#   Copyright (c) 2019 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.

import numpy as np
import unittest

import paddle.fluid as fluid
import paddle.fluid.core as core
import paddle.fluid.layers as layers
from paddle.fluid.framework import Program, program_guard
from functools import partial


class TestAPISwitchCase(unittest.TestCase):

    def test_return_single_var(self):

        def fn_1():
            return layers.fill_constant(shape=[4, 2], dtype='int32', value=1)

        def fn_2():
            return layers.fill_constant(shape=[4, 2], dtype='int32', value=2)

        def fn_3():
            return layers.fill_constant(shape=[4, 3], dtype='int32', value=3)

        main_program = Program()
        startup_program = Program()
        with program_guard(main_program, startup_program):
            index_1 = layers.fill_constant(shape=[1], dtype='int32', value=1)
            index_2 = layers.fill_constant(shape=[1], dtype='int32', value=2)
            index_5 = layers.fill_constant(shape=[1], dtype='int32', value=5)

            # call fn_1
            out_0 = layers.switch_case(branch_index=index_1,
                                       branch_fns={
                                           1: fn_1,
                                           2: fn_2,
                                           3: fn_3
                                       })

            # call fn_2 : branch_fns={0: fn_1, 1:fn_2, 2:fn_3}
            out_1 = layers.switch_case(branch_index=index_1,
                                       branch_fns=(fn_1, fn_2, fn_3))

            # call default fn_3
            out_2 = layers.switch_case(branch_index=index_5,
                                       branch_fns=((1, fn_1), (2, fn_2)),
                                       default=fn_3)

            # no default, call fn_2
            out_3 = layers.switch_case(branch_index=index_2,
                                       branch_fns=[(1, fn_1), (2, fn_2)])

            # no default, call fn_2 but branch_index is 5
            out_4 = layers.switch_case(branch_index=index_5,
                                       branch_fns=[(1, fn_1), (3, fn_2),
                                                   (2, fn_3)])

            place = fluid.CUDAPlace(
                0) if core.is_compiled_with_cuda() else fluid.CPUPlace()
            exe = fluid.Executor(place)

            res = exe.run(main_program,
                          fetch_list=[out_0, out_1, out_2, out_3, out_4])

            np.testing.assert_allclose(
                res[0],
                1,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 1))
            np.testing.assert_allclose(
                res[1],
                2,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 2))
            np.testing.assert_allclose(
                res[2],
                3,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 3))
            np.testing.assert_allclose(
                res[3],
                2,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 2))
            np.testing.assert_allclose(
                res[4],
                2,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 2))

    def test_return_var_tuple(self):

        def fn_1():
            return layers.fill_constant(shape=[1, 2], dtype='int32',
                                        value=1), layers.fill_constant(
                                            shape=[2, 3],
                                            dtype='float32',
                                            value=2)

        def fn_2():
            return layers.fill_constant(shape=[3, 4], dtype='int32',
                                        value=3), layers.fill_constant(
                                            shape=[4, 5],
                                            dtype='float32',
                                            value=4)

        def fn_3():
            return layers.fill_constant(shape=[5], dtype='int32',
                                        value=5), layers.fill_constant(
                                            shape=[5, 6],
                                            dtype='float32',
                                            value=6)

        main_program = Program()
        startup_program = Program()
        with program_guard(main_program, startup_program):
            index_1 = layers.fill_constant(shape=[1], dtype='int32', value=1)

            out = layers.switch_case(index_1, ((1, fn_1), (2, fn_2)), fn_3)

            place = fluid.CUDAPlace(
                0) if core.is_compiled_with_cuda() else fluid.CPUPlace()
            exe = fluid.Executor(place)
            ret = exe.run(main_program, fetch_list=out)

            np.testing.assert_allclose(np.asarray(ret[0]),
                                       np.full((1, 2), 1, np.int32),
                                       rtol=1e-05)
            np.testing.assert_allclose(np.asarray(ret[1]),
                                       np.full((2, 3), 2, np.float32),
                                       rtol=1e-05)


class TestAPISwitchCase_Nested(unittest.TestCase):

    def test_nested_switch_case(self):

        def fn_1(x=1):
            out = layers.switch_case(branch_index=layers.fill_constant(
                shape=[1], dtype='int32', value=x),
                                     branch_fns={
                                         1:
                                         partial(layers.fill_constant,
                                                 shape=[1],
                                                 dtype='int32',
                                                 value=1),
                                         x:
                                         partial(layers.fill_constant,
                                                 shape=[2],
                                                 dtype='int32',
                                                 value=x)
                                     })
            return out

