__filename__ = "webapp_login.py"
__author__ = "Bob Mottram"
__license__ = "AGPL3+"
__version__ = "1.5.0"
__maintainer__ = "Bob Mottram"
__email__ = "bob@libreserver.org"
__status__ = "Production"
__module_group__ = "Web Interface"

import os
import time
import filecmp
from shutil import copyfile
from utils import data_dir
from utils import get_image_extensions
from utils import get_config_param
from utils import no_of_accounts
from utils import get_nickname_validation_pattern
from webapp_utils import set_custom_background
from webapp_utils import html_header_with_website_markup
from webapp_utils import html_footer
from webapp_utils import html_keyboard_navigation
from webapp_utils import text_mode_browser
from theme import get_text_mode_logo


def html_get_login_credentials(login_params: str,
                               last_login_time: int,
                               registrations_open: bool,
                               calling_domain: str,
                               ua_str: str) -> (str, str, bool):
    """Receives login credentials via HTTPServer POST
    """
    if not login_params.startswith('username='):
        if '&username=' not in login_params:
            print('WARN: invalid login parameters ' + calling_domain + ', ' +
                  ua_str + ', ' + login_params)
            return None, None, None
    # minimum time between login attempts
    curr_time = int(time.time())
    if curr_time < last_login_time + 10:
        print('WARN: login attempt too frequent ' + calling_domain + ', ' +
              ua_str)
        return None, None, None
    if '&' not in login_params:
        return None, None, None
    login_args = login_params.split('&')
    nickname = None
    password = None
    register = False
    for arg in login_args:
        if '=' not in arg:
            continue
        if arg.split('=', 1)[0] == 'username':
            nickname = arg.split('=', 1)[1]
            if nickname.startswith('@'):
                nickname = nickname[1:]
            if '@' in nickname:
                # the full nickname@domain has been entered
                nickname = nickname.split('@')[0]
            # validation on nickname
            if 'passwd' in nickname or \
               '`' in nickname or \
               ';' in nickname or \
               ' ' in nickname:
                nickname = None
        elif arg.split('=', 1)[0] == 'password':
            password = arg.split('=', 1)[1]
            # validation on password
            if '`' in password:
                password = None
        elif registrations_open and arg.split('=', 1)[0] == 'register':
            register = True
    return nickname, password, register


def html_login(translate: {},
               base_dir: str,
               http_prefix: str, domain: str,
               system_language: str,
               autocomplete: bool,
               ua_str: str,
               theme_name: str) -> str:
    """Shows the login screen
    """
    accounts = no_of_accounts(base_dir)
    extensions = get_image_extensions()
    login_image_filename = None

    # does a login image exist for the current theme?
    for ext in extensions:
        login_image = 'login.' + ext
        theme_image = \
            base_dir + '/theme/' + theme_name + \
            '/' + login_image
        if os.path.isfile(theme_image):
            login_image_filename = \
                data_dir(base_dir) + '/' + login_image
            if os.path.isfile(login_image_filename):
                if not filecmp.cmp(theme_image,
                                   login_image_filename):
                    copyfile(theme_image, login_image_filename)
            else:
                copyfile(theme_image, login_image_filename)
            break

    # does a custom login image exist?
    if not login_image_filename:
        for ext in extensions:
            login_image = 'login.' + ext
            image_filename = data_dir(base_dir) + '/' + login_image
            if os.path.isfile(image_filename):
                login_image_filename = image_filename
                break

    # no login image found, so use the default
    if not login_image_filename:
        login_image = 'login.png'
        login_image_filename = data_dir(base_dir) + '/' + login_image
        source_image = base_dir + '/img/login.png'
        copyfile(source_image, login_image_filename)

    text_mode_logo = get_text_mode_logo(base_dir)
    text_mode_logo_html = html_keyboard_navigation(text_mode_logo, {}, {},
                                                   None, None, None, False)

    set_custom_background(base_dir, 'login-background-custom',
                          'login-background')

