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 #
 # 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.
 #
 """
 User-defined function related classes and functions
 """
 import functools
 import sys
 
 from pyspark import SparkContext, since
 from pyspark.rdd import _prepare_for_python_RDD, PythonEvalType, ignore_unicode_prefix
 from pyspark.sql.column import Column, _to_java_column, _to_seq
 from pyspark.sql.types import StringType, DataType, StructType, _parse_datatype_string
 from pyspark.sql.pandas.types import to_arrow_type
 
 __all__ = ["UDFRegistration"]
 
 
 def _wrap_function(sc, func, returnType):
     command = (func, returnType)
     pickled_command, broadcast_vars, env, includes = _prepare_for_python_RDD(sc, command)
     return sc._jvm.PythonFunction(bytearray(pickled_command), env, includes, sc.pythonExec,
                                   sc.pythonVer, broadcast_vars, sc._javaAccumulator)
 
 
 def _create_udf(f, returnType, evalType):
     # Set the name of the UserDefinedFunction object to be the name of function f
     udf_obj = UserDefinedFunction(
         f, returnType=returnType, name=None, evalType=evalType, deterministic=True)
     return udf_obj._wrapped()
 
 
 class UserDefinedFunction(object):
     """
     User defined function in Python
 
     .. versionadded:: 1.3
 
     .. note:: The constructor of this class is not supposed to be directly called.
         Use :meth:`pyspark.sql.functions.udf` or :meth:`pyspark.sql.functions.pandas_udf`
         to create this instance.
     """
     def __init__(self, func,
                  returnType=StringType(),
                  name=None,
                  evalType=PythonEvalType.SQL_BATCHED_UDF,
                  deterministic=True):
         if not callable(func):
             raise TypeError(
                 "Invalid function: not a function or callable (__call__ is not defined): "
                 "{0}".format(type(func)))
 
         if not isinstance(returnType, (DataType, str)):
             raise TypeError(
                 "Invalid return type: returnType should be DataType or str "
                 "but is {}".format(returnType))
 
         if not isinstance(evalType, int):
             raise TypeError(
                 "Invalid evaluation type: evalType should be an int but is {}".format(evalType))
 
         self.func = func
         self._returnType = returnType
         # Stores UserDefinedPythonFunctions jobj, once initialized
         self._returnType_placeholder = None
         self._judf_placeholder = None
         self._name = name or (
             func.__name__ if hasattr(func, '__name__')
             else func.__class__.__name__)
         self.evalType = evalType
         self.deterministic = deterministic
 
     @property
     def returnType(self):
         # This makes sure this is called after SparkContext is initialized.
         # ``_parse_datatype_string`` accesses to JVM for parsing a DDL formatted string.
         if self._returnType_placeholder is None:
             if isinstance(self._returnType, DataType):
                 self._returnType_placeholder = self._returnType
             else:
                 self._returnType_placeholder = _parse_datatype_string(self._returnType)
 
         if self.evalType == PythonEvalType.SQL_SCALAR_PANDAS_UDF or \
                 self.evalType == PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF:
             try:
                 to_arrow_type(self._returnType_placeholder)
             except TypeError:
                 raise NotImplementedError(
                     "Invalid return type with scalar Pandas UDFs: %s is "
                     "not supported" % str(self._returnType_placeholder))
         elif self.evalType == PythonEvalType.SQL_GROUPED_MAP_PANDAS_UDF:
             if isinstance(self._returnType_placeholder, StructType):
                 try:
                     to_arrow_type(self._returnType_placeholder)
                 except TypeError:
                     raise NotImplementedError(
                         "Invalid return type with grouped map Pandas UDFs or "
                         "at groupby.applyInPandas: %s is not supported" % str(
                             self._returnType_placeholder))
             else:
                 raise TypeError("Invalid return type for grouped map Pandas "
                                 "UDFs or at groupby.applyInPandas: return type must be a "
                                 "StructType.")
         elif self.evalType == PythonEvalType.SQL_MAP_PANDAS_ITER_UDF:
             if isinstance(self._returnType_placeholder, StructType):
                 try:
                     to_arrow_type(self._returnType_placeholder)
                 except TypeError:
                     raise NotImplementedError(
                         "Invalid return type in mapInPandas: "
                         "%s is not supported" % str(self._returnType_placeholder))
             else:
                 raise TypeError("Invalid return type in mapInPandas: "
                                 "return type must be a StructType.")
         elif self.evalType == PythonEvalType.SQL_COGROUPED_MAP_PANDAS_UDF:
             if isinstance(self._returnType_placeholder, StructType):
                 try:
                     to_arrow_type(self._returnType_placeholder)
                 except TypeError:
                     raise NotImplementedError(
                         "Invalid return type in cogroup.applyInPandas: "
                         "%s is not supported" % str(self._returnType_placeholder))
             else:
                 raise TypeError("Invalid return type in cogroup.applyInPandas: "
                                 "return type must be a StructType.")
         elif self.evalType == PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF:
             try:
                 # StructType is not yet allowed as a return type, explicitly check here to fail fast
                 if isinstance(self._returnType_placeholder, StructType):
                     raise TypeError
                 to_arrow_type(self._returnType_placeholder)
             except TypeError:
                 raise NotImplementedError(
                     "Invalid  return type with grouped aggregate Pandas UDFs: "
                     "%s is not supported" % str(self._returnType_placeholder))
 
