from __future__ import unicode_literals

from django import forms
from django.core.exceptions import MultipleObjectsReturned
from django.db.models import Count

from dcim.models import Site, Rack, Device, Interface
from extras.forms import CustomFieldForm, CustomFieldBulkEditForm, CustomFieldFilterForm
from tenancy.forms import TenancyForm
from tenancy.models import Tenant
from utilities.forms import (
    APISelect, BootstrapMixin, BulkEditNullBooleanSelect, ChainedModelChoiceField, CSVChoiceField,
    ExpandableIPAddressField, FilterChoiceField, FlexibleModelChoiceField, Livesearch, ReturnURLForm, SlugField,
    add_blank_choice,
)
from virtualization.models import VirtualMachine
from .models import (
    Aggregate, IPAddress, IPADDRESS_ROLE_CHOICES, IPADDRESS_STATUS_CHOICES, Prefix, PREFIX_STATUS_CHOICES, RIR, Role,
    Service, VLAN, VLANGroup, VLAN_STATUS_CHOICES, VRF,
)


IP_FAMILY_CHOICES = [
    ('', 'All'),
    (4, 'IPv4'),
    (6, 'IPv6'),
]

PREFIX_MASK_LENGTH_CHOICES = add_blank_choice([(i, i) for i in range(1, 128)])
IPADDRESS_MASK_LENGTH_CHOICES = add_blank_choice([(i, i) for i in range(1, 129)])


#
# VRFs
#

class VRFForm(BootstrapMixin, TenancyForm, CustomFieldForm):

    class Meta:
        model = VRF
        fields = ['name', 'rd', 'enforce_unique', 'description', 'tenant_group', 'tenant']
        labels = {
            'rd': "RD",
        }
        help_texts = {
            'rd': "Route distinguisher in any format",
        }


class VRFCSVForm(forms.ModelForm):
    tenant = forms.ModelChoiceField(
        queryset=Tenant.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of assigned tenant',
        error_messages={
            'invalid_choice': 'Tenant not found.',
        }
    )

    class Meta:
        model = VRF
        fields = ['name', 'rd', 'tenant', 'enforce_unique', 'description']
        help_texts = {
            'name': 'VRF name',
        }


class VRFBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=VRF.objects.all(), widget=forms.MultipleHiddenInput)
    tenant = forms.ModelChoiceField(queryset=Tenant.objects.all(), required=False)
    enforce_unique = forms.NullBooleanField(
        required=False, widget=BulkEditNullBooleanSelect, label='Enforce unique space'
    )
    description = forms.CharField(max_length=100, required=False)

    class Meta:
        nullable_fields = ['tenant', 'description']


class VRFFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = VRF
    q = forms.CharField(required=False, label='Search')
    tenant = FilterChoiceField(queryset=Tenant.objects.annotate(filter_count=Count('vrfs')), to_field_name='slug',
                               null_option=(0, None))


#
# RIRs
#

class RIRForm(BootstrapMixin, forms.ModelForm):
    slug = SlugField()

    class Meta:
        model = RIR
        fields = ['name', 'slug', 'is_private']


class RIRCSVForm(forms.ModelForm):
    slug = SlugField()

    class Meta:
        model = RIR
        fields = ['name', 'slug', 'is_private']
        help_texts = {
            'name': 'RIR name',
        }


class RIRFilterForm(BootstrapMixin, forms.Form):
    is_private = forms.NullBooleanField(required=False, label='Private', widget=forms.Select(choices=[
        ('', '---------'),
        ('True', 'Yes'),
        ('False', 'No'),
    ]))


#
# Aggregates
#

class AggregateForm(BootstrapMixin, CustomFieldForm):

    class Meta:
        model = Aggregate
        fields = ['prefix', 'rir', 'date_added', 'description']
        help_texts = {
            'prefix': "IPv4 or IPv6 network",
            'rir': "Regional Internet Registry responsible for this prefix",
            'date_added': "Format: YYYY-MM-DD",
        }


class AggregateCSVForm(forms.ModelForm):
    rir = forms.ModelChoiceField(
        queryset=RIR.objects.all(),
        to_field_name='name',
        help_text='Name of parent RIR',
        error_messages={
            'invalid_choice': 'RIR not found.',
        }
    )