    if accounts > 0:
        login_text = \
            '<p class="login-text">' + \
            translate['Welcome. Please enter your login details below.'] + \
            '</p>'
    else:
        login_text = \
            '<p class="login-text">' + \
            translate['Please enter some credentials'] + '</p>' + \
            '<p class="login-text">' + \
            translate['You will become the admin of this site.'] + \
            '</p>'
    dir_str = data_dir(base_dir)
    if os.path.isfile(dir_str + '/login.txt'):
        # custom login message
        try:
            with open(dir_str + '/login.txt', 'r',
                      encoding='utf-8') as fp_login:
                login_text = \
                    '<p class="login-text">' + fp_login.read() + '</p>'
        except OSError:
            print('EX: html_login unable to read ' + dir_str + '/login.txt')

    css_filename = base_dir + '/epicyon-login.css'
    if os.path.isfile(base_dir + '/login.css'):
        css_filename = base_dir + '/login.css'

    # show the register button
    register_button_str = ''
    if get_config_param(base_dir, 'registration') == 'open':
        remaining = 0
        if get_config_param(base_dir, 'registrationsRemaining'):
            remaining = get_config_param(base_dir, 'registrationsRemaining')
            if isinstance(remaining, str):
                remaining = int(remaining)
        if remaining > 0:
            if accounts > 0:
                idx = 'Welcome. Please login or register a new account.'
                login_text = \
                    '<p class="login-text">' + \
                    translate[idx] + \
                    '</p>'
            register_button_str = \
                '<button type="submit" name="register" tabindex="1">' + \
                translate['Register'] + '</button>'

    tos_str = \
        '<p class="login-text"><a href="/about" tabindex="2">' + \
        translate['About this Instance'] + '</a></p>' + \
        '<p class="login-text"><a href="/terms" tabindex="2">' + \
        translate['Terms of Service'] + '</a></p>'

    login_button_str = ''
    if accounts > 0:
        login_button_str = \
            '<button type="submit" name="submit" tabindex="1">' + \
            translate['Login'] + '</button>'

    autocomplete_nickname_str = 'autocomplete="username"'
    autocomplete_password_str = 'autocomplete="current-password"'
    if not autocomplete:
        autocomplete_nickname_str = 'autocomplete="username" value=""'
        autocomplete_password_str = 'autocomplete="off" value=""'

    instance_title = \
        get_config_param(base_dir, 'instanceTitle')
    login_form = \
        html_header_with_website_markup(css_filename, instance_title,
                                        http_prefix, domain,
                                        system_language)

    nickname_pattern = get_nickname_validation_pattern()
    instance_title = get_config_param(base_dir, 'instanceTitle')
    login_form += \
        '<br>\n' + \
        '<form method="POST" action="/login">\n' + \
        '  <div class="imgcontainer">\n' + \
        text_mode_logo_html + '\n' + \
        '    <img loading="lazy" decoding="async" src="' + login_image + \
        '" alt="' + instance_title + '" class="loginimage">\n' + \
        login_text + tos_str + '\n' + \
        '  </div>\n' + \
        '\n' + \
        '  <div class="container">\n' + \
        '    <label for="nickname"><b>' + \
        translate['Nickname'] + '</b></label>\n' + \
        '    <input type="text" ' + autocomplete_nickname_str + \
        ' placeholder="' + translate['Enter Nickname'] + '" ' + \
        'pattern="' + nickname_pattern + '" name="username" tabindex="1" ' + \
        'required autofocus>'
    in_text_mode = text_mode_browser(ua_str)
    if in_text_mode:
        login_form += '<br>'
    login_form += \
        '\n\n' + \
        '    <label for="password"><b>' + \
        translate['Password'] + '</b></label>\n' + \
        '    <input type="password" ' + autocomplete_password_str + \
        ' placeholder="' + translate['Enter Password'] + '" ' + \
        'pattern="{8,256}" name="password" tabindex="1" required>'
    if in_text_mode:
        login_form += '<br><br>'
    login_form += \
        '\n' + login_button_str + register_button_str + '\n' + \
        '  </div>\n' + \
        '</form>\n' + \
        '<a href="https://gitlab.com/bashrc2/epicyon" tabindex="2">' + \
        '<img loading="lazy" decoding="async" class="license" title="' + \
        translate['Get the source code'] + '" alt="' + \
        translate['Get the source code'] + '" src="/icons/agpl.png" /></a>\n'
    login_form += html_footer()
    return login_form