django-helpdeskmig/helpdesk/views/staff.py

"""
django-helpdesk - A Django powered ticket tracker for small enterprise.

(c) Copyright 2008 Jutda. All Rights Reserved. See LICENSE for details.

views/staff.py - The bulk of the application - provides most business logic and
                 renders all staff-facing views.
"""
from copy import deepcopy
import json

from django import VERSION as DJANGO_VERSION
from django.conf import settings
from django.contrib.auth import get_user_model
from django.contrib.auth.decorators import user_passes_test
from django.contrib.contenttypes.models import ContentType
from django.urls import reverse, reverse_lazy
from django.core.exceptions import ValidationError, PermissionDenied
from django.db.models import Q
from django.http import HttpResponseRedirect, Http404, HttpResponse, JsonResponse
from django.shortcuts import render, get_object_or_404
from django.utils.dates import MONTHS_3
from django.utils.translation import ugettext as _
from django.utils.html import escape
from django import forms
from django.utils import timezone
from django.views.generic.edit import FormView, UpdateView
from django.core.cache import cache

from helpdesk.query import (
    query_to_dict,
    apply_query,
    query_tickets_by_args,
    query_to_base64,
    query_from_base64,
)

from helpdesk.serializers import DatatablesTicketSerializer

from helpdesk.decorators import (
    helpdesk_staff_member_required, helpdesk_superuser_required,
    is_helpdesk_staff
)
from helpdesk.forms import (
    TicketForm, UserSettingsForm, EmailIgnoreForm, EditTicketForm, TicketCCForm,
    TicketCCEmailForm, TicketCCUserForm, EditFollowUpForm, TicketDependencyForm
)
from helpdesk.decorators import staff_member_required, superuser_required
from helpdesk.lib import (
    safe_template_context,
    process_attachments,
    queue_template_context,
    format_time_spent,
)
from helpdesk.models import (
    Ticket, Queue, FollowUp, TicketChange, PreSetReply, FollowUpAttachment, SavedSearch,
    IgnoreEmail, TicketCC, TicketDependency, UserSettings,
)
from helpdesk import settings as helpdesk_settings
from helpdesk.views.permissions import MustBeStaffMixin
from ..lib import format_time_spent

from rest_framework import viewsets, status
from rest_framework.response import Response
from rest_framework.decorators import api_view

from datetime import date, datetime, timedelta
import re


User = get_user_model()

if helpdesk_settings.HELPDESK_ALLOW_NON_STAFF_TICKET_UPDATE:
    # treat 'normal' users like 'staff'
    staff_member_required = user_passes_test(
        lambda u: u.is_authenticated and u.is_active)
else:
    staff_member_required = user_passes_test(
        lambda u: u.is_authenticated and u.is_active and u.is_staff)


User = get_user_model()


def _get_queue_choices(queues):
    """Return list of `choices` array for html form for given queues

    idea is to return only one choice if there is only one queue or add empty
    choice at the beginning of the list, if there are more queues
    """

    queue_choices = []
    if len(queues) > 1:
        queue_choices = [('', '--------')]
    queue_choices += [(q.id, q.title) for q in queues]
    return queue_choices


def _get_user_queues(user):
    """Return the list of Queues the user can access.

    :param user: The User (the class should have the has_perm method)
    :return: A Python list of Queues
    """
    all_queues = Queue.objects.all()
    public_ids = [q.pk for q in
                  Queue.objects.filter(allow_public_submission=True)]

    limit_queues_by_user = \
        helpdesk_settings.HELPDESK_ENABLE_PER_QUEUE_STAFF_PERMISSION \
        and not user.is_superuser
    if limit_queues_by_user:
        id_list = [q.pk for q in all_queues if user.has_perm(q.permission_name)]
        id_list += public_ids
        return all_queues.filter(pk__in=id_list)
    else:
        return all_queues


def _has_access_to_queue(user, queue):
    """Check if a certain user can access a certain queue.

    :param user: The User (the class should have the has_perm method)
    :param queue: The django-helpdesk Queue instance
    :return: True if the user has permission (either by default or explicitly), false otherwise
    """
    if user.is_superuser or not helpdesk_settings.HELPDESK_ENABLE_PER_QUEUE_STAFF_PERMISSION:
        return True
    else:
        return user.has_perm(queue.permission_name)


def _is_my_ticket(user, ticket):
    """Check to see if the user has permission to access
    a ticket. If not then deny access."""
    if _has_access_to_queue(user, ticket.queue):
        return True
    elif user.is_superuser or user.is_staff or \
            (ticket.assigned_to and user.id == ticket.assigned_to.id):
        return True
    else:
        return False


@helpdesk_staff_member_required
def dashboard(request):
    """
    A quick summary overview for users: A list of their own tickets, a table
    showing ticket counts by queue/status, and a list of unassigned tickets
    with options for them to 'Take' ownership of said tickets.
    """
    active_tickets = Ticket.objects.select_related('queue').exclude(
        status__in=[Ticket.CLOSED_STATUS, Ticket.RESOLVED_STATUS],
    )

    # open & reopened tickets, assigned to current user
    tickets = active_tickets.filter(
        assigned_to=request.user,
    )

    # closed & resolved tickets, assigned to current user
    tickets_closed_resolved = Ticket.objects.select_related('queue').filter(
        assigned_to=request.user,
        status__in=[Ticket.CLOSED_STATUS, Ticket.RESOLVED_STATUS])

    user_queues = _get_user_queues(request.user)

    unassigned_tickets = active_tickets.filter(
        assigned_to__isnull=True,
        queue__in=user_queues
    )

    # all tickets, reported by current user
    all_tickets_reported_by_current_user = ''
    email_current_user = request.user.email
    if email_current_user:
        all_tickets_reported_by_current_user = Ticket.objects.select_related('queue').filter(
            submitter_email=email_current_user,
        ).order_by('status')

    tickets_in_queues = Ticket.objects.filter(
        queue__in=user_queues,
    )
    basic_ticket_stats = calc_basic_ticket_stats(tickets_in_queues)

    # The following query builds a grid of queues & ticket statuses,
    # to be displayed to the user. EG:
    #          Open  Resolved
    # Queue 1    10     4
    # Queue 2     4    12

    queues = _get_user_queues(request.user).values_list('id', flat=True)

    from_clause = """FROM    helpdesk_ticket t,
                    helpdesk_queue q"""
    if queues:
        where_clause = """WHERE   q.id = t.queue_id AND
                        q.id IN (%s)""" % (",".join(("%d" % pk for pk in queues)))
    else:
        where_clause = """WHERE   q.id = t.queue_id"""

    return render(request, 'helpdesk/dashboard.html', {
        'user_tickets': tickets,
        'user_tickets_closed_resolved': tickets_closed_resolved,
        'unassigned_tickets': unassigned_tickets,
        'all_tickets_reported_by_current_user': all_tickets_reported_by_current_user,
        'basic_ticket_stats': basic_ticket_stats,
    })


dashboard = staff_member_required(dashboard)


