# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed 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.

# TODO: define random api
import paddle.fluid as fluid
from paddle.fluid import core

__all__ = []


def seed(seed):
 """

 Sets the seed for global default generator, which manages the random number generation.

 Args:
 seed(int): The random seed to set. It is recommend to set a large int number.

 Returns:
 Generator: The global default generator object.

 Examples:
 .. code-block:: python

 import paddle
 gen = paddle.seed(102)

 """
 #TODO(zhiqiu): 1. remove program.random_seed when all random-related op upgrade
 # 2. support gpu generator by global device 

 seed = int(seed)

 if core.is_compiled_with_cuda():
 for i in range(core.get_cuda_device_count()):
 core.default_cuda_generator(i)._is_init_py = True
 core.default_cuda_generator(i).manual_seed(seed)

 core.default_cpu_generator()._is_init_py = True
 return core.default_cpu_generator().manual_seed(seed)


def get_cuda_rng_state():
 """

 Get random state of cuda generators.

 Args:
 None

 Returns:
 GeneratorState: object.

 Examples:
 .. code-block:: python

 import paddle
 sts = paddle.get_cuda_rng_state()

 """
 state_list = []
 if core.is_compiled_with_cuda():
 for i in range(core.get_cuda_device_count()):
 state_list.append(core.default_cuda_generator(i).get_state())

 return state_list


def set_cuda_rng_state(state_list):
 """

 Sets generator state for all cuda generators

 Args:
 state_list(list|tuple): The cuda states to set back to cuda generators. state_list is obtained from get_cuda_rng_state().

 Returns:
 None

 Examples:
 .. code-block:: python

 import paddle
 sts = paddle.get_cuda_rng_state()
 paddle.set_cuda_rng_state(sts)

 """
 if core.is_compiled_with_cuda():
 if not len(state_list) == core.get_cuda_device_count():
 raise ValueError(
 "Length of cuda state list shoule be equal to the cuda device count"
 )
 for i in range(core.get_cuda_device_count()):
 core.default_cuda_generator(i).set_state(state_list[i])


def _manual_program_seed(seed):
 """
 Sets global seed for generating random numbers.

 NOTE(zhiqiu): This is the original implemention of seed. Keeps it temporally
 since CUDA generator is not developed, so we need it in the unittest.

 Args:
 seed(int): The random seed to set. It is recommend to set a large int number.

 Returns:
 None
 """
 fluid.default_main_program().random_seed = seed
 fluid.default_startup_program().random_seed = seed
 program = fluid.Program()
 program.global_seed(seed)


def set_random_seed_generator(name, seed):
 core.set_random_seed_generator(name, seed)


def get_random_seed_generator(name):
 return core.get_random_seed_generator(name)