    class Meta:
        model = Aggregate
        fields = ['prefix', 'rir', 'date_added', 'description']


class AggregateBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=Aggregate.objects.all(), widget=forms.MultipleHiddenInput)
    rir = forms.ModelChoiceField(queryset=RIR.objects.all(), required=False, label='RIR')
    date_added = forms.DateField(required=False)
    description = forms.CharField(max_length=100, required=False)

    class Meta:
        nullable_fields = ['date_added', 'description']


class AggregateFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = Aggregate
    q = forms.CharField(required=False, label='Search')
    family = forms.ChoiceField(required=False, choices=IP_FAMILY_CHOICES, label='Address Family')
    rir = FilterChoiceField(
        queryset=RIR.objects.annotate(filter_count=Count('aggregates')),
        to_field_name='slug',
        label='RIR'
    )


#
# Roles
#

class RoleForm(BootstrapMixin, forms.ModelForm):
    slug = SlugField()

    class Meta:
        model = Role
        fields = ['name', 'slug']


class RoleCSVForm(forms.ModelForm):
    slug = SlugField()

    class Meta:
        model = Role
        fields = ['name', 'slug']
        help_texts = {
            'name': 'Role name',
        }


#
# Prefixes
#

class PrefixForm(BootstrapMixin, TenancyForm, CustomFieldForm):
    site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        label='Site',
        widget=forms.Select(
            attrs={'filter-for': 'vlan_group', 'nullable': 'true'}
        )
    )
    vlan_group = ChainedModelChoiceField(
        queryset=VLANGroup.objects.all(),
        chains=(
            ('site', 'site'),
        ),
        required=False,
        label='VLAN group',
        widget=APISelect(
            api_url='/api/ipam/vlan-groups/?site_id={{site}}',
            attrs={'filter-for': 'vlan', 'nullable': 'true'}
        )
    )
    vlan = ChainedModelChoiceField(
        queryset=VLAN.objects.all(),
        chains=(
            ('site', 'site'),
            ('group', 'vlan_group'),
        ),
        required=False,
        label='VLAN',
        widget=APISelect(
            api_url='/api/ipam/vlans/?site_id={{site}}&group_id={{vlan_group}}', display_field='display_name'
        )
    )

    class Meta:
        model = Prefix
        fields = ['prefix', 'vrf', 'site', 'vlan', 'status', 'role', 'is_pool', 'description', 'tenant_group', 'tenant']

    def __init__(self, *args, **kwargs):

        # Initialize helper selectors
        instance = kwargs.get('instance')
        initial = kwargs.get('initial', {}).copy()
        if instance and instance.vlan is not None:
            initial['vlan_group'] = instance.vlan.group
        kwargs['initial'] = initial

        super(PrefixForm, self).__init__(*args, **kwargs)

        self.fields['vrf'].empty_label = 'Global'


class PrefixCSVForm(forms.ModelForm):
    vrf = forms.ModelChoiceField(
        queryset=VRF.objects.all(),
        required=False,
        to_field_name='rd',
        help_text='Route distinguisher of parent VRF',
        error_messages={
            'invalid_choice': 'VRF not found.',
        }
    )
    tenant = forms.ModelChoiceField(
        queryset=Tenant.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of assigned tenant',
        error_messages={
            'invalid_choice': 'Tenant not found.',
        }
    )
    site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of parent site',
        error_messages={
            'invalid_choice': 'Site not found.',
        }
    )
    vlan_group = forms.CharField(
        help_text='Group name of assigned VLAN',
        required=False
    )
    vlan_vid = forms.IntegerField(
        help_text='Numeric ID of assigned VLAN',
        required=False
    )
    status = CSVChoiceField(
        choices=PREFIX_STATUS_CHOICES,
        help_text='Operational status'
    )
    role = forms.ModelChoiceField(
        queryset=Role.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Functional role',
        error_messages={
            'invalid_choice': 'Invalid role.',
        }
    )

    class Meta:
        model = Prefix
        fields = [
            'prefix', 'vrf', 'tenant', 'site', 'vlan_group', 'vlan_vid', 'status', 'role', 'is_pool', 'description',
        ]

    def clean(self):

        super(PrefixCSVForm, self).clean()

        site = self.cleaned_data.get('site')
        vlan_group = self.cleaned_data.get('vlan_group')
        vlan_vid = self.cleaned_data.get('vlan_vid')

