# Copyright (c) 2021 Baidu.com, Inc. 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 argparse
import json
import os
import random
import sys
import time

import numpy as np
import paddle
import paddle.nn as nn
import paddle.nn.functional as F
from data_loader import DataCollator, DuIEDataset
from paddle.io import DataLoader
from tqdm import tqdm
from utils import decoding, get_precision_recall_f1, write_prediction_results

from paddlenlp.transformers import (
    AutoModelForTokenClassification,
    AutoTokenizer,
    LinearDecayWithWarmup,
)

parser = argparse.ArgumentParser()
parser.add_argument("--do_train", action="store_true", default=False, help="do train")
parser.add_argument("--do_predict", action="store_true", default=False, help="do predict")
parser.add_argument("--init_checkpoint", default=None, type=str, required=False, help="Path to initialize params from")
parser.add_argument("--data_path", default="./data", type=str, required=False, help="Path to data.")
parser.add_argument(
    "--predict_data_file", default="./data/test_data.json", type=str, required=False, help="Path to data."
)
parser.add_argument(
    "--output_dir",
    default="./checkpoints",
    type=str,
    required=False,
    help="The output directory where the model predictions and checkpoints will be written.",
)
parser.add_argument(
    "--max_seq_length",
    default=128,
    type=int,
    help="The maximum total input sequence length after tokenization. Sequences longer than this will be truncated, sequences shorter will be padded.",
)
parser.add_argument(
    "--batch_size",
    default=8,
    type=int,
    help="Batch size per GPU/CPU for training.",
)
parser.add_argument("--learning_rate", default=5e-5, type=float, help="The initial learning rate for Adam.")
parser.add_argument("--weight_decay", default=0.0, type=float, help="Weight decay if we apply some.")
parser.add_argument("--num_train_epochs", default=3, type=int, help="Total number of training epochs to perform.")
parser.add_argument("--warmup_ratio", default=0, type=float, help="Linear warmup over warmup_ratio * total_steps.")
parser.add_argument("--seed", default=42, type=int, help="random seed for initialization")
parser.add_argument(
    "--device", choices=["cpu", "gpu"], default="gpu", help="Select which device to train model, defaults to gpu."
)
args = parser.parse_args()


class BCELossForDuIE(nn.Layer):
    def __init__(
        self,
    ):
        super(BCELossForDuIE, self).__init__()
        self.criterion = nn.BCEWithLogitsLoss(reduction="none")

    def forward(self, logits, labels, mask):
        loss = self.criterion(logits, labels)
        mask = paddle.cast(mask, "float32")
        loss = loss * mask.unsqueeze(-1)
        loss = paddle.sum(loss.mean(axis=2), axis=1) / paddle.sum(mask, axis=1)
        loss = loss.mean()
        return loss


def set_random_seed(seed):
    """sets random seed"""
    random.seed(seed)
    np.random.seed(seed)
    paddle.seed(seed)


@paddle.no_grad()
def evaluate(model, criterion, data_loader, file_path, mode):
    """
    mode eval:
    eval on development set and compute P/R/F1, called between training.
    mode predict:
    eval on development / test set, then write predictions to \
        predict_test.json and predict_test.json.zip \
        under args.data_path dir for later submission or evaluation.
    """
    example_all = []
    with open(file_path, "r", encoding="utf-8") as fp:
        for line in fp:
            example_all.append(json.loads(line))
    id2spo_path = os.path.join(os.path.dirname(file_path), "id2spo.json")
    with open(id2spo_path, "r", encoding="utf8") as fp:
        id2spo = json.load(fp)

