#   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 functions to get tensor attributes

import numpy as np

import paddle
from paddle import _C_ops, _legacy_C_ops

from ..fluid.data_feeder import check_type, check_variable_and_dtype
from ..fluid.framework import _in_legacy_dygraph, in_dygraph_mode
from ..framework import LayerHelper, core
from ..static import Variable
from .creation import _complex_to_real_dtype, assign

__all__ = []


def rank(input):
    """

    Returns the number of dimensions for a tensor, which is a 0-D int32 Tensor.

    Args:
        input (Tensor): The input Tensor with shape of :math:`[N_1, N_2, ..., N_k]`, the data type is arbitrary.

    Returns:
        Tensor, the output data type is int32.: The 0-D tensor with the dimensions of the input Tensor.

    Examples:
        .. code-block:: python

            import paddle

            input = paddle.rand((3, 100, 100))
            rank = paddle.rank(input)
            print(rank)
            # 3
    """
    check_type(input, 'input', (Variable), 'input')
    ndims = len(input.shape)
    out = assign(np.array(ndims, 'int32'))

    return out


def shape(input):
    """
    Get the shape of the input.

    .. code-block:: text

        Case1:
            Given N-D Tensor:
                input = [ [1, 2, 3, 4], [5, 6, 7, 8] ]

            Then:
                input.shape = [2, 4]

        Case2:
            Given SelectedRows:
                input.rows = [0, 4, 19]
                input.height = 20
                input.value = [ [1, 2], [3, 4], [5, 6] ]  # inner tensor
            Then:
                input.shape = [3, 2]

    Args:
        input (Variable): The input can be N-D Tensor or SelectedRows with data type bool, float16, float32, float64, int32, int64.
                          If input variable is type of SelectedRows, returns the shape of it's inner tensor.

    Returns:
        Variable (Tensor): The shape of the input variable.

    Examples:
        .. code-block:: python

            import paddle.fluid as fluid
            import numpy as np
            import paddle
            paddle.enable_static()

            inputs = fluid.data(name="x", shape=[3, 100, 100], dtype="float32")
            output = paddle.shape(inputs)

            exe = fluid.Executor(fluid.CPUPlace())
            exe.run(fluid.default_startup_program())

            img = np.ones((3, 100, 100)).astype(np.float32)

            res = exe.run(fluid.default_main_program(), feed={'x':img}, fetch_list=[output])
            print(res) # [array([  3, 100, 100], dtype=int32)]
    """
    if in_dygraph_mode():
        out = _C_ops.shape(input)
        out.stop_gradient = True
        return out
    if _in_legacy_dygraph():
        out = _legacy_C_ops.shape(input)
        out.stop_gradient = True
        return out

    check_variable_and_dtype(
        input,
        'input',
        [
            'bool',
            'float16',
            'float32',
            'float64',
            'int32',
            'int64',
            'complex64',
            'complex128',
        ],
        'shape',
    )
    helper = LayerHelper('shape', **locals())
    out = helper.create_variable_for_type_inference(dtype='int32')
    helper.append_op(
        type='shape',
        inputs={'Input': input},
        outputs={'Out': out},
        stop_gradient=True,
    )

    return out


def is_complex(x):
    """Return whether x is a tensor of complex data type(complex64 or complex128).

    Args:
        x (Tensor): The input tensor.

    Returns:
        bool: True if the data type of the input is complex data type, otherwise false.

    Examples:
        .. code-block:: python

            import paddle

            x = paddle.to_tensor([1 + 2j, 3 + 4j])
            print(paddle.is_complex(x))
            # True

            x = paddle.to_tensor([1.1, 1.2])
            print(paddle.is_complex(x))
            # False

            x = paddle.to_tensor([1, 2, 3])
            print(paddle.is_complex(x))
            # False
    """
    if not isinstance(x, (paddle.Tensor, paddle.static.Variable)):
        raise TypeError(
            "Expected Tensor, but received type of x: {}".format(type(x))
        )
    dtype = x.dtype
    is_complex_dtype = (
        dtype == core.VarDesc.VarType.COMPLEX64
        or dtype == core.VarDesc.VarType.COMPLEX128
    )
    return is_complex_dtype


def is_floating_point(x):
    """
    Returns whether the dtype of `x` is one of paddle.float64, paddle.float32, paddle.float16, and paddle.bfloat16.

    Args:
        x (Tensor): The input tensor.

    Returns:
        bool: True if the dtype of `x` is floating type, otherwise false.

    Examples:
        .. code-block:: python

            import paddle

            x = paddle.arange(1., 5., dtype='float32')
            y = paddle.arange(1, 5, dtype='int32')
            print(paddle.is_floating_point(x))
            # True
            print(paddle.is_floating_point(y))
            # False
    """
    if not isinstance(x, (paddle.Tensor, paddle.static.Variable)):
        raise TypeError(
            "Expected Tensor, but received type of x: {}".format(type(x))
        )
    dtype = x.dtype
    is_fp_dtype = (
        dtype == core.VarDesc.VarType.FP32
        or dtype == core.VarDesc.VarType.FP64
        or dtype == core.VarDesc.VarType.FP16
        or dtype == core.VarDesc.VarType.BF16
    )
    return is_fp_dtype


def is_integer(x):
    """Return whether x is a tensor of integeral data type.