         return self._returnType_placeholder
 
     @property
     def _judf(self):
         # It is possible that concurrent access, to newly created UDF,
         # will initialize multiple UserDefinedPythonFunctions.
         # This is unlikely, doesn't affect correctness,
         # and should have a minimal performance impact.
         if self._judf_placeholder is None:
             self._judf_placeholder = self._create_judf()
         return self._judf_placeholder
 
     def _create_judf(self):
         from pyspark.sql import SparkSession
 
         spark = SparkSession.builder.getOrCreate()
         sc = spark.sparkContext
 
         wrapped_func = _wrap_function(sc, self.func, self.returnType)
         jdt = spark._jsparkSession.parseDataType(self.returnType.json())
         judf = sc._jvm.org.apache.spark.sql.execution.python.UserDefinedPythonFunction(
             self._name, wrapped_func, jdt, self.evalType, self.deterministic)
         return judf
 
     def __call__(self, *cols):
         judf = self._judf
         sc = SparkContext._active_spark_context
         return Column(judf.apply(_to_seq(sc, cols, _to_java_column)))
 
     # This function is for improving the online help system in the interactive interpreter.
     # For example, the built-in help / pydoc.help. It wraps the UDF with the docstring and
     # argument annotation. (See: SPARK-19161)
     def _wrapped(self):
         """
         Wrap this udf with a function and attach docstring from func
         """
 
         # It is possible for a callable instance without __name__ attribute or/and
         # __module__ attribute to be wrapped here. For example, functools.partial. In this case,
         # we should avoid wrapping the attributes from the wrapped function to the wrapper
         # function. So, we take out these attribute names from the default names to set and
         # then manually assign it after being wrapped.
         assignments = tuple(
             a for a in functools.WRAPPER_ASSIGNMENTS if a != '__name__' and a != '__module__')
 
         @functools.wraps(self.func, assigned=assignments)
         def wrapper(*args):
             return self(*args)
 
         wrapper.__name__ = self._name
         wrapper.__module__ = (self.func.__module__ if hasattr(self.func, '__module__')
                               else self.func.__class__.__module__)
 
         wrapper.func = self.func
         wrapper.returnType = self.returnType
         wrapper.evalType = self.evalType
         wrapper.deterministic = self.deterministic
         wrapper.asNondeterministic = functools.wraps(
             self.asNondeterministic)(lambda: self.asNondeterministic()._wrapped())
         return wrapper
 
     def asNondeterministic(self):
         """
         Updates UserDefinedFunction to nondeterministic.
 
         .. versionadded:: 2.3
         """
         # Here, we explicitly clean the cache to create a JVM UDF instance
         # with 'deterministic' updated. See SPARK-23233.
         self._judf_placeholder = None
         self.deterministic = False
         return self
 
 
 class UDFRegistration(object):
     """
     Wrapper for user-defined function registration. This instance can be accessed by
     :attr:`spark.udf` or :attr:`sqlContext.udf`.
 
     .. versionadded:: 1.3.1
     """
 
     def __init__(self, sparkSession):
         self.sparkSession = sparkSession
 
     @ignore_unicode_prefix
     @since("1.3.1")
     def register(self, name, f, returnType=None):
         """Register a Python function (including lambda function) or a user-defined function
         as a SQL function.
 
