from __future__ import unicode_literals

from django.utils.translation import ugettext_lazy as _

from navigation import Link

from .models import DocumentVersionSignature
from .permissions import (
    permission_document_verify, permission_signature_delete,
    permission_signature_download, permission_signature_upload,
)


def can_upload_detached_signature(context):
    return not DocumentVersionSignature.objects.has_detached_signature(context['object'].latest_version) and not DocumentVersionSignature.objects.has_embedded_signature(context['object'].latest_version)


def can_delete_detached_signature(context):
    return DocumentVersionSignature.objects.has_detached_signature(context['object'].latest_version)


link_document_signature_delete = Link(condition=can_delete_detached_signature, permissions=[permission_signature_delete], tags='dangerous', text=_('Delete signature'), view='signatures:document_signature_delete', args='object.pk')
link_document_signature_download = Link(condition=can_delete_detached_signature, text=_('Download signature'), view='signatures:document_signature_download', args='object.pk', permissions=[permission_signature_download])
link_document_signature_upload = Link(condition=can_upload_detached_signature, permissions=[permission_signature_upload], text=_('Upload signature'), view='signatures:document_signature_upload', args='object.pk')
link_document_verify = Link(permissions=[permission_document_verify], text=_('Signatures'), view='signatures:document_verify', args='object.pk')