# -*- coding: utf-8 -*-
from itertools import chain

from django.contrib.sitemaps import Sitemap
from django.contrib.sites.models import Site
from django.db.models import Q
from django.core.urlresolvers import reverse

from cms.models import Title, Page, CMSPlugin


class CMSSitemap(Sitemap):
    """
        DjangoCMS Sitemap.

        Modified version of the original cms.sitemaps.CMSSitemap.
        Everything cached to minimize number of sql queries.

        Notes:
            - excluded pages that are redirected (items)
            - excluded pages that require login (items)
            - no multi language paths for pages (location)

        Project specific notes:
            - excluded pages that are not in navigation (items)
            - excluded page with 'guestbook' reverse_id (items)
    """
    changefreq = 'monthly'
    priority = None

    exclude_reverse_ids = ['guestbook']

    def items(self):
        self.all_page_placeholders = Page.placeholders.through.objects.all()
        self.all_plugins = CMSPlugin.objects.all()
        all_titles = (
            Title.objects.public()
                .filter(
                    Q(redirect='') | Q(redirect__isnull=True),
                    page__login_required=False,
                    page__site=Site.objects.get_current(),
                    page__in_navigation=True,
                )
                .exclude(page__reverse_id__in=self.exclude_reverse_ids)
                .select_related('page')
                .order_by('path')
        )
        return all_titles

    def lastmod(self, title):
        modification_dates = [title.page.changed_date, title.page.publication_date]
        plugins_for_placeholder = lambda placeholder: \
            [p for p in self.all_plugins if p.placeholder_id == placeholder.placeholder_id]
        page_placeholders = [pp for pp in self.all_page_placeholders if pp.page_id == title.page_id]
        plugins = chain.from_iterable(map(plugins_for_placeholder, page_placeholders))
        plugin_modification_dates = map(lambda plugin: plugin.changed_date, plugins)
        modification_dates.extend(plugin_modification_dates)
        return max(modification_dates)

    def location(self, title):
        if title.page.is_home():
            return reverse('pages-root')
        return reverse('pages-details-by-slug', kwargs={'slug': title.path})