        def fn_2(x=2):
            out = layers.switch_case(branch_index=layers.fill_constant(
                shape=[1], dtype='int32', value=2),
                                     branch_fns={
                                         1:
                                         partial(layers.fill_constant,
                                                 shape=[4, 3],
                                                 dtype='int32',
                                                 value=1),
                                         2:
                                         partial(fn_1, x=x)
                                     })
            return out

        def fn_3():
            out = layers.switch_case(branch_index=layers.fill_constant(
                shape=[1], dtype='int32', value=3),
                                     branch_fns={
                                         1:
                                         partial(layers.fill_constant,
                                                 shape=[4, 3],
                                                 dtype='int32',
                                                 value=1),
                                         3:
                                         partial(fn_2, x=3)
                                     })
            return out

        main_program = Program()
        startup_program = Program()
        with program_guard(main_program, startup_program):
            index_1 = fluid.data(name="index_1", shape=[1], dtype='uint8')
            index_2 = layers.fill_constant(shape=[1], dtype='int32', value=2)
            index_3 = layers.fill_constant(shape=[1], dtype='int64', value=3)

            out_1 = layers.switch_case(branch_index=index_1,
                                       branch_fns={
                                           1: fn_1,
                                           2: fn_2,
                                           3: fn_3
                                       })
            out_2 = layers.switch_case(branch_index=index_2,
                                       branch_fns={
                                           1: fn_1,
                                           2: fn_2,
                                           3: fn_3
                                       })

            out_3 = layers.switch_case(branch_index=index_3,
                                       branch_fns={
                                           1: fn_1,
                                           2: fn_2,
                                           3: fn_3
                                       })

            place = fluid.CUDAPlace(
                0) if core.is_compiled_with_cuda() else fluid.CPUPlace()
            exe = fluid.Executor(place)

            res = exe.run(main_program,
                          feed={"index_1": np.array([1], dtype="uint8")},
                          fetch_list=[out_1, out_2, out_3])

            np.testing.assert_allclose(
                res[0],
                1,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[0], 1))
            np.testing.assert_allclose(
                res[1],
                2,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[1], 2))
            np.testing.assert_allclose(
                res[2],
                3,
                rtol=1e-05,
                err_msg='result is {} but answer is {}'.format(res[2], 3))


# test TypeError and ValueError of api switch_case
class TestAPISwitchCase_Error(unittest.TestCase):

    def test_error(self):

        def fn_1():
            return layers.fill_constant(shape=[4, 2], dtype='int32', value=1)

        def fn_2():
            return layers.fill_constant(shape=[4, 2], dtype='int32', value=2)

        def fn_3():
            return layers.fill_constant(shape=[4, 3], dtype='int32', value=3)

        main_program = Program()
        startup_program = Program()
        with program_guard(main_program, startup_program):
            key_float32 = layers.fill_constant(shape=[1],
                                               dtype='float32',
                                               value=0.23)
            key_int32 = layers.fill_constant(shape=[1],
                                             dtype='int32',
                                             value=0.23)

            # The type of 'branch_index' in Op(switch_case) must be Variable
            def type_error_branch_index():
                layers.switch_case(branch_index=1,
                                   branch_fns=[(1, fn_1)],
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_branch_index)

            # The data type of 'branch_index' in Op(switch_case) must be int32, int64 or uint8
            def dtype_error_branch_index():
                layers.switch_case(branch_index=key_float32,
                                   branch_fns=[(1, fn_1)],
                                   default=fn_3)

            self.assertRaises(TypeError, dtype_error_branch_index)

            # The type of 'branch_fns' in Op(switch_case) must be list, tuple or dict
            def type_error_branch_fns():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=1,
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_branch_fns)

            # The elements' type of 'branch_fns' in Op(switch_case) must be tuple
            def type_error_index_fn_pair_1():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[1],
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_index_fn_pair_1)

            # The tuple's size of 'branch_fns' in Op(switch_case) must be 2
            def type_error_index_fn_pair_2():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[(1, 2, 3)],
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_index_fn_pair_2)

            # The key's type of 'branch_fns' in Op(switch_case) must be int
            def type_error_key():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[(2.3, 2)],
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_key)

            # The key in 'branch_fns' must be unique
            def value_error_key():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[(2, fn_1), (2, fn_2)],
                                   default=fn_3)

            self.assertRaises(ValueError, value_error_key)

            # The type of function in 'branch_fns' must be callable
            def type_error_fn():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[(1, 1), (2, fn_2)],
                                   default=fn_3)

            self.assertRaises(TypeError, type_error_fn)

            # The default in Op(case) must be callable
            def type_error_default():
                layers.switch_case(branch_index=key_int32,
                                   branch_fns=[(1, fn_1), (2, fn_2)],
                                   default=1)

            self.assertRaises(TypeError, type_error_default)


if __name__ == '__main__':
    unittest.main()