@helpdesk_staff_member_required
def delete_ticket(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if request.method == 'GET':
        return render(request, 'helpdesk/delete_ticket.html', {
            'ticket': ticket,
        })
    else:
        ticket.delete()
        return HttpResponseRedirect(reverse('helpdesk:home'))


delete_ticket = staff_member_required(delete_ticket)


@helpdesk_staff_member_required
def followup_edit(request, ticket_id, followup_id):
    """Edit followup options with an ability to change the ticket."""
    followup = get_object_or_404(FollowUp, id=followup_id)
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if request.method == 'GET':
        form = EditFollowUpForm(initial={
            'title': escape(followup.title),
            'ticket': followup.ticket,
            'comment': escape(followup.comment),
            'public': followup.public,
            'new_status': followup.new_status,
            'time_spent': format_time_spent(followup.time_spent),
        })

        ticketcc_string, show_subscribe = \
            return_ticketccstring_and_show_subscribe(request.user, ticket)

        return render(request, 'helpdesk/followup_edit.html', {
            'followup': followup,
            'ticket': ticket,
            'form': form,
            'ticketcc_string': ticketcc_string,
        })
    elif request.method == 'POST':
        form = EditFollowUpForm(request.POST)
        if form.is_valid():
            title = form.cleaned_data['title']
            _ticket = form.cleaned_data['ticket']
            comment = form.cleaned_data['comment']
            public = form.cleaned_data['public']
            new_status = form.cleaned_data['new_status']
            time_spent = form.cleaned_data['time_spent']
            # will save previous date
            old_date = followup.date
            new_followup = FollowUp(title=title, date=old_date, ticket=_ticket,
                                    comment=comment, public=public,
                                    new_status=new_status,
                                    time_spent=time_spent)
            # keep old user if one did exist before.
            if followup.user:
                new_followup.user = followup.user
            new_followup.save()
            # get list of old attachments & link them to new_followup
            attachments = FollowUpAttachment.objects.filter(followup=followup)
            for attachment in attachments:
                attachment.followup = new_followup
                attachment.save()
            # delete old followup
            followup.delete()
        return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket.id]))


followup_edit = staff_member_required(followup_edit)


@helpdesk_staff_member_required
def followup_delete(request, ticket_id, followup_id):
    """followup delete for superuser"""

    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not request.user.is_superuser:
        return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket.id]))

    followup = get_object_or_404(FollowUp, id=followup_id)
    followup.delete()
    return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket.id]))


followup_delete = staff_member_required(followup_delete)


@helpdesk_staff_member_required
def view_ticket(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if 'take' in request.GET:
        # Allow the user to assign the ticket to themselves whilst viewing it.

        # Trick the update_ticket() view into thinking it's being called with
        # a valid POST.
        request.POST = {
            'owner': request.user.id,
            'public': 1,
            'title': ticket.title,
            'comment': ''
        }
        return update_ticket(request, ticket_id)

    if 'subscribe' in request.GET:
        # Allow the user to subscribe him/herself to the ticket whilst viewing it.
        ticket_cc, show_subscribe = \
            return_ticketccstring_and_show_subscribe(request.user, ticket)
        if show_subscribe:
            subscribe_staff_member_to_ticket(ticket, request.user)
            return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket.id]))

    if 'close' in request.GET and ticket.status == Ticket.RESOLVED_STATUS:
        if not ticket.assigned_to:
            owner = 0
        else:
            owner = ticket.assigned_to.id

        # Trick the update_ticket() view into thinking it's being called with
        # a valid POST.
        request.POST = {
            'new_status': Ticket.CLOSED_STATUS,
            'public': 1,
            'owner': owner,
            'title': ticket.title,
            'comment': _('Accepted resolution and closed ticket'),
        }

        return update_ticket(request, ticket_id)

    if helpdesk_settings.HELPDESK_STAFF_ONLY_TICKET_OWNERS:
        users = User.objects.filter(is_active=True, is_staff=True).order_by(User.USERNAME_FIELD)
    else:
        users = User.objects.filter(is_active=True).order_by(User.USERNAME_FIELD)

    queues = _get_user_queues(request.user)
    queue_choices = _get_queue_choices(queues)
    # TODO: shouldn't this template get a form to begin with?
    form = TicketForm(initial={'due_date': ticket.due_date},
                      queue_choices=queue_choices)

    ticketcc_string, show_subscribe = \
        return_ticketccstring_and_show_subscribe(request.user, ticket)

    submitter_userprofile = ticket.get_submitter_userprofile()
    if submitter_userprofile is not None:
        content_type = ContentType.objects.get_for_model(submitter_userprofile)
        submitter_userprofile_url = reverse(
            'admin:{app}_{model}_change'.format(app=content_type.app_label, model=content_type.model),
            kwargs={'object_id': submitter_userprofile.id}
        )
    else:
        submitter_userprofile_url = None
    return render(request, 'helpdesk/ticket.html', {
        'ticket': ticket,
        'submitter_userprofile_url': submitter_userprofile_url,
        'form': form,
        'active_users': users,
        'priorities': Ticket.PRIORITY_CHOICES,
        'preset_replies': PreSetReply.objects.filter(
            Q(queues=ticket.queue) | Q(queues__isnull=True)),
        'ticketcc_string': ticketcc_string,
        'SHOW_SUBSCRIBE': show_subscribe,
    })


def return_ticketccstring_and_show_subscribe(user, ticket):
    """used in view_ticket() and followup_edit()"""
    # create the ticketcc_string and check whether current user is already
    # subscribed
    username = user.get_username().upper()
    useremail = user.email.upper()
    strings_to_check = list()
    strings_to_check.append(username)
    strings_to_check.append(useremail)

    ticketcc_string = ''
    all_ticketcc = ticket.ticketcc_set.all()
    counter_all_ticketcc = len(all_ticketcc) - 1
    show_subscribe = True
    for i, ticketcc in enumerate(all_ticketcc):
        ticketcc_this_entry = str(ticketcc.display)
        ticketcc_string += ticketcc_this_entry
        if i < counter_all_ticketcc:
            ticketcc_string += ', '
        if strings_to_check.__contains__(ticketcc_this_entry.upper()):
            show_subscribe = False

