from django.shortcuts import render
from django.http import HttpResponse, Http404, HttpResponseRedirect
from django.http import HttpResponseNotModified
from django.template import TemplateDoesNotExist, loader
from django.contrib.auth.decorators import user_passes_test
from pgweb.util.decorators import login_required
from django.contrib import messages
from django.views.decorators.csrf import csrf_exempt
from django.db.models import Count
from django.db import connection, transaction
from django.utils.http import http_date, parse_http_date
from django.conf import settings
import django

from datetime import date, datetime, timedelta
import os
import re
import urllib

from pgweb.util.decorators import cache, nocache
from pgweb.util.contexts import render_pgweb, get_nav_menu, PGWebContextProcessor
from pgweb.util.helpers import simple_form, PgXmlHelper, HttpServerError
from pgweb.util.moderation import get_all_pending_moderations
from pgweb.util.misc import get_client_ip, varnish_purge, varnish_purge_expr, varnish_purge_xkey
from pgweb.util.sitestruct import get_all_pages_struct

# models needed for the pieces on the frontpage
from pgweb.news.models import NewsArticle, NewsTag
from pgweb.events.models import Event
from pgweb.quotes.models import Quote
from models import Version, ImportedRSSItem

# models needed for the pieces on the community page
from pgweb.survey.models import Survey

# models and forms needed for core objects
from models import Organisation
from forms import OrganisationForm, MergeOrgsForm

# Front page view
@cache(minutes=10)
def home(request):
	news = NewsArticle.objects.filter(approved=True)[:5]
	today = date.today()
	# get up to seven events to display on the homepage
	event_base_queryset = Event.objects.select_related('country').filter(
		approved=True,
		training=False,
		enddate__gte=today,
	)
	# first, see if there are up to two non-badged events within 90 days
	other_events = event_base_queryset.filter(
		badged=False,
		startdate__lte=today + timedelta(days=90),
	).order_by('enddate', 'startdate')[:2]
	# based on that, get 7 - |other_events| community events to display
	community_event_queryset = event_base_queryset.filter(badged=True).order_by('enddate', 'startdate')[:(7 - other_events.count())]
	# now, return all the events in one unioned array!
	events = community_event_queryset.union(other_events).order_by('enddate', 'startdate').all()
	versions = Version.objects.filter(supported=True)
	planet = ImportedRSSItem.objects.filter(feed__internalname="planet").order_by("-posttime")[:9]

	traininginfo = Event.objects.filter(approved=True, training=True).extra(where=("startdate <= (CURRENT_DATE + '6 Months'::interval) AND enddate >= CURRENT_DATE",)).aggregate(Count('id'), Count('country', distinct=True))
	# can't figure out how to make django do this
	curs = connection.cursor()
	curs.execute("SELECT * FROM (SELECT DISTINCT(core_organisation.name) FROM events_event INNER JOIN core_organisation ON org_id=core_organisation.id WHERE startdate <= (CURRENT_DATE + '6 Months'::interval) AND enddate >= CURRENT_DATE AND events_event.approved AND training AND org_id IS NOT NULL) x ORDER BY random() LIMIT 3")
	trainingcompanies = [r[0] for r in curs.fetchall()]

	return render(request, 'index.html', {
		'title': 'The world\'s most advanced open source database',
		'news': news,
		'newstags': NewsTag.objects.all(),
		'events': events,
		'traininginfo': traininginfo,
		'trainingcompanies': trainingcompanies,
		'versions': versions,
		'planet': planet,
	})

# About page view (contains information about PostgreSQL + random quotes)
@cache(minutes=10)
def about(request):
	# get 5 random quotes
	quotes = Quote.objects.filter(approved=True).order_by('?').all()[:5]
	return render_pgweb(request, 'about', 'core/about.html', {
		'quotes': quotes,
	})

# Community main page (contains surveys and potentially more)
def community(request):
	s = Survey.objects.filter(current=True)
	try:
		s = s[0]
	except:
		s = None
	planet = ImportedRSSItem.objects.filter(feed__internalname="planet").order_by("-posttime")[:7]
	return render_pgweb(request, 'community', 'core/community.html', {
		'survey': s,
		'planet': planet,
	})

