import os
import re
from io import StringIO
from unittest import mock, skipUnless

from django.core.management import call_command
from django.db import connection
from django.db.backends.base.introspection import TableInfo
from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature

from .models import PeopleMoreData, test_collation


def inspectdb_tables_only(table_name):
    """
    Limit introspection to tables created for models of this app.
    Some databases such as Oracle are extremely slow at introspection.
    """
    return table_name.startswith("inspectdb_")


def inspectdb_views_only(table_name):
    return table_name.startswith("inspectdb_") and table_name.endswith(
        ("_materialized", "_view")
    )


def special_table_only(table_name):
    return table_name.startswith("inspectdb_special")


class InspectDBTestCase(TestCase):
    unique_re = re.compile(r".*unique_together = \((.+),\).*")

    def test_stealth_table_name_filter_option(self):
        out = StringIO()
        call_command("inspectdb", table_name_filter=inspectdb_tables_only, stdout=out)
        error_message = (
            "inspectdb has examined a table that should have been filtered out."
        )
        # contrib.contenttypes is one of the apps always installed when running
        # the Django test suite, check that one of its tables hasn't been
        # inspected
        self.assertNotIn(
            "class DjangoContentType(models.Model):", out.getvalue(), msg=error_message
        )

    def test_table_option(self):
        """
        inspectdb can inspect a subset of tables by passing the table names as
        arguments.
        """
        out = StringIO()
        call_command("inspectdb", "inspectdb_people", stdout=out)
        output = out.getvalue()
        self.assertIn("class InspectdbPeople(models.Model):", output)
        self.assertNotIn("InspectdbPeopledata", output)

    def make_field_type_asserter(self):
        """
        Call inspectdb and return a function to validate a field type in its
        output.
        """
        out = StringIO()
        call_command("inspectdb", "inspectdb_columntypes", stdout=out)
        output = out.getvalue()

        def assertFieldType(name, definition):
            out_def = re.search(r"^\s*%s = (models.*)$" % name, output, re.MULTILINE)[1]
            self.assertEqual(definition, out_def)

        return assertFieldType

    def test_field_types(self):
        """Test introspection of various Django field types"""
        assertFieldType = self.make_field_type_asserter()
        introspected_field_types = connection.features.introspected_field_types
        char_field_type = introspected_field_types["CharField"]
        # Inspecting Oracle DB doesn't produce correct results (#19884):
        # - it reports fields as blank=True when they aren't.
        if (
            not connection.features.interprets_empty_strings_as_nulls
            and char_field_type == "CharField"
        ):
            assertFieldType("char_field", "models.CharField(max_length=10)")
            assertFieldType(
                "null_char_field",
                "models.CharField(max_length=10, blank=True, null=True)",
            )
            assertFieldType("email_field", "models.CharField(max_length=254)")
            assertFieldType("file_field", "models.CharField(max_length=100)")
            assertFieldType("file_path_field", "models.CharField(max_length=100)")
            assertFieldType("slug_field", "models.CharField(max_length=50)")
            assertFieldType("text_field", "models.TextField()")
            assertFieldType("url_field", "models.CharField(max_length=200)")
        if char_field_type == "TextField":
            assertFieldType("char_field", "models.TextField()")
            assertFieldType(
                "null_char_field", "models.TextField(blank=True, null=True)"
            )
            assertFieldType("email_field", "models.TextField()")
            assertFieldType("file_field", "models.TextField()")
            assertFieldType("file_path_field", "models.TextField()")
            assertFieldType("slug_field", "models.TextField()")
            assertFieldType("text_field", "models.TextField()")
            assertFieldType("url_field", "models.TextField()")
        assertFieldType("date_field", "models.DateField()")
        assertFieldType("date_time_field", "models.DateTimeField()")
        if introspected_field_types["GenericIPAddressField"] == "GenericIPAddressField":
            assertFieldType("gen_ip_address_field", "models.GenericIPAddressField()")
        elif not connection.features.interprets_empty_strings_as_nulls:
            assertFieldType("gen_ip_address_field", "models.CharField(max_length=39)")
        assertFieldType(
            "time_field", "models.%s()" % introspected_field_types["TimeField"]
        )
        if connection.features.has_native_uuid_field:
            assertFieldType("uuid_field", "models.UUIDField()")
        elif not connection.features.interprets_empty_strings_as_nulls:
            assertFieldType("uuid_field", "models.CharField(max_length=32)")

