# pylint: disable=keyword-arg-before-vararg
import json

from django.contrib.auth import get_user_model
from django.db import IntegrityError
from django.http import JsonResponse
from django.shortcuts import render
from django.urls import reverse
from django.utils.translation import gettext as _
from social_core.pipeline.partial import partial
from unidecode import unidecode

from ..core.exceptions import SocialAuthBanned, SocialAuthFailed
from ..legal.models import Agreement
from ..users.bans import get_request_ip_ban, get_user_ban
from ..users.forms.register import SocialAuthRegisterForm
from ..users.models import Ban
from ..users.registration import (
    get_registration_result_json,
    save_user_agreements,
    send_welcome_email,
)
from ..users.setupnewuser import setup_new_user
from ..users.validators import (
    ValidationError,
    validate_email,
    validate_new_registration,
    validate_username,
)
from .providers import providers

User = get_user_model()


def validate_ip_not_banned(strategy, details, backend, user=None, *args, **kwargs):
    """
    Pipeline step that interrupts pipeline if found user is non-staff and IP banned
    """
    if not user or user.is_staff:
        return None

    ban = get_request_ip_ban(strategy.request)
    if ban:
        hydrated_ban = Ban(
            check_type=Ban.IP, user_message=ban["message"], expires_on=ban["expires_on"]
        )
        raise SocialAuthBanned(backend, hydrated_ban)


def validate_user_not_banned(strategy, details, backend, user=None, *args, **kwargs):
    """Pipeline step that interrupts pipeline if found user is non-staff and banned"""
    if not user or user.is_staff:
        return None

    user_ban = get_user_ban(user, strategy.request.cache_versions)
    if user_ban:
        raise SocialAuthBanned(backend, user_ban)


def perpare_username(username):
    return "".join(filter(str.isalnum, unidecode(username)))


def associate_by_email(strategy, details, backend, user=None, *args, **kwargs):
    """If user with e-mail from provider exists in database and is active,
    this step authenticates them.
    """
    enable_step = strategy.setting("ASSOCIATE_BY_EMAIL", default=False, backend=backend)

    if user or not enable_step:
        return None

    email = details.get("email")
    if not email:
        return None

    try:
        user = User.objects.get_by_email(email)
    except User.DoesNotExist:
        return None

    backend_name = providers.get_name(backend.name)

    if not user.is_active:
        raise SocialAuthFailed(
            backend,
            _(
                "The e-mail address associated with your %(backend)s account is "
                "not available for use on this site."
            )
            % {"backend": backend_name},
        )

    if user.requires_activation_by_admin:
        raise SocialAuthFailed(
            backend,
            _(
                "Your account has to be activated by site administrator "
                "before you will be able to sign in with %(backend)s."
            )
            % {"backend": backend_name},
        )

    return {"user": user, "is_new": False}


def get_username(strategy, details, backend, user=None, *args, **kwargs):
    """Resolve valid username for use in new account"""
    if user:
        return None

    settings = strategy.request.settings

    username = perpare_username(details.get("username", ""))
    full_name = perpare_username(details.get("full_name", ""))
    first_name = perpare_username(details.get("first_name", ""))
    last_name = perpare_username(details.get("last_name", ""))

    names_to_try = [username, first_name]

    if username:
        names_to_try.append(username)

    if first_name:
        names_to_try.append(first_name)
        if last_name:
            # if first name is taken, try first name + first char of last name
            names_to_try.append(first_name + last_name[0])

    if full_name:
        names_to_try.append(full_name)

    username_length_max = settings.username_length_max
    for name in names_to_try:
        if len(name) > username_length_max:
            names_to_try.append(name[:username_length_max])

    for name in filter(bool, names_to_try):
        try:
            validate_username(settings, name)
            return {"clean_username": name}
        except ValidationError:
            pass


def create_user(strategy, details, backend, user=None, *args, **kwargs):
    """Aggressively attempt to register and sign in new user"""
    if user:
        return None

    request = strategy.request
    settings = request.settings

    email = details.get("email")
    username = kwargs.get("clean_username")

    if not email or not username:
        return None

    try:
        validate_email(email)
        validate_new_registration(request, {"email": email, "username": username})
    except ValidationError:
        return None

    activation_kwargs = {}
    if settings.account_activation == "admin":
        activation_kwargs = {"requires_activation": User.ACTIVATION_ADMIN}

    new_user = User.objects.create_user(
        username, email, joined_from_ip=request.user_ip, **activation_kwargs
    )

    setup_new_user(settings, new_user)
    send_welcome_email(request, new_user)

    return {"user": new_user, "is_new": True}


@partial
def create_user_with_form(strategy, details, backend, user=None, *args, **kwargs):
    """
    create_user lets user confirm account creation by entering final username or email
    """
    if user:
        return None

    request = strategy.request
    settings = request.settings
    backend_name = providers.get_name(backend.name)

    if request.method == "POST":
        try:
            request_data = json.loads(request.body)
        except (TypeError, ValueError):
            request_data = request.POST.copy()

        form = SocialAuthRegisterForm(
            request_data, request=request, agreements=Agreement.objects.get_agreements()
        )

        if not form.is_valid():
            return JsonResponse(form.errors, status=400)

        email_verified = form.cleaned_data["email"] == details.get("email")

        activation_kwargs = {}
        if settings.account_activation == "admin":
            activation_kwargs = {"requires_activation": User.ACTIVATION_ADMIN}
        elif settings.account_activation == "user" and not email_verified:
            activation_kwargs = {"requires_activation": User.ACTIVATION_USER}

        try:
            new_user = User.objects.create_user(
                form.cleaned_data["username"],
                form.cleaned_data["email"],
                joined_from_ip=request.user_ip,
                **activation_kwargs
            )
            setup_new_user(settings, new_user)
        except IntegrityError:
            return JsonResponse(
                {"__all__": _("Please try resubmitting the form.")}, status=400
            )

        save_user_agreements(new_user, form)
        send_welcome_email(request, new_user)

        return {"user": new_user, "is_new": True}

    request.frontend_context["SOCIAL_AUTH_FORM"] = {
        "backend_name": backend_name,
        "step": "register",
        "email": details.get("email"),
        "username": kwargs.get("clean_username"),
        "url": reverse("misago:social-complete", kwargs={"backend": backend.name}),
    }

    return render(request, "misago/socialauth.html", {"backend_name": backend_name})


@partial
def require_activation(
    strategy, details, backend, user=None, is_new=False, *args, **kwargs
):
    if not user:
        # Social auth pipeline has entered corrupted state
        # Remove partial auth state and redirect user to beginning
        partial_token = strategy.session.get("partial_pipeline_token")
        if partial_token:
            strategy.clean_partial_pipeline(partial_token)
        return None

    if not user.requires_activation:
        return None

    request = strategy.request
    backend_name = providers.get_name(backend.name)

    response_data = get_registration_result_json(user)
    response_data.update({"step": "done", "backend_name": backend_name})

    if request.method == "POST":
        # we are carrying on from requestration request
        return JsonResponse(response_data)

    request.frontend_context["SOCIAL_AUTH_FORM"] = response_data
    request.frontend_context["SOCIAL_AUTH_FORM"].update(
        {"url": reverse("misago:social-complete", kwargs={"backend": backend.name})}
    )

    return render(request, "misago/socialauth.html", {"backend_name": backend_name})