# 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.
# ============================================================================
"""Test train gat"""
import argparse
import os

import numpy as np
import mindspore.context as context
from mindspore.train.serialization import _exec_save_checkpoint, load_checkpoint

from src.config import GatConfig
from src.dataset import load_and_process
from src.gat import GAT
from src.utils import LossAccuracyWrapper, TrainGAT


def train():
    """Train GAT model."""
    parser = argparse.ArgumentParser()
    parser.add_argument('--data_dir', type=str, default='./data/cora/cora_mr', help='Data dir')
    parser.add_argument('--train_nodes_num', type=int, default=140, help='Nodes numbers for training')
    parser.add_argument('--eval_nodes_num', type=int, default=500, help='Nodes numbers for evaluation')
    parser.add_argument('--test_nodes_num', type=int, default=1000, help='Nodes numbers for test')
    args = parser.parse_args()
    if not os.path.exists("ckpts"):
        os.mkdir("ckpts")
    context.set_context(mode=context.GRAPH_MODE,
                        device_target="Ascend",
                        save_graphs=False)
    # train parameters
    hid_units = GatConfig.hid_units
    n_heads = GatConfig.n_heads
    early_stopping = GatConfig.early_stopping
    lr = GatConfig.lr
    l2_coeff = GatConfig.l2_coeff
    num_epochs = GatConfig.num_epochs
    feature, biases, y_train, train_mask, y_val, eval_mask, y_test, test_mask = load_and_process(args.data_dir,
                                                                                                 args.train_nodes_num,
                                                                                                 args.eval_nodes_num,
                                                                                                 args.test_nodes_num)
    feature_size = feature.shape[2]
    num_nodes = feature.shape[1]
    num_class = y_train.shape[2]

    gat_net = GAT(feature,
                  biases,
                  feature_size,
                  num_class,
                  num_nodes,
                  hid_units,
                  n_heads,
                  attn_drop=GatConfig.attn_dropout,
                  ftr_drop=GatConfig.feature_dropout)
    gat_net.add_flags_recursive(fp16=True)

    eval_net = LossAccuracyWrapper(gat_net,
                                   num_class,
                                   y_val,
                                   eval_mask,
                                   l2_coeff)

    train_net = TrainGAT(gat_net,
                         num_class,
                         y_train,
                         train_mask,
                         lr,
                         l2_coeff)

    train_net.set_train(True)
    val_acc_max = 0.0
    val_loss_min = np.inf
    for _epoch in range(num_epochs):
        train_result = train_net()
        train_loss = train_result[0].asnumpy()
        train_acc = train_result[1].asnumpy()

        eval_result = eval_net()
        eval_loss = eval_result[0].asnumpy()
        eval_acc = eval_result[1].asnumpy()

        print("Epoch:{}, train loss={:.5f}, train acc={:.5f} | val loss={:.5f}, val acc={:.5f}".format(
            _epoch, train_loss, train_acc, eval_loss, eval_acc))
        if eval_acc >= val_acc_max or eval_loss < val_loss_min:
            if eval_acc >= val_acc_max and eval_loss < val_loss_min:
                val_acc_model = eval_acc
                val_loss_model = eval_loss
                if os.path.exists("ckpts/gat.ckpt"):
                    os.remove("ckpts/gat.ckpt")
                _exec_save_checkpoint(train_net.network, "ckpts/gat.ckpt")
            val_acc_max = np.max((val_acc_max, eval_acc))
            val_loss_min = np.min((val_loss_min, eval_loss))
            curr_step = 0
        else:
            curr_step += 1
            if curr_step == early_stopping:
                print("Early Stop Triggered!, Min loss: {}, Max accuracy: {}".format(val_loss_min, val_acc_max))
                print("Early stop model validation loss: {}, accuracy{}".format(val_loss_model, val_acc_model))
                break
    gat_net_test = GAT(feature,
                       biases,
                       feature_size,
                       num_class,
                       num_nodes,
                       hid_units,
                       n_heads,
                       attn_drop=0.0,
                       ftr_drop=0.0)
    load_checkpoint("ckpts/gat.ckpt", net=gat_net_test)
    gat_net_test.add_flags_recursive(fp16=True)

    test_net = LossAccuracyWrapper(gat_net_test,
                                   num_class,
                                   y_test,
                                   test_mask,
                                   l2_coeff)
    test_result = test_net()
    print("Test loss={}, test acc={}".format(test_result[0], test_result[1]))


if __name__ == "__main__":
    train()
