from django import forms
from django.conf import settings
from django.db import models
from django.http import QueryDict
from django.template import Context
from django.test import RequestFactory, TestCase

import dcim.filtersets  # noqa: F401 - Import to register Device filterset
from core.models import ObjectType
from dcim.forms.filtersets import DeviceFilterForm, SiteFilterForm
from dcim.models import Device, Manufacturer, Site
from extras.choices import CustomFieldTypeChoices
from extras.models import CustomField
from netbox.filtersets import BaseFilterSet
from tenancy.models import Tenant
from users.models import User
from utilities.filtersets import register_filterset
from utilities.forms.fields import TagFilterField
from utilities.forms.mixins import FilterModifierMixin
from utilities.forms.widgets import FilterModifierWidget
from utilities.templatetags.helpers import applied_filters


# Test model for FilterModifierMixin tests
class TestModel(models.Model):
    """Dummy model for testing filter modifiers."""
    char_field = models.CharField(max_length=100, blank=True)
    integer_field = models.IntegerField(null=True, blank=True)
    decimal_field = models.DecimalField(max_digits=5, decimal_places=2, null=True, blank=True)
    date_field = models.DateField(null=True, blank=True)
    boolean_field = models.BooleanField(default=False)

    class Meta:
        app_label = 'utilities'
        managed = False  # Don't create actual database table


# Test filterset using BaseFilterSet to automatically generate lookups
@register_filterset
class TestFilterSet(BaseFilterSet):
    class Meta:
        model = TestModel
        fields = ['char_field', 'integer_field', 'decimal_field', 'date_field', 'boolean_field']


class FilterModifierWidgetTestCase(TestCase):
    """Tests for FilterModifierWidget value extraction and rendering."""

    def test_value_from_datadict_finds_value_in_lookup_variant(self):
        """
        Widget should find value from serial__ic when field is named serial.
        This is critical for form redisplay after validation errors.
        """
        widget = FilterModifierWidget(
            widget=forms.TextInput(),
            lookups=[('exact', 'Is'), ('ic', 'Contains'), ('isw', 'Starts With')]
        )
        data = QueryDict('serial__ic=test123')

        result = widget.value_from_datadict(data, {}, 'serial')

        self.assertEqual(result, 'test123')

    def test_value_from_datadict_handles_exact_match(self):
        """Widget should detect exact match when field name has no modifier."""
        widget = FilterModifierWidget(
            widget=forms.TextInput(),
            lookups=[('exact', 'Is'), ('ic', 'Contains')]
        )
        data = QueryDict('serial=test456')

        result = widget.value_from_datadict(data, {}, 'serial')

        self.assertEqual(result, 'test456')

    def test_value_from_datadict_returns_none_when_no_value(self):
        """Widget should return None when no data present to avoid appearing in changed_data."""
        widget = FilterModifierWidget(
            widget=forms.TextInput(),
            lookups=[('exact', 'Is'), ('ic', 'Contains')]
        )
        data = QueryDict('')

        result = widget.value_from_datadict(data, {}, 'serial')

        self.assertIsNone(result)

    def test_get_context_includes_original_widget_and_lookups(self):
        """Widget context should include original widget context and lookup choices."""
        widget = FilterModifierWidget(
            widget=forms.TextInput(),
            lookups=[('exact', 'Is'), ('ic', 'Contains'), ('isw', 'Starts With')]
        )
        value = 'test'

        context = widget.get_context('serial', value, {})

        self.assertIn('original_widget', context['widget'])
        self.assertEqual(
            context['widget']['lookups'],
            [('exact', 'Is'), ('ic', 'Contains'), ('isw', 'Starts With')]
        )
        self.assertEqual(context['widget']['field_name'], 'serial')
        self.assertEqual(context['widget']['current_modifier'], 'exact')  # Defaults to exact, JS updates from URL
        self.assertEqual(context['widget']['current_value'], 'test')

    def test_get_context_handles_null_selection(self):
        """Widget should preserve the 'null' choice when rendering."""

