#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

import datetime
import os
import shutil
import tempfile
from contextlib import contextmanager

from pyspark.sql import SparkSession
from pyspark.sql.types import ArrayType, DoubleType, UserDefinedType, Row
from pyspark.testing.utils import ReusedPySparkTestCase
from pyspark.util import _exception_message


pandas_requirement_message = None
try:
    from pyspark.sql.utils import require_minimum_pandas_version
    require_minimum_pandas_version()
except ImportError as e:
    # If Pandas version requirement is not satisfied, skip related tests.
    pandas_requirement_message = _exception_message(e)

pyarrow_requirement_message = None
try:
    from pyspark.sql.utils import require_minimum_pyarrow_version
    require_minimum_pyarrow_version()
except ImportError as e:
    # If Arrow version requirement is not satisfied, skip related tests.
    pyarrow_requirement_message = _exception_message(e)

test_not_compiled_message = None
try:
    from pyspark.sql.utils import require_test_compiled
    require_test_compiled()
except Exception as e:
    test_not_compiled_message = _exception_message(e)

have_pandas = pandas_requirement_message is None
have_pyarrow = pyarrow_requirement_message is None
test_compiled = test_not_compiled_message is None


class UTCOffsetTimezone(datetime.tzinfo):
    """
    Specifies timezone in UTC offset
    """

    def __init__(self, offset=0):
        self.ZERO = datetime.timedelta(hours=offset)

    def utcoffset(self, dt):
        return self.ZERO

    def dst(self, dt):
        return self.ZERO


class ExamplePointUDT(UserDefinedType):
    """
    User-defined type (UDT) for ExamplePoint.
    """

    @classmethod
    def sqlType(self):
        return ArrayType(DoubleType(), False)

    @classmethod
    def module(cls):
        return 'pyspark.sql.tests'

    @classmethod
    def scalaUDT(cls):
        return 'org.apache.spark.sql.test.ExamplePointUDT'

    def serialize(self, obj):
        return [obj.x, obj.y]

    def deserialize(self, datum):
        return ExamplePoint(datum[0], datum[1])


class ExamplePoint:
    """
    An example class to demonstrate UDT in Scala, Java, and Python.
    """

    __UDT__ = ExamplePointUDT()

    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __repr__(self):
        return "ExamplePoint(%s,%s)" % (self.x, self.y)

    def __str__(self):
        return "(%s,%s)" % (self.x, self.y)

    def __eq__(self, other):
        return isinstance(other, self.__class__) and \
            other.x == self.x and other.y == self.y


class PythonOnlyUDT(UserDefinedType):
    """
    User-defined type (UDT) for ExamplePoint.
    """

    @classmethod
    def sqlType(self):
        return ArrayType(DoubleType(), False)

    @classmethod
    def module(cls):
        return '__main__'

    def serialize(self, obj):
        return [obj.x, obj.y]

    def deserialize(self, datum):
        return PythonOnlyPoint(datum[0], datum[1])

    @staticmethod
    def foo():
        pass

    @property
    def props(self):
        return {}


class PythonOnlyPoint(ExamplePoint):
    """
    An example class to demonstrate UDT in only Python
    """
    __UDT__ = PythonOnlyUDT()


class MyObject(object):
    def __init__(self, key, value):
        self.key = key
        self.value = value


class SQLTestUtils(object):
    """
    This util assumes the instance of this to have 'spark' attribute, having a spark session.
    It is usually used with 'ReusedSQLTestCase' class but can be used if you feel sure the
    the implementation of this class has 'spark' attribute.
    """

    @contextmanager
    def sql_conf(self, pairs):
        """
        A convenient context manager to test some configuration specific logic. This sets
        `value` to the configuration `key` and then restores it back when it exits.
        """
        assert isinstance(pairs, dict), "pairs should be a dictionary."
        assert hasattr(self, "spark"), "it should have 'spark' attribute, having a spark session."

        keys = pairs.keys()
        new_values = pairs.values()
        old_values = [self.spark.conf.get(key, None) for key in keys]
        for key, new_value in zip(keys, new_values):
            self.spark.conf.set(key, new_value)
        try:
            yield
        finally:
            for key, old_value in zip(keys, old_values):
                if old_value is None:
                    self.spark.conf.unset(key)
                else:
                    self.spark.conf.set(key, old_value)

    @contextmanager
    def database(self, *databases):
        """
        A convenient context manager to test with some specific databases. This drops the given
        databases if it exists and sets current database to "default" when it exits.
        """
        assert hasattr(self, "spark"), "it should have 'spark' attribute, having a spark session."

        try:
            yield
        finally:
            for db in databases:
                self.spark.sql("DROP DATABASE IF EXISTS %s CASCADE" % db)
            self.spark.catalog.setCurrentDatabase("default")

    @contextmanager
    def table(self, *tables):
        """
        A convenient context manager to test with some specific tables. This drops the given tables
        if it exists.
        """
        assert hasattr(self, "spark"), "it should have 'spark' attribute, having a spark session."

        try:
            yield
        finally:
            for t in tables:
                self.spark.sql("DROP TABLE IF EXISTS %s" % t)

    @contextmanager
    def tempView(self, *views):
        """
        A convenient context manager to test with some specific views. This drops the given views
        if it exists.
        """
        assert hasattr(self, "spark"), "it should have 'spark' attribute, having a spark session."

        try:
            yield
        finally:
            for v in views:
                self.spark.catalog.dropTempView(v)

    @contextmanager
    def function(self, *functions):
        """
        A convenient context manager to test with some specific functions. This drops the given
        functions if it exists.
        """
        assert hasattr(self, "spark"), "it should have 'spark' attribute, having a spark session."

        try:
            yield
        finally:
            for f in functions:
                self.spark.sql("DROP FUNCTION IF EXISTS %s" % f)


class ReusedSQLTestCase(ReusedPySparkTestCase, SQLTestUtils):
    @classmethod
    def setUpClass(cls):
        super(ReusedSQLTestCase, cls).setUpClass()
        cls.spark = SparkSession(cls.sc)
        cls.tempdir = tempfile.NamedTemporaryFile(delete=False)
        os.unlink(cls.tempdir.name)
        cls.testData = [Row(key=i, value=str(i)) for i in range(100)]
        cls.df = cls.spark.createDataFrame(cls.testData)

    @classmethod
    def tearDownClass(cls):
        super(ReusedSQLTestCase, cls).tearDownClass()
        cls.spark.stop()
        shutil.rmtree(cls.tempdir.name, ignore_errors=True)

    def assertPandasEqual(self, expected, result):
        msg = ("DataFrames are not equal: " +
               "\n\nExpected:\n%s\n%s" % (expected, expected.dtypes) +
               "\n\nResult:\n%s\n%s" % (result, result.dtypes))
        self.assertTrue(expected.equals(result), msg=msg)
