"""
    Functions for network related stuff.
"""

import requests
import hashlib
from bs4 import BeautifulSoup
import os

not_login = 0
F_not_anymore = 0
session = requests.Session()

def _read_shadow() -> str:
    """
        Reads the shadow file and returns it in
        a suitable format for other functions.
    """
    
    result = ""
    try:
        with open(f"{os.environ['HOME']}/.local/lib/solendata/shadow", "r") as f:
            for row in f:
                result += row+";"
    except FileNotFoundError:
        os.system(f"touch {os.environ['HOME']}/.local/lib/solendata/shadow")
        with open(f"{os.environ['HOME']}/.local/lib/solendata/shadow", "r") as f:
            for row in f:
                result += row+";"

    return result

def _save_creds(user: str, pwd: str):
    """
        Saves credentials into the shadow file
        by appending them.
    """

    creds = ";" + _get_creds_hash(user, pwd)

    try:
        with open(f"{os.environ['HOME']}/.local/lib/solendata/shadow", "a+") as f:
            if not creds in _read_shadow():
                f.write(creds)
    except FileNotFoundError:
        os.system(f"touch {os.environ['HOME']}/.local/lib/solendata/shadow")
        with open(f"{os.environ['HOME']}/.local/lib/solendata/shadow", "a+") as f:
            if not creds in _read_shadow():
                f.write(creds)

def _eval_creds(creds: str) -> bool:
    """
        Evaluates the credentials for if
        they are in the shadow file or not.
    """

    shadow = _read_shadow()

    if creds in shadow:
        return True
    else:
        return False

def _get_creds_hash(user: str, pwd: str) -> str:
    """
        Creates a sha512 hash from the username
        and password.
    """

    user_hash = hashlib.sha512(bytes(user, 'utf-8')).hexdigest()
    pwd_hash = hashlib.sha512(bytes(pwd, 'utf-8')).hexdigest()
    creds = user_hash+":"+pwd_hash    

    return creds

def get_user_hash(user: str) -> str:
    return str(hashlib.sha512(bytes(user, 'utf-8')).hexdigest())

def login(user: str, pwd: str) -> bool:
    """
        Tries to send a request to the SOL
        servers in order to log in. 
    """

    if is_connected():
        url: str = "https://aplikace.skolaonline.cz/SOL/Prihlaseni.aspx"
        data = {
            "__EVENTTARGET": "dnn$ctr994$SOLLogin$btnODeslat",
            "__EVENTARGUMENT": "",
            "__VIEWSTATE": "",
            "__VIEWSTATEGENERATOR": "",
            "__VIEWSTATEENCRYPTED": "",
            "__PREVIOUSPAGE": "",
            "__EVENTVALIDATION": "",
            "dnn$dnnSearch$txtSearch": "",
            "JmenoUzivatele": user,  # username
            "HesloUzivatele": pwd,  # password
            "ScrollTop": "",
            "__dnnVariable": "",
            "__RequestVerificationToken": ""
        }

        post_login = session.post(url, data=data)
        if post_login.status_code != 200:
            return False
        else:
            return True
    else:
        if _eval_creds(_get_creds_hash(user, pwd)):
            return True
        else:
            return False

def is_connected() -> bool:
    """
        Checks whether there is internet
        access present.
    """

    import socket

    try:
        host = socket.gethostbyname("one.one.one.one")
        s = socket.create_connection((host, 80), 2)
        s.close()
        return True
    except:
        pass
    return False

def get_html_from(params=None) -> str:
    """
        Fetches the HTML markup of
        a specified subsite of SOL.
    """

    base = "https://aplikace.skolaonline.cz"

    if params is not None:
        base += params

    response = session.get(base)
    if response.status_code == 200:
        return response
    else:
        return ""