         :param name: name of the user-defined function in SQL statements.
         :param f: a Python function, or a user-defined function. The user-defined function can
             be either row-at-a-time or vectorized. See :meth:`pyspark.sql.functions.udf` and
             :meth:`pyspark.sql.functions.pandas_udf`.
         :param returnType: the return type of the registered user-defined function. The value can
             be either a :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
         :return: a user-defined function.
 
         To register a nondeterministic Python function, users need to first build
         a nondeterministic user-defined function for the Python function and then register it
         as a SQL function.
 
         `returnType` can be optionally specified when `f` is a Python function but not
         when `f` is a user-defined function. Please see below.
 
         1. When `f` is a Python function:
 
             `returnType` defaults to string type and can be optionally specified. The produced
             object must match the specified type. In this case, this API works as if
             `register(name, f, returnType=StringType())`.
 
             >>> strlen = spark.udf.register("stringLengthString", lambda x: len(x))
             >>> spark.sql("SELECT stringLengthString('test')").collect()
             [Row(stringLengthString(test)=u'4')]
 
             >>> spark.sql("SELECT 'foo' AS text").select(strlen("text")).collect()
             [Row(stringLengthString(text)=u'3')]
 
             >>> from pyspark.sql.types import IntegerType
             >>> _ = spark.udf.register("stringLengthInt", lambda x: len(x), IntegerType())
             >>> spark.sql("SELECT stringLengthInt('test')").collect()
             [Row(stringLengthInt(test)=4)]
 
             >>> from pyspark.sql.types import IntegerType
             >>> _ = spark.udf.register("stringLengthInt", lambda x: len(x), IntegerType())
             >>> spark.sql("SELECT stringLengthInt('test')").collect()
             [Row(stringLengthInt(test)=4)]
 
         2. When `f` is a user-defined function:
 
             Spark uses the return type of the given user-defined function as the return type of
             the registered user-defined function. `returnType` should not be specified.
             In this case, this API works as if `register(name, f)`.
 
             >>> from pyspark.sql.types import IntegerType
             >>> from pyspark.sql.functions import udf
             >>> slen = udf(lambda s: len(s), IntegerType())
             >>> _ = spark.udf.register("slen", slen)
             >>> spark.sql("SELECT slen('test')").collect()
             [Row(slen(test)=4)]
 
             >>> import random
             >>> from pyspark.sql.functions import udf
             >>> from pyspark.sql.types import IntegerType
             >>> random_udf = udf(lambda: random.randint(0, 100), IntegerType()).asNondeterministic()
             >>> new_random_udf = spark.udf.register("random_udf", random_udf)
             >>> spark.sql("SELECT random_udf()").collect()  # doctest: +SKIP
             [Row(random_udf()=82)]
 
             >>> import pandas as pd  # doctest: +SKIP
             >>> from pyspark.sql.functions import pandas_udf
             >>> @pandas_udf("integer")  # doctest: +SKIP
             ... def add_one(s: pd.Series) -> pd.Series:
             ...     return s + 1
             ...
             >>> _ = spark.udf.register("add_one", add_one)  # doctest: +SKIP
             >>> spark.sql("SELECT add_one(id) FROM range(3)").collect()  # doctest: +SKIP
             [Row(add_one(id)=1), Row(add_one(id)=2), Row(add_one(id)=3)]
 
             >>> @pandas_udf("integer")  # doctest: +SKIP
             ... def sum_udf(v: pd.Series) -> int:
             ...     return v.sum()
             ...
             >>> _ = spark.udf.register("sum_udf", sum_udf)  # doctest: +SKIP
             >>> q = "SELECT sum_udf(v1) FROM VALUES (3, 0), (2, 0), (1, 1) tbl(v1, v2) GROUP BY v2"
             >>> spark.sql(q).collect()  # doctest: +SKIP
             [Row(sum_udf(v1)=1), Row(sum_udf(v1)=5)]
 
             .. note:: Registration for a user-defined function (case 2.) was added from
                 Spark 2.3.0.
         """
 
