from __future__ import unicode_literals

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

from extras.forms import CustomFieldBulkEditForm, CustomFieldForm, CustomFieldFilterForm
from tenancy.forms import TenancyForm
from tenancy.models import Tenant
from utilities.forms import APISelect, BootstrapMixin, ChainedModelChoiceField, FilterChoiceField, SlugField
from .models import Cluster, ClusterGroup, ClusterType, VirtualMachine


#
# Cluster types
#

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

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


#
# Cluster groups
#

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

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


#
# Clusters
#

class ClusterForm(BootstrapMixin, CustomFieldForm):

    class Meta:
        model = Cluster
        fields = ['name', 'type', 'group']


class ClusterCSVForm(forms.ModelForm):
    type = forms.ModelChoiceField(
        queryset=ClusterType.objects.all(),
        to_field_name='name',
        help_text='Name of cluster type',
        error_messages={
            'invalid_choice': 'Invalid cluster type name.',
        }
    )
    group = forms.ModelChoiceField(
        queryset=ClusterGroup.objects.all(),
        to_field_name='name',
        required=False,
        help_text='Name of cluster group',
        error_messages={
            'invalid_choice': 'Invalid cluster group name.',
        }
    )

    class Meta:
        fields = ['name', 'type', 'group']


class ClusterFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = Cluster
    q = forms.CharField(required=False, label='Search')
    group = FilterChoiceField(
        queryset=ClusterGroup.objects.annotate(filter_count=Count('clusters')),
        to_field_name='slug',
        null_option=(0, 'None'),
        required=False,
    )
    type = FilterChoiceField(
        queryset=ClusterType.objects.annotate(filter_count=Count('clusters')),
        to_field_name='slug',
        required=False,
    )


#
# Virtual Machines
#

class VirtualMachineForm(BootstrapMixin, TenancyForm, CustomFieldForm):
    cluster_group = forms.ModelChoiceField(
        queryset=ClusterGroup.objects.all(),
        required=False,
        widget=forms.Select(
            attrs={'filter-for': 'cluster', 'nullable': 'true'}
        )
    )
    cluster = ChainedModelChoiceField(
        queryset=Cluster.objects.all(),
        chains=(
            ('group', 'cluster_group'),
        ),
        widget=APISelect(
            api_url='/api/virtualization/clusters/?group_id={{cluster_group}}'
        )
    )

    class Meta:
        model = VirtualMachine
        fields = ['name', 'cluster_group', 'cluster', 'tenant', 'platform', 'vcpus', 'memory', 'disk', 'comments']

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

        # Initialize helper selector
        instance = kwargs.get('instance')
        if instance.pk and instance.cluster is not None:
            initial = kwargs.get('initial', {}).copy()
            initial['cluster_group'] = instance.cluster.group
            kwargs['initial'] = initial

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


class VirtualMachineCSVForm(forms.ModelForm):
    cluster = forms.ModelChoiceField(
        queryset=Cluster.objects.all(),
        to_field_name='name',
        help_text='Name of parent cluster',
        error_messages={
            'invalid_choice': 'Invalid cluster name.',
        }
    )

    class Meta:
        fields = ['cluster', 'name', 'tenant', 'platform', 'vcpus', 'memory', 'disk', 'comments']


class VirtualMachineBulkEditForm(BootstrapMixin, CustomFieldBulkEditForm):
    pk = forms.ModelMultipleChoiceField(queryset=VirtualMachine.objects.all(), widget=forms.MultipleHiddenInput)
    cluster = forms.ModelChoiceField(queryset=Cluster.objects.all(), required=False, label='Cluster')
    tenant = forms.ModelChoiceField(queryset=Tenant.objects.all(), required=False)

    class Meta:
        nullable_fields = ['tenant']


class VirtualMachineFilterForm(BootstrapMixin, CustomFieldFilterForm):
    model = VirtualMachine
    q = forms.CharField(required=False, label='Search')
    cluster_group = FilterChoiceField(
        queryset=ClusterGroup.objects.all(),
        to_field_name='slug',
        null_option=(0, 'None'),
    )
    cluster_id = FilterChoiceField(
        queryset=Cluster.objects.annotate(filter_count=Count('virtual_machines')),
        label='Cluster'
    )