# Copyright (c) 2020 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.

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from __future__ import unicode_literals

import os
import sys
import numpy as np
import paddle
import signal
import random

__dir__ = os.path.dirname(os.path.abspath(__file__))
sys.path.append(os.path.abspath(os.path.join(__dir__, '../..')))

import copy
from paddle.io import Dataset, DataLoader, BatchSampler, DistributedBatchSampler
# from paddle.fluid.io import DataLoader
# from paddle.fluid.dataloader import Dataset, BatchSampler, DistributedBatchSampler
import paddle.distributed as dist

from ocr.ppocr.data.imaug import transform, create_operators
from ocr.ppocr.data.simple_dataset import SimpleDataSet
from ocr.ppocr.data.lmdb_dataset import LMDBDataSet

__all__ = ['build_dataloader', 'transform', 'create_operators']


def term_mp(sig_num, frame):
    """ kill all child processes
    """
    pid = os.getpid()
    pgid = os.getpgid(os.getpid())
    print("main proc {} exit, kill process group " "{}".format(pid, pgid))
    os.killpg(pgid, signal.SIGKILL)


signal.signal(signal.SIGINT, term_mp)
signal.signal(signal.SIGTERM, term_mp)


def build_dataloader(config, mode, device, logger, seed=None):
    config = copy.deepcopy(config)

    # 从配置文件中读取相关配置，并判断是否包含在支持中
    assert mode in ['Train', 'Eval', 'Test'
                    ], "Mode should be Train, Eval or Test."
    module_name = config[mode]['dataset']['name']

    support_dict = ['SimpleDataSet', 'LMDBDataSet']
    assert module_name in support_dict, Exception(
        'DataSet only support {}'.format(support_dict))

    # 初始化对应的Dataset类
    # eval: 根据字符串调用同名类
    # eval('SimpleDataSet')(config) = SimpleDataSet(config)
    dataset = eval(module_name)(config, mode, logger, seed)

    # 读取其他参数
    loader_config = config[mode]['loader']
    batch_size = loader_config['batch_size_per_card']
    drop_last = loader_config['drop_last']
    shuffle = loader_config['shuffle']
    num_workers = loader_config['num_workers']
    if 'use_shared_memory' in loader_config.keys():
        use_shared_memory = loader_config['use_shared_memory']
    else:
        use_shared_memory = True

    # Train模式，可多个GPU同时训练，Eval模式则是单卡，分多个Batch
    if mode == "Train":
        #Distribute data to multiple cards
        batch_sampler = DistributedBatchSampler(
            dataset=dataset,
            batch_size=batch_size,
            shuffle=shuffle,
            drop_last=drop_last)
        # random_epoch = np.random.randint(1, 10)
        # batch_sampler.set_epoch(random_epoch)
    else:
        #Distribute data to single card
        batch_sampler = BatchSampler(
            dataset=dataset,
            batch_size=batch_size,
            shuffle=shuffle,
            drop_last=drop_last)

    # 根据已设参数，初始化数据集读取对象
    data_loader = DataLoader(
        dataset=dataset,
        batch_sampler=batch_sampler,
        places=device,
        num_workers=num_workers,
        return_list=True,
        use_shared_memory=use_shared_memory)
    return data_loader