    @skipUnlessDBFeature("can_introspect_json_field", "supports_json_field")
    def test_json_field(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_jsonfieldcolumntype", stdout=out)
        output = out.getvalue()
        if not connection.features.interprets_empty_strings_as_nulls:
            self.assertIn("json_field = models.JSONField()", output)
        self.assertIn(
            "null_json_field = models.JSONField(blank=True, null=True)", output
        )

    @skipUnlessDBFeature("supports_comments")
    def test_db_comments(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_dbcomment", stdout=out)
        output = out.getvalue()
        integer_field_type = connection.features.introspected_field_types[
            "IntegerField"
        ]
        self.assertIn(
            f"rank = models.{integer_field_type}("
            f"db_comment=\"'Rank' column comment\")",
            output,
        )
        self.assertIn(
            "        db_table_comment = 'Custom table comment'",
            output,
        )

    @skipUnlessDBFeature("supports_collation_on_charfield")
    @skipUnless(test_collation, "Language collations are not supported.")
    def test_char_field_db_collation(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_charfielddbcollation", stdout=out)
        output = out.getvalue()
        if not connection.features.interprets_empty_strings_as_nulls:
            self.assertIn(
                "char_field = models.CharField(max_length=10, "
                "db_collation='%s')" % test_collation,
                output,
            )
        else:
            self.assertIn(
                "char_field = models.CharField(max_length=10, "
                "db_collation='%s', blank=True, null=True)" % test_collation,
                output,
            )

    @skipUnlessDBFeature("supports_collation_on_textfield")
    @skipUnless(test_collation, "Language collations are not supported.")
    def test_text_field_db_collation(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_textfielddbcollation", stdout=out)
        output = out.getvalue()
        if not connection.features.interprets_empty_strings_as_nulls:
            self.assertIn(
                "text_field = models.TextField(db_collation='%s')" % test_collation,
                output,
            )
        else:
            self.assertIn(
                "text_field = models.TextField(db_collation='%s, blank=True, "
                "null=True)" % test_collation,
                output,
            )

    @skipUnlessDBFeature("supports_unlimited_charfield")
    def test_char_field_unlimited(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_charfieldunlimited", stdout=out)
        output = out.getvalue()
        self.assertIn("char_field = models.CharField()", output)

    def test_number_field_types(self):
        """Test introspection of various Django field types"""
        assertFieldType = self.make_field_type_asserter()
        introspected_field_types = connection.features.introspected_field_types

        auto_field_type = connection.features.introspected_field_types["AutoField"]
        if auto_field_type != "AutoField":
            assertFieldType(
                "id", "models.%s(primary_key=True)  # AutoField?" % auto_field_type
            )

        assertFieldType(
            "big_int_field", "models.%s()" % introspected_field_types["BigIntegerField"]
        )

        bool_field_type = introspected_field_types["BooleanField"]
        assertFieldType("bool_field", "models.{}()".format(bool_field_type))
        assertFieldType(
            "null_bool_field",
            "models.{}(blank=True, null=True)".format(bool_field_type),
        )

        if connection.vendor != "sqlite":
            assertFieldType(
                "decimal_field", "models.DecimalField(max_digits=6, decimal_places=1)"
            )
        else:  # Guessed arguments on SQLite, see #5014
            assertFieldType(
                "decimal_field",
                "models.DecimalField(max_digits=10, decimal_places=5)  "
                "# max_digits and decimal_places have been guessed, "
                "as this database handles decimal fields as float",
            )

        assertFieldType("float_field", "models.FloatField()")
        assertFieldType(
            "int_field", "models.%s()" % introspected_field_types["IntegerField"]
        )
        assertFieldType(
            "pos_int_field",
            "models.%s()" % introspected_field_types["PositiveIntegerField"],
        )
        assertFieldType(
            "pos_big_int_field",
            "models.%s()" % introspected_field_types["PositiveBigIntegerField"],
        )
        assertFieldType(
            "pos_small_int_field",
            "models.%s()" % introspected_field_types["PositiveSmallIntegerField"],
        )
        assertFieldType(
            "small_int_field",
            "models.%s()" % introspected_field_types["SmallIntegerField"],
        )

