# Copyright 2020 Huawei Technologies Co., Ltd
#
# 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.
# ============================================================================
"""train resnet."""
import os
import random
import argparse
import numpy as np
from mindspore import context
from mindspore import Tensor
from mindspore import dataset as de
from mindspore.parallel._auto_parallel_context import auto_parallel_context
from mindspore.train.model import Model
from mindspore.context import ParallelMode
from mindspore.train.callback import ModelCheckpoint, CheckpointConfig, LossMonitor, TimeMonitor
from mindspore.train.loss_scale_manager import FixedLossScaleManager
from mindspore.train.serialization import load_checkpoint, load_param_into_net
from mindspore.communication.management import init, get_rank, get_group_size
import mindspore.nn as nn
import mindspore.common.initializer as weight_init
from src.lr_generator import get_lr, warmup_cosine_annealing_lr
from src.CrossEntropySmooth import CrossEntropySmooth

parser = argparse.ArgumentParser(description='Image classification')
parser.add_argument('--run_distribute', type=bool, default=False, help='Run distribute')
parser.add_argument('--device_num', type=int, default=1, help='Device num.')

parser.add_argument('--dataset_path', type=str, default=None, help='Dataset path')
parser.add_argument('--device_target', type=str, default='Ascend', help='Device target: "Ascend", "GPU"')
parser.add_argument('--pre_trained', type=str, default=None, help='Pretrained checkpoint path')
parser.add_argument('--dataset_sink_mode', type=str, default='True', choices = ['True', 'False'],
                    help='DataSet sink mode is True or False')
args_opt = parser.parse_args()

random.seed(1)
np.random.seed(1)
de.config.set_seed(1)


from src.resnet50 import resnet50
from src.config import cfg
from src.dataset import create_dataset


if __name__ == '__main__':
    target = args_opt.device_target
    ckpt_save_dir = cfg.save_checkpoint_path
    dataset_sink_mode = args_opt.dataset_sink_mode=='True'

    # init context
    context.set_context(mode=context.GRAPH_MODE, device_target=target, save_graphs=False)
    if args_opt.run_distribute:
        if target == "Ascend":
            device_id = int(os.getenv('DEVICE_ID'))
            context.set_context(device_id=device_id, enable_auto_mixed_precision=True)
            context.set_auto_parallel_context(device_num=args_opt.device_num, parallel_mode=ParallelMode.DATA_PARALLEL,
                                              gradients_mean=True)
            auto_parallel_context().set_all_reduce_fusion_split_indices([107, 160])

            init()
        # GPU target
        else:
            init("nccl")
            context.set_auto_parallel_context(device_num=get_group_size(), parallel_mode=ParallelMode.DATA_PARALLEL,
                                              gradients_mean=True)
            ckpt_save_dir = cfg.save_checkpoint_path + "ckpt_" + str(get_rank()) + "/"

    # create dataset
    dataset = create_dataset(data_path=args_opt.dataset_path, do_train=True, batch_size=cfg.batch_size, target=target,
                             run_distribute=args_opt.run_distribute)

    step_size = dataset.get_dataset_size()

    # define net
    net = resnet50(class_num=cfg.num_classes)

    # init weight
    if args_opt.pre_trained:
        param_dict = load_checkpoint(args_opt.pre_trained)
        load_param_into_net(net, param_dict)
    else:
        for _, cell in net.cells_and_names():
            if isinstance(cell, nn.Conv2d):
                cell.weight.set_data(weight_init.initializer(weight_init.XavierUniform(),
                                                             cell.weight.shape,
                                                             cell.weight.dtype))
            if isinstance(cell, nn.Dense):
                cell.weight.set_data(weight_init.initializer(weight_init.TruncatedNormal(),
                                                             cell.weight.shape,
                                                             cell.weight.dtype))

