#   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 paddle.fluid.core as core
import math
import os
import sys
import unittest

import numpy

import paddle
import paddle.fluid as fluid

paddle.enable_static()

BATCH_SIZE = 64


def loss_net(hidden, label):
    prediction = fluid.layers.fc(input=hidden, size=10, act='softmax')
    loss = fluid.layers.cross_entropy(input=prediction, label=label)
    avg_loss = paddle.mean(loss)
    acc = fluid.layers.accuracy(input=prediction, label=label)
    return prediction, avg_loss, acc


def mlp(img, label):
    hidden = fluid.layers.fc(input=img, size=200, act='tanh')
    hidden = fluid.layers.fc(input=hidden, size=200, act='tanh')
    return loss_net(hidden, label)


def conv_net(img, label):
    conv_pool_1 = fluid.nets.simple_img_conv_pool(input=img,
                                                  filter_size=5,
                                                  num_filters=20,
                                                  pool_size=2,
                                                  pool_stride=2,
                                                  act="relu")
    conv_pool_1 = fluid.layers.batch_norm(conv_pool_1)
    conv_pool_2 = fluid.nets.simple_img_conv_pool(input=conv_pool_1,
                                                  filter_size=5,
                                                  num_filters=50,
                                                  pool_size=2,
                                                  pool_stride=2,
                                                  act="relu")
    return loss_net(conv_pool_2, label)


def train(nn_type,
          use_cuda,
          parallel,
          save_dirname=None,
          save_full_dirname=None,
          model_filename=None,
          params_filename=None,
          is_local=True):
    if use_cuda and not fluid.core.is_compiled_with_cuda():
        return
    img = fluid.layers.data(name='img', shape=[1, 28, 28], dtype='float32')
    label = fluid.layers.data(name='label', shape=[1], dtype='int64')

    if nn_type == 'mlp':
        net_conf = mlp
    else:
        net_conf = conv_net

    if parallel:
        raise NotImplementedError()
    else:
        prediction, avg_loss, acc = net_conf(img, label)

    test_program = fluid.default_main_program().clone(for_test=True)

    optimizer = fluid.optimizer.Adam(learning_rate=0.001)
    optimizer.minimize(avg_loss)

    place = fluid.CUDAPlace(0) if use_cuda else fluid.CPUPlace()

    exe = fluid.Executor(place)

    train_reader = paddle.batch(paddle.reader.shuffle(
        paddle.dataset.mnist.train(), buf_size=500),
                                batch_size=BATCH_SIZE)
    test_reader = paddle.batch(paddle.dataset.mnist.test(),
                               batch_size=BATCH_SIZE)
    feeder = fluid.DataFeeder(feed_list=[img, label], place=place)

    def train_loop(main_program):
        exe.run(fluid.default_startup_program())

        PASS_NUM = 100
        for pass_id in range(PASS_NUM):
            for batch_id, data in enumerate(train_reader()):
                # train a mini-batch, fetch nothing
                exe.run(main_program, feed=feeder.feed(data))
                if (batch_id + 1) % 10 == 0:
                    acc_set = []
                    avg_loss_set = []
                    for test_data in test_reader():
                        acc_np, avg_loss_np = exe.run(
                            program=test_program,
                            feed=feeder.feed(test_data),
                            fetch_list=[acc, avg_loss])
                        acc_set.append(float(acc_np))
                        avg_loss_set.append(float(avg_loss_np))
                    # get test acc and loss
                    acc_val = numpy.array(acc_set).mean()
                    avg_loss_val = numpy.array(avg_loss_set).mean()
                    if float(acc_val) > 0.2 or pass_id == (PASS_NUM - 1):
                        # Smaller value to increase CI speed
                        if save_dirname is not None:
                            fluid.io.save_inference_model(
                                save_dirname, ["img"], [prediction],
                                exe,
                                model_filename=model_filename,
                                params_filename=params_filename)
                        if save_full_dirname is not None:
                            fluid.io.save_inference_model(
                                save_full_dirname, [], [],
                                exe,
                                model_filename=model_filename,
                                params_filename=params_filename,
                                export_for_deployment=False)
                        return
                    else:
                        print(
                            'PassID {0:1}, BatchID {1:04}, Test Loss {2:2.2}, Acc {3:2.2}'
                            .format(pass_id, batch_id + 1, float(avg_loss_val),
                                    float(acc_val)))
                        if math.isnan(float(avg_loss_val)):
                            sys.exit("got NaN loss, training failed.")
        raise AssertionError("Loss of recognize digits is too large")

