from netaddr import IPNetwork

from django import forms
from django.db.models import Count

from dcim.models import Site, Device, Interface
from utilities.forms import BootstrapMixin, ConfirmationForm, APISelect, Livesearch, CSVDataField, BulkImportForm
from .models import VRF, RIR, Aggregate, Prefix, IPAddress, VLAN, Status, Role


#
# VRFs
#

class VRFForm(forms.ModelForm, BootstrapMixin):

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


class VRFFromCSVForm(forms.ModelForm):

    class Meta:
        model = VRF
        fields = ['name', 'rd', 'description']


class VRFImportForm(BulkImportForm, BootstrapMixin):
    csv = CSVDataField(csv_form=VRFFromCSVForm)


class VRFBulkEditForm(forms.Form, BootstrapMixin):
    pk = forms.ModelMultipleChoiceField(queryset=VRF.objects.all(), widget=forms.MultipleHiddenInput)
    description = forms.CharField(max_length=100, required=False)


class VRFBulkDeleteForm(ConfirmationForm):
    pk = forms.ModelMultipleChoiceField(queryset=VRF.objects.all(), widget=forms.MultipleHiddenInput)


#
# Aggregates
#

class AggregateForm(forms.ModelForm, BootstrapMixin):

    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 AggregateFromCSVForm(forms.ModelForm):
    rir = forms.ModelChoiceField(queryset=RIR.objects.all(), to_field_name='name',
                                 error_messages={'invalid_choice': 'RIR not found.'})

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


class AggregateImportForm(BulkImportForm, BootstrapMixin):
    csv = CSVDataField(csv_form=AggregateFromCSVForm)


class AggregateBulkEditForm(forms.Form, BootstrapMixin):
    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=50, required=False)


class AggregateBulkDeleteForm(ConfirmationForm):
    pk = forms.ModelMultipleChoiceField(queryset=Aggregate.objects.all(), widget=forms.MultipleHiddenInput)


def aggregate_rir_choices():
    rir_choices = RIR.objects.annotate(aggregate_count=Count('aggregates'))
    return [(r.slug, '{} ({})'.format(r.name, r.aggregate_count)) for r in rir_choices]


class AggregateFilterForm(forms.Form, BootstrapMixin):
    rir = forms.MultipleChoiceField(required=False, choices=aggregate_rir_choices, label='RIR',
                                    widget=forms.SelectMultiple(attrs={'size': 8}))


#
# Prefixes
#

class PrefixForm(forms.ModelForm, BootstrapMixin):
    site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False, label='Site',
                                  widget=forms.Select(attrs={'filter-for': 'vlan'}))
    vlan = forms.ModelChoiceField(queryset=VLAN.objects.all(), required=False, label='VLAN',
                                  widget=APISelect(api_url='/api/ipam/vlans/?site_id={{site}}'))

    class Meta:
        model = Prefix
        fields = ['prefix', 'vrf', 'site', 'vlan', 'status', 'role', 'description']
        help_texts = {
            'prefix': "IPv4 or IPv6 network",
            'vrf': "VRF (if applicable)",
            'site': "The site to which this prefix is assigned (if applicable)",
            'vlan': "The VLAN to which this prefix is assigned (if applicable)",
            'status': "Operational status of this prefix",
            'role': "The primary function of this prefix",
        }

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

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

        # Initialize field without choices to avoid pulling all VLANs from the database
        if self.is_bound and self.data.get('site'):
            self.fields['vlan'].queryset = VLAN.objects.filter(site__pk=self.data['site'])
        elif self.initial.get('site'):
            self.fields['vlan'].queryset = VLAN.objects.filter(site=self.initial['site'])
        else:
            self.fields['vlan'].choices = []

    def clean_prefix(self):
        data = self.cleaned_data['prefix']
        try:
            prefix = IPNetwork(data)
        except:
            raise
        if prefix.version == 4 and prefix.prefixlen == 32:
            raise forms.ValidationError("Cannot create host addresses (/32) as prefixes. These should be IPv4 "
                                        "addresses instead.")
        elif prefix.version == 6 and prefix.prefixlen == 128:
            raise forms.ValidationError("Cannot create host addresses (/128) as prefixes. These should be IPv6 "
                                        "addresses instead.")
        return data


class PrefixFromCSVForm(forms.ModelForm):
    vrf = forms.ModelChoiceField(queryset=VRF.objects.all(), required=False, to_field_name='rd',
                                 error_messages={'invalid_choice': 'VRF not found.'})
    site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False, to_field_name='name',
                                  error_messages={'invalid_choice': 'Site not found.'})
    status = forms.ModelChoiceField(queryset=Status.objects.all(), to_field_name='name',
                                    error_messages={'invalid_choice': 'Invalid status.'})
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False, to_field_name='name',
                                  error_messages={'invalid_choice': 'Invalid role.'})