# List of supported versions
def versions(request):
	return render_pgweb(request, 'support', 'support/versioning.html', {
			'versions': Version.objects.filter(tree__gt=0).filter(testing=0),
	})

re_staticfilenames = re.compile("^[0-9A-Z/_-]+$", re.IGNORECASE)
# Generic fallback view for static pages
def fallback(request, url):
	if url.find('..') > -1:
		raise Http404('Page not found.')

	if not re_staticfilenames.match(url):
		raise Http404('Page not found.')

	try:
		t = loader.get_template('pages/%s.html' % url)
	except TemplateDoesNotExist:
		try:
			t = loader.get_template('pages/%s/en.html' % url)
		except TemplateDoesNotExist:
			raise Http404('Page not found.')

	# Guestimate the nav section by looking at the URL and taking the first
	# piece of it.
	try:
		navsect = url.split('/',2)[0]
	except:
		navsect = ''
	c = PGWebContextProcessor(request)
	c.update({'navmenu': get_nav_menu(navsect)})
	return HttpResponse(t.render(c))

# Edit-forms for core objects
@login_required
def organisationform(request, itemid):
	return simple_form(Organisation, itemid, request, OrganisationForm,
					   redirect='/account/edit/organisations/')

# robots.txt
def robots(request):
	return HttpResponse("""User-agent: *
Disallow: /admin/
Disallow: /account/
Disallow: /docs/devel/
Disallow: /list/
Disallow: /search/
Disallow: /message-id/raw/
Disallow: /message-id/flat/

Sitemap: https://www.postgresql.org/sitemap.xml
""", content_type='text/plain')


def _make_sitemap(pagelist):
	resp = HttpResponse(content_type='text/xml')
	x = PgXmlHelper(resp)
	x.startDocument()
	x.startElement('urlset', {'xmlns': 'http://www.sitemaps.org/schemas/sitemap/0.9'})
	pages = 0
	for p in pagelist:
		pages+=1
		x.startElement('url', {})
		x.add_xml_element('loc', 'https://www.postgresql.org/%s' % urllib.quote(p[0]))
		if len(p) > 1 and p[1]:
			x.add_xml_element('priority', unicode(p[1]))
		if len(p) > 2 and p[2]:
			x.add_xml_element('lastmod', p[2].isoformat() + "Z")
		x.endElement('url')
	x.endElement('urlset')
	x.endDocument()
	return resp

# Sitemap (XML format)
@cache(hours=6)
def sitemap(request):
	return _make_sitemap(get_all_pages_struct())

# Internal sitemap (only for our own search engine)
# Note! Still served up to anybody who wants it, so don't
# put anything secret in it...
@cache(hours=6)
def sitemap_internal(request):
	return _make_sitemap(get_all_pages_struct(method='get_internal_struct'))

# dynamic CSS serving, meaning we merge a number of different CSS into a
# single one, making sure it turns into a single http response. We do this
# dynamically, since the output will be cached.
_dynamic_cssmap = {
	'base': ['media/css/main.css',
			 'media/css/normalize.css',],
	'docs': ['media/css/global.css',
			 'media/css/table.css',
			 'media/css/text.css',
		     'media/css/docs.css'],
	}

@cache(hours=6)
def dynamic_css(request, css):
	if not _dynamic_cssmap.has_key(css):
		raise Http404('CSS not found')
	files = _dynamic_cssmap[css]
	resp = HttpResponse(content_type='text/css')

	# We honor if-modified-since headers by looking at the most recently
	# touched CSS file.
	latestmod = 0
	for fn in files:
		try:
			stime = os.stat(fn).st_mtime
			if latestmod < stime:
				latestmod = stime
		except OSError:
			# If we somehow referred to a file that didn't exist, or
			# one that we couldn't access.
			raise Http404('CSS (sub) not found')
	if request.META.has_key('HTTP_IF_MODIFIED_SINCE'):
		# This code is mostly stolen from django :)
		matches = re.match(r"^([^;]+)(; length=([0-9]+))?$",
						   request.META.get('HTTP_IF_MODIFIED_SINCE'),
						   re.IGNORECASE)
		header_mtime = parse_http_date(matches.group(1))
		# We don't do length checking, just the date
		if int(latestmod) <= header_mtime:
			return HttpResponseNotModified(content_type='text/css')
	resp['Last-Modified'] = http_date(latestmod)

	for fn in files:
		with open(fn) as f:
			resp.write("/* %s */\n" % fn)
			resp.write(f.read())
			resp.write("\n")

	return resp

@nocache
def csrf_failure(request, reason=''):
	resp = render(request, 'errors/csrf_failure.html', {
			'reason': reason,
			})
	resp.status_code = 403 # Forbidden
	return resp