        null_value = settings.FILTERS_NULL_CHOICE_VALUE
        null_label = settings.FILTERS_NULL_CHOICE_LABEL

        # Simulate a query for objects with no tenant assigned (?tenant_id=null)
        query_params = QueryDict(f'tenant_id={null_value}')
        form = DeviceFilterForm(query_params)

        # Rendering the field triggers FilterModifierWidget.get_context()
        try:
            html = form['tenant_id'].as_widget()
        except ValueError as e:
            # ValueError: Field 'id' expected a number but got 'null'
            self.fail(f"FilterModifierWidget raised ValueError on 'null' selection: {e}")

        # Verify the "None" option is rendered so user selection is preserved in the UI
        self.assertIn(f'value="{null_value}"', html)
        self.assertIn(null_label, html)

    def test_get_context_handles_mixed_selection(self):
        """Widget should preserve both real objects and the 'null' choice together."""

        null_value = settings.FILTERS_NULL_CHOICE_VALUE

        # Create a tenant to simulate a real object
        tenant = Tenant.objects.create(name='Tenant A', slug='tenant-a')

        # Simulate a selection containing both a real PK and the null sentinel
        query_params = QueryDict('', mutable=True)
        query_params.setlist('tenant_id', [str(tenant.pk), null_value])
        form = DeviceFilterForm(query_params)

        # Rendering the field triggers FilterModifierWidget.get_context()
        try:
            html = form['tenant_id'].as_widget()
        except ValueError as e:
            # ValueError: Field 'id' expected a number but got 'null'
            self.fail(f"FilterModifierWidget raised ValueError on 'null' selection: {e}")

        # Verify both the real object and the null option are present in the output
        self.assertIn(f'value="{tenant.pk}"', html)
        self.assertIn(f'value="{null_value}"', html)

    def test_widget_renders_modifier_dropdown_and_input(self):
        """Widget should render modifier dropdown alongside original input."""
        widget = FilterModifierWidget(
            widget=forms.TextInput(),
            lookups=[('exact', 'Is'), ('ic', 'Contains')]
        )

        html = widget.render('serial', 'test', {})

        # Should contain modifier dropdown
        self.assertIn('class="form-select modifier-select"', html)
        self.assertIn('data-field="serial"', html)
        self.assertIn('<option value="exact" selected>Is</option>', html)
        self.assertIn('<option value="ic">Contains</option>', html)

        # Should contain original input
        self.assertIn('type="text"', html)
        self.assertIn('name="serial"', html)
        self.assertIn('value="test"', html)


class FilterModifierMixinTestCase(TestCase):
    """Tests for FilterModifierMixin form field enhancement."""

    def test_mixin_enhances_char_field_with_modifiers(self):
        """CharField should be enhanced with contains/starts/ends modifiers."""
        class TestForm(FilterModifierMixin, forms.Form):
            char_field = forms.CharField(required=False)
            model = TestModel

        form = TestForm()

        self.assertIsInstance(form.fields['char_field'].widget, FilterModifierWidget)
        lookup_codes = [lookup[0] for lookup in form.fields['char_field'].widget.lookups]
        expected_lookups = ['exact', 'n', 'ic', 'isw', 'iew', 'ie', 'regex', 'iregex', 'empty_true', 'empty_false']
        self.assertEqual(lookup_codes, expected_lookups)

    def test_mixin_skips_boolean_fields(self):
        """Boolean fields should not be enhanced."""
        class TestForm(FilterModifierMixin, forms.Form):
            boolean_field = forms.BooleanField(required=False)
            model = TestModel

        form = TestForm()

        self.assertNotIsInstance(form.fields['boolean_field'].widget, FilterModifierWidget)

    def test_mixin_enhances_tag_filter_field(self):
        """TagFilterField should be enhanced even though it's a MultipleChoiceField."""
        class TestForm(FilterModifierMixin, forms.Form):
            tag = TagFilterField(Device)
            model = Device

        form = TestForm()