    Args:
        x (Tensor): The input tensor.

    Returns:
        bool: True if the data type of the input is integer data type, otherwise false.

    Examples:
        .. code-block:: python

            import paddle

            x = paddle.to_tensor([1 + 2j, 3 + 4j])
            print(paddle.is_integer(x))
            # False

            x = paddle.to_tensor([1.1, 1.2])
            print(paddle.is_integer(x))
            # False

            x = paddle.to_tensor([1, 2, 3])
            print(paddle.is_integer(x))
            # True
    """
    if not isinstance(x, (paddle.Tensor, paddle.static.Variable)):
        raise TypeError(
            "Expected Tensor, but received type of x: {}".format(type(x))
        )
    dtype = x.dtype
    is_int_dtype = (
        dtype == core.VarDesc.VarType.UINT8
        or dtype == core.VarDesc.VarType.INT8
        or dtype == core.VarDesc.VarType.INT16
        or dtype == core.VarDesc.VarType.INT32
        or dtype == core.VarDesc.VarType.INT64
    )
    return is_int_dtype


def real(x, name=None):
    """
    Returns a new Tensor containing real values of the input Tensor.

    Args:
        x (Tensor): the input Tensor, its data type could be complex64 or complex128.
        name (str, optional): The default value is None. Normally there is no need for
            user to set this property. For more information, please refer to :ref:`api_guide_Name` .

    Returns:
        Tensor: a Tensor containing real values of the input Tensor.

    Examples:
        .. code-block:: python

            import paddle

            x = paddle.to_tensor(
                [[1 + 6j, 2 + 5j, 3 + 4j], [4 + 3j, 5 + 2j, 6 + 1j]])
            # Tensor(shape=[2, 3], dtype=complex64, place=CUDAPlace(0), stop_gradient=True,
            #        [[(1+6j), (2+5j), (3+4j)],
            #         [(4+3j), (5+2j), (6+1j)]])

            real_res = paddle.real(x)
            # Tensor(shape=[2, 3], dtype=float32, place=CUDAPlace(0), stop_gradient=True,
            #        [[1., 2., 3.],
            #         [4., 5., 6.]])

            real_t = x.real()
            # Tensor(shape=[2, 3], dtype=float32, place=CUDAPlace(0), stop_gradient=True,
            #        [[1., 2., 3.],
            #         [4., 5., 6.]])
    """
    if in_dygraph_mode():
        return _C_ops.real(x)
    if _in_legacy_dygraph():
        return _legacy_C_ops.real(x)

    check_variable_and_dtype(x, 'x', ['complex64', 'complex128'], 'real')
    helper = LayerHelper('real', **locals())
    out = helper.create_variable_for_type_inference(
        dtype=_complex_to_real_dtype(helper.input_dtype())
    )
    helper.append_op(type='real', inputs={'X': x}, outputs={'Out': out})
    return out


def imag(x, name=None):
    """
    Returns a new tensor containing imaginary values of input tensor.

    Args:
        x (Tensor): the input tensor, its data type could be complex64 or complex128.
        name (str, optional): The default value is None. Normally there is no need for
            user to set this property. For more information, please refer to :ref:`api_guide_Name` .

    Returns:
        Tensor: a tensor containing imaginary values of the input tensor.

    Examples:
        .. code-block:: python

            import paddle

            x = paddle.to_tensor(
                [[1 + 6j, 2 + 5j, 3 + 4j], [4 + 3j, 5 + 2j, 6 + 1j]])
            # Tensor(shape=[2, 3], dtype=complex64, place=CUDAPlace(0), stop_gradient=True,
            #        [[(1+6j), (2+5j), (3+4j)],
            #         [(4+3j), (5+2j), (6+1j)]])

            imag_res = paddle.imag(x)
            # Tensor(shape=[2, 3], dtype=float32, place=CUDAPlace(0), stop_gradient=True,
            #        [[6., 5., 4.],
            #         [3., 2., 1.]])

            imag_t = x.imag()
            # Tensor(shape=[2, 3], dtype=float32, place=CUDAPlace(0), stop_gradient=True,
            #        [[6., 5., 4.],
            #         [3., 2., 1.]])
    """
    if in_dygraph_mode():
        return _C_ops.imag(x)
    if _in_legacy_dygraph():
        return _legacy_C_ops.imag(x)

    check_variable_and_dtype(x, 'x', ['complex64', 'complex128'], 'imag')
    helper = LayerHelper('imag', **locals())
    out = helper.create_variable_for_type_inference(
        dtype=_complex_to_real_dtype(helper.input_dtype())
    )
    helper.append_op(type='imag', inputs={'X': x}, outputs={'Out': out})
    return out