    # init lr

    {% if dataset=='Cifar10' %}
    lr = get_lr(lr_init=cfg.lr_init, lr_end=cfg.lr_end, lr_max=cfg.lr_max,
                warmup_epochs=cfg.warmup_epochs, total_epochs=cfg.epoch_size, steps_per_epoch=step_size,
                lr_decay_mode='poly')
    {% else %}
    lr = get_lr(lr_init=cfg.lr_init, lr_end=0.0, lr_max=cfg.lr_max,
                warmup_epochs=cfg.warmup_epochs, total_epochs=cfg.epoch_size, steps_per_epoch=step_size,
                lr_decay_mode='cosine')
    {% endif %}

    lr = Tensor(lr)

    # define opt
    {% if optimizer=='Momentum' %}
    opt = nn.Momentum(filter(lambda x: x.requires_grad, net.get_parameters()), learning_rate=lr, momentum=cfg.momentum,
                      weight_decay=cfg.weight_decay, loss_scale=cfg.loss_scale)
    {% else %}
    opt = nn.{{optimizer}}(filter(lambda x: x.requires_grad, net.get_parameters()), learning_rate=cfg.lr)
    {% endif %}

    # define loss, model
    if target == "Ascend":
        {% if dataset=='ImageNet' %}
        {% if loss=='SoftmaxCrossEntropyWithLogits' %}
        if not cfg.use_label_smooth:
            cfg.label_smooth_factor = 0.0
        loss = CrossEntropySmooth(sparse=True, reduction='mean',
                                  smooth_factor=cfg.label_smooth_factor, num_classes=cfg.num_classes)
        {% elif loss=='SoftmaxCrossEntropyExpand' %}
        loss = nn.SoftmaxCrossEntropyExpand(sparse=True)
        {% endif %}
        {% else %}
        {% if loss=='SoftmaxCrossEntropyWithLogits' %}
        loss = nn.SoftmaxCrossEntropyWithLogits(sparse=True, reduction='mean')
        {% elif loss=='SoftmaxCrossEntropyExpand' %}
        loss = nn.SoftmaxCrossEntropyExpand(sparse=True)
        {% endif %}
        {% endif %}
        loss_scale = FixedLossScaleManager(cfg.loss_scale, drop_overflow_update=False)
        model = Model(net, loss_fn=loss, optimizer=opt, loss_scale_manager=loss_scale, metrics={'acc'},
                      amp_level="O2", keep_batchnorm_fp32=False)
    else:
        # GPU target
        {% if dataset=='ImageNet' %}
        {% if loss=='SoftmaxCrossEntropyWithLogits' %}
        if not cfg.use_label_smooth:
            cfg.label_smooth_factor = 0.0
        loss = CrossEntropySmooth(sparse=True, reduction='mean',
                                  smooth_factor=cfg.label_smooth_factor, num_classes=cfg.num_classes)
        {% elif loss=='SoftmaxCrossEntropyExpand' %}
        loss = nn.SoftmaxCrossEntropyExpand(sparse=True)
        {% endif %}
        {% else %}
        {% if loss=='SoftmaxCrossEntropyWithLogits' %}
        loss = nn.SoftmaxCrossEntropyWithLogits(sparse=True, reduction='mean')
        {% elif loss=='SoftmaxCrossEntropyExpand' %}
        loss = nn.SoftmaxCrossEntropyExpand(sparse=True)
        {% endif %}
        {% endif %}
        loss_scale = FixedLossScaleManager(cfg.loss_scale, drop_overflow_update=False)
        model = Model(net, loss_fn=loss, optimizer=opt, loss_scale_manager=loss_scale, metrics={'acc'},
                      amp_level="O2", keep_batchnorm_fp32=True)

    # define callbacks
    time_cb = TimeMonitor(data_size=step_size)
    loss_cb = LossMonitor()
    cb = [time_cb, loss_cb]
    if cfg.save_checkpoint:
        cfg_ck = CheckpointConfig(save_checkpoint_steps=cfg.save_checkpoint_epochs * step_size,
                                     keep_checkpoint_max=cfg.keep_checkpoint_max)
        ckpt_cb = ModelCheckpoint(prefix="resnet", directory=ckpt_save_dir, config=cfg_ck)
        cb += [ckpt_cb]

    # train model
    model.train(cfg.epoch_size, dataset, callbacks=cb, dataset_sink_mode=dataset_sink_mode)
