from django import forms
from django.contrib.auth.models import User
from django.contrib.contenttypes.models import ContentType
from mptt.forms import TreeNodeMultipleChoiceField
from taggit.forms import TagField

from dcim.models import DeviceRole, Platform, Region, Site
from tenancy.models import Tenant, TenantGroup
from utilities.forms import (
    add_blank_choice, APISelectMultiple, BootstrapMixin, BulkEditForm, BulkEditNullBooleanSelect, ColorSelect,
    CommentField, ContentTypeSelect, DateTimePicker, DynamicModelMultipleChoiceField, JSONField, SlugField,
    StaticSelect2, StaticSelect2Multiple, BOOLEAN_WITH_BLANK_CHOICES,
)
from virtualization.models import Cluster, ClusterGroup
from .choices import *
from .models import ConfigContext, CustomField, CustomFieldValue, ImageAttachment, ObjectChange, Tag


#
# Custom fields
#

class CustomFieldModelForm(forms.ModelForm):

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

        self.obj_type = ContentType.objects.get_for_model(self._meta.model)
        self.custom_fields = []
        self.custom_field_values = {}

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

        self._append_customfield_fields()

    def _append_customfield_fields(self):
        """
        Append form fields for all CustomFields assigned to this model.
        """
        # Retrieve initial CustomField values for the instance
        if self.instance.pk:
            for cfv in CustomFieldValue.objects.filter(
                obj_type=self.obj_type,
                obj_id=self.instance.pk
            ).prefetch_related('field'):
                self.custom_field_values[cfv.field.name] = cfv.serialized_value

        # Append form fields; assign initial values if modifying and existing object
        for cf in CustomField.objects.filter(obj_type=self.obj_type):
            field_name = 'cf_{}'.format(cf.name)
            if self.instance.pk:
                self.fields[field_name] = cf.to_form_field(set_initial=False)
                self.fields[field_name].initial = self.custom_field_values.get(cf.name)
            else:
                self.fields[field_name] = cf.to_form_field()

            # Annotate the field in the list of CustomField form fields
            self.custom_fields.append(field_name)

    def _save_custom_fields(self):

        for field_name in self.custom_fields:
            try:
                cfv = CustomFieldValue.objects.prefetch_related('field').get(
                    field=self.fields[field_name].model,
                    obj_type=self.obj_type,
                    obj_id=self.instance.pk
                )
            except CustomFieldValue.DoesNotExist:
                # Skip this field if none exists already and its value is empty
                if self.cleaned_data[field_name] in [None, '']:
                    continue
                cfv = CustomFieldValue(
                    field=self.fields[field_name].model,
                    obj_type=self.obj_type,
                    obj_id=self.instance.pk
                )
            cfv.value = self.cleaned_data[field_name]
            cfv.save()

    def save(self, commit=True):
        obj = super().save(commit)

        # Handle custom fields the same way we do M2M fields
        if commit:
            self._save_custom_fields()
        else:
            self.save_custom_fields = self._save_custom_fields

        return obj


class CustomFieldModelCSVForm(CustomFieldModelForm):

    def _append_customfield_fields(self):

        # Append form fields
        for cf in CustomField.objects.filter(obj_type=self.obj_type):
            field_name = 'cf_{}'.format(cf.name)
            self.fields[field_name] = cf.to_form_field(for_csv_import=True)

            # Annotate the field in the list of CustomField form fields
            self.custom_fields.append(field_name)


class CustomFieldBulkEditForm(BulkEditForm):

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

        self.custom_fields = []
        self.obj_type = ContentType.objects.get_for_model(self.model)

        # Add all applicable CustomFields to the form
        custom_fields = CustomField.objects.filter(obj_type=self.obj_type)
        for cf in custom_fields:
            # Annotate non-required custom fields as nullable
            if not cf.required:
                self.nullable_fields.append(cf.name)
            self.fields[cf.name] = cf.to_form_field(set_initial=False, enforce_required=False)
            # Annotate this as a custom field
            self.custom_fields.append(cf.name)


class CustomFieldFilterForm(forms.Form):

