# Copyright (c) 2021 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.

import os
import sys

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

import random
import copy
import logging

import argparse
import paddle
import numpy as np
from seqeval.metrics import classification_report, f1_score, precision_score, recall_score
from paddlenlp.transformers import LayoutXLMModel, LayoutXLMTokenizer, LayoutXLMForTokenClassification
from xfun import XFUNDataset
from utils import parse_args
from utils import get_bio_label_maps
from utils import print_arguments

from ppocr.utils.logging import get_logger


def set_seed(args):
    random.seed(args.seed)
    np.random.seed(args.seed)
    paddle.seed(args.seed)


def train(args):
    os.makedirs(args.output_dir, exist_ok=True)
    logger = get_logger(log_file=os.path.join(args.output_dir, "train.log"))
    print_arguments(args, logger)

    label2id_map, id2label_map = get_bio_label_maps(args.label_map_path)
    pad_token_label_id = paddle.nn.CrossEntropyLoss().ignore_index

    # dist mode
    if paddle.distributed.get_world_size() > 1:
        paddle.distributed.init_parallel_env()

    tokenizer = LayoutXLMTokenizer.from_pretrained(args.model_name_or_path)
    base_model = LayoutXLMModel.from_pretrained(args.model_name_or_path)
    model = LayoutXLMForTokenClassification(
        base_model, num_classes=len(label2id_map), dropout=None)

    # dist mode
    if paddle.distributed.get_world_size() > 1:
        model = paddle.DataParallel(model)

    train_dataset = XFUNDataset(
        tokenizer,
        data_dir=args.train_data_dir,
        label_path=args.train_label_path,
        label2id_map=label2id_map,
        img_size=(224, 224),
        pad_token_label_id=pad_token_label_id,
        contains_re=False,
        add_special_ids=False,
        return_attention_mask=True,
        load_mode='all')

    train_sampler = paddle.io.DistributedBatchSampler(
        train_dataset, batch_size=args.per_gpu_train_batch_size, shuffle=True)

    args.train_batch_size = args.per_gpu_train_batch_size * max(
        1, paddle.distributed.get_world_size())

    train_dataloader = paddle.io.DataLoader(
        train_dataset,
        batch_sampler=train_sampler,
        num_workers=0,
        use_shared_memory=True,
        collate_fn=None, )

    t_total = len(train_dataloader) * args.num_train_epochs

    # build linear decay with warmup lr sch
    lr_scheduler = paddle.optimizer.lr.PolynomialDecay(
        learning_rate=args.learning_rate,
        decay_steps=t_total,
        end_lr=0.0,
        power=1.0)
    if args.warmup_steps > 0:
        lr_scheduler = paddle.optimizer.lr.LinearWarmup(
            lr_scheduler,
            args.warmup_steps,
            start_lr=0,
            end_lr=args.learning_rate, )

    optimizer = paddle.optimizer.AdamW(
        learning_rate=lr_scheduler,
        parameters=model.parameters(),
        epsilon=args.adam_epsilon,
        weight_decay=args.weight_decay)

    # Train!
    logger.info("***** Running training *****")
    logger.info("  Num examples = %d", len(train_dataset))
    logger.info("  Num Epochs = %d", args.num_train_epochs)
    logger.info("  Instantaneous batch size per GPU = %d",
                args.per_gpu_train_batch_size)
    logger.info(
        "  Total train batch size (w. parallel, distributed) = %d",
        args.train_batch_size * paddle.distributed.get_world_size(), )
    logger.info("  Total optimization steps = %d", t_total)

    global_step = 0
    tr_loss = 0.0
    set_seed(args)
    best_metrics = None

    for epoch_id in range(args.num_train_epochs):
        for step, batch in enumerate(train_dataloader):
            model.train()
            outputs = model(**batch)
            # model outputs are always tuple in ppnlp (see doc)
            loss = outputs[0]
            loss = loss.mean()
            logger.info(
                "epoch: [{}/{}], iter: [{}/{}], global_step:{}, train loss: {}, lr: {}".
                format(epoch_id, args.num_train_epochs, step,
                       len(train_dataloader), global_step,
                       loss.numpy()[0], lr_scheduler.get_lr()))

            loss.backward()
            tr_loss += loss.item()
            optimizer.step()
            lr_scheduler.step()  # Update learning rate schedule
            optimizer.clear_grad()
            global_step += 1

            if (paddle.distributed.get_rank() == 0 and args.eval_steps > 0 and
                    global_step % args.eval_steps == 0):
                # Log metrics
                # Only evaluate when single GPU otherwise metrics may not average well
                if paddle.distributed.get_rank(
                ) == 0 and args.evaluate_during_training:
                    results, _ = evaluate(args, model, tokenizer, label2id_map,
                                          id2label_map, pad_token_label_id,
                                          logger)

