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

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 = 10

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

PARAMETER_PREV_LINK = 'prev_page_link'
PARAMETER_NEXT_LINK = 'next_page_link'

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


class FeedView(PostMixin, BaseBoardView):

    def get(self, request):
        page = request.GET.get('page', DEFAULT_PAGE)
        tripcode = request.GET.get('tripcode', None)

        params = self.get_context_data(request=request)

        settings_manager = get_settings_manager(request)

        posts = Post.objects.exclude(
            threads__tags__in=settings_manager.get_hidden_tags()).order_by(
            '-pub_time').prefetch_related('images', 'thread', 'threads')
        if tripcode:
            posts = posts.filter(tripcode=tripcode)

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

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

        additional_params = dict()
        if tripcode:
            additional_params['tripcode'] = tripcode
            params[PARAMETER_ADDITONAL_ATTRS] = '&tripcode=' + tripcode

        self.get_page_context(paginator, params, page, additional_params)

        return render(request, TEMPLATE, params)

    # TODO Dedup this into PagedMixin
    def get_page_context(self, paginator, params, page, additional_params):
        """
        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] = self.get_previous_page_link(
                    current_page)
            for param in additional_params.keys():
                params[PARAMETER_PREV_LINK] += '&{}={}'.format(
                    param, additional_params[param])
        if current_page.has_next():
            params[PARAMETER_NEXT_LINK] = self.get_next_page_link(current_page)
            for param in additional_params.keys():
                params[PARAMETER_NEXT_LINK] += '&{}={}'.format(
                    param, additional_params[param])

    def get_previous_page_link(self, current_page):
        return reverse('feed') + '?page={}'.format(
                current_page.previous_page_number())

    def get_next_page_link(self, current_page):
        return reverse('feed') + '?page={}'.format(
                current_page.next_page_number())