# Basic information about the connection
@cache(seconds=30)
def system_information(request):
	return render(request,'core/system_information.html', {
			'server': os.uname()[1],
			'cache_server': request.META['REMOTE_ADDR'] or None,
			'client_ip': get_client_ip(request),
			'django_version': django.get_version(),
	})

# Sync timestamp for automirror. Keep it around for 30 seconds
# Basically just a check that we can access the backend still...
@cache(seconds=30)
def sync_timestamp(request):
	s = datetime.now().strftime("%Y-%m-%d %H:%M:%S\n")
	r = HttpResponse(s,	content_type='text/plain')
	r['Content-Length'] = len(s)
	return r

# List of all unapproved objects, for the special admin page
@login_required
@user_passes_test(lambda u: u.is_staff)
@user_passes_test(lambda u: u.groups.filter(name='web slaves').exists())
def admin_pending(request):
	return render(request, 'core/admin_pending.html', {
			'app_list': get_all_pending_moderations(),
			})

# Purge objects from varnish, for the admin pages
@login_required
@user_passes_test(lambda u: u.is_staff)
@user_passes_test(lambda u: u.groups.filter(name='varnish purgers').exists())
def admin_purge(request):
	if request.method == 'POST':
		url = request.POST['url']
		expr = request.POST['expr']
		xkey = request.POST['xkey']
		l = len(filter(None, [url, expr, xkey]))
		if l == 0:
			# Nothing specified
			return HttpResponseRedirect('.')
		elif l > 1:
			messages.error(request, "Can only specify one of url, expression and xkey!")
			return HttpResponseRedirect('.')

		if url:
			varnish_purge(url)
		elif expr:
			varnish_purge_expr(expr)
		else:
			varnish_purge_xkey(xkey)

		messages.info(request, "Purge added.")
		return HttpResponseRedirect('.')

	# Fetch list of latest purges
	curs = connection.cursor()
	curs.execute("SELECT added, completed, consumer, mode, expr FROM varnishqueue.queue q LEFT JOIN varnishqueue.consumers c ON c.consumerid=q.consumerid ORDER BY added DESC")
	latest = curs.fetchall()

	return render(request, 'core/admin_purge.html', {
			'latest_purges': latest,
			})

@csrf_exempt
def api_varnish_purge(request):
	if not request.META['REMOTE_ADDR'] in settings.VARNISH_PURGERS:
		return HttpServerError(request, "Invalid client address")
	if request.method != 'POST':
		return HttpServerError(request, "Can't use this way")
	n = int(request.POST['n'])
	curs = connection.cursor()
	for i in range(0, n):
		expr = request.POST['p%s' % i]
		curs.execute("SELECT varnish_purge_expr(%s)", (expr, ))
	return HttpResponse("Purged %s entries\n" % n)

# Merge two organisations
@login_required
@user_passes_test(lambda u: u.is_superuser)
@transaction.atomic
def admin_mergeorg(request):
	if request.method == 'POST':
		form = MergeOrgsForm(data=request.POST)
		if form.is_valid():
			# Ok, try to actually merge organisations, by moving all objects
			# attached
			f = form.cleaned_data['merge_from']
			t = form.cleaned_data['merge_into']
			for e in f.event_set.all():
				e.org = t
				e.save()
			for n in f.newsarticle_set.all():
				n.org = t
				n.save()
			for p in f.product_set.all():
				p.org = t
				p.save()
			for p in f.professionalservice_set.all():
				p.organisation = t
				p.save()
			# Now that everything is moved, we can delete the organisation
			f.delete()

			return HttpResponseRedirect("/admin/core/organisation/")
		# Else fall through to re-render form with errors
	else:
		form = MergeOrgsForm()

	return render(request, 'core/admin_mergeorg.html', {
			'form': form,
    })