# Copyright (c) 2022 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 paddle
import numpy as np
import unittest


def call_TripletMarginLoss_layer(
    input,
    positive,
    negative,
    p=2,
    margin=0.3,
    swap=False,
    eps=1e-6,
    reduction='mean',
):
    triplet_margin_loss = paddle.nn.TripletMarginLoss(p=p,
                                                      epsilon=eps,
                                                      margin=margin,
                                                      swap=swap,
                                                      reduction=reduction)
    res = triplet_margin_loss(
        input=input,
        positive=positive,
        negative=negative,
    )
    return res


def call_TripletMarginLoss_functional(
    input,
    positive,
    negative,
    p=2,
    margin=0.3,
    swap=False,
    eps=1e-6,
    reduction='mean',
):
    res = paddle.nn.functional.triplet_margin_loss(input=input,
                                                   positive=positive,
                                                   negative=negative,
                                                   p=p,
                                                   epsilon=eps,
                                                   margin=margin,
                                                   swap=swap,
                                                   reduction=reduction)
    return res


def test_static(place,
                input_np,
                positive_np,
                negative_np,
                p=2,
                margin=0.3,
                swap=False,
                eps=1e-6,
                reduction='mean',
                functional=False):
    prog = paddle.static.Program()
    startup_prog = paddle.static.Program()
    with paddle.static.program_guard(prog, startup_prog):
        input = paddle.static.data(name='input',
                                   shape=input_np.shape,
                                   dtype='float64')
        positive = paddle.static.data(name='positive',
                                      shape=positive_np.shape,
                                      dtype='float64')
        negative = paddle.static.data(name='negative',
                                      shape=negative_np.shape,
                                      dtype='float64')
        feed_dict = {
            "input": input_np,
            "positive": positive_np,
            "negative": negative_np
        }

        if functional:
            res = call_TripletMarginLoss_functional(input=input,
                                                    positive=positive,
                                                    negative=negative,
                                                    p=p,
                                                    eps=eps,
                                                    margin=margin,
                                                    swap=swap,
                                                    reduction=reduction)
        else:
            res = call_TripletMarginLoss_layer(input=input,
                                               positive=positive,
                                               negative=negative,
                                               p=p,
                                               eps=eps,
                                               margin=margin,
                                               swap=swap,
                                               reduction=reduction)

        exe = paddle.static.Executor(place)
        static_result = exe.run(prog, feed=feed_dict, fetch_list=[res])
    return static_result


def test_dygraph(place,
                 input,
                 positive,
                 negative,
                 p=2,
                 margin=0.3,
                 swap=False,
                 eps=1e-6,
                 reduction='mean',
                 functional=False):
    paddle.disable_static()
    input = paddle.to_tensor(input)
    positive = paddle.to_tensor(positive)
    negative = paddle.to_tensor(negative)

    if functional:
        dy_res = call_TripletMarginLoss_functional(input=input,
                                                   positive=positive,
                                                   negative=negative,
                                                   p=p,
                                                   eps=eps,
                                                   margin=margin,
                                                   swap=swap,
                                                   reduction=reduction)
    else:
        dy_res = call_TripletMarginLoss_layer(input=input,
                                              positive=positive,
                                              negative=negative,
                                              p=p,
                                              eps=eps,
                                              margin=margin,
                                              swap=swap,
                                              reduction=reduction)
    dy_result = dy_res.numpy()
    paddle.enable_static()
    return dy_result


def calc_triplet_margin_loss(
    input,
    positive,
    negative,
    p=2,
    margin=0.3,
    swap=False,
    reduction='mean',
):
    positive_dist = np.linalg.norm((input - positive), p, axis=1)
    negative_dist = np.linalg.norm((input - negative), p, axis=1)

    if swap:
        swap_dist = np.linalg.norm((positive - negative), p, axis=1)
        negative_dist = np.minimum(negative_dist, swap_dist)
    expected = np.maximum(positive_dist - negative_dist + margin, 0)

    if reduction == 'mean':
        expected = np.mean(expected)
    elif reduction == 'sum':
        expected = np.sum(expected)
    else:
        expected = expected

    return expected


class TestTripletMarginLoss(unittest.TestCase):

    def test_TripletMarginLoss(self):
        shape = (2, 2)
        input = np.random.uniform(0.1, 0.8, size=shape).astype(np.float64)
        positive = np.random.uniform(0, 2, size=shape).astype(np.float64)
        negative = np.random.uniform(0, 2, size=shape).astype(np.float64)

        places = [paddle.CPUPlace()]
        if paddle.device.is_compiled_with_cuda():
            places.append(paddle.CUDAPlace(0))
        reductions = ['sum', 'mean', 'none']
        for place in places:
            for reduction in reductions:
                expected = calc_triplet_margin_loss(input=input,
                                                    positive=positive,
                                                    negative=negative,
                                                    reduction=reduction)

                dy_result = test_dygraph(
                    place=place,
                    input=input,
                    positive=positive,
                    negative=negative,
                    reduction=reduction,
                )

                static_result = test_static(
                    place=place,
                    input_np=input,
                    positive_np=positive,
                    negative_np=negative,
                    reduction=reduction,
                )
                self.assertTrue(np.allclose(static_result, expected))
                self.assertTrue(np.allclose(static_result, dy_result))
                self.assertTrue(np.allclose(dy_result, expected))
                static_functional = test_static(place=place,
                                                input_np=input,
                                                positive_np=positive,
                                                negative_np=negative,
                                                reduction=reduction,
                                                functional=True)
                dy_functional = test_dygraph(place=place,
                                             input=input,
                                             positive=positive,
                                             negative=negative,
                                             reduction=reduction,
                                             functional=True)
                self.assertTrue(np.allclose(static_functional, expected))
                self.assertTrue(np.allclose(static_functional, dy_functional))
                self.assertTrue(np.allclose(dy_functional, expected))