        # Validate VLAN
        if vlan_group and vlan_vid:
            try:
                self.instance.vlan = VLAN.objects.get(site=site, group__name=vlan_group, vid=vlan_vid)
            except VLAN.DoesNotExist:
                if site:
                    raise forms.ValidationError("VLAN {} not found in site {} group {}".format(
                        vlan_vid, site, vlan_group
                    ))
                else:
                    raise forms.ValidationError("Global VLAN {} not found in group {}".format(vlan_vid, vlan_group))
            except MultipleObjectsReturned:
                raise forms.ValidationError(
                    "Multiple VLANs with VID {} found in group {}".format(vlan_vid, vlan_group)
                )
        elif vlan_vid:
            try:
                self.instance.vlan = VLAN.objects.get(site=site, group__isnull=True, vid=vlan_vid)
            except VLAN.DoesNotExist:
                if site:
                    raise forms.ValidationError("VLAN {} not found in site {}".format(vlan_vid, site))
                else:
                    raise forms.ValidationError("Global VLAN {} not found".format(vlan_vid))
            except MultipleObjectsReturned:
                raise forms.ValidationError("Multiple VLANs with VID {} found".format(vlan_vid))


class PrefixBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=Prefix.objects.all(), widget=forms.MultipleHiddenInput)
    site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False)
    vrf = forms.ModelChoiceField(queryset=VRF.objects.all(), required=False, label='VRF')
    tenant = forms.ModelChoiceField(queryset=Tenant.objects.all(), required=False)
    status = forms.ChoiceField(choices=add_blank_choice(PREFIX_STATUS_CHOICES), required=False)
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False)
    is_pool = forms.NullBooleanField(required=False, widget=BulkEditNullBooleanSelect, label='Is a pool')
    description = forms.CharField(max_length=100, required=False)

    class Meta:
        nullable_fields = ['site', 'vrf', 'tenant', 'role', 'description']


def prefix_status_choices():
    status_counts = {}
    for status in Prefix.objects.values('status').annotate(count=Count('status')).order_by('status'):
        status_counts[status['status']] = status['count']
    return [(s[0], '{} ({})'.format(s[1], status_counts.get(s[0], 0))) for s in PREFIX_STATUS_CHOICES]


class PrefixFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = Prefix
    q = forms.CharField(required=False, label='Search')
    parent = forms.CharField(required=False, label='Parent prefix', widget=forms.TextInput(attrs={
        'placeholder': 'Prefix',
    }))
    family = forms.ChoiceField(required=False, choices=IP_FAMILY_CHOICES, label='Address family')
    mask_length = forms.ChoiceField(required=False, choices=PREFIX_MASK_LENGTH_CHOICES, label='Mask length')
    vrf = FilterChoiceField(
        queryset=VRF.objects.annotate(filter_count=Count('prefixes')),
        to_field_name='rd',
        label='VRF',
        null_option=(0, 'Global')
    )
    tenant = FilterChoiceField(
        queryset=Tenant.objects.annotate(filter_count=Count('prefixes')),
        to_field_name='slug',
        null_option=(0, 'None')
    )
    status = forms.MultipleChoiceField(choices=prefix_status_choices, required=False)
    site = FilterChoiceField(
        queryset=Site.objects.annotate(filter_count=Count('prefixes')),
        to_field_name='slug',
        null_option=(0, 'None')
    )
    role = FilterChoiceField(
        queryset=Role.objects.annotate(filter_count=Count('prefixes')),
        to_field_name='slug',
        null_option=(0, 'None')
    )
    expand = forms.BooleanField(required=False, label='Expand prefix hierarchy')