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

        self.obj_type = ContentType.objects.get_for_model(self.model)

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

        # Add all applicable CustomFields to the form
        custom_fields = CustomField.objects.filter(obj_type=self.obj_type).exclude(
            filter_logic=CustomFieldFilterLogicChoices.FILTER_DISABLED
        )
        for cf in custom_fields:
            field_name = 'cf_{}'.format(cf.name)
            self.fields[field_name] = cf.to_form_field(set_initial=True, enforce_required=False)


#
# Tags
#

class TagForm(BootstrapMixin, forms.ModelForm):
    slug = SlugField()
    comments = CommentField()

    class Meta:
        model = Tag
        fields = [
            'name', 'slug', 'color', 'comments'
        ]


class AddRemoveTagsForm(forms.Form):

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

        # Add add/remove tags fields
        self.fields['add_tags'] = TagField(required=False)
        self.fields['remove_tags'] = TagField(required=False)


class TagFilterForm(BootstrapMixin, forms.Form):
    model = Tag
    q = forms.CharField(
        required=False,
        label='Search'
    )


class TagBulkEditForm(BootstrapMixin, BulkEditForm):
    pk = forms.ModelMultipleChoiceField(
        queryset=Tag.objects.all(),
        widget=forms.MultipleHiddenInput
    )
    color = forms.CharField(
        max_length=6,
        required=False,
        widget=ColorSelect()
    )

    class Meta:
        nullable_fields = []


#
# Config contexts
#

class ConfigContextForm(BootstrapMixin, forms.ModelForm):
    regions = TreeNodeMultipleChoiceField(
        queryset=Region.objects.all(),
        required=False,
        widget=StaticSelect2Multiple()
    )
    sites = DynamicModelMultipleChoiceField(
        queryset=Site.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/sites/"
        )
    )
    roles = DynamicModelMultipleChoiceField(
        queryset=DeviceRole.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/device-roles/"
        )
    )
    platforms = DynamicModelMultipleChoiceField(
        queryset=Platform.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/platforms/"
        )
    )
    cluster_groups = DynamicModelMultipleChoiceField(
        queryset=ClusterGroup.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/virtualization/cluster-groups/"
        )
    )
    clusters = DynamicModelMultipleChoiceField(
        queryset=Cluster.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/virtualization/clusters/"
        )
    )
    tenant_groups = DynamicModelMultipleChoiceField(
        queryset=TenantGroup.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/tenancy/tenant-groups/"
        )
    )
    tenants = DynamicModelMultipleChoiceField(
        queryset=Tenant.objects.all(),
        required=False,
        widget=APISelectMultiple(
            api_url="/api/tenancy/tenants/"
        )
    )
    tags = DynamicModelMultipleChoiceField(
        queryset=Tag.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/extras/tags/"
        )
    )
    data = JSONField(
        label=''
    )

    class Meta:
        model = ConfigContext
        fields = (
            'name', 'weight', 'description', 'is_active', 'regions', 'sites', 'roles', 'platforms', 'cluster_groups',
            'clusters', 'tenant_groups', 'tenants', 'tags', 'data',
        )


class ConfigContextBulkEditForm(BootstrapMixin, BulkEditForm):
    pk = forms.ModelMultipleChoiceField(
        queryset=ConfigContext.objects.all(),
        widget=forms.MultipleHiddenInput
    )
    weight = forms.IntegerField(
        required=False,
        min_value=0
    )
    is_active = forms.NullBooleanField(
        required=False,
        widget=BulkEditNullBooleanSelect()
    )
    description = forms.CharField(
        required=False,
        max_length=100
    )

    class Meta:
        nullable_fields = [
            'description',
        ]