    # check whether current user is a submitter or assigned to ticket
    assignedto_username = str(ticket.assigned_to).upper()
    strings_to_check = list()
    if ticket.submitter_email is not None:
        submitter_email = ticket.submitter_email.upper()
        strings_to_check.append(submitter_email)
    strings_to_check.append(assignedto_username)
    if strings_to_check.__contains__(username) or strings_to_check.__contains__(useremail):
        show_subscribe = False

    return ticketcc_string, show_subscribe


def subscribe_to_ticket_updates(ticket, user=None, email=None, can_view=True, can_update=False):

    if ticket is not None:

        queryset = TicketCC.objects.filter(ticket=ticket, user=user, email=email)

        # Don't create duplicate entries for subscribers
        if queryset.count() > 0:
            return queryset.first()

        if user is None and len(email) < 5:
            raise ValidationError(
                _('When you add somebody on Cc, you must provide either a User or a valid email. Email: %s' % email)
            )

        ticketcc = TicketCC(
            ticket=ticket,
            user=user,
            email=email,
            can_view=can_view,
            can_update=can_update
        )
        ticketcc.save()

        return ticketcc


def subscribe_staff_member_to_ticket(ticket, user, email=''):
    """used in view_ticket() and update_ticket()"""
    return subscribe_to_ticket_updates(ticket=ticket, user=user, email=email, can_view=can_view, can_update=can_update)


def update_ticket(request, ticket_id, public=False):

    ticket = None

    if not (public or (
            request.user.is_authenticated and
            request.user.is_active and (
                is_helpdesk_staff(request.user) or
                helpdesk_settings.HELPDESK_ALLOW_NON_STAFF_TICKET_UPDATE))):

        key = request.POST.get('key')
        email = request.POST.get('mail')

        if key and email:
            ticket = Ticket.objects.get(
                id=ticket_id,
                submitter_email__iexact=email,
                secret_key__iexact=key
            )

        if not ticket:
            return HttpResponseRedirect(
                '%s?next=%s' % (reverse('helpdesk:login'), request.path)
            )

    if not ticket:
        ticket = get_object_or_404(Ticket, id=ticket_id)

    date_re = re.compile(
        r'(?P<month>\d{1,2})/(?P<day>\d{1,2})/(?P<year>\d{4})$'
    )

    comment = request.POST.get('comment', '')
    new_status = int(request.POST.get('new_status', ticket.status))
    title = request.POST.get('title', '')
    public = request.POST.get('public', False)
    owner = int(request.POST.get('owner', -1))
    priority = int(request.POST.get('priority', ticket.priority))
    due_date_year = int(request.POST.get('due_date_year', 0))
    due_date_month = int(request.POST.get('due_date_month', 0))
    due_date_day = int(request.POST.get('due_date_day', 0))
    if request.POST.get("time_spent"):
        (hours, minutes) = [int(f) for f in request.POST.get("time_spent").split(":")]
        time_spent = timedelta(hours=hours, minutes=minutes)
    else:
        time_spent = None
    # NOTE: jQuery's default for dates is mm/dd/yy
    # very US-centric but for now that's the only format supported
    # until we clean up code to internationalize a little more
    due_date = request.POST.get('due_date', None) or None

    if due_date is not None:
        # based on Django code to parse dates:
        # https://docs.djangoproject.com/en/2.0/_modules/django/utils/dateparse/
        match = date_re.match(due_date)
        if match:
            kw = {k: int(v) for k, v in match.groupdict().items()}
            due_date = date(**kw)
    else:
        # old way, probably deprecated?
        if not (due_date_year and due_date_month and due_date_day):
            due_date = ticket.due_date
        else:
            # NOTE: must be an easier way to create a new date than doing it this way?
            if ticket.due_date:
                due_date = ticket.due_date
            else:
                due_date = timezone.now()
            due_date = due_date.replace(due_date_year, due_date_month, due_date_day)

    no_changes = all([
        not request.FILES,
        not comment,
        new_status == ticket.status,
        title == ticket.title,
        priority == int(ticket.priority),
        due_date == ticket.due_date,
        (owner == -1) or (not owner and not ticket.assigned_to) or
        (owner and User.objects.get(id=owner) == ticket.assigned_to),
    ])
    if no_changes:
        return return_to_ticket(request.user, helpdesk_settings, ticket)

    # We need to allow the 'ticket' and 'queue' contexts to be applied to the
    # comment.
    context = safe_template_context(ticket)

    from django.template import engines
    template_func = engines['django'].from_string
    # this prevents system from trying to render any template tags
    # broken into two stages to prevent changes from first replace being themselves
    # changed by the second replace due to conflicting syntax
    comment = comment.replace('{%', 'X-HELPDESK-COMMENT-VERBATIM').replace('%}', 'X-HELPDESK-COMMENT-ENDVERBATIM')
    comment = comment.replace('X-HELPDESK-COMMENT-VERBATIM', '{% verbatim %}{%').replace('X-HELPDESK-COMMENT-ENDVERBATIM', '%}{% endverbatim %}')
    # render the neutralized template
    comment = template_func(comment).render(context)

    if owner is -1 and ticket.assigned_to:
        owner = ticket.assigned_to.id

    f = FollowUp(ticket=ticket, date=timezone.now(), comment=comment,
                 time_spent=time_spent)

    if is_helpdesk_staff(request.user):
        f.user = request.user

    f.public = public

    reassigned = False

    old_owner = ticket.assigned_to
    if owner is not -1:
        if owner != 0 and ((ticket.assigned_to and owner != ticket.assigned_to.id) or not ticket.assigned_to):
            new_user = User.objects.get(id=owner)
            f.title = _('Assigned to %(username)s') % {
                'username': new_user.get_username(),
            }
            ticket.assigned_to = new_user
            reassigned = True
        # user changed owner to 'unassign'
        elif owner == 0 and ticket.assigned_to is not None:
            f.title = _('Unassigned')
            ticket.assigned_to = None

    old_status_str = ticket.get_status_display()
    old_status = ticket.status
    if new_status != ticket.status:
        ticket.status = new_status
        ticket.save()
        f.new_status = new_status
        ticket_status_changed = True
        if f.title:
            f.title += ' and %s' % ticket.get_status_display()
        else:
            f.title = '%s' % ticket.get_status_display()

    if not f.title:
        if f.comment:
            f.title = _('Comment')
        else:
            f.title = _('Updated')

    f.save()

    files = []
    if request.FILES:
        files = process_attachments(f, request.FILES.getlist('attachment'))

