import re
import secrets
import pandas as pd
import streamlit as st
from trycourier import Courier
from argon2 import PasswordHasher
from argon2.exceptions import VerifyMismatchError

ph = PasswordHasher()


def check_usr_pass(user_log_in_database, user_name: str, password: str) -> bool:
    """
    Authenticates the user_name and password.
    """
    registered_user = user_log_in_database.fetch({'user_name': user_name}).items
    try:
        passwd_verification_bool = ph.verify(registered_user[0]['password'], password)
        if passwd_verification_bool:
            return True
        return False
    except VerifyMismatchError:
        pass
    return False


def check_valid_name(name_sign_up: str) -> bool:
    """
    Checks if the user entered a valid name while creating the account.
    """
    name_regex_eng = r'^[A-Za-z_]\w *'
    name_regex_rus = r'^[А-Яа-я_][А-Яа-я0-9_] *'

    if re.search(name_regex_eng, name_sign_up) or re.search(name_regex_rus, name_sign_up):
        return True
    return False


def check_valid_email(email_sign_up: str) -> bool:
    """
    Checks if the user entered a valid e-mail while creating the account.
    """
    regex = re.compile(r'([A-Za-z0-9]+[.-_])*[A-Za-z0-9]+@[A-Za-z0-9-]+(\.[A-Z|a-z]{2,})+')

    if re.fullmatch(regex, email_sign_up):
        return True
    return False


def check_unique_email(user_log_in_database, email_sign_up: str) -> bool:
    """
    Checks if the e-mail already exists (since e-mail needs to be unique).
    """
    authorized_users_data = user_log_in_database.fetch({'e-mail': email_sign_up}).items
    if len(authorized_users_data) == 0:
        return True
    return False


def non_empty_str_check(user_name_sign_up: str) -> bool:
    """
    Checks for non-empty strings.
    """
    empty_count = 0
    for i in user_name_sign_up:
        if i == ' ':
            empty_count = empty_count + 1
            if empty_count == len(user_name_sign_up):
                return False
    if not user_name_sign_up:
        return False
    return True


def check_unique_usr(user_log_in_database, user_name_sign_up: str):
    """
    Checks if the user_name already exists (since user_name needs to be unique),
    also checks for non-empty user_name.
    """
    authorized_users_data = user_log_in_database.fetch({'user_name': user_name_sign_up}).items
    if len(authorized_users_data) != 0:
        return False
    if user_name_sign_up in authorized_users_data:
        return False
    non_empty_check = non_empty_str_check(user_name_sign_up)
    if not non_empty_check:
        return None
    return True


def register_new_usr(user_log_in_database, name_sign_up: str, email_sign_up: str, user_name_sign_up: str,
                     password_sign_up: str, professional_level: str, timestamp: str) -> None:
    """
    Saves the information of the new user in the _secret_auth.json file.
    """
    new_usr_data = {'user_name': user_name_sign_up,
                    'name': name_sign_up,
                    'e-mail': email_sign_up,
                    'password': ph.hash(password_sign_up),
                    'professional_level': professional_level,
                    'time_stamp': timestamp}

    return user_log_in_database.put(new_usr_data)


def check_user_name_exists(user_log_in_database, user_name: str) -> bool:
    """
    Checks if the user_name exists in the _secret_auth.json file.
    """
    authorized_users_data = user_log_in_database.fetch({'user_name': user_name}).items
    if len(authorized_users_data) == 1:
        return True
    return False


def check_email_exists(user_log_in_database, email_forgot_passwd: str):
    """
    Checks if the e-mail entered is present in the _secret_auth.json file.
    """
    authorized_users_data = user_log_in_database.fetch({'e-mail': email_forgot_passwd}).items
    if len(authorized_users_data) == 1:
        return True, authorized_users_data[0]['user_name']
    return False, None


def generate_random_passwd() -> str:
    """
    Generates a random password to be sent in e-mail.
    """
    password_length = 10
    return secrets.token_urlsafe(password_length)


def send_passwd_in_email(auth_token: str, user_name_forgot_passwd: str, email_forgot_passwd: str, company_name: str,
                         random_password: str) -> None:
    """
    Triggers an e-mail to the user containing the randomly generated password.
    """
    client = Courier(auth_token=auth_token)

    client.send_message(
        message={
            "to": {
                "email": email_forgot_passwd
            },
            "content": {
                "title": f'{company_name}: Login Password!',
                "body": f'Hi! {user_name_forgot_passwd},\n\nYour temporary login password is: {random_password}\n\n'
                        + '{{info}}'
            },
            "data": {
                "info": "Please reset your password at the earliest for security reasons."
            }
        }
    )


