interactable(driver, By.NAME, USERNAME_INPUT_NAME):
        raise ValueError("Could not find username field!")
    driver.find_element(By.NAME, USERNAME_INPUT_NAME).send_keys(username)
    click_continue(driver)

    if not _element_interactable(driver, By.NAME, PASSWORD_INPUT_NAME):
        raise ValueError("Could not find password input!")
    driver.find_element(By.NAME, PASSWORD_INPUT_NAME).send_keys(password)
    click_continue(driver)

    on_login_form = lambda: "saml2" in driver.current_url

    retries = MAX_RETRY_DOMAIN_CHECK
    while on_login_form() and retries > 0:
        LOGGER.info(
            f"Login information may not have yet been confirmed. Checking again (Try {MAX_RETRY_DOMAIN_CHECK - retries + 1} of {MAX_RETRY_DOMAIN_CHECK})"
        )
        time.sleep(ELEMENT_CHECK_DELAY)

        if on_login_form():
            LOGGER.info("Login information has not yet been confirmed. Trying again")
            click_continue(driver)  # Confirm password
        retries -= 1

    if retries < 0:
        raise ValueError("Failed to confirm login form!")

    LOGGER.info("Login information filled out")


def _fill_mfa(driver: webdriver.Firefox, mfa_secret: Optional[str]) -> None:
    LOGGER.info("Checking if we can fill in MFA information")

    _check_on_ms_login_page(driver)

    # Check if we have the MFA page
    if driver.current_url.endswith("/login") and mfa_secret is None:
        raise ValueError("You need to supply your MFA secret to log in!")

    # Check if we have an MFA code to enter
    if mfa_secret is None:
        LOGGER.info("Filling in login information")
        return

    for i in range(MFA_MAX_RETRY_COUNT):
        LOGGER.info(
            f"Filling in MFA information (Try {i + 1} of {MFA_MAX_RETRY_COUNT})"
        )
        if not _find_element(driver, By.NAME, MFA_INPUT_NAME):
            time.sleep(ELEMENT_CHECK_DELAY)
            continue

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

        LOGGER.info(f"Confirmed MFA code")

        if not driver.current_url.endswith("/login"):
            # We have moved on
            LOGGER.info(f"We have moved away from the MFA page")
            break

        # Check for any errors
        if not _find_element(driver, By.ID, MFA_ERROR_TEXT_ID, 2):
            # Did not find an error
            LOGGER.info(f"MFA seems to have been accepted, no errors")
            break


def _confirm_stay_signed_in(driver: webdriver.Firefox) -> bool:
    LOGGER.info(f"Cheking if we should confirm if we should stay signed in")

    if not _is_on_ms_login_page(driver):
        LOGGER.info(f"Already logged in, can't confirm 'stay signed in'")
        return False

    if not driver.current_url.endswith("/common/SAS/ProcessAuth"):
        LOGGER.info(
            f"We have reached a dead end. We have completed the login, but not on the 'stay signed in' page"
        )
        return False

    click_continue(driver)  # Confirm stay signed in
    LOGGER.info(f"Confirmed to 'stay signed in'")
    return True


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

    except ElementNotInteractableException:
        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 _check_on_ms_login_page(driver: webdriver.Firefox) -> None:
    if not _is_on_ms_login_page(driver):
        raise ValueError("We should still be on the MS login page but we aren't!")


def _is_on_ms_login_page(driver: webdriver.Firefox) -> bool:
    return urlparse(driver.current_url).netloc == "login.microsoftonline.com"


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:
            pass

        time.sleep(ELEMENT_CHECK_DELAY)
    return False


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