    if title and title != ticket.title:
        c = TicketChange(
            followup=f,
            field=_('Title'),
            old_value=ticket.title,
            new_value=title,
        )
        c.save()
        ticket.title = title

    if new_status != old_status:
        c = TicketChange(
            followup=f,
            field=_('Status'),
            old_value=old_status_str,
            new_value=ticket.get_status_display(),
        )
        c.save()

    if ticket.assigned_to != old_owner:
        c = TicketChange(
            followup=f,
            field=_('Owner'),
            old_value=old_owner,
            new_value=ticket.assigned_to,
        )
        c.save()

    if priority != ticket.priority:
        c = TicketChange(
            followup=f,
            field=_('Priority'),
            old_value=ticket.priority,
            new_value=priority,
        )
        c.save()
        ticket.priority = priority

    if due_date != ticket.due_date:
        c = TicketChange(
            followup=f,
            field=_('Due on'),
            old_value=ticket.due_date,
            new_value=due_date,
        )
        c.save()
        ticket.due_date = due_date

    if new_status in (Ticket.RESOLVED_STATUS, Ticket.CLOSED_STATUS):
        if new_status == Ticket.RESOLVED_STATUS or ticket.resolution is None:
            ticket.resolution = comment

    # ticket might have changed above, so we re-instantiate context with the
    # (possibly) updated ticket.
    context = safe_template_context(ticket)
    context.update(
        resolution=ticket.resolution,
        comment=f.comment,
    )

    messages_sent_to = set()
    try:
        messages_sent_to.add(request.user.email)
    except AttributeError:
        pass
    if public and (f.comment or (
        f.new_status in (Ticket.RESOLVED_STATUS,
                         Ticket.CLOSED_STATUS))):
        if f.new_status == Ticket.RESOLVED_STATUS:
            template = 'resolved_'
        elif f.new_status == Ticket.CLOSED_STATUS:
            template = 'closed_'
        else:
            template = 'updated_'

        roles = {
            'submitter': (template + 'submitter', context),
            'ticket_cc': (template + 'cc', context),
        }
        if ticket.assigned_to and ticket.assigned_to.usersettings_helpdesk.email_on_ticket_change:
            roles['assigned_to'] = (template + 'cc', context)
        messages_sent_to.update(ticket.send(roles, dont_send_to=messages_sent_to, fail_silently=True, files=files,))

    if reassigned:
        template_staff = 'assigned_owner'
    elif f.new_status == Ticket.RESOLVED_STATUS:
        template_staff = 'resolved_owner'
    elif f.new_status == Ticket.CLOSED_STATUS:
        template_staff = 'closed_owner'
    else:
        template_staff = 'updated_owner'

    if ticket.assigned_to and (ticket.assigned_to.usersettings_helpdesk.email_on_ticket_change or (reassigned and ticket.assigned_to.usersettings_helpdesk.email_on_ticket_assigned)):
        messages_sent_to.update(ticket.send(
            {'assigned_to': (template_staff, context)},
            dont_send_to=messages_sent_to,
            fail_silently=True,
            files=files,
        ))

    if reassigned:
        template_cc = 'assigned_cc'
    elif f.new_status == Ticket.RESOLVED_STATUS:
        template_cc = 'resolved_cc'
    elif f.new_status == Ticket.CLOSED_STATUS:
        template_cc = 'closed_cc'
    else:
        template_cc = 'updated_cc'

    messages_sent_to.update(ticket.send(
        {'ticket_cc': (template_cc, context)},
        dont_send_to=messages_sent_to,
        fail_silently=True,
        files=files,
    ))

    ticket.save()

    # auto subscribe user if enabled
    if helpdesk_settings.HELPDESK_AUTO_SUBSCRIBE_ON_TICKET_RESPONSE and request.user.is_authenticated:
        ticketcc_string, SHOW_SUBSCRIBE = return_ticketccstring_and_show_subscribe(request.user, ticket)
        if SHOW_SUBSCRIBE:
            subscribe_staff_member_to_ticket(ticket, request.user)

    return return_to_ticket(request.user, helpdesk_settings, ticket)


def return_to_ticket(user, helpdesk_settings, ticket):
    """Helper function for update_ticket"""

    if is_helpdesk_staff(user):
        return HttpResponseRedirect(ticket.get_absolute_url())
    else:
        return HttpResponseRedirect(ticket.ticket_url)


@helpdesk_staff_member_required
def mass_update(request):
    tickets = request.POST.getlist('ticket_id')
    action = request.POST.get('action', None)
    if not (tickets and action):
        return HttpResponseRedirect(reverse('helpdesk:list'))

    if action.startswith('assign_'):
        parts = action.split('_')
        user = User.objects.get(id=parts[1])
        action = 'assign'
    elif action == 'take':
        user = request.user
        action = 'assign'

    for t in Ticket.objects.filter(id__in=tickets):
        if not _has_access_to_queue(request.user, t.queue):
            continue

        if action == 'assign' and t.assigned_to != user:
            t.assigned_to = user
            t.save()
            f = FollowUp(ticket=t,
                         date=timezone.now(),
                         title=_('Assigned to %(username)s in bulk update' % {
                             'username': user.get_username()
                         }),
                         public=True,
                         user=request.user)
            f.save()
        elif action == 'unassign' and t.assigned_to is not None:
            t.assigned_to = None
            t.save()
            f = FollowUp(ticket=t,
                         date=timezone.now(),
                         title=_('Unassigned in bulk update'),
                         public=True,
                         user=request.user)
            f.save()
        elif action == 'close' and t.status != Ticket.CLOSED_STATUS:
            t.status = Ticket.CLOSED_STATUS
            t.save()
            f = FollowUp(ticket=t,
                         date=timezone.now(),
                         title=_('Closed in bulk update'),
                         public=False,
                         user=request.user,
                         new_status=Ticket.CLOSED_STATUS)
            f.save()
        elif action == 'close_public' and t.status != Ticket.CLOSED_STATUS:
            t.status = Ticket.CLOSED_STATUS
            t.save()
            f = FollowUp(ticket=t,
                         date=timezone.now(),
                         title=_('Closed in bulk update'),
                         public=True,
                         user=request.user,
                         new_status=Ticket.CLOSED_STATUS)
            f.save()
            # Send email to Submitter, Owner, Queue CC
            context = safe_template_context(t)
            context.update(resolution=t.resolution,
                           queue=queue_template_context(t.queue))

            messages_sent_to = set()
            try:
                messages_sent_to.add(request.user.email)
            except AttributeError:
                pass

            roles = {
                'submitter': ('closed_submitter', context),
                'ticket_cc': ('closed_cc', context),
            }
            if ticket.assigned_to and ticket.assigned_to.usersettings_helpdesk.email_on_ticket_change:
                roles['assigned_to'] = ('closed_owner', context),

            messages_sent_to.update(t.send(
                roles,
                dont_send_to=messages_sent_to,
                fail_silently=True,
            ))

        elif action == 'delete':
            t.delete()

    return HttpResponseRedirect(reverse('helpdesk:list'))


mass_update = staff_member_required(mass_update)