         # This is to check whether the input function is from a user-defined function or
         # Python function.
         if hasattr(f, 'asNondeterministic'):
             if returnType is not None:
                 raise TypeError(
                     "Invalid return type: data type can not be specified when f is"
                     "a user-defined function, but got %s." % returnType)
             if f.evalType not in [PythonEvalType.SQL_BATCHED_UDF,
                                   PythonEvalType.SQL_SCALAR_PANDAS_UDF,
                                   PythonEvalType.SQL_SCALAR_PANDAS_ITER_UDF,
                                   PythonEvalType.SQL_GROUPED_AGG_PANDAS_UDF,
                                   PythonEvalType.SQL_MAP_PANDAS_ITER_UDF]:
                 raise ValueError(
                     "Invalid f: f must be SQL_BATCHED_UDF, SQL_SCALAR_PANDAS_UDF, "
                     "SQL_SCALAR_PANDAS_ITER_UDF, SQL_GROUPED_AGG_PANDAS_UDF or "
                     "SQL_MAP_PANDAS_ITER_UDF.")
             register_udf = UserDefinedFunction(f.func, returnType=f.returnType, name=name,
                                                evalType=f.evalType,
                                                deterministic=f.deterministic)
             return_udf = f
         else:
             if returnType is None:
                 returnType = StringType()
             register_udf = UserDefinedFunction(f, returnType=returnType, name=name,
                                                evalType=PythonEvalType.SQL_BATCHED_UDF)
             return_udf = register_udf._wrapped()
         self.sparkSession._jsparkSession.udf().registerPython(name, register_udf._judf)
         return return_udf
 
     @ignore_unicode_prefix
     @since(2.3)
     def registerJavaFunction(self, name, javaClassName, returnType=None):
         """Register a Java user-defined function as a SQL function.
 
         In addition to a name and the function itself, the return type can be optionally specified.
         When the return type is not specified we would infer it via reflection.
 
         :param name: name of the user-defined function
         :param javaClassName: fully qualified name of java class
         :param returnType: the return type of the registered Java function. The value can be either
             a :class:`pyspark.sql.types.DataType` object or a DDL-formatted type string.
 
         >>> from pyspark.sql.types import IntegerType
         >>> spark.udf.registerJavaFunction(
         ...     "javaStringLength", "test.org.apache.spark.sql.JavaStringLength", IntegerType())
         >>> spark.sql("SELECT javaStringLength('test')").collect()
         [Row(javaStringLength(test)=4)]
 
         >>> spark.udf.registerJavaFunction(
         ...     "javaStringLength2", "test.org.apache.spark.sql.JavaStringLength")
         >>> spark.sql("SELECT javaStringLength2('test')").collect()
         [Row(javaStringLength2(test)=4)]
 
         >>> spark.udf.registerJavaFunction(
         ...     "javaStringLength3", "test.org.apache.spark.sql.JavaStringLength", "integer")
         >>> spark.sql("SELECT javaStringLength3('test')").collect()
         [Row(javaStringLength3(test)=4)]
         """
 
         jdt = None
         if returnType is not None:
             if not isinstance(returnType, DataType):
                 returnType = _parse_datatype_string(returnType)
             jdt = self.sparkSession._jsparkSession.parseDataType(returnType.json())
         self.sparkSession._jsparkSession.udf().registerJava(name, javaClassName, jdt)
 
     @ignore_unicode_prefix
     @since(2.3)
     def registerJavaUDAF(self, name, javaClassName):
         """Register a Java user-defined aggregate function as a SQL function.
 
         :param name: name of the user-defined aggregate function
         :param javaClassName: fully qualified name of java class
 
         >>> spark.udf.registerJavaUDAF("javaUDAF", "test.org.apache.spark.sql.MyDoubleAvg")
         >>> df = spark.createDataFrame([(1, "a"),(2, "b"), (3, "a")],["id", "name"])
         >>> df.createOrReplaceTempView("df")
         >>> spark.sql("SELECT name, javaUDAF(id) as avg from df group by name order by name desc") \
                 .collect()
         [Row(name=u'b', avg=102.0), Row(name=u'a', avg=102.0)]
         """
 
         self.sparkSession._jsparkSession.udf().registerJavaUDAF(name, javaClassName)
 
 
 def _test():
     import doctest
     from pyspark.sql import SparkSession
     import pyspark.sql.udf
     globs = pyspark.sql.udf.__dict__.copy()
     spark = SparkSession.builder\
         .master("local[4]")\
         .appName("sql.udf tests")\
         .getOrCreate()
     globs['spark'] = spark
     # Hack to skip the unit tests in register. These are currently being tested in proper tests.
     # We should reenable this test once we completely drop Python 2.
     del pyspark.sql.udf.UDFRegistration.register
     (failure_count, test_count) = doctest.testmod(
         pyspark.sql.udf, globs=globs,
         optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE)
     spark.stop()
     if failure_count:
         sys.exit(-1)
 
 
 if __name__ == "__main__":
     _test()

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