        self.assertIsInstance(form.fields['tag'].widget, FilterModifierWidget)
        tag_lookups = [lookup[0] for lookup in form.fields['tag'].widget.lookups]
        # Device filterset has tag, tag__any, and tag__n but not tag__empty
        expected_lookups = ['exact', 'any', 'n']
        self.assertEqual(tag_lookups, expected_lookups)

    def test_mixin_enhances_integer_field(self):
        """IntegerField should be enhanced with comparison modifiers."""
        class TestForm(FilterModifierMixin, forms.Form):
            integer_field = forms.IntegerField(required=False)
            model = TestModel

        form = TestForm()

        self.assertIsInstance(form.fields['integer_field'].widget, FilterModifierWidget)
        lookup_codes = [lookup[0] for lookup in form.fields['integer_field'].widget.lookups]
        expected_lookups = ['exact', 'n', 'gt', 'gte', 'lt', 'lte', 'empty_true', 'empty_false']
        self.assertEqual(lookup_codes, expected_lookups)

    def test_mixin_enhances_decimal_field(self):
        """DecimalField should be enhanced with comparison modifiers."""
        class TestForm(FilterModifierMixin, forms.Form):
            decimal_field = forms.DecimalField(required=False)
            model = TestModel

        form = TestForm()

        self.assertIsInstance(form.fields['decimal_field'].widget, FilterModifierWidget)
        lookup_codes = [lookup[0] for lookup in form.fields['decimal_field'].widget.lookups]
        expected_lookups = ['exact', 'n', 'gt', 'gte', 'lt', 'lte', 'empty_true', 'empty_false']
        self.assertEqual(lookup_codes, expected_lookups)

    def test_mixin_enhances_date_field(self):
        """DateField should be enhanced with date-appropriate modifiers."""
        class TestForm(FilterModifierMixin, forms.Form):
            date_field = forms.DateField(required=False)
            model = TestModel

        form = TestForm()

        self.assertIsInstance(form.fields['date_field'].widget, FilterModifierWidget)
        lookup_codes = [lookup[0] for lookup in form.fields['date_field'].widget.lookups]
        expected_lookups = ['exact', 'n', 'gt', 'gte', 'lt', 'lte', 'empty_true', 'empty_false']
        self.assertEqual(lookup_codes, expected_lookups)


class ExtendedLookupFilterPillsTestCase(TestCase):
    """Tests for filter pill rendering of extended lookups."""

    @classmethod
    def setUpTestData(cls):
        cls.user = User.objects.create(username='test_user')

    def test_negation_lookup_filter_pill(self):
        """Filter pill should show 'is not' for negation lookup."""
        query_params = QueryDict('serial__n=ABC123')
        form = DeviceFilterForm(query_params)

        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Device, form, query_params)

        self.assertGreater(len(result['applied_filters']), 0)
        filter_pill = result['applied_filters'][0]
        self.assertIn('is not', filter_pill['link_text'].lower())
        self.assertIn('ABC123', filter_pill['link_text'])

    def test_regex_lookup_filter_pill(self):
        """Filter pill should show 'matches pattern' for regex lookup."""
        query_params = QueryDict('serial__regex=^ABC.*')
        form = DeviceFilterForm(query_params)

        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Device, form, query_params)

        self.assertGreater(len(result['applied_filters']), 0)
        filter_pill = result['applied_filters'][0]
        self.assertIn('matches pattern', filter_pill['link_text'].lower())

    def test_exact_lookup_filter_pill(self):
        """Filter pill should show field label and value without lookup modifier for exact match."""
        query_params = QueryDict('serial=ABC123')
        form = DeviceFilterForm(query_params)

        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Device, form, query_params)

        self.assertGreater(len(result['applied_filters']), 0)
        filter_pill = result['applied_filters'][0]
        # Should not contain lookup modifier text
        self.assertNotIn('is not', filter_pill['link_text'].lower())
        self.assertNotIn('matches pattern', filter_pill['link_text'].lower())
        self.assertNotIn('contains', filter_pill['link_text'].lower())
        # Should contain field label and value
        self.assertIn('Serial', filter_pill['link_text'])
        self.assertIn('ABC123', filter_pill['link_text'])


class EmptyLookupTestCase(TestCase):
    """Tests for empty (is empty/not empty) lookup support."""

