#   Copyright (c) 2018 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 contextlib
import random
import unittest
from functools import partial

import numpy as np

import paddle
from paddle import fluid
from paddle.fluid import core


def bow_net(
    data,
    label,
    dict_dim,
    is_sparse=False,
    emb_dim=8,
    hid_dim=8,
    hid_dim2=6,
    class_dim=2,
):
    """
    BOW net
    This model is from https://github.com/PaddlePaddle/models:
    fluid/PaddleNLP/text_classification/nets.py
    """
    emb = paddle.static.nn.embedding(
        input=data, is_sparse=is_sparse, size=[dict_dim, emb_dim]
    )
    bow = paddle.static.nn.sequence_lod.sequence_pool(
        input=emb, pool_type='sum'
    )
    bow_tanh = paddle.tanh(bow)
    fc_1 = paddle.static.nn.fc(x=bow_tanh, size=hid_dim, activation="tanh")
    fc_2 = paddle.static.nn.fc(x=fc_1, size=hid_dim2, activation="tanh")
    prediction = paddle.static.nn.fc(
        x=[fc_2], size=class_dim, activation="softmax"
    )
    cost = paddle.nn.functional.cross_entropy(
        input=prediction, label=label, reduction='none', use_softmax=False
    )
    avg_cost = paddle.mean(x=cost)

    return avg_cost


class TestRegularizer(unittest.TestCase):
    def setUp(self):
        self.word_len = 1500
        self.train_data = [
            [(random.sample(range(1000), 10), [0])] for _ in range(2)
        ]

    def get_places(self):
        places = [core.CPUPlace()]
        if core.is_compiled_with_cuda():
            places.append(core.CUDAPlace(0))
        return places

    @contextlib.contextmanager
    def scope_prog_guard(self, main_prog, startup_prog):
        scope = fluid.core.Scope()
        with fluid.unique_name.guard():
            with fluid.scope_guard(scope):
                with fluid.program_guard(main_prog, startup_prog):
                    yield

    def run_program(self, place, feed_list):
        exe = fluid.Executor(place)
        feeder = fluid.DataFeeder(feed_list=feed_list, place=place)
        exe.run(fluid.default_startup_program())

        main_prog = fluid.default_main_program()
        param_list = [var.name for var in main_prog.block(0).all_parameters()]

        param_sum = []
        for data in self.train_data:
            out = exe.run(
                main_prog, feed=feeder.feed(data), fetch_list=param_list
            )
            p_sum = 0
            for v in out:
                p_sum += np.sum(np.abs(v))
            param_sum.append(p_sum)
        return param_sum

    def check_l2decay_regularizer(self, place, model):
        paddle.seed(1)
        paddle.framework.random._manual_program_seed(1)
        main_prog = fluid.framework.Program()
        startup_prog = fluid.framework.Program()
        with self.scope_prog_guard(
            main_prog=main_prog, startup_prog=startup_prog
        ):
            data = paddle.static.data(
                name="words", shape=[-1, 1], dtype="int64", lod_level=1
            )
            label = paddle.static.data(
                name="label", shape=[-1, 1], dtype="int64"
            )

            avg_cost = model(data, label, self.word_len)

            optimizer = paddle.optimizer.Adagrad(
                learning_rate=0.1,
                weight_decay=paddle.regularizer.L2Decay(1.0),
            )
            optimizer.minimize(avg_cost)
            param_sum = self.run_program(place, [data, label])
        return param_sum

    def check_l2decay(self, place, model):
        paddle.seed(1)
        paddle.framework.random._manual_program_seed(1)
        main_prog = fluid.framework.Program()
        startup_prog = fluid.framework.Program()

        with self.scope_prog_guard(
            main_prog=main_prog, startup_prog=startup_prog
        ):
            data = paddle.static.data(
                name="words", shape=[-1, 1], dtype="int64", lod_level=1
            )
            label = paddle.static.data(
                name="label", shape=[-1, 1], dtype="int64"
            )

            avg_cost_l2 = model(data, label, self.word_len)

            param_list = fluid.default_main_program().block(0).all_parameters()
            para_sum = []
            for para in param_list:
                para_mul = paddle.square(x=para)
                para_sum.append(paddle.sum(para_mul))
            avg_cost_l2 += paddle.add_n(para_sum) * 0.5

            optimizer = paddle.optimizer.Adagrad(learning_rate=0.1)
            optimizer.minimize(avg_cost_l2)
            param_sum = self.run_program(place, [data, label])
        return param_sum

    def test_l2(self):
        paddle.enable_static()
        for place in self.get_places():
            dense_sparse_p_sum = []
            for sparse in [True, False]:
                model = partial(bow_net, is_sparse=sparse)
                framework_l2 = self.check_l2decay_regularizer(place, model)
                l2 = self.check_l2decay(place, model)
                assert len(l2) == len(framework_l2)
                for i in range(len(l2)):
                    assert np.isclose(a=framework_l2[i], b=l2[i], rtol=5e-5)
                dense_sparse_p_sum.append(framework_l2)

            assert len(dense_sparse_p_sum[0]) == len(dense_sparse_p_sum[1])
            for i in range(len(dense_sparse_p_sum[0])):
                assert np.isclose(
                    a=dense_sparse_p_sum[0][i],
                    b=dense_sparse_p_sum[1][i],
                    rtol=5e-5,
                )

    def test_repeated_regularization(self):
        paddle.enable_static()
        l1 = paddle.regularizer.L1Decay(0.1)
        l2 = paddle.regularizer.L2Decay(0.01)
        fc_param_attr = paddle.ParamAttr(
            regularizer=paddle.regularizer.L1Decay()
        )
        with fluid.program_guard(fluid.Program(), fluid.Program()):
            x = paddle.uniform([2, 2, 3])
            out = paddle.static.nn.fc(x, 5, weight_attr=fc_param_attr)
            loss = paddle.sum(out)
            sgd = paddle.optimizer.SGD(learning_rate=0.1, weight_decay=l2)
            sgd.minimize(loss)
        with fluid.dygraph.guard():
            input = fluid.dygraph.to_variable(
                np.random.randn(3, 2).astype('float32')
            )
            paddle.seed(1)
            paddle.framework.random._manual_program_seed(1)

            linear1 = paddle.nn.Linear(
                2, 2, weight_attr=fc_param_attr, bias_attr=fc_param_attr
            )
            linear2 = paddle.nn.Linear(
                2, 2, weight_attr=fc_param_attr, bias_attr=fc_param_attr
            )

            loss1 = linear1(input)
            loss1.backward()
            # set l2 regularizer in optimizer, but l1 in fluid.ParamAttr

            paddle.optimizer.SGD(
                parameters=linear1.parameters(),
                learning_rate=1e-2,
                weight_decay=l2,
            ).minimize(loss1)
            # only set l1 in fluid.ParamAttr
            loss2 = linear2(input)
            loss2.backward()
            paddle.optimizer.SGD(
                parameters=linear2.parameters(), learning_rate=1e-2
            ).minimize(loss2)
            # they should both be applied by l1, and keep the same
            np.testing.assert_allclose(
                linear1.weight.numpy(),
                linear2.weight.numpy(),
                rtol=1e-05,
                err_msg='weight should use the regularization in fluid.ParamAttr!',
            )
            np.testing.assert_allclose(
                linear1.bias.numpy(),
                linear2.bias.numpy(),
                rtol=1e-05,
                err_msg='bias should use the regularization in fluid.ParamAttr!',
            )


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