@helpdesk_staff_member_required
def ticket_list(request):
    context = {}

    user_queues = _get_user_queues(request.user)
    # Prefilter the allowed tickets
    base_tickets = Ticket.objects.filter(queue__in=user_queues)

    # Query_params will hold a dictionary of parameters relating to
    # a query, to be saved if needed:
    query_params = {
        'filtering': {},
        'sorting': None,
        'sortreverse': False,
        'search_string': '',
    }
    default_query_params = {
        'filtering': {'status__in': [1, 2, 3]},
        'sorting': 'created',
        'search_string': '',
        'sortreverse': False,
    }

    # If the user is coming from the header/navigation search box, lets' first
    # look at their query to see if they have entered a valid ticket number. If
    # they have, just redirect to that ticket number. Otherwise, we treat it as
    # a keyword search.

    if request.GET.get('search_type', None) == 'header':
        query = request.GET.get('q')
        filter = None
        if query.find('-') > 0:
            try:
                queue, id = Ticket.queue_and_id_from_query(query)
                id = int(id)
            except ValueError:
                id = None

            if id:
                filter = {'queue__slug': queue, 'id': id}
        else:
            try:
                query = int(query)
            except ValueError:
                query = None

            if query:
                filter = {'id': int(query)}

        if filter:
            try:
                ticket = base_tickets.get(**filter)
                return HttpResponseRedirect(ticket.staff_url)
            except Ticket.DoesNotExist:
                # Go on to standard keyword searching
                pass

    try:
        saved_query, query_params = load_saved_query(request, query_params)
    except QueryLoadError:
        return HttpResponseRedirect(reverse('helpdesk:list'))

    if saved_query:
        pass
    elif not {'queue', 'assigned_to', 'status', 'q', 'sort', 'sortreverse'}.intersection(request.GET):
        # Fall-back if no querying is being done
        all_queues = Queue.objects.all()
        query_params = deepcopy(default_query_params)
    else:
        filter_in_params = [
            ('queue', 'queue__id__in'),
            ('assigned_to', 'assigned_to__id__in'),
            ('status', 'status__in'),
        ]

        for param, filter_command in filter_in_params:
            patterns = request.GET.getlist(param)
            if patterns:
                try:
                    pattern_pks = [int(pattern) for pattern in patterns]
                    query_params['filtering'][filter_command] = pattern_pks
                except ValueError:
                    pass

        date_from = request.GET.get('date_from')
        if date_from:
            query_params['filtering']['created__gte'] = date_from

        date_to = request.GET.get('date_to')
        if date_to:
            query_params['filtering']['created__lte'] = date_to

        # KEYWORD SEARCHING
        q = request.GET.get('q', '')
        context['query'] = q
        query_params['search_string'] = q

        # SORTING
        sort = request.GET.get('sort', None)
        if sort not in ('status', 'assigned_to', 'created', 'title', 'queue', 'priority'):
            sort = 'created'
        query_params['sorting'] = sort

        sortreverse = request.GET.get('sortreverse', None)
        query_params['sortreverse'] = sortreverse

    tickets = base_tickets.select_related()

    try:
        ticket_qs = apply_query(tickets, query_params)
    except ValidationError:
        # invalid parameters in query, return default query
        ticket_qs = apply_query(tickets, default_query_params)

    urlsafe_query = query_to_base64(query_params)

    cache.set(request.user.email + urlsafe_query, ticket_qs, timeout=60*60)

    user_saved_queries = SavedSearch.objects.filter(Q(user=request.user) | Q(shared__exact=True))

    search_message = ''
    if query_params['search_string'] and settings.DATABASES['default']['ENGINE'].endswith('sqlite'):
        search_message = _(
            '<p><strong>Note:</strong> Your keyword search is case sensitive '
            'because of your database. This means the search will <strong>not</strong> '
            'be accurate. By switching to a different database system you will gain '
            'better searching! For more information, read the '
            '<a href="http://docs.djangoproject.com/en/dev/ref/databases/#sqlite-string-matching">'
            'Django Documentation on string matching in SQLite</a>.')


    return render(request, 'helpdesk/ticket_list.html', dict(
        context,
        default_tickets_per_page=request.user.usersettings_helpdesk.tickets_per_page,
        user_choices=User.objects.filter(is_active=True, is_staff=True),
        queue_choices=user_queues,
        status_choices=Ticket.STATUS_CHOICES,
        urlsafe_query=urlsafe_query,
        user_saved_queries=user_saved_queries,
        query_params=query_params,
        from_saved_query=saved_query is not None,
        saved_query=saved_query,
        search_message=search_message,
    ))


ticket_list = staff_member_required(ticket_list)


class QueryLoadError(Exception):
    pass


def load_saved_query(request, query_params=None):
    saved_query = None

    if request.GET.get('saved_query', None):
        try:
            saved_query = SavedSearch.objects.get(pk=request.GET.get('saved_query'))
        except SavedSearch.DoesNotExist:
            raise QueryLoadError()
        if not (saved_query.shared or saved_query.user == request.user):
            raise QueryLoadError()

        try:
            # we get a string like: b'stuff'
            # so leave of the first two chars (b') and last (')
            if saved_query.query.startswith('b\''):
                b64query = saved_query.query[2:-1]
            else:
                b64query = saved_query.query
            query_params = query_from_base64(b64query)
        except json.JSONDecodeError:
            raise QueryLoadError()
    return (saved_query, query_params)


@helpdesk_staff_member_required
@api_view(['GET'])
def datatables_ticket_list(request, query):
    """
    Datatable on ticket_list.html uses this view from to get objects to display
    on the table. query_tickets_by_args is at lib.py, DatatablesTicketSerializer is in
    serializers.py. The serializers and this view use django-rest_framework methods
    """
    objects = cache.get(request.user.email + query)
    query_params = query_from_base64(query)
    model_object = query_tickets_by_args(objects, '-date_created', **request.query_params)
    serializer = DatatablesTicketSerializer(model_object['items'], many=True)
    result = dict()
    result['data'] = serializer.data
    result['draw'] = model_object['draw']
    result['recordsTotal'] = model_object['total']
    result['recordsFiltered'] = model_object['count']
    return (JsonResponse(result, status=status.HTTP_200_OK))