    @skipUnlessDBFeature("can_introspect_foreign_keys")
    def test_attribute_name_not_python_keyword(self):
        out = StringIO()
        call_command("inspectdb", table_name_filter=inspectdb_tables_only, stdout=out)
        output = out.getvalue()
        error_message = (
            "inspectdb generated an attribute name which is a Python keyword"
        )
        # Recursive foreign keys should be set to 'self'
        self.assertIn("parent = models.ForeignKey('self', models.DO_NOTHING)", output)
        self.assertNotIn(
            "from = models.ForeignKey(InspectdbPeople, models.DO_NOTHING)",
            output,
            msg=error_message,
        )
        # As InspectdbPeople model is defined after InspectdbMessage, it should
        # be quoted.
        self.assertIn(
            "from_field = models.ForeignKey('InspectdbPeople', models.DO_NOTHING, "
            "db_column='from_id')",
            output,
        )
        self.assertIn(
            "people_pk = models.OneToOneField(InspectdbPeople, models.DO_NOTHING, "
            "primary_key=True)",
            output,
        )
        self.assertIn(
            "people_unique = models.OneToOneField(InspectdbPeople, models.DO_NOTHING)",
            output,
        )

    @skipUnlessDBFeature("can_introspect_foreign_keys")
    def test_foreign_key_to_field(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_foreignkeytofield", stdout=out)
        self.assertIn(
            "to_field_fk = models.ForeignKey('InspectdbPeoplemoredata', "
            "models.DO_NOTHING, to_field='people_unique_id')",
            out.getvalue(),
        )

    def test_digits_column_name_introspection(self):
        """Introspection of column names consist/start with digits (#16536/#17676)"""
        char_field_type = connection.features.introspected_field_types["CharField"]
        out = StringIO()
        call_command("inspectdb", "inspectdb_digitsincolumnname", stdout=out)
        output = out.getvalue()
        error_message = "inspectdb generated a model field name which is a number"
        self.assertNotIn(
            "    123 = models.%s" % char_field_type, output, msg=error_message
        )
        self.assertIn("number_123 = models.%s" % char_field_type, output)

        error_message = (
            "inspectdb generated a model field name which starts with a digit"
        )
        self.assertNotIn(
            "    4extra = models.%s" % char_field_type, output, msg=error_message
        )
        self.assertIn("number_4extra = models.%s" % char_field_type, output)

        self.assertNotIn(
            "    45extra = models.%s" % char_field_type, output, msg=error_message
        )
        self.assertIn("number_45extra = models.%s" % char_field_type, output)

    def test_special_column_name_introspection(self):
        """
        Introspection of column names containing special characters,
        unsuitable for Python identifiers
        """
        out = StringIO()
        call_command("inspectdb", table_name_filter=special_table_only, stdout=out)
        output = out.getvalue()
        base_name = connection.introspection.identifier_converter("Field")
        integer_field_type = connection.features.introspected_field_types[
            "IntegerField"
        ]
        self.assertIn("field = models.%s()" % integer_field_type, output)
        self.assertIn(
            "field_field = models.%s(db_column='%s_')"
            % (integer_field_type, base_name),
            output,
        )
        self.assertIn(
            "field_field_0 = models.%s(db_column='%s__')"
            % (integer_field_type, base_name),
            output,
        )
        self.assertIn(
            "field_field_1 = models.%s(db_column='__field')" % integer_field_type,
            output,
        )
        self.assertIn(
            "prc_x = models.{}(db_column='prc(%) x')".format(integer_field_type), output
        )
        self.assertIn("tamaño = models.%s()" % integer_field_type, output)

    def test_table_name_introspection(self):
        """
        Introspection of table names containing special characters,
        unsuitable for Python identifiers
        """
        out = StringIO()
        call_command("inspectdb", table_name_filter=special_table_only, stdout=out)
        output = out.getvalue()
        self.assertIn("class InspectdbSpecialTableName(models.Model):", output)

    @skipUnlessDBFeature("supports_expression_indexes")
    def test_table_with_func_unique_constraint(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_funcuniqueconstraint", stdout=out)
        output = out.getvalue()
        self.assertIn("class InspectdbFuncuniqueconstraint(models.Model):", output)

    def test_managed_models(self):
        """
        By default the command generates models with `Meta.managed = False`.
        """
        out = StringIO()
        call_command("inspectdb", "inspectdb_columntypes", stdout=out)
        output = out.getvalue()
        self.longMessage = False
        self.assertIn(
            "        managed = False",
            output,
            msg="inspectdb should generate unmanaged models.",
        )

    def test_unique_together_meta(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_uniquetogether", stdout=out)
        output = out.getvalue()
        self.assertIn("    unique_together = (('", output)
        unique_together_match = self.unique_re.findall(output)
        # There should be one unique_together tuple.
        self.assertEqual(len(unique_together_match), 1)
        fields = unique_together_match[0]
        # Fields with db_column = field name.
        self.assertIn("('field1', 'field2')", fields)
        # Fields from columns whose names are Python keywords.
        self.assertIn("('field1', 'field2')", fields)
        # Fields whose names normalize to the same Python field name and hence
        # are given an integer suffix.
        self.assertIn("('non_unique_column', 'non_unique_column_0')", fields)