    model.eval()
    loss_all = 0
    eval_steps = 0
    formatted_outputs = []
    current_idx = 0
    for batch in tqdm(data_loader, total=len(data_loader)):
        eval_steps += 1
        input_ids, seq_len, tok_to_orig_start_index, tok_to_orig_end_index, labels = batch
        logits = model(input_ids=input_ids)
        mask = (input_ids != 0).logical_and((input_ids != 1)).logical_and((input_ids != 2))
        loss = criterion(logits, labels, mask)
        loss_all += loss.item()
        probs = F.sigmoid(logits)
        logits_batch = probs.numpy()
        seq_len_batch = seq_len.numpy()
        tok_to_orig_start_index_batch = tok_to_orig_start_index.numpy()
        tok_to_orig_end_index_batch = tok_to_orig_end_index.numpy()
        formatted_outputs.extend(
            decoding(
                example_all[current_idx : current_idx + len(logits)],
                id2spo,
                logits_batch,
                seq_len_batch,
                tok_to_orig_start_index_batch,
                tok_to_orig_end_index_batch,
            )
        )
        current_idx = current_idx + len(logits)
    loss_avg = loss_all / eval_steps
    print("eval loss: %f" % (loss_avg))

    if mode == "predict":
        predict_file_path = os.path.join(args.data_path, "predictions.json")
    else:
        predict_file_path = os.path.join(args.data_path, "predict_eval.json")

    predict_zipfile_path = write_prediction_results(formatted_outputs, predict_file_path)

    if mode == "eval":
        precision, recall, f1 = get_precision_recall_f1(file_path, predict_zipfile_path)
        os.system("rm {} {}".format(predict_file_path, predict_zipfile_path))
        return precision, recall, f1
    elif mode != "predict":
        raise Exception("wrong mode for eval func")


def do_train():
    paddle.set_device(args.device)
    rank = paddle.distributed.get_rank()
    if paddle.distributed.get_world_size() > 1:
        paddle.distributed.init_parallel_env()

    # Reads label_map.
    label_map_path = os.path.join(args.data_path, "predicate2id.json")
    if not (os.path.exists(label_map_path) and os.path.isfile(label_map_path)):
        sys.exit("{} dose not exists or is not a file.".format(label_map_path))
    with open(label_map_path, "r", encoding="utf8") as fp:
        label_map = json.load(fp)
    num_classes = (len(label_map.keys()) - 2) * 2 + 2

    # Loads pretrained model ERNIE
    model = AutoModelForTokenClassification.from_pretrained("ernie-3.0-medium-zh", num_classes=num_classes)
    model = paddle.DataParallel(model)
    tokenizer = AutoTokenizer.from_pretrained("ernie-3.0-medium-zh")
    criterion = BCELossForDuIE()

    # Loads dataset.
    train_dataset = DuIEDataset.from_file(
        os.path.join(args.data_path, "train_data.json"), tokenizer, args.max_seq_length, True
    )
    train_batch_sampler = paddle.io.DistributedBatchSampler(
        train_dataset, batch_size=args.batch_size, shuffle=True, drop_last=True
    )
    collator = DataCollator()
    train_data_loader = DataLoader(
        dataset=train_dataset, batch_sampler=train_batch_sampler, collate_fn=collator, return_list=True
    )
    eval_file_path = os.path.join(args.data_path, "dev_data.json")
    test_dataset = DuIEDataset.from_file(eval_file_path, tokenizer, args.max_seq_length, True)
    test_batch_sampler = paddle.io.BatchSampler(
        test_dataset, batch_size=args.batch_size, shuffle=False, drop_last=True
    )
    test_data_loader = DataLoader(
        dataset=test_dataset, batch_sampler=test_batch_sampler, collate_fn=collator, return_list=True
    )

    # Defines learning rate strategy.
    steps_by_epoch = len(train_data_loader)
    num_training_steps = steps_by_epoch * args.num_train_epochs
    lr_scheduler = LinearDecayWithWarmup(args.learning_rate, num_training_steps, args.warmup_ratio)
    # Generate parameter names needed to perform weight decay.
    # All bias and LayerNorm parameters are excluded.
    decay_params = [p.name for n, p in model.named_parameters() if not any(nd in n for nd in ["bias", "norm"])]
    optimizer = paddle.optimizer.AdamW(
        learning_rate=lr_scheduler,
        parameters=model.parameters(),
        weight_decay=args.weight_decay,
        apply_decay_param_fun=lambda x: x in decay_params,
    )