@helpdesk_staff_member_required
def edit_ticket(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if request.method == 'POST':
        form = EditTicketForm(request.POST, instance=ticket)
        if form.is_valid():
            ticket = form.save()
            return HttpResponseRedirect(ticket.get_absolute_url())
    else:
        form = EditTicketForm(instance=ticket)

    return render(request, 'helpdesk/edit_ticket.html', {'form': form, 'ticket': ticket})


edit_ticket = staff_member_required(edit_ticket)


class CreateTicketView(MustBeStaffMixin, FormView):
    template_name = 'helpdesk/create_ticket.html'
    form_class = TicketForm

    def get_initial(self):
        initial_data = {}
        request = self.request
        if request.user.usersettings_helpdesk.use_email_as_submitter and request.user.email:
            initial_data['submitter_email'] = request.user.email
        if 'queue' in request.GET:
            initial_data['queue'] = request.GET['queue']
        return initial_data

    def get_form_kwargs(self):
        kwargs = super().get_form_kwargs()
        queues = _get_user_queues(self.request.user)
        kwargs["queue_choices"] = _get_queue_choices(queues)
        return kwargs

    def form_valid(self, form):
        self.ticket = form.save()
        return super().form_valid(form)

    def get_success_url(self):
        request = self.request
        if _has_access_to_queue(request.user, self.ticket.queue):
            return self.ticket.get_absolute_url()
        else:
            return reverse('helpdesk:dashboard')


@helpdesk_staff_member_required
def raw_details(request, type):
    # TODO: This currently only supports spewing out 'PreSetReply' objects,
    # in the future it needs to be expanded to include other items. All it
    # does is return a plain-text representation of an object.

    if type not in ('preset',):
        raise Http404

    if type == 'preset' and request.GET.get('id', False):
        try:
            preset = PreSetReply.objects.get(id=request.GET.get('id'))
            return HttpResponse(preset.body)
        except PreSetReply.DoesNotExist:
            raise Http404

    raise Http404


raw_details = staff_member_required(raw_details)


@helpdesk_staff_member_required
def hold_ticket(request, ticket_id, unhold=False):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if unhold:
        ticket.on_hold = False
        title = _('Ticket taken off hold')
    else:
        ticket.on_hold = True
        title = _('Ticket placed on hold')

    f = FollowUp(
        ticket=ticket,
        user=request.user,
        title=title,
        date=timezone.now(),
        public=True,
    )
    f.save()

    ticket.save()

    return HttpResponseRedirect(ticket.get_absolute_url())


hold_ticket = staff_member_required(hold_ticket)


@helpdesk_staff_member_required
def unhold_ticket(request, ticket_id):
    return hold_ticket(request, ticket_id, unhold=True)


unhold_ticket = staff_member_required(unhold_ticket)


@helpdesk_staff_member_required
def rss_list(request):
    return render(request, 'helpdesk/rss_list.html', {'queues': Queue.objects.all()})


rss_list = staff_member_required(rss_list)


@helpdesk_staff_member_required
def report_index(request):
    number_tickets = Ticket.objects.all().count()
    saved_query = request.GET.get('saved_query', None)

    user_queues = _get_user_queues(request.user)
    Tickets = Ticket.objects.filter(queue__in=user_queues)
    basic_ticket_stats = calc_basic_ticket_stats(Tickets)

    # The following query builds a grid of queues & ticket statuses,
    # to be displayed to the user. EG:
    #          Open  Resolved
    # Queue 1    10     4
    # Queue 2     4    12
    Queues = user_queues if user_queues else Queue.objects.all()

    dash_tickets = []
    for queue in Queues:
        dash_ticket = {
            'queue': queue.id,
            'name': queue.title,
            'open': queue.ticket_set.filter(status__in=[1, 2]).count(),
            'resolved': queue.ticket_set.filter(status=3).count(),
            'closed': queue.ticket_set.filter(status=4).count(),
            'time_spent': format_time_spent(queue.time_spent),
            'dedicated_time': format_time_spent(queue.dedicated_time)
        }
        dash_tickets.append(dash_ticket)

    return render(request, 'helpdesk/report_index.html', {
        'number_tickets': number_tickets,
        'saved_query': saved_query,
        'basic_ticket_stats': basic_ticket_stats,
        'dash_tickets': dash_tickets,
    })


report_index = staff_member_required(report_index)


@helpdesk_staff_member_required
def run_report(request, report):
    if Ticket.objects.all().count() == 0 or report not in (
            'queuemonth', 'usermonth', 'queuestatus', 'queuepriority', 'userstatus',
            'userpriority', 'userqueue', 'daysuntilticketclosedbymonth'):
        return HttpResponseRedirect(reverse("helpdesk:report_index"))

    report_queryset = Ticket.objects.all().select_related().filter(
        queue__in=_get_user_queues(request.user)
    )

    try:
        saved_query, query_params = load_saved_query(request)
    except QueryLoadError:
        return HttpResponseRedirect(reverse('helpdesk:report_index'))

    if request.GET.get('saved_query', None):
        report_queryset = apply_query(report_queryset, query_params)

    from collections import defaultdict
    summarytable = defaultdict(int)
    # a second table for more complex queries
    summarytable2 = defaultdict(int)

    def month_name(m):
        MONTHS_3[m].title()

    first_ticket = Ticket.objects.all().order_by('created')[0]
    first_month = first_ticket.created.month
    first_year = first_ticket.created.year

    last_ticket = Ticket.objects.all().order_by('-created')[0]
    last_month = last_ticket.created.month
    last_year = last_ticket.created.year

    periods = []
    year, month = first_year, first_month
    working = True
    periods.append("%s-%s" % (year, month))

    while working:
        month += 1
        if month > 12:
            year += 1
            month = 1
        if (year > last_year) or (month > last_month and year >= last_year):
            working = False
        periods.append("%s-%s" % (year, month))

    if report == 'userpriority':
        title = _('User by Priority')
        col1heading = _('User')
        possible_options = [t[1].title() for t in Ticket.PRIORITY_CHOICES]
        charttype = 'bar'

    elif report == 'userqueue':
        title = _('User by Queue')
        col1heading = _('User')
        queue_options = _get_user_queues(request.user)
        possible_options = [q.title for q in queue_options]
        charttype = 'bar'

    elif report == 'userstatus':
        title = _('User by Status')
        col1heading = _('User')
        possible_options = [s[1].title() for s in Ticket.STATUS_CHOICES]
        charttype = 'bar'

    elif report == 'usermonth':
        title = _('User by Month')
        col1heading = _('User')
        possible_options = periods
        charttype = 'date'

