from django.contrib.postgres.indexes import BrinIndex, GinIndex
from django.db import connection
from django.test import skipUnlessDBFeature

from . import PostgreSQLTestCase
from .models import CharFieldModel, DateTimeArrayModel, IntegerArrayModel


@skipUnlessDBFeature('has_brin_index_support')
class BrinIndexTests(PostgreSQLTestCase):

    def test_suffix(self):
        self.assertEqual(BrinIndex.suffix, 'brin')

    def test_not_eq(self):
        index = BrinIndex(fields=['title'])
        index_with_page_range = BrinIndex(fields=['title'], pages_per_range=16)
        self.assertNotEqual(index, index_with_page_range)

    def test_name_auto_generation(self):
        """
        A name longer than 30 characters (since len(BrinIndex.suffix) is 4
        rather than usual limit of 3) is okay for PostgreSQL. For this test,
        the name of the field ('datetimes') must be at least 7 characters to
        generate a name longer than 30 characters.
        """
        index = BrinIndex(fields=['datetimes'])
        index.set_name_with_model(DateTimeArrayModel)
        self.assertEqual(index.name, 'postgres_te_datetim_abf104_brin')

    def test_deconstruction(self):
        index = BrinIndex(fields=['title'], name='test_title_brin')
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.BrinIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_brin', 'pages_per_range': None})

    def test_deconstruction_with_pages_per_range(self):
        index = BrinIndex(fields=['title'], name='test_title_brin', pages_per_range=16)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.BrinIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_brin', 'pages_per_range': 16})

    def test_invalid_pages_per_range(self):
        with self.assertRaisesMessage(ValueError, 'pages_per_range must be None or a positive integer'):
            BrinIndex(fields=['title'], name='test_title_brin', pages_per_range=0)


class GinIndexTests(PostgreSQLTestCase):

    def test_suffix(self):
        self.assertEqual(GinIndex.suffix, 'gin')

    def test_eq(self):
        index = GinIndex(fields=['title'])
        same_index = GinIndex(fields=['title'])
        another_index = GinIndex(fields=['author'])
        self.assertEqual(index, same_index)
        self.assertNotEqual(index, another_index)

    def test_name_auto_generation(self):
        index = GinIndex(fields=['field'])
        index.set_name_with_model(IntegerArrayModel)
        self.assertEqual(index.name, 'postgres_te_field_def2f8_gin')

    def test_deconstruction(self):
        index = GinIndex(fields=['title'], name='test_title_gin')
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.GinIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_gin'})


class SchemaTests(PostgreSQLTestCase):

    def get_constraints(self, table):
        """
        Get the indexes on the table using a new cursor.
        """
        with connection.cursor() as cursor:
            return connection.introspection.get_constraints(cursor, table)

    def test_gin_index(self):
        # Ensure the table is there and doesn't have an index.
        self.assertNotIn('field', self.get_constraints(IntegerArrayModel._meta.db_table))
        # Add the index
        index_name = 'integer_array_model_field_gin'
        index = GinIndex(fields=['field'], name=index_name)
        with connection.schema_editor() as editor:
            editor.add_index(IntegerArrayModel, index)
        constraints = self.get_constraints(IntegerArrayModel._meta.db_table)
        # Check gin index was added
        self.assertEqual(constraints[index_name]['type'], GinIndex.suffix)
        # Drop the index
        with connection.schema_editor() as editor:
            editor.remove_index(IntegerArrayModel, index)
        self.assertNotIn(index_name, self.get_constraints(IntegerArrayModel._meta.db_table))

    @skipUnlessDBFeature('has_brin_index_support')
    def test_brin_index(self):
        index_name = 'char_field_model_field_brin'
        index = BrinIndex(fields=['field'], name=index_name, pages_per_range=4)
        with connection.schema_editor() as editor:
            editor.add_index(CharFieldModel, index)
        constraints = self.get_constraints(CharFieldModel._meta.db_table)
        self.assertEqual(constraints[index_name]['type'], BrinIndex.suffix)
        self.assertEqual(constraints[index_name]['options'], ['pages_per_range=4'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))