''' non-interactive pages '''
from django.contrib.auth.decorators import login_required
from django.core.paginator import Paginator
from django.db.models import Q
from django.http import HttpResponseNotFound
from django.template.response import TemplateResponse
from django.utils import timezone
from django.utils.decorators import method_decorator
from django.views import View

from bookwyrm import forms, models
from bookwyrm.activitypub import ActivitypubResponse
from bookwyrm.settings import PAGE_LENGTH
from .helpers import get_activity_feed
from .helpers import get_user_from_username
from .helpers import is_api_request, is_bookwyrm_request, object_visible_to_user


# pylint: disable= no-self-use
@method_decorator(login_required, name='dispatch')
class Feed(View):
    ''' activity stream '''
    def get(self, request, tab):
        ''' user's homepage with activity feed '''
        try:
            page = int(request.GET.get('page', 1))
        except ValueError:
            page = 1

        if tab == 'home':
            activities = get_activity_feed(request.user, following_only=True)
            # we only want to show private messages if they're related to books
            activities = activities.exclude(
                review__isnull=True,
                comment__isnull=True,
                quotation__isnull=True,
                generatednote__isnull=True,
                privacy='direct'
            )
        elif tab == 'local':
            activities = get_activity_feed(
                request.user, privacy=['public', 'followers'], local_only=True)
        else:
            activities = get_activity_feed(
                request.user, privacy=['public', 'followers'])
        paginated = Paginator(activities, PAGE_LENGTH)

        data = {**feed_page_data(request.user), **{
            'title': 'Updates Feed',
            'user': request.user,
            'activities': paginated.page(page),
            'tab': tab,
            'goal_form': forms.GoalForm(),
            'path': '/%s' % tab,
        }}
        return TemplateResponse(request, 'feed/feed.html', data)


@method_decorator(login_required, name='dispatch')
class DirectMessage(View):
    ''' dm view '''
    def get(self, request, username=None):
        ''' like a feed but for dms only '''
        try:
            page = int(request.GET.get('page', 1))
        except ValueError:
            page = 1

        queryset = models.Status.objects

        user = None
        if username:
            try:
                user = get_user_from_username(request.user, username)
            except models.User.DoesNotExist:
                pass
        if user:
            queryset = queryset.filter(Q(user=user) | Q(mention_users=user))

        activities = get_activity_feed(
            request.user, privacy=['direct'], queryset=queryset)

        paginated = Paginator(activities, PAGE_LENGTH)
        activity_page = paginated.page(page)
        data = {**feed_page_data(request.user), **{
            'title': 'Direct Messages',
            'user': request.user,
            'partner': user,
            'activities': activity_page,
            'path': '/direct-messages',
        }}
        return TemplateResponse(request, 'feed/direct_messages.html', data)


class Status(View):
    ''' get posting '''
    def get(self, request, username, status_id):
        ''' display a particular status (and replies, etc) '''
        try:
            user = get_user_from_username(request.user, username)
            status = models.Status.objects.select_subclasses().get(
                id=status_id, deleted=False)
        except ValueError:
            return HttpResponseNotFound()

        # the url should have the poster's username in it
        if user != status.user:
            return HttpResponseNotFound()

        # make sure the user is authorized to see the status
        if not object_visible_to_user(request.user, status):
            return HttpResponseNotFound()

        if is_api_request(request):
            return ActivitypubResponse(
                status.to_activity(pure=not is_bookwyrm_request(request)))

        data = {**feed_page_data(request.user), **{
            'title': 'Status by %s' % user.username,
            'status': status,
        }}
        return TemplateResponse(request, 'feed/status.html', data)


class Replies(View):
    ''' replies page (a json view of status) '''
    def get(self, request, username, status_id):
        ''' ordered collection of replies to a status '''
        # the html view is the same as Status
        if not is_api_request(request):
            status_view = Status.as_view()
            return status_view(request, username, status_id)

        # the json view is different than Status
        status = models.Status.objects.get(id=status_id)
        if status.user.localname != username:
            return HttpResponseNotFound()

        return ActivitypubResponse(status.to_replies(**request.GET))


def feed_page_data(user):
    ''' info we need for every feed page '''
    if not user.is_authenticated:
        return {}

    goal = models.AnnualGoal.objects.filter(
        user=user, year=timezone.now().year
    ).first()
    return {
        'suggested_books': get_suggested_books(user),
        'goal': goal,
        'goal_form': forms.GoalForm(),
    }

def get_suggested_books(user, max_books=5):
    ''' helper to get a user's recent books '''
    book_count = 0
    preset_shelves = [
        ('reading', max_books), ('read', 2), ('to-read', max_books)
    ]
    suggested_books = []
    for (preset, shelf_max) in preset_shelves:
        limit = shelf_max if shelf_max < (max_books - book_count) \
                else max_books - book_count
        shelf = user.shelf_set.get(identifier=preset)

        shelf_books = shelf.shelfbook_set.order_by(
            '-updated_date'
        ).all()[:limit]
        if not shelf_books:
            continue
        shelf_preview = {
            'name': shelf.name,
            'books': [s.book for s in shelf_books]
        }
        suggested_books.append(shelf_preview)
        book_count += len(shelf_preview['books'])
    return suggested_books