#   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 contextlib
import unittest

import numpy as np
import seresnext_net
from simple_nets import fc_with_batchnorm, init_data, simple_fc_net
from test_parallel_executor_transformer import (
    DeviceType,
    get_feed_data_reader,
    transformer,
)

import paddle
import paddle.fluid as fluid
import paddle.fluid.core as core


def simple_fc_net_with_accuracy(use_feed):
    img = paddle.static.data(name='image', shape=[-1, 784], dtype='float32')
    label = paddle.static.data(name='label', shape=[-1, 1], dtype='int64')

    hidden = img
    for _ in range(4):
        hidden = paddle.static.nn.fc(
            hidden,
            size=200,
            activation='relu',
            bias_attr=fluid.ParamAttr(
                initializer=fluid.initializer.Constant(value=1.0)
            ),
        )
    prediction = paddle.static.nn.fc(hidden, size=10, activation='softmax')
    loss = paddle.nn.functional.cross_entropy(
        input=prediction, label=label, reduction='none', use_softmax=False
    )
    loss = paddle.mean(loss)
    accuracy_out = paddle.static.accuracy(input=prediction, label=label, k=5)
    return loss


def cond_net(use_feed=None):
    x = paddle.static.data(name="x", shape=[-1, 4], dtype='float32')
    label = paddle.static.data('label', shape=[-1, 1], dtype='int64')
    prediction = paddle.static.nn.fc(x, size=1, activation=None)

    def loss1(pred, label):
        x = paddle.static.data(name="x", shape=[-1, 4], dtype='float32')
        loss = paddle.nn.functional.cross_entropy(
            input=pred, label=label, reduction='none', use_softmax=False
        )
        avg_loss = paddle.mean(loss, name='mean_cross_entropy_loss')
        return avg_loss

    def loss2(pred, label):
        loss = paddle.nn.functional.softmax_with_cross_entropy(
            logits=pred, label=label
        )
        avg_loss = paddle.mean(loss, name='mean_softmax_loss')
        return avg_loss

    two = fluid.layers.fill_constant([1], 'int32', 2)
    pred = two == 0
    avg_loss = paddle.static.nn.case(
        [(pred, lambda: loss1(prediction, label))],
        lambda: loss2(prediction, label),
    )
    return avg_loss


def optimization_in_cond_net(with_optimize=False):
    x = paddle.static.data(name="x", shape=[-1, 4], dtype='float32')
    label = paddle.static.data('label', shape=[-1, 1], dtype='int64')
    prediction = paddle.static.nn.fc(x, size=1, activation=None)

    def loss1(opt, pred, label, with_optimize):
        x = paddle.static.data(name="x", shape=[-1, 4], dtype='float32')
        loss = paddle.nn.functional.cross_entropy(
            input=pred, label=label, reduction='none', use_softmax=False
        )
        avg_loss = paddle.mean(loss, name='mean_cross_entropy_loss')
        if with_optimize:
            opt.minimize(avg_loss)
        return avg_loss

    def loss2(opt, pred, label, with_optimize):
        loss = paddle.nn.functional.softmax_with_cross_entropy(
            logits=pred, label=label
        )
        avg_loss = paddle.mean(loss, name='mean_softmax_loss')
        if with_optimize:
            opt.minimize(avg_loss)
        return avg_loss

    sgd = fluid.optimizer.SGD(learning_rate=0.1)
    two = fluid.layers.fill_constant([1], 'int32', 2)
    pred = two == 0
    avg_loss = paddle.static.nn.case(
        [(pred, lambda: loss1(sgd, prediction, label, with_optimize))],
        lambda: loss2(sgd, prediction, label, with_optimize),
    )
    return avg_loss


class TestProgramPruneBackward(unittest.TestCase):
    def program_compare(self, program_a, program_b):
        assert isinstance(
            program_a, fluid.framework.Program
        ), "The first argument should be fluid.framework.Program."
        assert isinstance(
            program_b, fluid.framework.Program
        ), "The second argument should be fluid.framework Program."

        self.assertEqual(len(program_a.blocks), len(program_b.blocks))
        for idx in range(len(program_a.blocks)):
            block_a = program_a.blocks[idx]
            block_b = program_b.blocks[idx]
            self.assertEqual(len(block_a.ops), len(block_b.ops))
            self.assertEqual(len(block_a.vars), len(block_b.vars))
            for op_idx in range(len(block_a.ops)):
                self.assertEqual(
                    block_a.ops[op_idx].type, block_b.ops[op_idx].type
                )
            for var_key in list(block_a.vars.keys()):
                self.assertTrue(block_b.has_var(var_key))

    def check_prune_correctness(self, method, feed_dict, optimizer):
        loss = method(use_feed=False)

        main_program = fluid.default_main_program()
        test_prog_orig = main_program.clone(for_test=True)
        optimizer().minimize(loss)
        test_prog_prune = main_program.clone(for_test=True)

        self.program_compare(test_prog_orig, test_prog_prune)

        places = [core.CPUPlace()]
        if core.is_compiled_with_cuda():
            places.append(core.CUDAPlace(0))

        for place in places:
            exe = fluid.Executor(place)
            exe.run(fluid.default_startup_program())