def change_passwd(user_log_in_database, email_forgot_passwd: str, random_password: str) -> None:
    """
    Replaces the old password with the newly generated password.
    """
    user_key = user_log_in_database.fetch({'e-mail': email_forgot_passwd}).items[0]['key']
    updates = {'password': ph.hash(random_password)}
    return user_log_in_database.update(updates, user_key)


def check_current_passwd(user_log_in_database, email_reset_passwd: str, current_passwd: str = None) -> bool:
    """
    Authenticates the password entered against the user_name when
    resetting the password.
    """
    authorized_user_data = user_log_in_database.fetch({'e-mail': email_reset_passwd}).items[0]
    if current_passwd is None:
        current_passwd = 'b'
    try:
        if ph.verify(authorized_user_data['password'], current_passwd):
            return True
    except VerifyMismatchError:
        pass
    return False


def save_data_in_database(user_task_database, save_type, save_name, cefr_level, time_stamp, creator_name=None,
                          generated_result=None, test_taker_name=None, test_taker_answers=None, test_taker_result=None,
                          comments=None, distractor_model=None, allow=False):
    already_saved_names = user_task_database.fetch({'creator_name': creator_name,
                                                    'save_name': save_name,
                                                    'cefr_level': cefr_level}).items
    already_saved_tasks = user_task_database.fetch({'creator_name': creator_name,
                                                    'generated_result': generated_result,
                                                    'cefr_level': cefr_level}).items
    already_saved_tests = user_task_database.fetch({'test_taker_name': test_taker_name,
                                                    'save_name': save_name,
                                                    'cefr_level': cefr_level}).items
    if save_name == '' and save_type == 'download':
        save_name = generated_result['name']
    if len(already_saved_names) != 0 and save_type == 'download':
        return st.success('Файл с таким названием уже существует! Введите другое название и повторите попытку.')
    elif len(already_saved_tasks) != 0 and save_type == 'download':
        return st.error(f'Вы уже сохраняли эти задания под именем {already_saved_tasks[0]["save_name"]}. ')
    elif (len(already_saved_tests) != 0
          and save_type == 'online_test'):  # and int(test_taker_result) == int(already_saved_tests[0]["user_points"])
        return st.error('Вы уже решали данный тест!')
    else:
        if save_type == 'download':
            new_save_data = {
                'save_type': save_type,
                'save_name': save_name,
                'cefr_level': cefr_level,
                'time_stamp': time_stamp,
                'creator_name': creator_name,
                'generated_result': generated_result,
                'distractor_model': distractor_model
            }
        else:
            new_save_data = {
                'save_type': save_type,
                'save_name': save_name,
                'cefr_level': cefr_level,
                'time_stamp': time_stamp,
                'creator_name': creator_name,
                'test_taker_name': test_taker_name,
                'test_taker_answers': test_taker_answers,
                'generated_result': generated_result,
                'test_taker_result': test_taker_result,
                'comments': comments}
        user_task_database.put(new_save_data)
        if save_type == 'download':
            if allow:
                return st.success('Задания успешно сохранены! Можете переходить на следующие вкладки')
        elif save_type == 'online_test':
            return st.success('Ответы успешно сохранены!')


def load_user_tasks_data(user_task_database, save_type, creator_name=None, test_taker_name=None):
    if save_type == 'download':
        user_data = user_task_database.fetch({'creator_name': creator_name, 'save_type': save_type}).items
        names = [item['save_name'] for item in user_data]
        cefr_level = [item['cefr_level'] for item in user_data]
        time_stamps = [item['time_stamp'] for item in user_data]
        return_data = pd.DataFrame([names, cefr_level, time_stamps]).transpose()
        return_data.columns = ['Название', 'Уровень', 'Время создания']
    else:
        user_data = user_task_database.fetch({'test_taker_name': test_taker_name, 'save_type': save_type}).items
        names = [item['save_name'] for item in user_data]
        cefr_level = [item['cefr_level'] for item in user_data]
        time_stamps = [item['time_stamp'] for item in user_data]
        creator_name = [item['creator_name'] for item in user_data]
        test_taker_result = [item['test_taker_result'] for item in user_data]
        return_data = pd.DataFrame([names, cefr_level, test_taker_result, time_stamps, creator_name]).transpose()
        return_data.columns = ['Название', 'Уровень', 'Оценка', 'Дата прохождения', 'Автор заданий']
    return return_data


def load_users_particular_task(user_task_database, load_mode, creator_name, save_name, cefr_level,):
    return_data = user_task_database.fetch({'creator_name': creator_name,
                                            'save_name': save_name,
                                            'save_type': load_mode,
                                            'cefr_level': cefr_level}).items[0]['generated_result']
    return return_data