    def test_TripletMarginLoss_error(self):
        paddle.disable_static()
        self.assertRaises(ValueError,
                          paddle.nn.loss.TripletMarginLoss,
                          reduction="unsupport reduction")
        input = paddle.to_tensor([[0.1, 0.3]], dtype='float32')
        positive = paddle.to_tensor([[0.0, 1.0]], dtype='float32')
        negative = paddle.to_tensor([[0.2, 0.1]], dtype='float32')
        self.assertRaises(ValueError,
                          paddle.nn.functional.triplet_margin_loss,
                          input=input,
                          positive=positive,
                          negative=negative,
                          reduction="unsupport reduction")
        paddle.enable_static()

    def test_TripletMarginLoss_dimension(self):
        paddle.disable_static()

        input = paddle.to_tensor([[0.1, 0.3], [1, 2]], dtype='float32')
        positive = paddle.to_tensor([[0.0, 1.0]], dtype='float32')
        negative = paddle.to_tensor([[0.2, 0.1]], dtype='float32')
        self.assertRaises(
            ValueError,
            paddle.nn.functional.triplet_margin_loss,
            input=input,
            positive=positive,
            negative=negative,
        )
        TMLoss = paddle.nn.loss.TripletMarginLoss()
        self.assertRaises(
            ValueError,
            TMLoss,
            input=input,
            positive=positive,
            negative=negative,
        )
        paddle.enable_static()

    def test_TripletMarginLoss_swap(self):
        reduction = 'mean'
        place = paddle.CPUPlace()
        shape = (2, 2)
        input = np.random.uniform(0.1, 0.8, size=shape).astype(np.float64)
        positive = np.random.uniform(0, 2, size=shape).astype(np.float64)
        negative = np.random.uniform(0, 2, size=shape).astype(np.float64)
        expected = calc_triplet_margin_loss(input=input,
                                            swap=True,
                                            positive=positive,
                                            negative=negative,
                                            reduction=reduction)

        dy_result = test_dygraph(
            place=place,
            swap=True,
            input=input,
            positive=positive,
            negative=negative,
            reduction=reduction,
        )

        static_result = test_static(
            place=place,
            swap=True,
            input_np=input,
            positive_np=positive,
            negative_np=negative,
            reduction=reduction,
        )
        self.assertTrue(np.allclose(static_result, expected))
        self.assertTrue(np.allclose(static_result, dy_result))
        self.assertTrue(np.allclose(dy_result, expected))
        static_functional = test_static(place=place,
                                        swap=True,
                                        input_np=input,
                                        positive_np=positive,
                                        negative_np=negative,
                                        reduction=reduction,
                                        functional=True)
        dy_functional = test_dygraph(place=place,
                                     swap=True,
                                     input=input,
                                     positive=positive,
                                     negative=negative,
                                     reduction=reduction,
                                     functional=True)
        self.assertTrue(np.allclose(static_functional, expected))
        self.assertTrue(np.allclose(static_functional, dy_functional))
        self.assertTrue(np.allclose(dy_functional, expected))

    def test_TripletMarginLoss_margin(self):
        paddle.disable_static()

        input = paddle.to_tensor([[0.1, 0.3]], dtype='float32')
        positive = paddle.to_tensor([[0.0, 1.0]], dtype='float32')
        negative = paddle.to_tensor([[0.2, 0.1]], dtype='float32')
        margin = -0.5
        self.assertRaises(
            ValueError,
            paddle.nn.functional.triplet_margin_loss,
            margin=margin,
            input=input,
            positive=positive,
            negative=negative,
        )
        paddle.enable_static()

    def test_TripletMarginLoss_p(self):
        p = 3
        shape = (2, 2)
        reduction = 'mean'
        place = paddle.CPUPlace()
        input = np.random.uniform(0.1, 0.8, size=shape).astype(np.float64)
        positive = np.random.uniform(0, 2, size=shape).astype(np.float64)
        negative = np.random.uniform(0, 2, size=shape).astype(np.float64)
        expected = calc_triplet_margin_loss(input=input,
                                            p=p,
                                            positive=positive,
                                            negative=negative,
                                            reduction=reduction)

        dy_result = test_dygraph(
            place=place,
            p=p,
            input=input,
            positive=positive,
            negative=negative,
            reduction=reduction,
        )

        static_result = test_static(
            place=place,
            p=p,
            input_np=input,
            positive_np=positive,
            negative_np=negative,
            reduction=reduction,
        )
        self.assertTrue(np.allclose(static_result, expected))
        self.assertTrue(np.allclose(static_result, dy_result))
        self.assertTrue(np.allclose(dy_result, expected))
        static_functional = test_static(place=place,
                                        p=p,
                                        input_np=input,
                                        positive_np=positive,
                                        negative_np=negative,
                                        reduction=reduction,
                                        functional=True)
        dy_functional = test_dygraph(place=place,
                                     p=p,
                                     input=input,
                                     positive=positive,
                                     negative=negative,
                                     reduction=reduction,
                                     functional=True)
        self.assertTrue(np.allclose(static_functional, expected))
        self.assertTrue(np.allclose(static_functional, dy_functional))
        self.assertTrue(np.allclose(dy_functional, expected))


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