from django.core.urlresolvers import reverse
from django.shortcuts import render

from boards import settings
from boards.abstracts.paginator import get_paginator
from boards.abstracts.settingsmanager import get_settings_manager
from boards.models import Post
from boards.views.base import BaseBoardView
from boards.views.posting_mixin import PostMixin

POSTS_PER_PAGE = settings.get_int('View', 'PostsPerPage')

PARAMETER_CURRENT_PAGE = 'current_page'
PARAMETER_PAGINATOR = 'paginator'
PARAMETER_POSTS = 'posts'

PARAMETER_PREV_LINK = 'prev_page_link'
PARAMETER_NEXT_LINK = 'next_page_link'

TEMPLATE = 'boards/feed.html'
DEFAULT_PAGE = 1


class FeedFilter:
    @staticmethod
    def get_filtered_posts(request, posts):
        return posts


class TripcodeFilter(FeedFilter):
    @staticmethod
    def get_filtered_posts(request, posts):
        filtered_posts = posts
        tripcode = request.GET.get('tripcode', None)
        if tripcode:
            filtered_posts = filtered_posts.filter(tripcode)
        return filtered_posts


class FavoritesFilter(FeedFilter):
    @staticmethod
    def get_filtered_posts(request, posts):
        filtered_posts = posts

        favorites = 'favorites' in request.GET
        if favorites:
            settings_manager = get_settings_manager(request)
            fav_thread_ops = Post.objects.filter(id__in=settings_manager.get_fav_threads().keys())
            fav_threads = [op.get_thread() for op in fav_thread_ops]
            filtered_posts = filtered_posts.filter(thread__in=fav_threads)
        return filtered_posts


class IpFilter(FeedFilter):
    @staticmethod
    def get_filtered_posts(request, posts):
        filtered_posts = posts

        ip = request.GET.get('ip', None)
        if ip and request.user.has_perm('post_delete'):
            filtered_posts = filtered_posts.filter(poster_ip=ip)
        return filtered_posts


class HashFilter(FeedFilter):
    @staticmethod
    def get_filtered_posts(request, posts):
        filtered_posts = posts

        image_hash = request.GET.get('image_hash', None)
        if image_hash:
            filtered_posts = filtered_posts.filter(attachments__hash=image_hash)
        return filtered_posts


class FeedView(PostMixin, BaseBoardView):
    filters = (
            TripcodeFilter,
            FavoritesFilter,
            IpFilter,
            HashFilter,
    )

    def get(self, request):
        page = request.GET.get('page', DEFAULT_PAGE)

        params = self.get_context_data(request=request)

        settings_manager = get_settings_manager(request)

        posts = Post.objects.exclude(
            thread__tags__in=settings_manager.get_hidden_tags()).order_by(
            '-pub_time').prefetch_related('attachments', 'thread')
        for filter in self.filters:
            posts = filter.get_filtered_posts(request, posts)

        paginator = get_paginator(posts, POSTS_PER_PAGE)
        paginator.current_page = int(page)

        params[PARAMETER_POSTS] = paginator.page(page).object_list

        paginator.set_url(reverse('feed'), request.GET.dict())

        self.get_page_context(paginator, params, page)

        return render(request, TEMPLATE, params)

    # TODO Dedup this into PagedMixin
    def get_page_context(self, paginator, params, page):
        """
        Get pagination context variables
        """

        params[PARAMETER_PAGINATOR] = paginator
        current_page = paginator.page(int(page))
        params[PARAMETER_CURRENT_PAGE] = current_page
        if current_page.has_previous():
            params[PARAMETER_PREV_LINK] = paginator.get_page_url(
                    current_page.previous_page_number())
        if current_page.has_next():
            params[PARAMETER_NEXT_LINK] = paginator.get_page_url(
                    current_page.next_page_number())