from __future__ import absolute_import, unicode_literals

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 documents.models import Document
from documents.views import DocumentListView

from acls.models import AccessControlList
from common.utils import encapsulate, get_object_name
from permissions import Permission

from .exceptions import DocumentAlreadyCheckedOut, DocumentNotCheckedOut
from .forms import DocumentCheckoutForm
from .literals import STATE_LABELS
from .models import DocumentCheckout
from .permissions import (
    permission_document_checkin, permission_document_checkin_override,
    permission_document_checkout
)


class CheckoutListView(DocumentListView):
    def get_document_queryset(self):
        return DocumentCheckout.objects.checked_out_documents()

    extra_context = {
        'title': _('Documents checked out'),
        'hide_links': True,
        'extra_columns': [
            {'name': _('User'), 'attribute': encapsulate(lambda document: get_object_name(document.checkout_info().user))},
            {'name': _('Checkout time and date'), 'attribute': encapsulate(lambda document: document.checkout_info().checkout_datetime)},
            {'name': _('Checkout expiration'), 'attribute': encapsulate(lambda document: document.checkout_info().expiration_datetime)},
        ],
    }


def checkout_info(request, document_pk):
    document = get_object_or_404(Document, pk=document_pk)
    try:
        Permission.check_permissions(request.user, [permission_document_checkout, permission_document_checkin])
    except PermissionDenied:
        AccessControlList.objects.check_access([permission_document_checkout, permission_document_checkin], request.user, document)

    paragraphs = [_('Document status: %s') % STATE_LABELS[document.checkout_state()]]

    if document.is_checked_out():
        checkout_info = document.checkout_info()
        paragraphs.append(_('User: %s') % get_object_name(checkout_info.user))
        paragraphs.append(_('Check out time: %s') % checkout_info.checkout_datetime)
        paragraphs.append(_('Check out expiration: %s') % checkout_info.expiration_datetime)
        paragraphs.append(_('New versions allowed: %s') % (_('Yes') if not checkout_info.block_new_version else _('No')))

    return render_to_response('appearance/generic_template.html', {
        'paragraphs': paragraphs,
        'object': document,
        'title': _('Check out details for document: %s') % document
    }, context_instance=RequestContext(request))


def checkout_document(request, document_pk):
    document = get_object_or_404(Document, pk=document_pk)
    try:
        Permission.check_permissions(request.user, [permission_document_checkout])
    except PermissionDenied:
        AccessControlList.objects.check_access(permission_document_checkout, request.user, document)

    if request.method == 'POST':
        form = DocumentCheckoutForm(data=request.POST, initial={'document': document})
        if form.is_valid():
            try:
                DocumentCheckout.objects.checkout_document(
                    document=document,
                    expiration_datetime=form.cleaned_data['expiration_datetime'],
                    user=request.user,
                    block_new_version=form.cleaned_data['block_new_version'],
                )
            except DocumentAlreadyCheckedOut:
                messages.error(request, _('Document already checked out.'))
                return HttpResponseRedirect(reverse('checkouts:checkout_info', args=[document.pk]))
            except Exception as exception:
                messages.error(request, _('Error trying to check out document; %s') % exception)
            else:
                messages.success(request, _('Document "%s" checked out successfully.') % document)
                return HttpResponseRedirect(reverse('checkouts:checkout_info', args=[document.pk]))
    else:
        form = DocumentCheckoutForm(initial={'document': document})

    return render_to_response('appearance/generic_form.html', {
        'form': form,
        'object': document,
        'title': _('Check out document: %s') % document
    }, context_instance=RequestContext(request))


def checkin_document(request, document_pk):
    document = get_object_or_404(Document, pk=document_pk)
    post_action_redirect = reverse('checkouts:checkout_info', args=[document.pk])

    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 not document.is_checked_out():
        messages.error(request, _('Document has not been checked out.'))
        return HttpResponseRedirect(previous)

    # If the user trying to check in the document is the same as the check out
    # user just check for the normal permission otherwise check for the forceful
    # checkin permission
    if document.checkout_info().user == request.user:
        try:
            Permission.check_permissions(request.user, [permission_document_checkin])
        except PermissionDenied:
            AccessControlList.objects.check_access(permission_document_checkin, request.user, document)
    else:
        try:
            Permission.check_permissions(request.user, [permission_document_checkin_override])
        except PermissionDenied:
            AccessControlList.objects.check_access(permission_document_checkin_override, request.user, document)

    if request.method == 'POST':
        try:
            document.check_in(user=request.user)
        except DocumentNotCheckedOut:
            messages.error(request, _('Document has not been checked out.'))
        except Exception as exception:
            messages.error(request, _('Error trying to check in document; %s') % exception)
        else:
            messages.success(request, _('Document "%s" checked in successfully.') % document)
            return HttpResponseRedirect(next)

    context = {
        'delete_view': False,
        'previous': previous,
        'next': next,
        'object': document,
    }

    if document.checkout_info().user != request.user:
        context['title'] = _('You didn\'t originally checked out this document.  Are you sure you wish to forcefully check in document: %s?') % document
    else:
        context['title'] = _('Are you sure you wish to check in document: %s?') % document

    return render_to_response('appearance/generic_confirm.html', context,
                              context_instance=RequestContext(request))