            (loss_data_prune,) = exe.run(
                test_prog_prune, feed=feed_dict, fetch_list=[loss.name]
            )
            (loss_data_orig,) = exe.run(
                test_prog_orig, feed=feed_dict, fetch_list=[loss.name]
            )
            self.assertEqual(loss_data_orig, loss_data_prune)

    def test_simple_fc_net(self):
        def optimizer():
            optimizer = fluid.optimizer.SGD(
                learning_rate=0.001,
                regularization=fluid.regularizer.L2Decay(1e-4),
            )
            return optimizer

        with self.program_scope_guard():
            img, label = init_data()
            self.check_prune_correctness(
                method=simple_fc_net,
                feed_dict={"image": img, "label": label},
                optimizer=optimizer,
            )

    def test_simple_fc_net_with_accuracy(self):
        def optimizer():
            optimizer = fluid.optimizer.SGD(
                learning_rate=0.001,
                regularization=fluid.regularizer.L2Decay(1e-4),
            )
            return optimizer

        with self.program_scope_guard():
            img, label = init_data()
            self.check_prune_correctness(
                method=simple_fc_net_with_accuracy,
                feed_dict={"image": img, "label": label},
                optimizer=optimizer,
            )

    def test_batchnorm_fc(self):
        def optimizer():
            optimizer = fluid.optimizer.SGD(
                learning_rate=0.001,
                regularization=fluid.regularizer.L2Decay(1e-4),
            )
            return optimizer

        with self.program_scope_guard():
            img, label = init_data()
            self.check_prune_correctness(
                method=fc_with_batchnorm,
                feed_dict={"image": img, "label": label},
                optimizer=optimizer,
            )

    def test_seresnet(self):
        with self.program_scope_guard():
            self.check_prune_correctness(
                method=seresnext_net.model,
                feed_dict=seresnext_net.feed_dict(use_device=DeviceType.CPU),
                optimizer=seresnext_net.optimizer,
            )

    def test_transformer(self):
        def optimizer():
            optimizer = fluid.optimizer.Adam(
                learning_rate=0.001,
                regularization=fluid.regularizer.L2Decay(1e-4),
            )
            return optimizer

        with self.program_scope_guard():
            # the program argument is used to distinguish Program and CompiledProgram
            feed_dict = get_feed_data_reader().get_next(
                fluid.Executor(core.CPUPlace()), fluid.default_main_program()
            )
            self.check_prune_correctness(
                method=transformer, feed_dict=feed_dict, optimizer=optimizer
            )

    def test_cond(self):
        def optimizer():
            optimizer = fluid.optimizer.SGD(learning_rate=0.01)
            return optimizer

        with self.program_scope_guard():
            x_in = np.random.random(size=(10, 4)).astype('float32')
            label_in = np.random.randint(1, size=(10, 1)).astype('int64')
            feed_dict = {'x': x_in, 'label': label_in}
            self.check_prune_correctness(
                method=cond_net, feed_dict=feed_dict, optimizer=optimizer
            )

    def test_optimization_in_cond(self):
        x_in = np.random.random(size=(10, 4)).astype('float32')
        label_in = np.random.randint(1, size=(10, 1)).astype('int64')
        feed_dict = {'x': x_in, 'label': label_in}
        with self.program_scope_guard():
            loss = optimization_in_cond_net(False)
            main_program = fluid.default_main_program()
            test_prog_orig = main_program.clone(for_test=True)
            place = core.CPUPlace()
            exe = fluid.Executor(place)
            exe.run(fluid.default_startup_program())
            (loss_data_orig,) = exe.run(
                test_prog_orig, feed=feed_dict, fetch_list=[loss.name]
            )

        with self.program_scope_guard():
            loss = optimization_in_cond_net(True)
            main_program = fluid.default_main_program()
            test_prog_prune = main_program.clone(for_test=True)

            place = core.CPUPlace()
            exe = fluid.Executor(place)
            exe.run(fluid.default_startup_program())
            (loss_data_prune,) = exe.run(
                test_prog_prune, feed=feed_dict, fetch_list=[loss.name]
            )

        self.program_compare(test_prog_orig, test_prog_prune)
        self.assertEqual(loss_data_orig, loss_data_prune)

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


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