#
# IP addresses
#

class IPAddressForm(BootstrapMixin, TenancyForm, ReturnURLForm, CustomFieldForm):
    interface = forms.ModelChoiceField(
        queryset=Interface.objects.all(),
        required=False
    )
    nat_site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        label='Site',
        widget=forms.Select(
            attrs={'filter-for': 'nat_rack'}
        )
    )
    nat_rack = ChainedModelChoiceField(
        queryset=Rack.objects.all(),
        chains=(
            ('site', 'nat_site'),
        ),
        required=False,
        label='Rack',
        widget=APISelect(
            api_url='/api/dcim/racks/?site_id={{nat_site}}',
            display_field='display_name',
            attrs={'filter-for': 'nat_device', 'nullable': 'true'}
        )
    )
    nat_device = ChainedModelChoiceField(
        queryset=Device.objects.all(),
        chains=(
            ('site', 'nat_site'),
            ('rack', 'nat_rack'),
        ),
        required=False,
        label='Device',
        widget=APISelect(
            api_url='/api/dcim/devices/?site_id={{nat_site}}&rack_id={{nat_rack}}',
            display_field='display_name',
            attrs={'filter-for': 'nat_inside'}
        )
    )
    nat_inside = ChainedModelChoiceField(
        queryset=IPAddress.objects.all(),
        chains=(
            ('interface__device', 'nat_device'),
        ),
        required=False,
        label='IP Address',
        widget=APISelect(
            api_url='/api/ipam/ip-addresses/?device_id={{nat_device}}',
            display_field='address'
        )
    )
    livesearch = forms.CharField(
        required=False,
        label='Search',
        widget=Livesearch(
            query_key='q',
            query_url='ipam-api:ipaddress-list',
            field_to_update='nat_inside',
            obj_label='address'
        )
    )
    primary_for_parent = forms.BooleanField(required=False, label='Make this the primary IP for the device/VM')

    class Meta:
        model = IPAddress
        fields = [
            'address', 'vrf', 'status', 'role', 'description', 'interface', 'primary_for_parent', 'nat_site',
            'nat_rack', 'nat_inside', 'tenant_group', 'tenant',
        ]

    def __init__(self, *args, **kwargs):

        # Initialize helper selectors
        instance = kwargs.get('instance')
        initial = kwargs.get('initial', {}).copy()
        if instance and instance.nat_inside and instance.nat_inside.device is not None:
            initial['nat_site'] = instance.nat_inside.device.site
            initial['nat_rack'] = instance.nat_inside.device.rack
            initial['nat_device'] = instance.nat_inside.device
        kwargs['initial'] = initial

        super(IPAddressForm, self).__init__(*args, **kwargs)

        self.fields['vrf'].empty_label = 'Global'

        # Limit interface selections to those belonging to the parent device/VM
        if self.instance and self.instance.interface:
            self.fields['interface'].queryset = Interface.objects.filter(
                device=self.instance.interface.device, virtual_machine=self.instance.interface.virtual_machine
            )
        else:
            self.fields['interface'].choices = []

        # Initialize primary_for_parent if IP address is already assigned
        if self.instance.pk and self.instance.interface is not None:
            parent = self.instance.interface.parent
            if (
                self.instance.address.version == 4 and parent.primary_ip4_id == self.instance.pk or
                self.instance.address.version == 6 and parent.primary_ip6_id == self.instance.pk
            ):
                self.initial['primary_for_parent'] = True

    def clean(self):
        super(IPAddressForm, self).clean()

        # Primary IP assignment is only available if an interface has been assigned.
        if self.cleaned_data.get('primary_for_parent') and not self.cleaned_data.get('interface'):
            self.add_error(
                'primary_for_parent', "Only IP addresses assigned to an interface can be designated as primary IPs."
            )

    def save(self, *args, **kwargs):

        ipaddress = super(IPAddressForm, self).save(*args, **kwargs)

        # Assign this IPAddress as the primary for the associated Device.
        if self.cleaned_data['primary_for_parent']:
            parent = self.cleaned_data['interface'].parent
            if ipaddress.address.version == 4:
                parent.primary_ip4 = ipaddress
            else:
                parent.primary_ip6 = ipaddress
            parent.save()

        # Clear assignment as primary for device if set.
        else:
            try:
                if ipaddress.address.version == 4:
                    device = ipaddress.primary_ip4_for
                    device.primary_ip4 = None
                else:
                    device = ipaddress.primary_ip6_for
                    device.primary_ip6 = None
                device.save()
            except Device.DoesNotExist:
                pass

        return ipaddress


class IPAddressBulkCreateForm(BootstrapMixin, forms.Form):
    pattern = ExpandableIPAddressField(label='Address pattern')


class IPAddressBulkAddForm(BootstrapMixin, TenancyForm, CustomFieldForm):

    class Meta:
        model = IPAddress
        fields = ['address', 'vrf', 'status', 'role', 'description', 'tenant_group', 'tenant']

