from netaddr import IPSet

from django_tables2 import RequestConfig
from django.conf import settings
from django.contrib import messages
from django.contrib.auth.mixins import PermissionRequiredMixin
from django.shortcuts import get_object_or_404, render

from dcim.models import Device
from utilities.paginator import EnhancedPaginator
from utilities.views import BulkImportView, BulkEditView, BulkDeleteView, ObjectListView, ObjectEditView,\
    ObjectDeleteView

from .filters import AggregateFilter, PrefixFilter, IPAddressFilter, VLANFilter, VRFFilter
from .forms import AggregateForm, AggregateImportForm, AggregateBulkEditForm, AggregateBulkDeleteForm,\
    AggregateFilterForm, PrefixForm, PrefixImportForm, PrefixBulkEditForm, PrefixBulkDeleteForm, PrefixFilterForm,\
    IPAddressForm, IPAddressImportForm, IPAddressBulkEditForm, IPAddressBulkDeleteForm, IPAddressFilterForm, VLANForm,\
    VLANImportForm, VLANBulkEditForm, VLANBulkDeleteForm, VRFForm, VRFImportForm, VRFBulkEditForm, VRFBulkDeleteForm,\
    VLANFilterForm
from .models import VRF, Aggregate, Prefix, IPAddress, VLAN
from .tables import AggregateTable, PrefixTable, PrefixBriefTable, IPAddressBriefTable, IPAddressTable, VLANTable,\
    VRFTable


def add_available_prefixes(parent, prefix_list):
    """
    Create fake Prefix objects for all unallocated space within a prefix.
    """

    # Find all unallocated space
    available_prefixes = IPSet(parent) ^ IPSet([p.prefix for p in prefix_list])
    available_prefixes = [Prefix(prefix=p) for p in available_prefixes.iter_cidrs()]

    # Concatenate and sort complete list of children
    prefix_list = list(prefix_list) + available_prefixes
    prefix_list.sort(key=lambda p: p.prefix)

    return prefix_list


#
# VRFs
#

class VRFListView(ObjectListView):
    queryset = VRF.objects.all()
    filter = VRFFilter
    table = VRFTable
    edit_permissions = ['ipam.change_vrf', 'ipam.delete_vrf']
    template_name = 'ipam/vrf_list.html'


def vrf(request, pk):

    vrf = get_object_or_404(VRF.objects.all(), pk=pk)
    prefixes = Prefix.objects.filter(vrf=vrf)

    return render(request, 'ipam/vrf.html', {
        'vrf': vrf,
        'prefixes': prefixes,
    })


class VRFEditView(PermissionRequiredMixin, ObjectEditView):
    permission_required = 'ipam.change_vrf'
    model = VRF
    form_class = VRFForm
    cancel_url = 'ipam:vrf_list'


class VRFDeleteView(PermissionRequiredMixin, ObjectDeleteView):
    permission_required = 'ipam.delete_vrf'
    model = VRF
    redirect_url = 'ipam:vrf_list'


class VRFBulkImportView(PermissionRequiredMixin, BulkImportView):
    permission_required = 'ipam.add_vrf'
    form = VRFImportForm
    table = VRFTable
    template_name = 'ipam/vrf_import.html'
    obj_list_url = 'ipam:vrf_list'


class VRFBulkEditView(PermissionRequiredMixin, BulkEditView):
    permission_required = 'ipam.change_vrf'
    cls = VRF
    form = VRFBulkEditForm
    template_name = 'ipam/vrf_bulk_edit.html'
    default_redirect_url = 'ipam:vrf_list'

    def update_objects(self, pk_list, form):

        fields_to_update = {}
        for field in ['description']:
            if form.cleaned_data[field]:
                fields_to_update[field] = form.cleaned_data[field]

        updated_count = self.cls.objects.filter(pk__in=pk_list).update(**fields_to_update)
        messages.success(self.request, "Updated {} VRFs".format(updated_count))


class VRFBulkDeleteView(PermissionRequiredMixin, BulkDeleteView):
    permission_required = 'ipam.delete_vrf'
    cls = VRF
    form = VRFBulkDeleteForm
    default_redirect_url = 'ipam:vrf_list'


#
# Aggregates
#

class AggregateListView(ObjectListView):
    queryset = Aggregate.objects.select_related('rir').extra(select={
        'child_count': 'SELECT COUNT(*) FROM ipam_prefix WHERE ipam_prefix.prefix <<= ipam_aggregate.prefix',
    })
    filter = AggregateFilter
    filter_form = AggregateFilterForm
    table = AggregateTable
    edit_permissions = ['ipam.change_aggregate', 'ipam.delete_aggregate']
    template_name = 'ipam/aggregate_list.html'


def aggregate(request, pk):

    aggregate = get_object_or_404(Aggregate, pk=pk)