    elif report == 'queuepriority':
        title = _('Queue by Priority')
        col1heading = _('Queue')
        possible_options = [t[1].title() for t in Ticket.PRIORITY_CHOICES]
        charttype = 'bar'

    elif report == 'queuestatus':
        title = _('Queue by Status')
        col1heading = _('Queue')
        possible_options = [s[1].title() for s in Ticket.STATUS_CHOICES]
        charttype = 'bar'

    elif report == 'queuemonth':
        title = _('Queue by Month')
        col1heading = _('Queue')
        possible_options = periods
        charttype = 'date'

    elif report == 'daysuntilticketclosedbymonth':
        title = _('Days until ticket closed by Month')
        col1heading = _('Queue')
        possible_options = periods
        charttype = 'date'

    metric3 = False
    for ticket in report_queryset:
        if report == 'userpriority':
            metric1 = u'%s' % ticket.get_assigned_to
            metric2 = u'%s' % ticket.get_priority_display()

        elif report == 'userqueue':
            metric1 = u'%s' % ticket.get_assigned_to
            metric2 = u'%s' % ticket.queue.title

        elif report == 'userstatus':
            metric1 = u'%s' % ticket.get_assigned_to
            metric2 = u'%s' % ticket.get_status_display()

        elif report == 'usermonth':
            metric1 = u'%s' % ticket.get_assigned_to
            metric2 = u'%s-%s' % (ticket.created.year, ticket.created.month)

        elif report == 'queuepriority':
            metric1 = u'%s' % ticket.queue.title
            metric2 = u'%s' % ticket.get_priority_display()

        elif report == 'queuestatus':
            metric1 = u'%s' % ticket.queue.title
            metric2 = u'%s' % ticket.get_status_display()

        elif report == 'queuemonth':
            metric1 = u'%s' % ticket.queue.title
            metric2 = u'%s-%s' % (ticket.created.year, ticket.created.month)

        elif report == 'daysuntilticketclosedbymonth':
            metric1 = u'%s' % ticket.queue.title
            metric2 = u'%s-%s' % (ticket.created.year, ticket.created.month)
            metric3 = ticket.modified - ticket.created
            metric3 = metric3.days

        summarytable[metric1, metric2] += 1
        if metric3:
            if report == 'daysuntilticketclosedbymonth':
                summarytable2[metric1, metric2] += metric3

    table = []

    if report == 'daysuntilticketclosedbymonth':
        for key in summarytable2.keys():
            summarytable[key] = summarytable2[key] / summarytable[key]

    header1 = sorted(set(list(i for i, _ in summarytable.keys())))

    column_headings = [col1heading] + possible_options

    # Pivot the data so that 'header1' fields are always first column
    # in the row, and 'possible_options' are always the 2nd - nth columns.
    for item in header1:
        data = []
        for hdr in possible_options:
            data.append(summarytable[item, hdr])
        table.append([item] + data)

    # Zip data and headers together in one list for Morris.js charts
    # will get a list like [(Header1, Data1), (Header2, Data2)...]
    seriesnum = 0
    morrisjs_data = []
    for label in column_headings[1:]:
        seriesnum += 1
        datadict = {"x": label}
        for n in range(0, len(table)):
            datadict[n] = table[n][seriesnum]
        morrisjs_data.append(datadict)

    series_names = []
    for series in table:
        series_names.append(series[0])

    return render(request, 'helpdesk/report_output.html', {
        'title': title,
        'charttype': charttype,
        'data': table,
        'headings': column_headings,
        'series_names': series_names,
        'morrisjs_data': morrisjs_data,
        'from_saved_query': saved_query is not None,
        'saved_query': saved_query,
    })


run_report = staff_member_required(run_report)


@helpdesk_staff_member_required
def save_query(request):
    title = request.POST.get('title', None)
    shared = request.POST.get('shared', False)
    if shared == 'on':  # django only translates '1', 'true', 't' into True
        shared = True
    query_encoded = request.POST.get('query_encoded', None)

    if not title or not query_encoded:
        return HttpResponseRedirect(reverse('helpdesk:list'))

    query = SavedSearch(title=title, shared=shared, query=query_encoded, user=request.user)
    query.save()

    return HttpResponseRedirect('%s?saved_query=%s' % (reverse('helpdesk:list'), query.id))


save_query = staff_member_required(save_query)


@helpdesk_staff_member_required
def delete_saved_query(request, id):
    query = get_object_or_404(SavedSearch, id=id, user=request.user)

    if request.method == 'POST':
        query.delete()
        return HttpResponseRedirect(reverse('helpdesk:list'))
    else:
        return render(request, 'helpdesk/confirm_delete_saved_query.html', {'query': query})


delete_saved_query = staff_member_required(delete_saved_query)


class EditUserSettingsView(MustBeStaffMixin, UpdateView):
    template_name = 'helpdesk/user_settings.html'
    form_class = UserSettingsForm
    model = UserSettings
    success_url = reverse_lazy('helpdesk:dashboard')

    def get_object(self):
        return UserSettings.objects.get_or_create(user=self.request.user)[0]


@helpdesk_superuser_required
def email_ignore(request):
    return render(request, 'helpdesk/email_ignore_list.html', {
        'ignore_list': IgnoreEmail.objects.all(),
    })


email_ignore = superuser_required(email_ignore)


@helpdesk_superuser_required
def email_ignore_add(request):
    if request.method == 'POST':
        form = EmailIgnoreForm(request.POST)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect(reverse('helpdesk:email_ignore'))
    else:
        form = EmailIgnoreForm(request.GET)

    return render(request, 'helpdesk/email_ignore_add.html', {'form': form})


email_ignore_add = superuser_required(email_ignore_add)


@helpdesk_superuser_required
def email_ignore_del(request, id):
    ignore = get_object_or_404(IgnoreEmail, id=id)
    if request.method == 'POST':
        ignore.delete()
        return HttpResponseRedirect(reverse('helpdesk:email_ignore'))
    else:
        return render(request, 'helpdesk/email_ignore_del.html', {'ignore': ignore})


email_ignore_del = superuser_required(email_ignore_del)


@helpdesk_staff_member_required
def ticket_cc(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    copies_to = ticket.ticketcc_set.all()
    return render(request, 'helpdesk/ticket_cc_list.html', {
        'copies_to': copies_to,
        'ticket': ticket,
    })


ticket_cc = staff_member_required(ticket_cc)