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


class PrefixImportForm(BulkImportForm, BootstrapMixin):
    csv = CSVDataField(csv_form=PrefixFromCSVForm)


class PrefixBulkEditForm(forms.Form, BootstrapMixin):
    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',
                                 help_text="Select the VRF to assign, or check below to remove VRF assignment")
    vrf_global = forms.BooleanField(required=False, label='Set VRF to global')
    status = forms.ModelChoiceField(queryset=Status.objects.all(), required=False)
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False)
    description = forms.CharField(max_length=50, required=False)


class PrefixBulkDeleteForm(ConfirmationForm):
    pk = forms.ModelMultipleChoiceField(queryset=Prefix.objects.all(), widget=forms.MultipleHiddenInput)


def prefix_vrf_choices():
    vrf_choices = [('', 'All'), (0, 'Global')]
    vrf_choices += [(v.pk, v.name) for v in VRF.objects.all()]
    return vrf_choices


def prefix_status_choices():
    status_choices = Status.objects.annotate(prefix_count=Count('prefixes'))
    return [(s.slug, '{} ({})'.format(s.name, s.prefix_count)) for s in status_choices]


def prefix_site_choices():
    site_choices = Site.objects.annotate(prefix_count=Count('prefixes'))
    return [(s.slug, '{} ({})'.format(s.name, s.prefix_count)) for s in site_choices]


def prefix_role_choices():
    role_choices = Role.objects.annotate(prefix_count=Count('prefixes'))
    return [(r.slug, '{} ({})'.format(r.name, r.prefix_count)) for r in role_choices]


class PrefixFilterForm(forms.Form, BootstrapMixin):
    parent = forms.CharField(required=False, label='Search Within')
    vrf = forms.ChoiceField(required=False, choices=prefix_vrf_choices, label='VRF')
    status = forms.MultipleChoiceField(required=False, choices=prefix_status_choices)
    site = forms.MultipleChoiceField(required=False, choices=prefix_site_choices,
                                     widget=forms.SelectMultiple(attrs={'size': 8}))
    role = forms.MultipleChoiceField(required=False, choices=prefix_role_choices,
                                     widget=forms.SelectMultiple(attrs={'size': 8}))
    expand = forms.BooleanField(required=False, label='Expand prefix hierarchy')


#
# IP addresses
#

class IPAddressForm(forms.ModelForm, BootstrapMixin):
    nat_site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False, label='Site',
                                      widget=forms.Select(attrs={'filter-for': 'nat_device'}))
    nat_device = forms.ModelChoiceField(queryset=Device.objects.all(), required=False, label='Device',
                                        widget=APISelect(api_url='/api/dcim/devices/?site_id={{nat_site}}',
                                                         attrs={'filter-for': 'nat_inside'}))
    livesearch = forms.CharField(required=False, label='IP Address', widget=Livesearch(
        query_key='q', query_url='ipam-api:ipaddress_list', field_to_update='nat_inside', obj_label='address')
    )
    nat_inside = forms.ModelChoiceField(queryset=IPAddress.objects.all(), required=False, label='NAT (Inside)',
                                        widget=APISelect(api_url='/api/ipam/ip-addresses/?device_id={{nat_device}}',
                                                         display_field='address'))

    class Meta:
        model = IPAddress
        fields = ['address', 'vrf', 'nat_device', 'nat_inside', 'description']
        help_texts = {
            'address': "IPv4 or IPv6 address and mask",
            'vrf': "VRF (if applicable)",
        }

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

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

        if self.instance.nat_inside:

            nat_inside = self.instance.nat_inside
            # If the IP is assigned to an interface, populate site/device fields accordingly
            if self.instance.nat_inside.interface:
                self.initial['nat_site'] = self.instance.nat_inside.interface.device.rack.site.pk
                self.initial['nat_device'] = self.instance.nat_inside.interface.device.pk
                self.fields['nat_device'].queryset = Device.objects.filter(rack__site=nat_inside.interface.device.rack.site)
                self.fields['nat_inside'].queryset = IPAddress.objects.filter(interface__device=nat_inside.interface.device)
            else:
                self.fields['nat_inside'].queryset = IPAddress.objects.filter(pk=nat_inside.pk)

        else:

            # Initialize nat_device choices if nat_site is set
            if self.is_bound and self.data.get('nat_site'):
                self.fields['nat_device'].queryset = Device.objects.filter(rack__site__pk=self.data['nat_site'])
            elif self.initial.get('nat_site'):
                self.fields['nat_device'].queryset = Device.objects.filter(rack__site=self.initial['nat_site'])
            else:
                self.fields['nat_device'].choices = []

            # Initialize nat_inside choices if nat_device is set
            if self.is_bound and self.data.get('nat_device'):
                self.fields['nat_inside'].queryset = IPAddress.objects.filter(interface__device__pk=self.data['nat_device'])
            elif self.initial.get('nat_device'):
                self.fields['nat_inside'].queryset = IPAddress.objects.filter(interface__device__pk=self.initial['nat_device'])
            else:
                self.fields['nat_inside'].choices = []


class IPAddressFromCSVForm(forms.ModelForm):
    vrf = forms.ModelChoiceField(queryset=VRF.objects.all(), required=False, to_field_name='rd',
                                 error_messages={'invalid_choice': 'Site not found.'})
    device = forms.ModelChoiceField(queryset=Device.objects.all(), required=False, to_field_name='name',
                                    error_messages={'invalid_choice': 'Device not found.'})
    interface_name = forms.CharField(required=False)
    is_primary = forms.BooleanField(required=False)