    # Find all child prefixes contained by this aggregate
    child_prefixes = Prefix.objects.filter(prefix__net_contained_or_equal=str(aggregate.prefix))\
        .select_related('site', 'status', 'role').annotate_depth(limit=0)
    child_prefixes = add_available_prefixes(aggregate.prefix, child_prefixes)

    prefix_table = PrefixTable(child_prefixes)
    if request.user.has_perm('ipam.change_prefix') or request.user.has_perm('ipam.delete_prefix'):
        prefix_table.base_columns['pk'].visible = True
    RequestConfig(request, paginate={'per_page': settings.PAGINATE_COUNT, 'klass': EnhancedPaginator})\
        .configure(prefix_table)

    return render(request, 'ipam/aggregate.html', {
        'aggregate': aggregate,
        'prefix_table': prefix_table,
    })


class AggregateEditView(PermissionRequiredMixin, ObjectEditView):
    permission_required = 'ipam.change_aggregate'
    model = Aggregate
    form_class = AggregateForm
    cancel_url = 'ipam:aggregate_list'


class AggregateDeleteView(PermissionRequiredMixin, ObjectDeleteView):
    permission_required = 'ipam.delete_aggregate'
    model = Aggregate
    redirect_url = 'ipam:aggregate_list'


class AggregateBulkImportView(PermissionRequiredMixin, BulkImportView):
    permission_required = 'ipam.add_aggregate'
    form = AggregateImportForm
    table = AggregateTable
    template_name = 'ipam/aggregate_import.html'
    obj_list_url = 'ipam:aggregate_list'


class AggregateBulkEditView(PermissionRequiredMixin, BulkEditView):
    permission_required = 'ipam.change_aggregate'
    cls = Aggregate
    form = AggregateBulkEditForm
    template_name = 'ipam/aggregate_bulk_edit.html'
    default_redirect_url = 'ipam:aggregate_list'

    def update_objects(self, pk_list, form):

        fields_to_update = {}
        for field in ['rir', 'date_added', 'description']:
            if form.cleaned_data[field]:
                fields_to_update[field] = form.cleaned_data[field]

        updated_count = self.cls.objects.filter(pk__in=pk_list).update(**fields_to_update)
        messages.success(self.request, "Updated {} aggregates".format(updated_count))


class AggregateBulkDeleteView(PermissionRequiredMixin, BulkDeleteView):
    permission_required = 'ipam.delete_aggregate'
    cls = Aggregate
    form = AggregateBulkDeleteForm
    default_redirect_url = 'ipam:aggregate_list'


#
# Prefixes
#

class PrefixListView(ObjectListView):
    queryset = Prefix.objects.select_related('site', 'status', 'role')
    filter = PrefixFilter
    filter_form = PrefixFilterForm
    table = PrefixTable
    edit_permissions = ['ipam.change_prefix', 'ipam.delete_prefix']
    template_name = 'ipam/prefix_list.html'

    def alter_queryset(self, request):
        # Show only top-level prefixes by default (unless searching)
        limit = None if request.GET.get('expand') or request.GET.get('q') else 0
        return self.queryset.annotate_depth(limit=limit)


def prefix(request, pk):

    prefix = get_object_or_404(Prefix.objects.select_related('site', 'vlan', 'status', 'role'), pk=pk)

    try:
        aggregate = Aggregate.objects.get(prefix__net_contains_or_equals=str(prefix.prefix))
    except Aggregate.DoesNotExist:
        aggregate = None

    # Count child IP addresses
    ipaddress_count = IPAddress.objects.filter(address__net_contained_or_equal=str(prefix.prefix)).count()

    # Parent prefixes table
    parent_prefixes = Prefix.objects.filter(vrf=prefix.vrf, prefix__net_contains=str(prefix.prefix))\
        .select_related('site', 'status', 'role').annotate_depth()
    parent_prefix_table = PrefixBriefTable(parent_prefixes)

    # Duplicate prefixes table
    duplicate_prefixes = Prefix.objects.filter(vrf=prefix.vrf, prefix=str(prefix.prefix)).exclude(pk=prefix.pk)\
        .select_related('site', 'status', 'role')
    duplicate_prefix_table = PrefixBriefTable(duplicate_prefixes)