    @skipUnless(connection.vendor == "postgresql", "PostgreSQL specific SQL")
    def test_unsupported_unique_together(self):
        """Unsupported index types (COALESCE here) are skipped."""
        with connection.cursor() as c:
            c.execute(
                "CREATE UNIQUE INDEX Findex ON %s "
                "(id, people_unique_id, COALESCE(message_id, -1))"
                % PeopleMoreData._meta.db_table
            )
        try:
            out = StringIO()
            call_command(
                "inspectdb",
                table_name_filter=lambda tn: tn.startswith(
                    PeopleMoreData._meta.db_table
                ),
                stdout=out,
            )
            output = out.getvalue()
            self.assertIn("# A unique constraint could not be introspected.", output)
            self.assertEqual(
                self.unique_re.findall(output), ["('id', 'people_unique')"]
            )
        finally:
            with connection.cursor() as c:
                c.execute("DROP INDEX Findex")

    @skipUnless(
        connection.vendor == "sqlite",
        "Only patched sqlite's DatabaseIntrospection.data_types_reverse for this test",
    )
    def test_custom_fields(self):
        """
        Introspection of columns with a custom field (#21090)
        """
        out = StringIO()
        with mock.patch(
            "django.db.connection.introspection.data_types_reverse."
            "base_data_types_reverse",
            {
                "text": "myfields.TextField",
                "bigint": "BigIntegerField",
            },
        ):
            call_command("inspectdb", "inspectdb_columntypes", stdout=out)
            output = out.getvalue()
            self.assertIn("text_field = myfields.TextField()", output)
            self.assertIn("big_int_field = models.BigIntegerField()", output)

    def test_introspection_errors(self):
        """
        Introspection errors should not crash the command, and the error should
        be visible in the output.
        """
        out = StringIO()
        with mock.patch(
            "django.db.connection.introspection.get_table_list",
            return_value=[TableInfo(name="nonexistent", type="t")],
        ):
            call_command("inspectdb", stdout=out)
        output = out.getvalue()
        self.assertIn("# Unable to inspect table 'nonexistent'", output)
        # The error message depends on the backend
        self.assertIn("# The error was:", output)

    def test_same_relations(self):
        out = StringIO()
        call_command("inspectdb", "inspectdb_message", stdout=out)
        self.assertIn(
            "author = models.ForeignKey('InspectdbPeople', models.DO_NOTHING, "
            "related_name='inspectdbmessage_author_set')",
            out.getvalue(),
        )


class InspectDBTransactionalTests(TransactionTestCase):
    available_apps = ["inspectdb"]

    def test_include_views(self):
        """inspectdb --include-views creates models for database views."""
        with connection.cursor() as cursor:
            cursor.execute(
                "CREATE VIEW inspectdb_people_view AS "
                "SELECT id, name FROM inspectdb_people"
            )
        out = StringIO()
        view_model = "class InspectdbPeopleView(models.Model):"
        view_managed = "managed = False  # Created from a view."
        try:
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_views_only,
                stdout=out,
            )
            no_views_output = out.getvalue()
            self.assertNotIn(view_model, no_views_output)
            self.assertNotIn(view_managed, no_views_output)
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_views_only,
                include_views=True,
                stdout=out,
            )
            with_views_output = out.getvalue()
            self.assertIn(view_model, with_views_output)
            self.assertIn(view_managed, with_views_output)
        finally:
            with connection.cursor() as cursor:
                cursor.execute("DROP VIEW inspectdb_people_view")

    @skipUnlessDBFeature("can_introspect_materialized_views")
    def test_include_materialized_views(self):
        """inspectdb --include-views creates models for materialized views."""
        with connection.cursor() as cursor:
            cursor.execute(
                "CREATE MATERIALIZED VIEW inspectdb_people_materialized AS "
                "SELECT id, name FROM inspectdb_people"
            )
        out = StringIO()
        view_model = "class InspectdbPeopleMaterialized(models.Model):"
        view_managed = "managed = False  # Created from a view."
        try:
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_views_only,
                stdout=out,
            )
            no_views_output = out.getvalue()
            self.assertNotIn(view_model, no_views_output)
            self.assertNotIn(view_managed, no_views_output)
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_views_only,
                include_views=True,
                stdout=out,
            )
            with_views_output = out.getvalue()
            self.assertIn(view_model, with_views_output)
            self.assertIn(view_managed, with_views_output)
        finally:
            with connection.cursor() as cursor:
                cursor.execute("DROP MATERIALIZED VIEW inspectdb_people_materialized")