    @classmethod
    def setUpTestData(cls):
        cls.user = User.objects.create(username='test_user')

    def test_empty_true_appears_in_filter_pills(self):
        """Filter pill should show 'Is Empty' for empty=true."""
        query_params = QueryDict('serial__empty=true')
        form = DeviceFilterForm(query_params)

        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Device, form, query_params)

        self.assertGreater(len(result['applied_filters']), 0)
        filter_pill = result['applied_filters'][0]
        self.assertIn('empty', filter_pill['link_text'].lower())

    def test_empty_false_appears_in_filter_pills(self):
        """Filter pill should show 'Is Not Empty' for empty=false."""
        query_params = QueryDict('serial__empty=false')
        form = DeviceFilterForm(query_params)

        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Device, form, query_params)

        self.assertGreater(len(result['applied_filters']), 0)
        filter_pill = result['applied_filters'][0]
        self.assertIn('not empty', filter_pill['link_text'].lower())


class ObjectCustomFieldEmptyLookupTestCase(TestCase):
    """
    Regression test for https://github.com/netbox-community/netbox/issues/21535.

    Rendering a filter form with an object-type custom field and the __empty modifier
    must not raise a ValueError or produce a form validation error.
    Filter pills must still appear for the empty modifier.
    """

    @classmethod
    def setUpTestData(cls):
        cls.user = User.objects.create(username='test_user_obj_cf')
        site_type = ObjectType.objects.get_for_model(Site)
        cf = CustomField(
            name='test_obj_cf',
            type=CustomFieldTypeChoices.TYPE_OBJECT,
            related_object_type=ObjectType.objects.get_for_model(Manufacturer),
        )
        cf.save()
        cf.object_types.set([site_type])

    def _make_form_and_result(self, querystring):
        query_params = QueryDict(querystring)
        form = SiteFilterForm(query_params)
        request = RequestFactory().get('/', query_params)
        request.user = self.user
        context = Context({'request': request})
        result = applied_filters(context, Site, form, query_params)
        return form, result

    def test_render_form_with_empty_true_no_error(self):
        """Rendering SiteFilterForm with cf__empty=true must not raise ValueError."""
        query_params = QueryDict('cf_test_obj_cf__empty=true')
        form = SiteFilterForm(query_params)
        try:
            str(form['cf_test_obj_cf'])
        except ValueError as e:
            self.fail(f"Rendering object-type custom field with __empty=true raised ValueError: {e}")

    def test_render_form_with_empty_false_no_error(self):
        """Rendering SiteFilterForm with cf__empty=false must not raise ValueError."""
        query_params = QueryDict('cf_test_obj_cf__empty=false')
        form = SiteFilterForm(query_params)
        try:
            str(form['cf_test_obj_cf'])
        except ValueError as e:
            self.fail(f"Rendering object-type custom field with __empty=false raised ValueError: {e}")

    def test_no_validation_error_on_empty_true(self):
        """The filter form must not have a validation error for the field when __empty=true."""
        form, _ = self._make_form_and_result('cf_test_obj_cf__empty=true')
        form.is_valid()
        self.assertNotIn('cf_test_obj_cf', form.errors)

    def test_filter_pill_appears_for_empty_true(self):
        """A filter pill showing 'is empty' must be generated for an object-type CF with __empty=true."""
        _, result = self._make_form_and_result('cf_test_obj_cf__empty=true')
        self.assertGreater(len(result['applied_filters']), 0)
        self.assertIn('empty', result['applied_filters'][0]['link_text'].lower())

    def test_filter_pill_appears_for_empty_false(self):
        """A filter pill showing 'is not empty' must be generated for an object-type CF with __empty=false."""
        _, result = self._make_form_and_result('cf_test_obj_cf__empty=false')
        self.assertGreater(len(result['applied_filters']), 0)
        self.assertIn('not empty', result['applied_filters'][0]['link_text'].lower())