    def __init__(self, *args, **kwargs):
        super(IPAddressBulkAddForm, self).__init__(*args, **kwargs)
        self.fields['vrf'].empty_label = 'Global'


class IPAddressCSVForm(forms.ModelForm):
    vrf = forms.ModelChoiceField(
        queryset=VRF.objects.all(),
        required=False,
        to_field_name='rd',
        help_text='Route distinguisher of the assigned VRF',
        error_messages={
            'invalid_choice': 'VRF not found.',
        }
    )
    tenant = forms.ModelChoiceField(
        queryset=Tenant.objects.all(),
        to_field_name='name',
        required=False,
        help_text='Name of the assigned tenant',
        error_messages={
            'invalid_choice': 'Tenant not found.',
        }
    )
    status = CSVChoiceField(
        choices=IPADDRESS_STATUS_CHOICES,
        help_text='Operational status'
    )
    role = CSVChoiceField(
        choices=IPADDRESS_ROLE_CHOICES,
        required=False,
        help_text='Functional role'
    )
    device = FlexibleModelChoiceField(
        queryset=Device.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name or ID of assigned device',
        error_messages={
            'invalid_choice': 'Device not found.',
        }
    )
    virtual_machine = forms.ModelChoiceField(
        queryset=VirtualMachine.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of assigned virtual machine',
        error_messages={
            'invalid_choice': 'Virtual machine not found.',
        }
    )
    interface_name = forms.CharField(
        help_text='Name of assigned interface',
        required=False
    )
    is_primary = forms.BooleanField(
        help_text='Make this the primary IP for the assigned device',
        required=False
    )

    class Meta:
        model = IPAddress
        fields = [
            'address', 'vrf', 'tenant', 'status', 'role', 'device', 'virtual_machine', 'interface_name', 'is_primary',
            'description',
        ]

    def clean(self):

        super(IPAddressCSVForm, self).clean()

        device = self.cleaned_data.get('device')
        virtual_machine = self.cleaned_data.get('virtual_machine')
        interface_name = self.cleaned_data.get('interface_name')
        is_primary = self.cleaned_data.get('is_primary')

        # Validate interface
        if interface_name and device:
            try:
                self.instance.interface = Interface.objects.get(device=device, name=interface_name)
            except Interface.DoesNotExist:
                raise forms.ValidationError("Invalid interface {} for device {}".format(
                    interface_name, device
                ))
        elif interface_name and virtual_machine:
            try:
                self.instance.interface = Interface.objects.get(virtual_machine=virtual_machine, name=interface_name)
            except Interface.DoesNotExist:
                raise forms.ValidationError("Invalid interface {} for virtual machine {}".format(
                    interface_name, virtual_machine
                ))
        elif interface_name:
            raise forms.ValidationError("Interface given ({}) but parent device/virtual machine not specified".format(
                interface_name
            ))
        elif device:
            raise forms.ValidationError("Device specified ({}) but interface missing".format(device))
        elif virtual_machine:
            raise forms.ValidationError("Virtual machine specified ({}) but interface missing".format(virtual_machine))

        # Validate is_primary
        if is_primary and not device and not virtual_machine:
            raise forms.ValidationError("No device or virtual machine specified; cannot set as primary IP")

    def save(self, *args, **kwargs):

        # Set interface
        if self.cleaned_data['device'] and self.cleaned_data['interface_name']:
            self.instance.interface = Interface.objects.get(
                device=self.cleaned_data['device'],
                name=self.cleaned_data['interface_name']
            )
        elif self.cleaned_data['virtual_machine'] and self.cleaned_data['interface_name']:
            self.instance.interface = Interface.objects.get(
                virtual_machine=self.cleaned_data['virtual_machine'],
                name=self.cleaned_data['interface_name']
            )

        ipaddress = super(IPAddressCSVForm, self).save(*args, **kwargs)

