#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserve.
#
# 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 paddle.fluid as fluid
import unittest
import os
import numpy as np
import math
import sys


def train(use_cuda, is_sparse, is_parallel, save_dirname, is_local=True):
    PASS_NUM = 100
    EMBED_SIZE = 32
    HIDDEN_SIZE = 256
    N = 5
    BATCH_SIZE = 32
    IS_SPARSE = is_sparse

    def __network__(words):
        embed_first = fluid.layers.embedding(
            input=words[0],
            size=[dict_size, EMBED_SIZE],
            dtype='float32',
            is_sparse=IS_SPARSE,
            param_attr='shared_w')
        embed_second = fluid.layers.embedding(
            input=words[1],
            size=[dict_size, EMBED_SIZE],
            dtype='float32',
            is_sparse=IS_SPARSE,
            param_attr='shared_w')
        embed_third = fluid.layers.embedding(
            input=words[2],
            size=[dict_size, EMBED_SIZE],
            dtype='float32',
            is_sparse=IS_SPARSE,
            param_attr='shared_w')
        embed_forth = fluid.layers.embedding(
            input=words[3],
            size=[dict_size, EMBED_SIZE],
            dtype='float32',
            is_sparse=IS_SPARSE,
            param_attr='shared_w')

        concat_embed = fluid.layers.concat(
            input=[embed_first, embed_second, embed_third, embed_forth], axis=1)
        hidden1 = fluid.layers.fc(input=concat_embed,
                                  size=HIDDEN_SIZE,
                                  act='sigmoid')
        predict_word = fluid.layers.fc(input=hidden1,
                                       size=dict_size,
                                       act='softmax')
        cost = fluid.layers.cross_entropy(input=predict_word, label=words[4])
        avg_cost = fluid.layers.mean(cost)
        return avg_cost, predict_word

    word_dict = paddle.dataset.imikolov.build_dict()
    dict_size = len(word_dict)

    first_word = fluid.layers.data(name='firstw', shape=[1], dtype='int64')
    second_word = fluid.layers.data(name='secondw', shape=[1], dtype='int64')
    third_word = fluid.layers.data(name='thirdw', shape=[1], dtype='int64')
    forth_word = fluid.layers.data(name='forthw', shape=[1], dtype='int64')
    next_word = fluid.layers.data(name='nextw', shape=[1], dtype='int64')

    if not is_parallel:
        avg_cost, predict_word = __network__(
            [first_word, second_word, third_word, forth_word, next_word])
    else:
        places = fluid.layers.get_places()
        pd = fluid.layers.ParallelDo(places)
        with pd.do():
            avg_cost, predict_word = __network__(
                map(pd.read_input, [
                    first_word, second_word, third_word, forth_word, next_word
                ]))
            pd.write_output(avg_cost)

        avg_cost = fluid.layers.mean(pd())

    sgd_optimizer = fluid.optimizer.SGD(learning_rate=0.001)
    sgd_optimizer.minimize(avg_cost)

    train_reader = paddle.batch(
        paddle.dataset.imikolov.train(word_dict, N), BATCH_SIZE)

    place = fluid.CUDAPlace(0) if use_cuda else fluid.CPUPlace()
    exe = fluid.Executor(place)
    feeder = fluid.DataFeeder(
        feed_list=[first_word, second_word, third_word, forth_word, next_word],
        place=place)

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

        for pass_id in range(PASS_NUM):
            for data in train_reader():
                avg_cost_np = exe.run(main_program,
                                      feed=feeder.feed(data),
                                      fetch_list=[avg_cost])
                if avg_cost_np[0] < 5.0:
                    if save_dirname is not None:
                        fluid.io.save_inference_model(save_dirname, [
                            'firstw', 'secondw', 'thirdw', 'forthw'
                        ], [predict_word], exe)
                    return
                if math.isnan(float(avg_cost_np[0])):
                    sys.exit("got NaN loss, training failed.")

        raise AssertionError("Cost is too large {0:2.2}".format(avg_cost_np[0]))

    if is_local:
        train_loop(fluid.default_main_program())
    else:
        port = os.getenv("PADDLE_INIT_PORT", "6174")
        pserver_ips = os.getenv("PADDLE_INIT_PSERVERS")  # 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("TRAINERS"))
        current_endpoint = os.getenv("POD_IP") + ":" + port
        trainer_id = int(os.getenv("PADDLE_INIT_TRAINER_ID"))
        training_role = os.getenv("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):
    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)

        word_dict = paddle.dataset.imikolov.build_dict()
        dict_size = len(word_dict)

        # Setup inputs by creating 4 LoDTensors representing 4 words. Here each word 
        # is simply an index to look up for the corresponding word vector and hence 
        # the shape of word (base_shape) should be [1]. The length-based level of 
        # detail (lod) info of each LoDtensor should be [[1]] meaning there is only 
        # one lod_level and there is only one sequence of one word on this level.
        # Note that lod info should be a list of lists.
        lod = [[1]]
        base_shape = [1]
        # The range of random integers is [low, high]
        first_word = fluid.create_random_int_lodtensor(
            lod, base_shape, place, low=0, high=dict_size - 1)
        second_word = fluid.create_random_int_lodtensor(
            lod, base_shape, place, low=0, high=dict_size - 1)
        third_word = fluid.create_random_int_lodtensor(
            lod, base_shape, place, low=0, high=dict_size - 1)
        fourth_word = fluid.create_random_int_lodtensor(
            lod, base_shape, place, low=0, high=dict_size - 1)

        assert feed_target_names[0] == 'firstw'
        assert feed_target_names[1] == 'secondw'
        assert feed_target_names[2] == 'thirdw'
        assert feed_target_names[3] == 'forthw'

        # 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]: first_word,
                              feed_target_names[1]: second_word,
                              feed_target_names[2]: third_word,
                              feed_target_names[3]: fourth_word
                          },
                          fetch_list=fetch_targets,
                          return_numpy=False)
        print(results[0].lod())
        np_data = np.array(results[0])
        print("Inference Shape: ", np_data.shape)


def main(use_cuda, is_sparse, is_parallel):
    if use_cuda and not fluid.core.is_compiled_with_cuda():
        return

    if not is_parallel:
        save_dirname = "word2vec.inference.model"
    else:
        save_dirname = None

    train(use_cuda, is_sparse, is_parallel, save_dirname)
    infer(use_cuda, save_dirname)


FULL_TEST = os.getenv('FULL_TEST',
                      '0').lower() in ['true', '1', 't', 'y', 'yes', 'on']
SKIP_REASON = "Only run minimum number of tests in CI server, to make CI faster"


class W2VTest(unittest.TestCase):
    pass


def inject_test_method(use_cuda, is_sparse, is_parallel):
    fn_name = "test_{0}_{1}_{2}".format("cuda" if use_cuda else "cpu", "sparse"
                                        if is_sparse else "dense", "parallel"
                                        if is_parallel else "normal")

    def __impl__(*args, **kwargs):
        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=use_cuda,
                    is_sparse=is_sparse,
                    is_parallel=is_parallel)

    if use_cuda and is_sparse:
        fn = __impl__
    else:
        # skip the other test when on CI server
        fn = unittest.skipUnless(
            condition=FULL_TEST, reason=SKIP_REASON)(__impl__)

    setattr(W2VTest, fn_name, fn)


for use_cuda in (False, True):
    for is_sparse in (False, True):
        for is_parallel in (False, True):
            inject_test_method(use_cuda, is_sparse, is_parallel)

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