    @skipUnless(connection.vendor == "postgresql", "PostgreSQL specific SQL")
    def test_include_partitions(self):
        """inspectdb --include-partitions creates models for partitions."""
        with connection.cursor() as cursor:
            cursor.execute(
                """\
                CREATE TABLE inspectdb_partition_parent (name text not null)
                PARTITION BY LIST (left(upper(name), 1))
            """
            )
            cursor.execute(
                """\
                CREATE TABLE inspectdb_partition_child
                PARTITION OF inspectdb_partition_parent
                FOR VALUES IN ('A', 'B', 'C')
            """
            )
        out = StringIO()
        partition_model_parent = "class InspectdbPartitionParent(models.Model):"
        partition_model_child = "class InspectdbPartitionChild(models.Model):"
        partition_managed = "managed = False  # Created from a partition."
        try:
            call_command(
                "inspectdb", table_name_filter=inspectdb_tables_only, stdout=out
            )
            no_partitions_output = out.getvalue()
            self.assertIn(partition_model_parent, no_partitions_output)
            self.assertNotIn(partition_model_child, no_partitions_output)
            self.assertNotIn(partition_managed, no_partitions_output)
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_tables_only,
                include_partitions=True,
                stdout=out,
            )
            with_partitions_output = out.getvalue()
            self.assertIn(partition_model_parent, with_partitions_output)
            self.assertIn(partition_model_child, with_partitions_output)
            self.assertIn(partition_managed, with_partitions_output)
        finally:
            with connection.cursor() as cursor:
                cursor.execute("DROP TABLE IF EXISTS inspectdb_partition_child")
                cursor.execute("DROP TABLE IF EXISTS inspectdb_partition_parent")

    @skipUnless(connection.vendor == "postgresql", "PostgreSQL specific SQL")
    def test_foreign_data_wrapper(self):
        with connection.cursor() as cursor:
            cursor.execute("CREATE EXTENSION IF NOT EXISTS file_fdw")
            cursor.execute(
                "CREATE SERVER inspectdb_server FOREIGN DATA WRAPPER file_fdw"
            )
            cursor.execute(
                connection.ops.compose_sql(
                    """
                    CREATE FOREIGN TABLE inspectdb_iris_foreign_table (
                        petal_length real,
                        petal_width real,
                        sepal_length real,
                        sepal_width real
                    ) SERVER inspectdb_server OPTIONS (
                        filename %s
                    )
                    """,
                    [os.devnull],
                )
            )
        out = StringIO()
        foreign_table_model = "class InspectdbIrisForeignTable(models.Model):"
        foreign_table_managed = "managed = False"
        try:
            call_command(
                "inspectdb",
                table_name_filter=inspectdb_tables_only,
                stdout=out,
            )
            output = out.getvalue()
            self.assertIn(foreign_table_model, output)
            self.assertIn(foreign_table_managed, output)
        finally:
            with connection.cursor() as cursor:
                cursor.execute(
                    "DROP FOREIGN TABLE IF EXISTS inspectdb_iris_foreign_table"
                )
                cursor.execute("DROP SERVER IF EXISTS inspectdb_server")
                cursor.execute("DROP EXTENSION IF EXISTS file_fdw")

    @skipUnlessDBFeature("create_test_table_with_composite_primary_key")
    def test_composite_primary_key(self):
        table_name = "test_table_composite_pk"
        with connection.cursor() as cursor:
            cursor.execute(
                connection.features.create_test_table_with_composite_primary_key
            )
        out = StringIO()
        if connection.vendor == "sqlite":
            field_type = connection.features.introspected_field_types["AutoField"]
        else:
            field_type = connection.features.introspected_field_types["IntegerField"]
        try:
            call_command("inspectdb", table_name, stdout=out)
            output = out.getvalue()
            self.assertIn(
                f"column_1 = models.{field_type}(primary_key=True)  # The composite "
                f"primary key (column_1, column_2) found, that is not supported. The "
                f"first column is selected.",
                output,
            )
            self.assertIn(
                "column_2 = models.%s()"
                % connection.features.introspected_field_types["IntegerField"],
                output,
            )
        finally:
            with connection.cursor() as cursor:
                cursor.execute("DROP TABLE %s" % table_name)