    if is_local:
        train_loop(fluid.default_main_program())
    else:
        port = os.getenv("PADDLE_PSERVER_PORT", "6174")
        pserver_ips = os.getenv("PADDLE_PSERVER_IPS")  # ip,ip...
        eplist = []
        for ip in pserver_ips.split(","):
            eplist.append(':'.join([ip, port]))
        pserver_endpoints = ",".join(eplist)  # ip:port,ip:port...
        trainers = int(os.getenv("PADDLE_TRAINERS"))
        current_endpoint = os.getenv("POD_IP") + ":" + port
        trainer_id = int(os.getenv("PADDLE_TRAINER_ID"))
        training_role = os.getenv("PADDLE_TRAINING_ROLE", "TRAINER")
        t = fluid.DistributeTranspiler()
        t.transpile(trainer_id, pservers=pserver_endpoints, trainers=trainers)
        if training_role == "PSERVER":
            pserver_prog = t.get_pserver_program(current_endpoint)
            pserver_startup = t.get_startup_program(current_endpoint,
                                                    pserver_prog)
            exe.run(pserver_startup)
            exe.run(pserver_prog)
        elif training_role == "TRAINER":
            train_loop(t.get_trainer_program())


def infer(use_cuda,
          save_dirname=None,
          model_filename=None,
          params_filename=None):
    if save_dirname is None:
        return

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

    inference_scope = fluid.core.Scope()
    with fluid.scope_guard(inference_scope):
        # Use fluid.io.load_inference_model to obtain the inference program desc,
        # the feed_target_names (the names of variables that will be feeded
        # data using feed operators), and the fetch_targets (variables that
        # we want to obtain data from using fetch operators).
        [inference_program, feed_target_names,
         fetch_targets] = fluid.io.load_inference_model(save_dirname, exe,
                                                        model_filename,
                                                        params_filename)

        # The input's dimension of conv should be 4-D or 5-D.
        # Use normilized image pixels as input data, which should be in the range [-1.0, 1.0].
        batch_size = 1
        tensor_img = numpy.random.uniform(
            -1.0, 1.0, [batch_size, 1, 28, 28]).astype("float32")

        # Construct feed as a dictionary of {feed_target_name: feed_target_data}
        # and results will contain a list of data corresponding to fetch_targets.
        results = exe.run(inference_program,
                          feed={feed_target_names[0]: tensor_img},
                          fetch_list=fetch_targets)
        print("infer results: ", results[0])


def main(use_cuda, parallel, nn_type, combine):
    save_dirname = None
    save_full_dirname = None
    model_filename = None
    params_filename = None
    if not use_cuda and not parallel:
        save_dirname = "recognize_digits_" + nn_type + ".inference.model"
        save_full_dirname = "recognize_digits_" + nn_type + ".train.model"
        if combine == True:
            model_filename = "__model_combined__"
            params_filename = "__params_combined__"

    # call train() with is_local argument to run distributed train
    train(nn_type=nn_type,
          use_cuda=use_cuda,
          parallel=parallel,
          save_dirname=save_dirname,
          save_full_dirname=save_full_dirname,
          model_filename=model_filename,
          params_filename=params_filename)
    infer(use_cuda=use_cuda,
          save_dirname=save_dirname,
          model_filename=model_filename,
          params_filename=params_filename)


class TestRecognizeDigits(unittest.TestCase):
    pass


def inject_test_method(use_cuda, parallel, nn_type, combine):

    def __impl__(self):
        prog = fluid.Program()
        startup_prog = fluid.Program()
        scope = fluid.core.Scope()
        with fluid.scope_guard(scope):
            with fluid.program_guard(prog, startup_prog):
                main(use_cuda, parallel, nn_type, combine)

    fn = 'test_{0}_{1}_{2}_{3}'.format(nn_type, 'cuda' if use_cuda else 'cpu',
                                       'parallel' if parallel else 'normal',
                                       'combine' if combine else 'separate')

    setattr(TestRecognizeDigits, fn, __impl__)


def inject_all_tests():
    for use_cuda in (False, True):
        if use_cuda and not core.is_compiled_with_cuda():
            continue
        for parallel in (False, ):
            for nn_type in ('mlp', 'conv'):
                inject_test_method(use_cuda, parallel, nn_type, True)

    # Two unit-test for saving parameters as separate files
    inject_test_method(False, False, 'mlp', False)
    inject_test_method(False, False, 'conv', False)


inject_all_tests()

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