        # Set as primary for device/VM
        if self.cleaned_data['is_primary']:
            parent = self.cleaned_data['device'] or self.cleaned_data['virtual_machine']
            if self.instance.address.version == 4:
                parent.primary_ip4 = ipaddress
            elif self.instance.address.version == 6:
                parent.primary_ip6 = ipaddress
            parent.save()

        return ipaddress


class IPAddressBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=IPAddress.objects.all(), widget=forms.MultipleHiddenInput)
    vrf = forms.ModelChoiceField(queryset=VRF.objects.all(), required=False, label='VRF')
    tenant = forms.ModelChoiceField(queryset=Tenant.objects.all(), required=False)
    status = forms.ChoiceField(choices=add_blank_choice(IPADDRESS_STATUS_CHOICES), required=False)
    role = forms.ChoiceField(choices=add_blank_choice(IPADDRESS_ROLE_CHOICES), required=False)
    description = forms.CharField(max_length=100, required=False)

    class Meta:
        nullable_fields = ['vrf', 'role', 'tenant', 'description']


def ipaddress_status_choices():
    status_counts = {}
    for status in IPAddress.objects.values('status').annotate(count=Count('status')).order_by('status'):
        status_counts[status['status']] = status['count']
    return [(s[0], '{} ({})'.format(s[1], status_counts.get(s[0], 0))) for s in IPADDRESS_STATUS_CHOICES]


def ipaddress_role_choices():
    role_counts = {}
    for role in IPAddress.objects.values('role').annotate(count=Count('role')).order_by('role'):
        role_counts[role['role']] = role['count']
    return [(r[0], '{} ({})'.format(r[1], role_counts.get(r[0], 0))) for r in IPADDRESS_ROLE_CHOICES]


class IPAddressFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = IPAddress
    q = forms.CharField(required=False, label='Search')
    parent = forms.CharField(required=False, label='Parent Prefix', widget=forms.TextInput(attrs={
        'placeholder': 'Prefix',
    }))
    family = forms.ChoiceField(required=False, choices=IP_FAMILY_CHOICES, label='Address family')
    mask_length = forms.ChoiceField(required=False, choices=IPADDRESS_MASK_LENGTH_CHOICES, label='Mask length')
    vrf = FilterChoiceField(
        queryset=VRF.objects.annotate(filter_count=Count('ip_addresses')),
        to_field_name='rd',
        label='VRF',
        null_option=(0, 'Global')
    )
    tenant = FilterChoiceField(
        queryset=Tenant.objects.annotate(filter_count=Count('ip_addresses')),
        to_field_name='slug',
        null_option=(0, 'None')
    )
    status = forms.MultipleChoiceField(choices=ipaddress_status_choices, required=False)
    role = forms.MultipleChoiceField(choices=ipaddress_role_choices, required=False)


#
# VLAN groups
#

class VLANGroupForm(BootstrapMixin, forms.ModelForm):
    slug = SlugField()

    class Meta:
        model = VLANGroup
        fields = ['site', 'name', 'slug']


class VLANGroupCSVForm(forms.ModelForm):
    site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of parent site',
        error_messages={
            'invalid_choice': 'Site not found.',
        }
    )
    slug = SlugField()

    class Meta:
        model = VLANGroup
        fields = ['site', 'name', 'slug']
        help_texts = {
            'name': 'Name of VLAN group',
        }


class VLANGroupFilterForm(BootstrapMixin, forms.Form):
    site = FilterChoiceField(
        queryset=Site.objects.annotate(filter_count=Count('vlan_groups')),
        to_field_name='slug',
        null_option=(0, 'Global')
    )


#
# VLANs
#

class VLANForm(BootstrapMixin, TenancyForm, CustomFieldForm):
    site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        widget=forms.Select(
            attrs={'filter-for': 'group', 'nullable': 'true'}
        )
    )
    group = ChainedModelChoiceField(
        queryset=VLANGroup.objects.all(),
        chains=(
            ('site', 'site'),
        ),
        required=False,
        label='Group',
        widget=APISelect(
            api_url='/api/ipam/vlan-groups/?site_id={{site}}',
        )
    )

    class Meta:
        model = VLAN
        fields = ['site', 'group', 'vid', 'name', 'status', 'role', 'description', 'tenant_group', 'tenant']
        help_texts = {
            'site': "Leave blank if this VLAN spans multiple sites",
            'group': "VLAN group (optional)",
            'vid': "Configured VLAN ID",
            'name': "Configured VLAN name",
            'status': "Operational status of this VLAN",
            'role': "The primary function of this VLAN",
        }