                    if best_metrics is None or results["f1"] >= best_metrics[
                            "f1"]:
                        best_metrics = copy.deepcopy(results)
                        output_dir = os.path.join(args.output_dir, "best_model")
                        os.makedirs(output_dir, exist_ok=True)
                        if paddle.distributed.get_rank() == 0:
                            model.save_pretrained(output_dir)
                            tokenizer.save_pretrained(output_dir)
                            paddle.save(
                                args,
                                os.path.join(output_dir, "training_args.bin"))
                            logger.info("Saving model checkpoint to %s",
                                        output_dir)

                    logger.info("[epoch {}/{}][iter: {}/{}] results: {}".format(
                        epoch_id, args.num_train_epochs, step,
                        len(train_dataloader), results))
                    if best_metrics is not None:
                        logger.info("best metrics: {}".format(best_metrics))

            if paddle.distributed.get_rank(
            ) == 0 and args.save_steps > 0 and global_step % args.save_steps == 0:
                # Save model checkpoint
                output_dir = os.path.join(args.output_dir,
                                          "checkpoint-{}".format(global_step))
                os.makedirs(output_dir, exist_ok=True)
                if paddle.distributed.get_rank() == 0:
                    model.save_pretrained(output_dir)
                    tokenizer.save_pretrained(output_dir)
                    paddle.save(args,
                                os.path.join(output_dir, "training_args.bin"))
                    logger.info("Saving model checkpoint to %s", output_dir)

    return global_step, tr_loss / global_step


def evaluate(args,
             model,
             tokenizer,
             label2id_map,
             id2label_map,
             pad_token_label_id,
             logger,
             prefix=""):
    eval_dataset = XFUNDataset(
        tokenizer,
        data_dir=args.eval_data_dir,
        label_path=args.eval_label_path,
        label2id_map=label2id_map,
        img_size=(224, 224),
        pad_token_label_id=pad_token_label_id,
        contains_re=False,
        add_special_ids=False,
        return_attention_mask=True,
        load_mode='all')

    args.eval_batch_size = args.per_gpu_eval_batch_size * max(
        1, paddle.distributed.get_world_size())

    eval_dataloader = paddle.io.DataLoader(
        eval_dataset,
        batch_size=args.eval_batch_size,
        num_workers=0,
        use_shared_memory=True,
        collate_fn=None, )

    # Eval!
    logger.info("***** Running evaluation %s *****", prefix)
    logger.info("  Num examples = %d", len(eval_dataset))
    logger.info("  Batch size = %d", args.eval_batch_size)
    eval_loss = 0.0
    nb_eval_steps = 0
    preds = None
    out_label_ids = None
    model.eval()
    for idx, batch in enumerate(eval_dataloader):
        with paddle.no_grad():
            outputs = model(**batch)
            tmp_eval_loss, logits = outputs[:2]

            tmp_eval_loss = tmp_eval_loss.mean()

            if paddle.distributed.get_rank() == 0:
                logger.info("[Eval]process: {}/{}, loss: {:.5f}".format(
                    idx, len(eval_dataloader), tmp_eval_loss.numpy()[0]))

            eval_loss += tmp_eval_loss.item()
        nb_eval_steps += 1
        if preds is None:
            preds = logits.numpy()
            out_label_ids = batch["labels"].numpy()
        else:
            preds = np.append(preds, logits.numpy(), axis=0)
            out_label_ids = np.append(
                out_label_ids, batch["labels"].numpy(), axis=0)

    eval_loss = eval_loss / nb_eval_steps
    preds = np.argmax(preds, axis=2)

    # label_map = {i: label.upper() for i, label in enumerate(labels)}

    out_label_list = [[] for _ in range(out_label_ids.shape[0])]
    preds_list = [[] for _ in range(out_label_ids.shape[0])]

    for i in range(out_label_ids.shape[0]):
        for j in range(out_label_ids.shape[1]):
            if out_label_ids[i, j] != pad_token_label_id:
                out_label_list[i].append(id2label_map[out_label_ids[i][j]])
                preds_list[i].append(id2label_map[preds[i][j]])

    results = {
        "loss": eval_loss,
        "precision": precision_score(out_label_list, preds_list),
        "recall": recall_score(out_label_list, preds_list),
        "f1": f1_score(out_label_list, preds_list),
    }

    with open(os.path.join(args.output_dir, "test_gt.txt"), "w") as fout:
        for lbl in out_label_list:
            for l in lbl:
                fout.write(l + "\t")
            fout.write("\n")
    with open(os.path.join(args.output_dir, "test_pred.txt"), "w") as fout:
        for lbl in preds_list:
            for l in lbl:
                fout.write(l + "\t")
            fout.write("\n")

    report = classification_report(out_label_list, preds_list)
    logger.info("\n" + report)

    logger.info("***** Eval results %s *****", prefix)
    for key in sorted(results.keys()):
        logger.info("  %s = %s", key, str(results[key]))

    return results, preds_list


if __name__ == "__main__":
    args = parse_args()
    train(args)