''' shelf views'''
from django.contrib.auth.decorators import login_required
from django.http import HttpResponseBadRequest, HttpResponseNotFound
from django.shortcuts import get_object_or_404, redirect
from django.template.response import TemplateResponse
from django.utils.decorators import method_decorator
from django.views import View
from django.views.decorators.http import require_POST

from bookwyrm import forms, models
from bookwyrm.activitypub import ActivitypubResponse
from .helpers import is_api_request, get_edition, get_user_from_username
from .helpers import handle_reading_status


# pylint: disable= no-self-use
class Shelf(View):
    ''' shelf page '''
    def get(self, request, username, shelf_identifier):
        ''' display a shelf '''
        try:
            user = get_user_from_username(request.user, username)
        except models.User.DoesNotExist:
            return HttpResponseNotFound()

        if shelf_identifier:
            shelf = user.shelf_set.get(identifier=shelf_identifier)
        else:
            shelf = user.shelf_set.first()

        is_self = request.user == user

        shelves = user.shelf_set
        if not is_self:
            follower = user.followers.filter(id=request.user.id).exists()
            # make sure the user has permission to view the shelf
            if shelf.privacy == 'direct' or \
                    (shelf.privacy == 'followers' and not follower):
                return HttpResponseNotFound()

            # only show other shelves that should be visible
            if follower:
                shelves = shelves.filter(privacy__in=['public', 'followers'])
            else:
                shelves = shelves.filter(privacy='public')


        if is_api_request(request):
            return ActivitypubResponse(shelf.to_activity(**request.GET))

        books = models.ShelfBook.objects.filter(
            user=user, shelf=shelf
        ).order_by('-updated_date').all()

        data = {
            'user': user,
            'is_self': is_self,
            'shelves': shelves.all(),
            'shelf': shelf,
            'books': [b.book for b in books],
        }

        return TemplateResponse(request, 'user/shelf.html', data)

    @method_decorator(login_required, name='dispatch')
    # pylint: disable=unused-argument
    def post(self, request, username, shelf_identifier):
        ''' edit a shelf '''
        try:
            shelf = request.user.shelf_set.get(identifier=shelf_identifier)
        except models.Shelf.DoesNotExist:
            return HttpResponseNotFound()

        if request.user != shelf.user:
            return HttpResponseBadRequest()
        if not shelf.editable and request.POST.get('name') != shelf.name:
            return HttpResponseBadRequest()

        form = forms.ShelfForm(request.POST, instance=shelf)
        if not form.is_valid():
            return redirect(shelf.local_path)
        shelf = form.save()
        return redirect(shelf.local_path)


def user_shelves_page(request, username):
    ''' default shelf '''
    return Shelf.as_view()(request, username, None)


@login_required
@require_POST
def create_shelf(request):
    ''' user generated shelves '''
    form = forms.ShelfForm(request.POST)
    if not form.is_valid():
        return redirect(request.headers.get('Referer', '/'))

    shelf = form.save()
    return redirect('/user/%s/shelf/%s' % \
            (request.user.localname, shelf.identifier))


@login_required
@require_POST
def delete_shelf(request, shelf_id):
    ''' user generated shelves '''
    shelf = get_object_or_404(models.Shelf, id=shelf_id)
    if request.user != shelf.user or not shelf.editable:
        return HttpResponseBadRequest()

    shelf.delete()
    return redirect('/user/%s/shelves' % request.user.localname)


@login_required
@require_POST
def shelve(request):
    ''' put a  on a user's shelf '''
    book = get_edition(request.POST.get('book'))

    desired_shelf = models.Shelf.objects.filter(
        identifier=request.POST.get('shelf'),
        user=request.user
    ).first()
    if not desired_shelf:
        return HttpResponseNotFound()

    if request.POST.get('reshelve', True):
        try:
            current_shelf = models.Shelf.objects.get(
                user=request.user,
                edition=book
            )
            handle_unshelve(request.user, book, current_shelf)
        except models.Shelf.DoesNotExist:
            # this just means it isn't currently on the user's shelves
            pass
    models.ShelfBook.objects.create(
        book=book, shelf=desired_shelf, user=request.user)

    # post about "want to read" shelves
    if desired_shelf.identifier == 'to-read' and \
            request.POST.get('post-status'):
        privacy = request.POST.get('privacy') or desired_shelf.privacy
        handle_reading_status(
            request.user,
            desired_shelf,
            book,
            privacy=privacy
        )

    return redirect('/')


@login_required
@require_POST
def unshelve(request):
    ''' put a  on a user's shelf '''
    book = models.Edition.objects.get(id=request.POST['book'])
    current_shelf = models.Shelf.objects.get(id=request.POST['shelf'])

    handle_unshelve(request.user, book, current_shelf)
    return redirect(request.headers.get('Referer', '/'))


#pylint: disable=unused-argument
def handle_unshelve(user, book, shelf):
    ''' unshelve a book '''
    row = models.ShelfBook.objects.get(book=book, shelf=shelf)
    row.delete()