class VLANCSVForm(forms.ModelForm):
    site = forms.ModelChoiceField(
        queryset=Site.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Name of parent site',
        error_messages={
            'invalid_choice': 'Site not found.',
        }
    )
    group_name = forms.CharField(
        help_text='Name of VLAN group',
        required=False
    )
    tenant = forms.ModelChoiceField(
        queryset=Tenant.objects.all(),
        to_field_name='name',
        required=False,
        help_text='Name of assigned tenant',
        error_messages={
            'invalid_choice': 'Tenant not found.',
        }
    )
    status = CSVChoiceField(
        choices=VLAN_STATUS_CHOICES,
        help_text='Operational status'
    )
    role = forms.ModelChoiceField(
        queryset=Role.objects.all(),
        required=False,
        to_field_name='name',
        help_text='Functional role',
        error_messages={
            'invalid_choice': 'Invalid role.',
        }
    )

    class Meta:
        model = VLAN
        fields = ['site', 'group_name', 'vid', 'name', 'tenant', 'status', 'role', 'description']
        help_texts = {
            'vid': 'Numeric VLAN ID (1-4095)',
            'name': 'VLAN name',
        }

    def clean(self):

        super(VLANCSVForm, self).clean()

        site = self.cleaned_data.get('site')
        group_name = self.cleaned_data.get('group_name')

        # Validate VLAN group
        if group_name:
            try:
                self.instance.group = VLANGroup.objects.get(site=site, name=group_name)
            except VLANGroup.DoesNotExist:
                if site:
                    raise forms.ValidationError("VLAN group {} not found for site {}".format(group_name, site))
                else:
                    raise forms.ValidationError("Global VLAN group {} not found".format(group_name))


class VLANBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=VLAN.objects.all(), widget=forms.MultipleHiddenInput)
    site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False)
    group = forms.ModelChoiceField(queryset=VLANGroup.objects.all(), required=False)
    tenant = forms.ModelChoiceField(queryset=Tenant.objects.all(), required=False)
    status = forms.ChoiceField(choices=add_blank_choice(VLAN_STATUS_CHOICES), required=False)
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False)
    description = forms.CharField(max_length=100, required=False)

    class Meta:
        nullable_fields = ['site', 'group', 'tenant', 'role', 'description']


def vlan_status_choices():
    status_counts = {}
    for status in VLAN.objects.values('status').annotate(count=Count('status')).order_by('status'):
        status_counts[status['status']] = status['count']
    return [(s[0], '{} ({})'.format(s[1], status_counts.get(s[0], 0))) for s in VLAN_STATUS_CHOICES]


class VLANFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = VLAN
    q = forms.CharField(required=False, label='Search')
    site = FilterChoiceField(
        queryset=Site.objects.annotate(filter_count=Count('vlans')),
        to_field_name='slug',
        null_option=(0, 'Global')
    )
    group_id = FilterChoiceField(
        queryset=VLANGroup.objects.annotate(filter_count=Count('vlans')),
        label='VLAN group',
        null_option=(0, 'None')
    )
    tenant = FilterChoiceField(
        queryset=Tenant.objects.annotate(filter_count=Count('vlans')),
        to_field_name='slug',
        null_option=(0, 'None')
    )
    status = forms.MultipleChoiceField(choices=vlan_status_choices, required=False)
    role = FilterChoiceField(
        queryset=Role.objects.annotate(filter_count=Count('vlans')),
        to_field_name='slug',
        null_option=(0, 'None')
    )


#
# Services
#

class ServiceForm(BootstrapMixin, forms.ModelForm):

    class Meta:
        model = Service
        fields = ['name', 'protocol', 'port', 'ipaddresses', 'description']
        help_texts = {
            'ipaddresses': "IP address assignment is optional. If no IPs are selected, the service is assumed to be "
                           "reachable via all IPs assigned to the device.",
        }

    def __init__(self, *args, **kwargs):

        super(ServiceForm, self).__init__(*args, **kwargs)

        # Limit IP address choices to those assigned to interfaces of the parent device/VM
        if self.instance.device:
            self.fields['ipaddresses'].queryset = IPAddress.objects.filter(
                interface__device=self.instance.device
            )
        elif self.instance.virtual_machine:
            self.fields['ipaddresses'].queryset = IPAddress.objects.filter(
                interface__virtual_machine=self.instance.virtual_machine
            )
        else:
            self.fields['ipaddresses'].choices = []