    # Starts training.
    global_step = 0
    logging_steps = 50
    save_steps = 10000
    tic_train = time.time()
    for epoch in range(args.num_train_epochs):
        print("\n=====start training of %d epochs=====" % epoch)
        tic_epoch = time.time()
        model.train()
        for step, batch in enumerate(train_data_loader):
            input_ids, seq_lens, tok_to_orig_start_index, tok_to_orig_end_index, labels = batch
            logits = model(input_ids=input_ids)
            mask = (input_ids != 0).logical_and((input_ids != 1)).logical_and((input_ids != 2))
            loss = criterion(logits, labels, mask)
            loss.backward()
            optimizer.step()
            lr_scheduler.step()
            optimizer.clear_grad()
            loss_item = loss.item()
            global_step += 1

            if global_step % logging_steps == 0 and rank == 0:
                print(
                    "epoch: %d / %d, steps: %d / %d, loss: %f, speed: %.2f step/s"
                    % (
                        epoch,
                        args.num_train_epochs,
                        step,
                        steps_by_epoch,
                        loss_item,
                        logging_steps / (time.time() - tic_train),
                    )
                )
                tic_train = time.time()

            if global_step % save_steps == 0 and rank == 0:
                print("\n=====start evaluating ckpt of %d steps=====" % global_step)
                precision, recall, f1 = evaluate(model, criterion, test_data_loader, eval_file_path, "eval")
                print("precision: %.2f\t recall: %.2f\t f1: %.2f\t" % (100 * precision, 100 * recall, 100 * f1))
                print("saving checkpoint model_%d.pdparams to %s " % (global_step, args.output_dir))
                paddle.save(model.state_dict(), os.path.join(args.output_dir, "model_%d.pdparams" % global_step))
                model.train()  # back to train mode

        tic_epoch = time.time() - tic_epoch
        print(
            "epoch time footprint: %d hour %d min %d sec"
            % (tic_epoch // 3600, (tic_epoch % 3600) // 60, tic_epoch % 60)
        )

    # Does final evaluation.
    if rank == 0:
        print("\n=====start evaluating last ckpt of %d steps=====" % global_step)
        precision, recall, f1 = evaluate(model, criterion, test_data_loader, eval_file_path, "eval")
        print("precision: %.2f\t recall: %.2f\t f1: %.2f\t" % (100 * precision, 100 * recall, 100 * f1))
        paddle.save(model.state_dict(), os.path.join(args.output_dir, "model_%d.pdparams" % global_step))
        print("\n=====training complete=====")


def do_predict():
    paddle.set_device(args.device)

    # Reads label_map.
    label_map_path = os.path.join(args.data_path, "predicate2id.json")
    if not (os.path.exists(label_map_path) and os.path.isfile(label_map_path)):
        sys.exit("{} dose not exists or is not a file.".format(label_map_path))
    with open(label_map_path, "r", encoding="utf8") as fp:
        label_map = json.load(fp)
    num_classes = (len(label_map.keys()) - 2) * 2 + 2

    # Loads pretrained model ERNIE
    model = AutoModelForTokenClassification.from_pretrained("ernie-3.0-medium-zh", num_classes=num_classes)
    tokenizer = AutoTokenizer.from_pretrained("ernie-3.0-medium-zh")
    criterion = BCELossForDuIE()

    # Loads dataset.
    test_dataset = DuIEDataset.from_file(args.predict_data_file, tokenizer, args.max_seq_length, True)
    collator = DataCollator()
    test_batch_sampler = paddle.io.BatchSampler(
        test_dataset, batch_size=args.batch_size, shuffle=False, drop_last=True
    )
    test_data_loader = DataLoader(
        dataset=test_dataset, batch_sampler=test_batch_sampler, collate_fn=collator, return_list=True
    )

    # Loads model parameters.
    if not (os.path.exists(args.init_checkpoint) and os.path.isfile(args.init_checkpoint)):
        sys.exit("wrong directory: init checkpoints {} not exist".format(args.init_checkpoint))
    state_dict = paddle.load(args.init_checkpoint)
    model.set_dict(state_dict)

    # Does predictions.
    print("\n=====start predicting=====")
    evaluate(model, criterion, test_data_loader, args.predict_data_file, "predict")
    print("=====predicting complete=====")


if __name__ == "__main__":

    if args.do_train:
        do_train()
    elif args.do_predict:
        do_predict()
