from unittest import mock

from django.contrib.postgres.indexes import (
    BrinIndex, BTreeIndex, GinIndex, GistIndex, HashIndex, SpGistIndex,
)
from django.db import connection
from django.db.models import CharField
from django.db.models.functions import Length
from django.db.models.query_utils import Q
from django.db.utils import NotSupportedError
from django.test import skipUnlessDBFeature
from django.test.utils import register_lookup

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


class IndexTestMixin:

    def test_name_auto_generation(self):
        index = self.index_class(fields=['field'])
        index.set_name_with_model(CharFieldModel)
        self.assertRegex(index.name, r'postgres_te_field_[0-9a-f]{6}_%s' % self.index_class.suffix)

    def test_deconstruction_no_customization(self):
        index = self.index_class(fields=['title'], name='test_title_%s' % self.index_class.suffix)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.%s' % self.index_class.__name__)
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_%s' % self.index_class.suffix})


class BrinIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = BrinIndex

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

    def test_deconstruction(self):
        index = BrinIndex(fields=['title'], name='test_title_brin', autosummarize=True, 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',
            'autosummarize': True,
            '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 BTreeIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = BTreeIndex

    def test_suffix(self):
        self.assertEqual(BTreeIndex.suffix, 'btree')

    def test_deconstruction(self):
        index = BTreeIndex(fields=['title'], name='test_title_btree', fillfactor=80)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.BTreeIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_btree', 'fillfactor': 80})


class GinIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = GinIndex

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

    def test_deconstruction(self):
        index = GinIndex(
            fields=['title'],
            name='test_title_gin',
            fastupdate=True,
            gin_pending_list_limit=128,
        )
        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',
            'fastupdate': True,
            'gin_pending_list_limit': 128,
        })


class GistIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = GistIndex

    def test_suffix(self):
        self.assertEqual(GistIndex.suffix, 'gist')

    def test_deconstruction(self):
        index = GistIndex(fields=['title'], name='test_title_gist', buffering=False, fillfactor=80)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.GistIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {
            'fields': ['title'],
            'name': 'test_title_gist',
            'buffering': False,
            'fillfactor': 80,
        })


class HashIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = HashIndex

    def test_suffix(self):
        self.assertEqual(HashIndex.suffix, 'hash')

    def test_deconstruction(self):
        index = HashIndex(fields=['title'], name='test_title_hash', fillfactor=80)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.HashIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_hash', 'fillfactor': 80})


class SpGistIndexTests(IndexTestMixin, PostgreSQLSimpleTestCase):
    index_class = SpGistIndex

    def test_suffix(self):
        self.assertEqual(SpGistIndex.suffix, 'spgist')

    def test_deconstruction(self):
        index = SpGistIndex(fields=['title'], name='test_title_spgist', fillfactor=80)
        path, args, kwargs = index.deconstruct()
        self.assertEqual(path, 'django.contrib.postgres.indexes.SpGistIndex')
        self.assertEqual(args, ())
        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_spgist', 'fillfactor': 80})


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))

    def test_gin_fastupdate(self):
        index_name = 'integer_array_gin_fastupdate'
        index = GinIndex(fields=['field'], name=index_name, fastupdate=False)
        with connection.schema_editor() as editor:
            editor.add_index(IntegerArrayModel, index)
        constraints = self.get_constraints(IntegerArrayModel._meta.db_table)
        self.assertEqual(constraints[index_name]['type'], 'gin')
        self.assertEqual(constraints[index_name]['options'], ['fastupdate=off'])
        with connection.schema_editor() as editor:
            editor.remove_index(IntegerArrayModel, index)
        self.assertNotIn(index_name, self.get_constraints(IntegerArrayModel._meta.db_table))

    def test_partial_gin_index(self):
        with register_lookup(CharField, Length):
            index_name = 'char_field_gin_partial_idx'
            index = GinIndex(fields=['field'], name=index_name, condition=Q(field__length=40))
            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'], 'gin')
            with connection.schema_editor() as editor:
                editor.remove_index(CharFieldModel, index)
            self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

    def test_partial_gin_index_with_tablespace(self):
        with register_lookup(CharField, Length):
            index_name = 'char_field_gin_partial_idx'
            index = GinIndex(
                fields=['field'],
                name=index_name,
                condition=Q(field__length=40),
                db_tablespace='pg_default',
            )
            with connection.schema_editor() as editor:
                editor.add_index(CharFieldModel, index)
                self.assertIn('TABLESPACE "pg_default" ', str(index.create_sql(CharFieldModel, editor)))
            constraints = self.get_constraints(CharFieldModel._meta.db_table)
            self.assertEqual(constraints[index_name]['type'], 'gin')
            with connection.schema_editor() as editor:
                editor.remove_index(CharFieldModel, index)
            self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