class ConfigContextFilterForm(BootstrapMixin, forms.Form):
    q = forms.CharField(
        required=False,
        label='Search'
    )
    region = DynamicModelMultipleChoiceField(
        queryset=Region.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/regions/",
            value_field="slug",
        )
    )
    site = DynamicModelMultipleChoiceField(
        queryset=Site.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/sites/",
            value_field="slug",
        )
    )
    role = DynamicModelMultipleChoiceField(
        queryset=DeviceRole.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/device-roles/",
            value_field="slug",
        )
    )
    platform = DynamicModelMultipleChoiceField(
        queryset=Platform.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/dcim/platforms/",
            value_field="slug",
        )
    )
    cluster_group = DynamicModelMultipleChoiceField(
        queryset=ClusterGroup.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/virtualization/cluster-groups/",
            value_field="slug",
        )
    )
    cluster_id = DynamicModelMultipleChoiceField(
        queryset=Cluster.objects.all(),
        required=False,
        label='Cluster',
        widget=APISelectMultiple(
            api_url="/api/virtualization/clusters/",
        )
    )
    tenant_group = DynamicModelMultipleChoiceField(
        queryset=TenantGroup.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/tenancy/tenant-groups/",
            value_field="slug",
        )
    )
    tenant = DynamicModelMultipleChoiceField(
        queryset=Tenant.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/tenancy/tenants/",
            value_field="slug",
        )
    )
    tag = DynamicModelMultipleChoiceField(
        queryset=Tag.objects.all(),
        to_field_name='slug',
        required=False,
        widget=APISelectMultiple(
            api_url="/api/extras/tags/",
            value_field="slug",
        )
    )


#
# Filter form for local config context data
#

class LocalConfigContextFilterForm(forms.Form):
    local_context_data = forms.NullBooleanField(
        required=False,
        label='Has local config context data',
        widget=StaticSelect2(
            choices=BOOLEAN_WITH_BLANK_CHOICES
        )
    )


#
# Image attachments
#

class ImageAttachmentForm(BootstrapMixin, forms.ModelForm):

    class Meta:
        model = ImageAttachment
        fields = [
            'name', 'image',
        ]


#
# Change logging
#

class ObjectChangeFilterForm(BootstrapMixin, forms.Form):
    model = ObjectChange
    q = forms.CharField(
        required=False,
        label='Search'
    )
    time_after = forms.DateTimeField(
        label='After',
        required=False,
        widget=DateTimePicker()
    )
    time_before = forms.DateTimeField(
        label='Before',
        required=False,
        widget=DateTimePicker()
    )
    action = forms.ChoiceField(
        choices=add_blank_choice(ObjectChangeActionChoices),
        required=False,
        widget=StaticSelect2()
    )
    # TODO: Convert to DynamicModelMultipleChoiceField once we have an API endpoint for users
    user = forms.ModelChoiceField(
        queryset=User.objects.order_by('username'),
        required=False,
        widget=StaticSelect2()
    )
    changed_object_type = forms.ModelChoiceField(
        queryset=ContentType.objects.order_by('model'),
        required=False,
        widget=ContentTypeSelect(),
        label='Object Type'
    )


#
# Scripts
#

class ScriptForm(BootstrapMixin, forms.Form):
    _commit = forms.BooleanField(
        required=False,
        initial=True,
        label="Commit changes",
        help_text="Commit changes to the database (uncheck for a dry-run)"
    )

    def __init__(self, vars, *args, commit_default=True, **kwargs):

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

        # Dynamically populate fields for variables
        for name, var in vars.items():
            self.fields[name] = var.as_field()

        # Toggle default commit behavior based on Meta option
        if not commit_default:
            self.fields['_commit'].initial = False

        # Move _commit to the end of the form
        self.fields.move_to_end('_commit', True)

    @property
    def requires_input(self):
        """
        A boolean indicating whether the form requires user input (ignore the _commit field).
        """
        return bool(len(self.fields) > 1)