# combo - content management system
# Copyright (C) 2014  Entr'ouvert
#
# This program is free software: you can redistribute it and/or modify it
# under the terms of the GNU Affero General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import urllib
import urlparse

from django.conf import settings
from django.contrib.auth import logout as auth_logout
from django.contrib.auth import views as auth_views
from django.core.exceptions import ObjectDoesNotExist, PermissionDenied
from django.http import (Http404, HttpResponse, HttpResponseRedirect,
        HttpResponsePermanentRedirect)
from django.shortcuts import render, resolve_url
from django.template import RequestContext

try:
    from mellon.utils import get_idps
except ImportError:
    get_idps = lambda: []

from combo.data.models import CellBase, Page


def login(request, *args, **kwargs):
    if any(get_idps()):
        if not 'next' in request.GET:
            return HttpResponseRedirect(resolve_url('mellon_login'))
        return HttpResponseRedirect(resolve_url('mellon_login') + '?next='
                                    + urllib.quote(request.GET.get('next')))
    return auth_views.login(request, *args, **kwargs)

def logout(request, next_page=None):
    if any(get_idps()):
        return HttpResponseRedirect(resolve_url('mellon_logout'))
    auth_logout(request)
    if next_page is not None:
        next_page = resolve_url(next_page)
    else:
        next_page = '/'
    return HttpResponseRedirect(next_page)

def ajax_page_cell(request, page_pk, cell_reference):
    try:
        page = Page.objects.get(id=page_pk)
    except Page.DoesNotExist:
        raise Http404()
    if not page.is_visible(request.user):
        raise PermissionDenied()
    try:
        cell = CellBase.get_cell(cell_reference, page_id=page_pk)
    except ObjectDoesNotExist:
        raise Http404()

    context = RequestContext(request, {
        'page': page,
        'request': request,
        'ajax': True,
        'site_base': request.build_absolute_uri('/')[:-1],
    })

    return HttpResponse(cell.render(context), content_type='text/html')


def extend_with_locked_placeholders_cells(cells, page, pages):
    locked_placeholders = page.get_locked_placeholders(cells)

    if locked_placeholders:
        # there are some acquired placeholders, look in parent pages for
        # appropriate content.
        try:
            # add the site index page as ultimate parent
            pages.insert(0, Page.objects.get(slug='index'))
        except Page.DoesNotExist:
            pass
        unlocker_cells = CellBase.get_cells(page_id__in=[x.id for x in pages])
        found_placeholders = {}
        for parent_page in reversed(pages[:-1]):
            for placeholder in parent_page.get_unlocked_placeholders(unlocker_cells):
                if not placeholder in locked_placeholders:
                    continue
                if not placeholder in found_placeholders:
                    found_placeholders[placeholder] = parent_page.id
            if len(found_placeholders) == len(locked_placeholders):
                break

        # add found cells to the page cells
        for placeholder_key, page_id in found_placeholders.items():
            cells.extend([x for x in unlocker_cells if x.page_id == page_id and
                x.placeholder == placeholder_key])


def skeleton(request):
    # Skeleton rendering is used to dynamically produce base templates to use
    # in other applications, based on configured combo cells.
    #
    # It takes a ?source= parameter that should contain the URL we want a
    # template for; it will be used to match the corresponding page, and thus
    # the corresponding content.  If there's no matching page, an error will be
    # raised. (403 Access Forbidden)
    #
    # While placeholders holding cells will get their cells rendered, empty
    # placeholders will get themself outputted as template blocks, named
    # placeholder-$name, and with a default content of a block named $name.
    #
    # ex:
    #   {% block placeholder-content %}
    #     {% block content %}
    #     {% endblock %}
    #   {% endblock %}
    if 'source' not in request.GET:
        raise PermissionDenied()
    source = request.GET['source']
    selected_page = None

    # look in redirect pages after the best match for the source
    redirect_pages = Page.objects.exclude(redirect_url__isnull=True).exclude(redirect_url='')
    for page in redirect_pages:
        if source.startswith(page.redirect_url):
            if selected_page is None or len(page.redirect_url) > len(selected_page.redirect_url):
                selected_page = page

    if selected_page is None:
        # if there was no page found, look for a domain match
        netloc = urlparse.urlparse(source).netloc
        for page in redirect_pages:
            if urlparse.urlparse(page.redirect_url).netloc == netloc:
                selected_page = page
                break
        else:
            raise PermissionDenied()

    pages = list(page.get_parents_and_self())
    cells = CellBase.get_cells(page_id=page.id)
    extend_with_locked_placeholders_cells(cells, page, pages)

    combo_template = settings.COMBO_PUBLIC_TEMPLATES[page.template_name]

    ctx = {
        'page': selected_page,
        'page_cells': cells,
        'request': request,
        'render_skeleton': True,
        'site_base': request.build_absolute_uri('/')[:-1],
    }

    template_name = combo_template['template']
    return render(request, template_name, ctx)


def empty_site(request):
    return render(request, 'combo/empty_site.html', {})


def page(request):
    url = request.path_info
    parts = [x for x in request.path_info.strip('/').split('/') if x]
    if not parts:
        parts = ['index']
    try:
        pages = [Page.objects.get(slug=x) for x in parts]
    except Page.DoesNotExist:
        if not url.endswith('/') and settings.APPEND_SLASH:
            return HttpResponsePermanentRedirect(url + '/')
        if Page.objects.count() == 0 and parts == ['index']:
            return empty_site(request)
        else:
            raise Http404()

    for i, page in enumerate(pages[1:]):
        if page.parent_id != pages[i].id:
            raise Http404()

    page = pages[-1]

    if not page.is_visible(request.user):
        if not request.user.is_authenticated():
            from django.contrib.auth.views import redirect_to_login
            return redirect_to_login(request.path)
        raise PermissionDenied()

    if page.redirect_url:
        return HttpResponseRedirect(page.redirect_url)

    combo_template = settings.COMBO_PUBLIC_TEMPLATES[page.template_name]

    cells = CellBase.get_cells(page_id=page.id)
    extend_with_locked_placeholders_cells(cells, page, pages)
    cells = [x for x in cells if x.is_visible(user=request.user)]

    ctx = {
        'page': page,
        'page_cells': cells,
        'request': request,
    }

    template_name = combo_template['template']
    return render(request, template_name, ctx)