import xml.etree.ElementTree as ET

from django.utils.timezone import datetime, timedelta
from django.shortcuts import render
from django.http import HttpResponse


def robots_txt(request):
    txt = '''User-agent: *
Disallow: 
Sitemap: {}
'''.format(request.build_absolute_uri('/sitemap.xml'))
    return HttpResponse(txt, 'text/plain')


def sitemap_xml(request):
    now = datetime.now()
    from .item.models import Item
    urlset = ET.Element('urlset')
    urlset.attrib['xmlns'] = "http://www.sitemaps.org/schemas/sitemap/0.9"
    urlset.attrib['xmlns:xsi'] = "http://www.w3.org/2001/XMLSchema-instance"
    urlset.attrib['xsi:schemaLocation'] = "http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd"

    url = ET.SubElement(urlset, "url")
    loc = ET.SubElement(url, "loc")
    loc.text = request.build_absolute_uri('/')
    lastmod = ET.SubElement(url, "lastmod")
    lastmod.text = now.strftime("%Y-%m-%d")
    changefreq = ET.SubElement(url, "changefreq")
    changefreq.text = 'hourly'
    priority = ET.SubElement(url, "priority")
    priority.text = '1.0'

    first = Item.objects.exclude(published=None).exclude(published__gt=now).order_by('published').first()
    if first:
        for year in reversed(range(first.published.year, now.year + 1)):
            url = ET.SubElement(urlset, "url")
            loc = ET.SubElement(url, "loc")
            loc.text = request.build_absolute_uri('/_%s/' % year)
            lastmod = ET.SubElement(url, "lastmod")
            changefreq = ET.SubElement(url, "changefreq")
            priority = ET.SubElement(url, "priority")
            if year == now.year:
                lastmod.text = now.strftime("%Y-%m-%d")
                changefreq.text = 'weekly'
                priority.text = '1.0'
            else:
                lastmod.text = now.strftime("%s-12-31" % year)
                changefreq.text = 'yearly'
                priority.text = '0.8'

    for item in Item.objects.exclude(published=None).exclude(published__gt=now).order_by('-published'):
        url = ET.SubElement(urlset, "url")
        loc = ET.SubElement(url, "loc")
        loc.text = request.build_absolute_uri(item.get_absolute_url())
        # This date should be in W3C Datetime format, can be %Y-%m-%d
        lastmod = ET.SubElement(url, "lastmod")
        lastmod.text = item.modified.strftime("%Y-%m-%d")
        # always, hourly, daily, weekly, monthly, yearly, never
        changefreq = ET.SubElement(url, "changefreq")
        changefreq.text = 'daily'
        # priority of page on site values 0.1 - 1.0
        priority = ET.SubElement(url, "priority")
        priority.text = '0.9'
    data = b'<?xml version="1.0" encoding="UTF-8"?>\n' + ET.tostring(urlset)
    return HttpResponse(data, 'application/xml')