    # Child prefixes table
    child_prefixes = Prefix.objects.filter(vrf=prefix.vrf, prefix__net_contained=str(prefix.prefix))\
        .select_related('site', 'status', 'role').annotate_depth(limit=0)
    if child_prefixes:
        child_prefixes = add_available_prefixes(prefix.prefix, child_prefixes)
    child_prefix_table = PrefixTable(child_prefixes)
    if request.user.has_perm('ipam.change_prefix') or request.user.has_perm('ipam.delete_prefix'):
        child_prefix_table.base_columns['pk'].visible = True
    RequestConfig(request, paginate={'per_page': settings.PAGINATE_COUNT, 'klass': EnhancedPaginator})\
        .configure(child_prefix_table)

    return render(request, 'ipam/prefix.html', {
        'prefix': prefix,
        'aggregate': aggregate,
        'ipaddress_count': ipaddress_count,
        'parent_prefix_table': parent_prefix_table,
        'child_prefix_table': child_prefix_table,
        'duplicate_prefix_table': duplicate_prefix_table,
    })


class PrefixEditView(PermissionRequiredMixin, ObjectEditView):
    permission_required = 'ipam.change_prefix'
    model = Prefix
    form_class = PrefixForm
    fields_initial = ['site', 'vrf', 'prefix']
    cancel_url = 'ipam:prefix_list'


class PrefixDeleteView(PermissionRequiredMixin, ObjectDeleteView):
    permission_required = 'ipam.delete_prefix'
    model = Prefix
    redirect_url = 'ipam:prefix_list'


class PrefixBulkImportView(PermissionRequiredMixin, BulkImportView):
    permission_required = 'ipam.add_prefix'
    form = PrefixImportForm
    table = PrefixTable
    template_name = 'ipam/prefix_import.html'
    obj_list_url = 'ipam:prefix_list'


class PrefixBulkEditView(PermissionRequiredMixin, BulkEditView):
    permission_required = 'ipam.change_prefix'
    cls = Prefix
    form = PrefixBulkEditForm
    template_name = 'ipam/prefix_bulk_edit.html'
    default_redirect_url = 'ipam:prefix_list'

    def update_objects(self, pk_list, form):

        fields_to_update = {}
        if form.cleaned_data['vrf']:
            fields_to_update['vrf'] = form.cleaned_data['vrf']
        elif form.cleaned_data['vrf_global']:
            fields_to_update['vrf'] = None
        for field in ['site', 'status', 'role', 'description']:
            if form.cleaned_data[field]:
                fields_to_update[field] = form.cleaned_data[field]

        updated_count = self.cls.objects.filter(pk__in=pk_list).update(**fields_to_update)
        messages.success(self.request, "Updated {} prefixes".format(updated_count))


class PrefixBulkDeleteView(PermissionRequiredMixin, BulkDeleteView):
    permission_required = 'ipam.delete_prefix'
    cls = Prefix
    form = PrefixBulkDeleteForm
    default_redirect_url = 'ipam:prefix_list'


def prefix_ipaddresses(request, pk):

    prefix = get_object_or_404(Prefix.objects.all(), pk=pk)

    # Find all IPAddresses belonging to this Prefix
    ipaddresses = IPAddress.objects.filter(address__net_contained_or_equal=str(prefix.prefix))\
        .select_related('vrf', 'interface__device', 'primary_for')

    ip_table = IPAddressTable(ipaddresses)
    if request.user.has_perm('ipam.change_ipaddress') or request.user.has_perm('ipam.delete_ipaddress'):
        ip_table.base_columns['pk'].visible = True
    RequestConfig(request, paginate={'per_page': settings.PAGINATE_COUNT, 'klass': EnhancedPaginator})\
        .configure(ip_table)

    return render(request, 'ipam/prefix_ipaddresses.html', {
        'prefix': prefix,
        'ip_table': ip_table,
    })


#
# IP addresses
#

class IPAddressListView(ObjectListView):
    queryset = IPAddress.objects.select_related('vrf', 'interface__device', 'primary_for')
    filter = IPAddressFilter
    filter_form = IPAddressFilterForm
    table = IPAddressTable
    edit_permissions = ['ipam.change_ipaddress', 'ipam.delete_ipaddress']
    template_name = 'ipam/ipaddress_list.html'


def ipaddress(request, pk):

    ipaddress = get_object_or_404(IPAddress.objects.select_related('interface__device'), pk=pk)

    parent_prefixes = Prefix.objects.filter(vrf=ipaddress.vrf, prefix__net_contains=str(ipaddress.address.ip))
    related_ips = IPAddress.objects.select_related('interface__device').exclude(pk=ipaddress.pk).filter(vrf=ipaddress.vrf, address__net_contained_or_equal=str(ipaddress.address))

    related_ips_table = IPAddressBriefTable(related_ips)
    RequestConfig(request, paginate={'per_page': settings.PAGINATE_COUNT, 'klass': EnhancedPaginator}).configure(related_ips_table)