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

    def clean(self):

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

        # Validate interface
        if device and interface_name:
            try:
                Interface.objects.get(device=device, name=interface_name)
            except Interface.DoesNotExist:
                self.add_error('interface_name', "Invalid interface ({}) for {}".format(interface_name, device))
        elif device and not interface_name:
            self.add_error('interface_name', "Device set ({}) but interface missing".format(device))
        elif interface_name and not device:
            self.add_error('device', "Interface set ({}) but device missing or invalid".format(interface_name))

        # Validate is_primary
        if is_primary and not device:
            self.add_error('is_primary', "No device specified; cannot set as primary IP")

    def save(self, commit=True):

        # 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'])
        # Set as primary for device
        if self.cleaned_data['is_primary']:
            self.instance.primary_for = self.cleaned_data['device']

        return super(IPAddressFromCSVForm, self).save(commit=commit)


class IPAddressImportForm(BulkImportForm, BootstrapMixin):
    csv = CSVDataField(csv_form=IPAddressFromCSVForm)


class IPAddressBulkEditForm(forms.Form, BootstrapMixin):
    pk = forms.ModelMultipleChoiceField(queryset=IPAddress.objects.all(), widget=forms.MultipleHiddenInput)
    vrf = forms.ModelChoiceField(queryset=VRF.objects.all(), required=False, label='VRF',
                                 help_text="Select the VRF to assign, or check below to remove VRF assignment")
    vrf_global = forms.BooleanField(required=False, label='Set VRF to global')
    description = forms.CharField(max_length=50, required=False)


class IPAddressBulkDeleteForm(ConfirmationForm):
    pk = forms.ModelMultipleChoiceField(queryset=IPAddress.objects.all(), widget=forms.MultipleHiddenInput)


def ipaddress_family_choices():
    return [('', 'All'), (4, 'IPv4'), (6, 'IPv6')]


class IPAddressFilterForm(forms.Form, BootstrapMixin):
    family = forms.ChoiceField(required=False, choices=ipaddress_family_choices, label='Address Family')


#
# VLANs
#

class VLANForm(forms.ModelForm, BootstrapMixin):

    class Meta:
        model = VLAN
        fields = ['site', 'vid', 'name', 'status', 'role']
        help_texts = {
            'site': "The site at which this VLAN exists",
            'vid': "Configured VLAN ID",
            'name': "Configured VLAN name",
            'status': "Operational status of this VLAN",
            'role': "The primary function of this VLAN",
        }


class VLANFromCSVForm(forms.ModelForm):
    site = forms.ModelChoiceField(queryset=Site.objects.all(), to_field_name='name',
                                  error_messages={'invalid_choice': 'Device not found.'})
    status = forms.ModelChoiceField(queryset=Status.objects.all(), to_field_name='name',
                                    error_messages={'invalid_choice': 'Invalid status.'})
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False, to_field_name='name',
                                  error_messages={'invalid_choice': 'Invalid role.'})

    class Meta:
        model = VLAN
        fields = ['site', 'vid', 'name', 'status', 'role']


class VLANImportForm(BulkImportForm, BootstrapMixin):
    csv = CSVDataField(csv_form=VLANFromCSVForm)


class VLANBulkEditForm(forms.Form, BootstrapMixin):
    pk = forms.ModelMultipleChoiceField(queryset=VLAN.objects.all(), widget=forms.MultipleHiddenInput)
    site = forms.ModelChoiceField(queryset=Site.objects.all(), required=False)
    status = forms.ModelChoiceField(queryset=Status.objects.all(), required=False)
    role = forms.ModelChoiceField(queryset=Role.objects.all(), required=False)


class VLANBulkDeleteForm(ConfirmationForm):
    pk = forms.ModelMultipleChoiceField(queryset=VLAN.objects.all(), widget=forms.MultipleHiddenInput)


def vlan_site_choices():
    site_choices = Site.objects.annotate(vlan_count=Count('vlans'))
    return [(s.slug, '{} ({})'.format(s.name, s.vlan_count)) for s in site_choices]


def vlan_status_choices():
    status_choices = Status.objects.annotate(vlan_count=Count('vlans'))
    return [(s.slug, '{} ({})'.format(s.name, s.vlan_count)) for s in status_choices]


def vlan_role_choices():
    role_choices = Role.objects.annotate(vlan_count=Count('vlans'))
    return [(r.slug, '{} ({})'.format(r.name, r.vlan_count)) for r in role_choices]


class VLANFilterForm(forms.Form, BootstrapMixin):
    site = forms.MultipleChoiceField(required=False, choices=vlan_site_choices,
                                     widget=forms.SelectMultiple(attrs={'size': 8}))
    status = forms.MultipleChoiceField(required=False, choices=vlan_status_choices)
    role = forms.MultipleChoiceField(required=False, choices=vlan_role_choices,
                                     widget=forms.SelectMultiple(attrs={'size': 8}))