from __future__ import absolute_import, unicode_literals

import logging

from django.conf import settings
from django.contrib import messages
from django.core.exceptions import PermissionDenied
from django.core.urlresolvers import reverse
from django.http import HttpResponseRedirect
from django.shortcuts import get_object_or_404, render_to_response
from django.template import RequestContext
from django.utils.translation import ugettext_lazy as _

from acls.models import AccessControlList
from common.generics import (
    SingleObjectDeleteView, SingleObjectDetailView, SingleObjectListView
)
from documents.models import DocumentVersion
from filetransfers.api import serve_file
from permissions import Permission

from .forms import DetachedSignatureForm, DocumentVersionSignatureDetailForm
from .models import DetachedSignature, SignatureBaseModel
from .permissions import (
    permission_document_version_signature_view,
    permission_document_version_signature_upload,
    permission_document_version_signature_download,
    permission_document_version_signature_delete
)

logger = logging.getLogger(__name__)


class DocumentVersionSignatureDeleteView(SingleObjectDeleteView):
    model = DetachedSignature

    def get_extra_context(self):
        return {
            'document': self.get_object().document_version.document,
            'document_version': self.get_object().document_version,
            'navigation_object_list': ('document', 'document_version', 'signature'),
            'signature': self.get_object(),
            'title': _('Delete detached signature: %s') % self.get_object()
        }

    def get_post_action_redirect(self):
        return reverse(
            'signatures:document_version_signature_list',
            args=(self.get_object().document_version.pk,)
        )


class DocumentVersionSignatureDetailView(SingleObjectDetailView):
    form_class = DocumentVersionSignatureDetailForm
    object_permission = permission_document_version_signature_view
    object_permission_related = 'document_version.document'

    def get_extra_context(self):
        return {
            'document': self.get_object().document_version.document,
            'document_version': self.get_object().document_version,
            'signature': self.get_object(),
            'navigation_object_list': ('document', 'document_version', 'signature'),
            'hide_object': True,
            'title': _(
                'Details for signature: %s'
            ) % self.get_object(),
        }

    def get_queryset(self):
        return SignatureBaseModel.objects.select_subclasses()


class DocumentVersionSignatureListView(SingleObjectListView):
    object_permission = permission_document_version_signature_view
    object_permission_related = 'document_version.document'

    def get_document_version(self):
        return get_object_or_404(DocumentVersion, pk=self.kwargs['pk'])

    def get_extra_context(self):
        return {
            'document': self.get_document_version().document,
            'document_version': self.get_document_version(),
            'navigation_object_list': ('document', 'document_version'),
            'hide_object': True,
            'title': _(
                'Signatures for document version: %s'
            ) % self.get_document_version(),
        }

    def get_queryset(self):
        queryset = self.get_document_version().signatures.all()

        try:
            Permission.check_permissions(
                self.request.user, (permission_document_version_signature_view,)
            )
        except PermissionDenied:
            return AccessControlList.objects.filter_by_access(
                permission_document_version_signature_view, self.request.user, queryset
            )
        else:
            return queryset


def document_version_signature_upload(request, pk):
    document_version = get_object_or_404(DocumentVersion, pk=pk)

    try:
        Permission.check_permissions(
            request.user, (permission_document_version_signature_upload,)
        )
    except PermissionDenied:
        AccessControlList.objects.check_access(
            permission_document_version_signature_upload, request.user, document_version.document
        )

    document_version.document.add_as_recent_document_for_user(request.user)

    post_action_redirect = None
    previous = request.POST.get('previous', request.GET.get('previous', request.META.get('HTTP_REFERER', reverse(settings.LOGIN_REDIRECT_URL))))
    next = request.POST.get('next', request.GET.get('next', post_action_redirect if post_action_redirect else request.META.get('HTTP_REFERER', reverse(settings.LOGIN_REDIRECT_URL))))

    if request.method == 'POST':
        form = DetachedSignatureForm(request.POST, request.FILES)
        if form.is_valid():
            try:
                DetachedSignature.objects.create(
                    document_version=document_version,
                    signature_file=request.FILES['file']
                )
                messages.success(
                    request, _('Detached signature uploaded successfully.')
                )
                return HttpResponseRedirect(next)
            except Exception as exception:
                messages.error(request, exception)
                return HttpResponseRedirect(previous)
    else:
        form = DetachedSignatureForm()

    return render_to_response('appearance/generic_form.html', {
        'form': form,
        'next': next,
        'document': document_version.document,
        'document_version': document_version,
        'navigation_object_list': ('document', 'document_version'),
        'previous': previous,
        'title': _('Upload detached signature for document version: %s') % document_version,
    }, context_instance=RequestContext(request))


def document_signature_download(request, pk):
    signature = get_object_or_404(DetachedSignature, pk=pk)

    try:
        Permission.check_permissions(
            request.user, (permission_document_version_signature_download,)
        )
    except PermissionDenied:
        AccessControlList.objects.check_access(
            permission_document_version_signature_download, request.user,
            signature.document_version.signature
        )

    return serve_file(
        request,
        signature,
        save_as='"%s.sig"' % signature.document_version.document,
        content_type='application/octet-stream'
    )