@helpdesk_staff_member_required
def ticket_cc_add(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    if request.method == 'POST':
        form = TicketCCForm(request.POST)
        if form.is_valid():
            ticketcc = form.save(commit=False)
            ticketcc.ticket = ticket
            ticketcc.save()
            return HttpResponseRedirect(reverse('helpdesk:ticket_cc',
                                                kwargs={'ticket_id': ticket.id}))
    else:
        form_email = TicketCCEmailForm()
        form_user = TicketCCUserForm()
    return render(request, 'helpdesk/ticket_cc_add.html', {
        'ticket': ticket,
        'form_email': form_email,
        'form_user': form_user,
    })


ticket_cc_add = staff_member_required(ticket_cc_add)


@helpdesk_staff_member_required
def ticket_cc_del(request, ticket_id, cc_id):
    cc = get_object_or_404(TicketCC, ticket__id=ticket_id, id=cc_id)

    if request.method == 'POST':
        cc.delete()
        return HttpResponseRedirect(reverse('helpdesk:ticket_cc',
                                            kwargs={'ticket_id': cc.ticket.id}))
    return render(request, 'helpdesk/ticket_cc_del.html', {'cc': cc})


ticket_cc_del = staff_member_required(ticket_cc_del)


@helpdesk_staff_member_required
def ticket_dependency_add(request, ticket_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()
    if request.method == 'POST':
        form = TicketDependencyForm(request.POST)
        if form.is_valid():
            ticketdependency = form.save(commit=False)
            ticketdependency.ticket = ticket
            if ticketdependency.ticket != ticketdependency.depends_on:
                ticketdependency.save()
            return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket.id]))
    else:
        form = TicketDependencyForm()
    return render(request, 'helpdesk/ticket_dependency_add.html', {
        'ticket': ticket,
        'form': form,
    })


ticket_dependency_add = staff_member_required(ticket_dependency_add)


@helpdesk_staff_member_required
def ticket_dependency_del(request, ticket_id, dependency_id):
    dependency = get_object_or_404(TicketDependency, ticket__id=ticket_id, id=dependency_id)
    if request.method == 'POST':
        dependency.delete()
        return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket_id]))
    return render(request, 'helpdesk/ticket_dependency_del.html', {'dependency': dependency})


ticket_dependency_del = staff_member_required(ticket_dependency_del)


@helpdesk_staff_member_required
def attachment_del(request, ticket_id, attachment_id):
    ticket = get_object_or_404(Ticket, id=ticket_id)
    if not _has_access_to_queue(request.user, ticket.queue):
        raise PermissionDenied()
    if not _is_my_ticket(request.user, ticket):
        raise PermissionDenied()

    attachment = get_object_or_404(FollowUpAttachment, id=attachment_id)
    if request.method == 'POST':
        attachment.delete()
        return HttpResponseRedirect(reverse('helpdesk:view', args=[ticket_id]))
    return render(request, 'helpdesk/ticket_attachment_del.html', {
        'attachment': attachment,
        'filename': attachment.filename,
    })


def calc_average_nbr_days_until_ticket_resolved(Tickets):
    nbr_closed_tickets = len(Tickets)
    days_per_ticket = 0
    days_each_ticket = list()

    for ticket in Tickets:
        time_ticket_open = ticket.modified - ticket.created
        days_this_ticket = time_ticket_open.days
        days_per_ticket += days_this_ticket
        days_each_ticket.append(days_this_ticket)

    if nbr_closed_tickets > 0:
        mean_per_ticket = days_per_ticket / nbr_closed_tickets
    else:
        mean_per_ticket = 0

    return mean_per_ticket


def calc_basic_ticket_stats(Tickets):
    # all not closed tickets (open, reopened, resolved,) - independent of user
    all_open_tickets = Tickets.exclude(status=Ticket.CLOSED_STATUS)
    today = datetime.today()

    date_30 = date_rel_to_today(today, 30)
    date_60 = date_rel_to_today(today, 60)
    date_30_str = date_30.strftime('%Y-%m-%d')
    date_60_str = date_60.strftime('%Y-%m-%d')

    # > 0 & <= 30
    ota_le_30 = all_open_tickets.filter(created__gte=date_30_str)
    N_ota_le_30 = len(ota_le_30)

    # >= 30 & <= 60
    ota_le_60_ge_30 = all_open_tickets.filter(created__gte=date_60_str, created__lte=date_30_str)
    N_ota_le_60_ge_30 = len(ota_le_60_ge_30)

    # >= 60
    ota_ge_60 = all_open_tickets.filter(created__lte=date_60_str)
    N_ota_ge_60 = len(ota_ge_60)

    # (O)pen (T)icket (S)tats
    ots = list()
    # label, number entries, color, sort_string
    ots.append(['Tickets < 30 days', N_ota_le_30, 'success',
                sort_string(date_30_str, ''), ])
    ots.append(['Tickets 30 - 60 days', N_ota_le_60_ge_30,
                'success' if N_ota_le_60_ge_30 == 0 else 'warning',
                sort_string(date_60_str, date_30_str), ])
    ots.append(['Tickets > 60 days', N_ota_ge_60,
                'success' if N_ota_ge_60 == 0 else 'danger',
                sort_string('', date_60_str), ])

    # all closed tickets - independent of user.
    all_closed_tickets = Tickets.filter(status=Ticket.CLOSED_STATUS)
    average_nbr_days_until_ticket_closed = \
        calc_average_nbr_days_until_ticket_resolved(all_closed_tickets)
    # all closed tickets that were opened in the last 60 days.
    all_closed_last_60_days = all_closed_tickets.filter(created__gte=date_60_str)
    average_nbr_days_until_ticket_closed_last_60_days = \
        calc_average_nbr_days_until_ticket_resolved(all_closed_last_60_days)

    # put together basic stats
    basic_ticket_stats = {
        'average_nbr_days_until_ticket_closed': average_nbr_days_until_ticket_closed,
        'average_nbr_days_until_ticket_closed_last_60_days':
            average_nbr_days_until_ticket_closed_last_60_days,
        'open_ticket_stats': ots,
    }

    return basic_ticket_stats


def get_color_for_nbr_days(nbr_days):
    if nbr_days < 5:
        color_string = 'green'
    elif nbr_days < 10:
        color_string = 'orange'
    else:  # more than 10 days
        color_string = 'red'

    return color_string


def days_since_created(today, ticket):
    return (today - ticket.created).days


def date_rel_to_today(today, offset):
    return today - timedelta(days=offset)


def sort_string(begin, end):
    return 'sort=created&date_from=%s&date_to=%s&status=%s&status=%s&status=%s' % (
        begin, end, Ticket.OPEN_STATUS, Ticket.REOPENED_STATUS, Ticket.RESOLVED_STATUS)