    return render(request, 'ipam/ipaddress.html', {
        'ipaddress': ipaddress,
        'parent_prefixes': parent_prefixes,
        'related_ips_table': related_ips_table,
    })


class IPAddressEditView(PermissionRequiredMixin, ObjectEditView):
    permission_required = 'ipam.change_ipaddress'
    model = IPAddress
    form_class = IPAddressForm
    fields_initial = ['ipaddress']
    template_name = 'ipam/ipaddress_edit.html'
    cancel_url = 'ipam:ipaddress_list'


class IPAddressDeleteView(PermissionRequiredMixin, ObjectDeleteView):
    permission_required = 'ipam.delete_ipaddress'
    model = IPAddress
    redirect_url = 'ipam:ipaddress_list'


class IPAddressBulkImportView(PermissionRequiredMixin, BulkImportView):
    permission_required = 'ipam.add_ipaddress'
    form = IPAddressImportForm
    table = IPAddressTable
    template_name = 'ipam/ipaddress_import.html'
    obj_list_url = 'ipam:ipaddress_list'

    def save_obj(self, obj):
        obj.save()
        # Update primary IP for device if needed
        try:
            device = obj.primary_for
            device.primary_ip = obj
            device.save()
        except Device.DoesNotExist:
            pass


class IPAddressBulkEditView(PermissionRequiredMixin, BulkEditView):
    permission_required = 'ipam.change_ipaddress'
    cls = IPAddress
    form = IPAddressBulkEditForm
    template_name = 'ipam/ipaddress_bulk_edit.html'
    default_redirect_url = 'ipam:ipaddress_list'

    def update_objects(self, pk_list, form):

        fields_to_update = {}
        if form.cleaned_data['vrf']:
            fields_to_update['vrf'] = form.cleaned_data['vrf']
        elif form.cleaned_data['vrf_global']:
            fields_to_update['vrf'] = None
        for field in ['description']:
            if form.cleaned_data[field]:
                fields_to_update[field] = form.cleaned_data[field]

        updated_count = self.cls.objects.filter(pk__in=pk_list).update(**fields_to_update)
        messages.success(self.request, "Updated {} IP addresses".format(updated_count))


class IPAddressBulkDeleteView(PermissionRequiredMixin, BulkDeleteView):
    permission_required = 'ipam.delete_ipaddress'
    cls = IPAddress
    form = IPAddressBulkDeleteForm
    default_redirect_url = 'ipam:ipaddress_list'


#
# VLANs
#

class VLANListView(ObjectListView):
    queryset = VLAN.objects.select_related('site', 'status', 'role')
    filter = VLANFilter
    filter_form = VLANFilterForm
    table = VLANTable
    edit_permissions = ['ipam.change_vlan', 'ipam.delete_vlan']
    template_name = 'ipam/vlan_list.html'


def vlan(request, pk):

    vlan = get_object_or_404(VLAN.objects.select_related('site', 'status', 'role'), pk=pk)
    prefixes = Prefix.objects.filter(vlan=vlan)

    return render(request, 'ipam/vlan.html', {
        'vlan': vlan,
        'prefixes': prefixes,
    })


class VLANEditView(PermissionRequiredMixin, ObjectEditView):
    permission_required = 'ipam.change_vlan'
    model = VLAN
    form_class = VLANForm
    cancel_url = 'ipam:vlan_list'


class VLANDeleteView(PermissionRequiredMixin, ObjectDeleteView):
    permission_required = 'ipam.delete_vlan'
    model = VLAN
    redirect_url = 'ipam:vlan_list'


class VLANBulkImportView(PermissionRequiredMixin, BulkImportView):
    permission_required = 'ipam.add_vlan'
    form = VLANImportForm
    table = VLANTable
    template_name = 'ipam/vlan_import.html'
    obj_list_url = 'ipam:vlan_list'


class VLANBulkEditView(PermissionRequiredMixin, BulkEditView):
    permission_required = 'ipam.change_vlan'
    cls = VLAN
    form = VLANBulkEditForm
    template_name = 'ipam/vlan_bulk_edit.html'
    default_redirect_url = 'ipam:vlan_list'

    def update_objects(self, pk_list, form):

        fields_to_update = {}
        for field in ['site', 'status', 'role']:
            if form.cleaned_data[field]:
                fields_to_update[field] = form.cleaned_data[field]

        updated_count = self.cls.objects.filter(pk__in=pk_list).update(**fields_to_update)
        messages.success(self.request, "Updated {} VLANs".format(updated_count))


class VLANBulkDeleteView(PermissionRequiredMixin, BulkDeleteView):
    permission_required = 'ipam.delete_vlan'
    cls = VLAN
    form = VLANBulkDeleteForm
    default_redirect_url = 'ipam:vlan_list'