# -*- coding: utf-8 -*-
#
# Copyright (C) 2012-2019 by the Free Software Foundation, Inc.
#
# This file is part of HyperKitty.
#
# HyperKitty is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# HyperKitty is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# HyperKitty.  If not, see <http://www.gnu.org/licenses/>.
#
# Author: Aurelien Bompard <abompard@fedoraproject.org>
#

import datetime
from functools import wraps

from django.http import Http404
from django.shortcuts import render
from django.utils.timezone import utc

from django_mailman3.lib.mailman import get_subscriptions

from hyperkitty.forms import CategoryForm
from hyperkitty.lib.posting import get_sender
from hyperkitty.models import MailingList, ThreadCategory


def get_months(mlist):
    """Return a dictionnary of years, months for which there are
    potentially archives available for a given list (based on the
    oldest post on the list).

    :param mlist: name of the mailing list in which this email should be
    searched.
    """
    date_first = mlist.cached_values["first_date"]()
    now = datetime.datetime.now()
    if not date_first:
        # No messages on this list, return the current month.
        return {now.year: [now.month]}
    archives = {}
    year = date_first.year
    month = date_first.month
    while year < now.year:
        archives[year] = range(1, 13)[(month-1):]
        year = year + 1
        month = 1
    archives[now.year] = range(1, 13)[:now.month]
    return archives


def get_display_dates(year, month, day):
    if day is None:
        start_day = 1
    else:
        start_day = int(day)
    begin_date = datetime.datetime(
        int(year), int(month), start_day, tzinfo=utc)

    if day is None:
        end_date = begin_date + datetime.timedelta(days=32)
        end_date = end_date.replace(day=1)
    else:
        end_date = begin_date + datetime.timedelta(days=1)

    return begin_date, end_date


def daterange(start_date, end_date):
    for n in range(int((end_date - start_date).days)):
        yield start_date + datetime.timedelta(n)


def get_category_widget(request, current_category=None):
    """
    Returns the category form and the applicable category object (or None if no
    category is set for this thread).

    If current_category is not provided or None, try to deduce it from the POST
    request.
    """

    categories = [
        (c.name, c.name.upper())
        for c in ThreadCategory.objects.all()
        ] + [("", "no category")]
    if request.method == "POST":
        category_form = CategoryForm(request.POST)
    else:
        category_form = CategoryForm(
            initial={"category": current_category or ""})
    category_form["category"].field.choices = categories

    if request.method == "POST" and category_form.is_valid():
        # is_valid() must be called after the choices have been set
        current_category = category_form.cleaned_data["category"]

    if not current_category:
        category = None
    else:
        try:
            category = ThreadCategory.objects.get(name=current_category)
        except ThreadCategory.DoesNotExist:
            category = None
    return category, category_form


# View decorator: check that the list is authorized
def check_mlist_private(func):
    @wraps(func)
    def inner(request, *args, **kwargs):
        if "mlist_fqdn" in kwargs:
            mlist_fqdn = kwargs["mlist_fqdn"]
        else:
            mlist_fqdn = args[0]
        try:
            mlist = MailingList.objects.get(name=mlist_fqdn)
        except MailingList.DoesNotExist:
            raise Http404("No archived mailing-list by that name.")
        if not is_mlist_authorized(request, mlist):
            return render(
                request, "hyperkitty/errors/private.html", {
                    "mlist": mlist,
                }, status=403)
        return func(request, *args, **kwargs)
    return inner


def is_mlist_authorized(request, mlist):
    if not mlist.is_private:
        return True
    if request.user.is_superuser:
        return True
    if not request.user.is_authenticated:
        return False
    # Private list and logged-in user: check subscriptions
    if mlist.list_id in get_subscriptions(request.user):
        return True
    else:
        return False


def get_posting_form(formclass, request, mlist, data=None):
    form = formclass(data, initial={
        "sender": get_sender(request, mlist)})
    if request.user.is_authenticated:
        form.fields['sender'].choices = [
            (a, a) for a in request.user.hyperkitty_profile.addresses]
    return form
