from django.dispatch import receiver
from django.contrib.auth.signals import user_logged_in
from django.conf import settings
from django.template import loader
from django.utils.timezone import get_current_timezone_name as timezone_get_current_timezone_name
from django.utils.timezone import now as timezone_now
from typing import Any, Dict, Optional
from zerver.lib.send_email import send_email, FromAddress
from zerver.models import UserProfile

def get_device_browser(user_agent):
    # type: (str) -> Optional[str]
    user_agent = user_agent.lower()
    if "zulip" in user_agent:
        return "Zulip"
    elif "edge" in user_agent:
        return "Edge"
    elif "opera" in user_agent or "opr/" in user_agent:
        return "Opera"
    elif "chrome" in user_agent and "chromium" not in user_agent:
        return 'Chrome'
    elif "firefox" in user_agent and "seamonkey" not in user_agent and "chrome" not in user_agent:
        return "Firefox"
    elif "chromium" in user_agent:
        return "Chromium"
    elif "safari" in user_agent and "chrome" not in user_agent and "chromium" not in user_agent:
        return "Safari"
    elif "msie" in user_agent or "trident" in user_agent:
        return "Internet Explorer"
    else:
        return None


def get_device_os(user_agent):
    # type: (str) -> Optional[str]
    user_agent = user_agent.lower()
    if "windows" in user_agent:
        return "Windows"
    elif "macintosh" in user_agent:
        return "macOS"
    elif "linux" in user_agent and "android" not in user_agent:
        return "Linux"
    elif "android" in user_agent:
        return "Android"
    elif "ios" in user_agent:
        return "iOS"
    elif "like mac os x" in user_agent:
        return "iOS"
    else:
        return None


@receiver(user_logged_in, dispatch_uid="only_on_login")
def email_on_new_login(sender, user, request, **kwargs):
    # type: (Any, UserProfile, Any, **Any) -> None

    # We import here to minimize the dependencies of this module,
    # since it runs as part of `manage.py` initialization
    from zerver.context_processors import common_context

    if not settings.SEND_LOGIN_EMAILS:
        return

    if request:
        # If the user's account was just created, avoid sending an email.
        if getattr(user, "just_registered", False):
            return

        login_time = timezone_now().strftime('%A, %B %d, %Y at %I:%M%p ') + \
            timezone_get_current_timezone_name()
        user_agent = request.META.get('HTTP_USER_AGENT', "").lower()
        device_browser = get_device_browser(user_agent)
        device_os = get_device_os(user_agent)
        device_ip = request.META.get('REMOTE_ADDR') or "Uknown IP address"
        device_info = {"device_browser": device_browser,
                       "device_os": device_os,
                       "device_ip": device_ip,
                       "login_time": login_time
                       }

        context = common_context(user)
        context['device_info'] = device_info
        context['user'] = user

        send_email('zerver/emails/notify_new_login', to_user_id=user.id,
                   from_name='Zulip Account Security', from_address=FromAddress.NOREPLY,
                   context=context)