    @skipUnlessDBFeature('has_gin_pending_list_limit')
    def test_gin_parameters(self):
        index_name = 'integer_array_gin_params'
        index = GinIndex(fields=['field'], name=index_name, fastupdate=True, gin_pending_list_limit=64)
        with connection.schema_editor() as editor:
            editor.add_index(IntegerArrayModel, index)
        constraints = self.get_constraints(IntegerArrayModel._meta.db_table)
        self.assertEqual(constraints[index_name]['type'], 'gin')
        self.assertEqual(constraints[index_name]['options'], ['gin_pending_list_limit=64', 'fastupdate=on'])
        with connection.schema_editor() as editor:
            editor.remove_index(IntegerArrayModel, index)
        self.assertNotIn(index_name, self.get_constraints(IntegerArrayModel._meta.db_table))

    @mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_gin_pending_list_limit', False)
    def test_gin_parameters_exception(self):
        index_name = 'gin_options_exception'
        index = GinIndex(fields=['field'], name=index_name, gin_pending_list_limit=64)
        msg = 'GIN option gin_pending_list_limit requires PostgreSQL 9.5+.'
        with self.assertRaisesMessage(NotSupportedError, msg):
            with connection.schema_editor() as editor:
                editor.add_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))

    @skipUnlessDBFeature('has_brin_index_support', 'has_brin_autosummarize')
    def test_brin_parameters(self):
        index_name = 'char_field_brin_params'
        index = BrinIndex(fields=['field'], name=index_name, autosummarize=True)
        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'], ['autosummarize=on'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

    def test_brin_index_not_supported(self):
        index_name = 'brin_index_exception'
        index = BrinIndex(fields=['field'], name=index_name)
        with self.assertRaisesMessage(NotSupportedError, 'BRIN indexes require PostgreSQL 9.5+.'):
            with mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_brin_index_support', False):
                with connection.schema_editor() as editor:
                    editor.add_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

    @skipUnlessDBFeature('has_brin_index_support')
    def test_brin_autosummarize_not_supported(self):
        index_name = 'brin_options_exception'
        index = BrinIndex(fields=['field'], name=index_name, autosummarize=True)
        with self.assertRaisesMessage(NotSupportedError, 'BRIN option autosummarize requires PostgreSQL 10+.'):
            with mock.patch('django.db.backends.postgresql.features.DatabaseFeatures.has_brin_autosummarize', False):
                with connection.schema_editor() as editor:
                    editor.add_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

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

    def test_btree_parameters(self):
        index_name = 'integer_array_btree_fillfactor'
        index = BTreeIndex(fields=['field'], name=index_name, fillfactor=80)
        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'], BTreeIndex.suffix)
        self.assertEqual(constraints[index_name]['options'], ['fillfactor=80'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

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

    def test_gist_parameters(self):
        index_name = 'integer_array_gist_buffering'
        index = GistIndex(fields=['field'], name=index_name, buffering=True, fillfactor=80)
        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'], GistIndex.suffix)
        self.assertEqual(constraints[index_name]['options'], ['buffering=on', 'fillfactor=80'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

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

    def test_hash_parameters(self):
        index_name = 'integer_array_hash_fillfactor'
        index = HashIndex(fields=['field'], name=index_name, fillfactor=80)
        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'], HashIndex.suffix)
        self.assertEqual(constraints[index_name]['options'], ['fillfactor=80'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))

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

    def test_spgist_parameters(self):
        index_name = 'integer_array_spgist_fillfactor'
        index = SpGistIndex(fields=['field'], name=index_name, fillfactor=80)
        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'], SpGistIndex.suffix)
        self.assertEqual(constraints[index_name]['options'], ['fillfactor=80'])
        with connection.schema_editor() as editor:
            editor.remove_index(CharFieldModel, index)
        self.assertNotIn(index_name, self.get_constraints(CharFieldModel._meta.db_table))
