#!/usr/bin/env python
# coding=utf-8
# Copyright 2021 The HuggingFace Team. 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.
"""
Fine-tuning the library models for sequence to sequence.
"""
# You can also adapt this script on your own sequence to sequence task. Pointers for this are left as comments.

import logging
import os
import sys
import json

import numpy as np
from datasets import load_dataset
import jieba 
from rouge_chinese import Rouge
from nltk.translate.bleu_score import sentence_bleu

import transformers
from transformers import (
    AutoConfig,
    AutoModel,
    AutoTokenizer,
    AutoTokenizer,
    DataCollatorForSeq2Seq,
    HfArgumentParser,
    Seq2SeqTrainingArguments,
    set_seed,
)
from trainer_seq2seq import Seq2SeqTrainer

from arguments import ModelArguments, DataTrainingArguments

logger = logging.getLogger(__name__)

def main():

    parser = HfArgumentParser((ModelArguments, DataTrainingArguments, Seq2SeqTrainingArguments))
    if len(sys.argv) == 2 and sys.argv[1].endswith(".json"):
        # If we pass only one argument to the script and it's the path to a json file,
        # let's parse it to get our arguments.
        model_args, data_args, training_args = parser.parse_json_file(json_file=os.path.abspath(sys.argv[1]))
    else:
        model_args, data_args, training_args = parser.parse_args_into_dataclasses()

    # Setup logging
    logging.basicConfig(
        format="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
        datefmt="%m/%d/%Y %H:%M:%S",
        handlers=[logging.StreamHandler(sys.stdout)],
    )

    if training_args.should_log:
        # The default of training_args.log_level is passive, so we set log level at info here to have that default.
        transformers.utils.logging.set_verbosity_info()

    log_level = training_args.get_process_log_level()
    logger.setLevel(log_level)
    # datasets.utils.logging.set_verbosity(log_level)
    transformers.utils.logging.set_verbosity(log_level)
    transformers.utils.logging.enable_default_handler()
    transformers.utils.logging.enable_explicit_format()

    # Log on each process the small summary:
    logger.warning(
        f"Process rank: {training_args.local_rank}, device: {training_args.device}, n_gpu: {training_args.n_gpu}"
        + f"distributed training: {bool(training_args.local_rank != -1)}, 16-bits training: {training_args.fp16}"
    )
    logger.info(f"Training/evaluation parameters {training_args}")

    # Set seed before initializing model.
    set_seed(training_args.seed)

    # Load dataset
    data_files = {}
    if data_args.train_file is not None:
        data_files["train"] = data_args.train_file
        extension = data_args.train_file.split(".")[-1]
    if data_args.validation_file is not None:
        data_files["validation"] = data_args.validation_file
        extension = data_args.validation_file.split(".")[-1]
    if data_args.test_file is not None:
        data_files["test"] = data_args.test_file
        extension = data_args.test_file.split(".")[-1]

    raw_datasets = load_dataset(
        extension,
        data_files=data_files,
        cache_dir=model_args.cache_dir,
        use_auth_token=True if model_args.use_auth_token else None,
    )

    # Load pretrained model and tokenizer
    config = AutoConfig.from_pretrained(model_args.model_name_or_path, trust_remote_code=True)
    config.pre_seq_len = model_args.pre_seq_len
    config.prefix_projection = model_args.prefix_projection

    tokenizer = AutoTokenizer.from_pretrained(model_args.model_name_or_path, trust_remote_code=True)

    model = AutoModel.from_pretrained(model_args.model_name_or_path, config=config, trust_remote_code=True)

    if model_args.quantization_bit is not None:
        print(f"Quantized to {model_args.quantization_bit} bit")
        model = model.quantize(model_args.quantization_bit)
    model = model.half()
    model.transformer.prefix_encoder.float()

    prefix = data_args.source_prefix if data_args.source_prefix is not None else ""

    # Preprocessing the datasets.
    # We need to tokenize inputs and targets.
    if training_args.do_train:
        column_names = raw_datasets["train"].column_names
    elif training_args.do_eval:
        column_names = raw_datasets["validation"].column_names
    elif training_args.do_predict:
        column_names = raw_datasets["test"].column_names
    else:
        logger.info("There is nothing to do. Please pass `do_train`, `do_eval` and/or `do_predict`.")
        return

    # Get the column names for input/target.
    prompt_column = data_args.prompt_column
    response_column = data_args.response_column
    
    # Temporarily set max_target_length for training.
    max_target_length = data_args.max_target_length

    def preprocess_function_eval(examples):
        inputs, targets = [], []
        for i in range(len(examples[prompt_column])):
            if examples[prompt_column][i] and examples[response_column][i]:
                inputs.append(examples[prompt_column][i])
                targets.append(examples[response_column][i])

        inputs = [prefix + inp for inp in inputs]
        model_inputs = tokenizer(inputs, max_length=data_args.max_source_length, truncation=True, padding=True)
        labels = tokenizer(text_target=targets, max_length=max_target_length, truncation=True)

        if data_args.ignore_pad_token_for_loss:
            labels["input_ids"] = [
                [(l if l != tokenizer.pad_token_id else -100) for l in label] for label in labels["input_ids"]
            ]
        model_inputs["labels"] = labels["input_ids"]

        return model_inputs
    
    def preprocess_function_train(examples):
        max_seq_length = data_args.max_source_length + data_args.max_target_length

        model_inputs = {
            "input_ids": [],
            "labels": [],
        }
        for i in range(len(examples[prompt_column])):
            if examples[prompt_column][i] and examples[response_column][i]:
                prompt, answer = examples[prompt_column][i], examples[response_column][i]
                prompt = prefix + prompt
                a_ids = tokenizer.encode(text=prompt, add_special_tokens=False)
                b_ids = tokenizer.encode(text=answer, add_special_tokens=False)

                if len(a_ids) > data_args.max_source_length - 1:
                    a_ids = a_ids[: data_args.max_source_length - 1]

                if len(b_ids) > data_args.max_target_length - 2:
                    b_ids = b_ids[: data_args.max_target_length - 2]

                input_ids = a_ids + [150001, 150004] + b_ids + [150005]

                context_length = input_ids.index(150004)
                mask_position = context_length - 1
                labels = [-100] * context_length + input_ids[mask_position+1:]
                
                pad_len = max_seq_length - len(input_ids)
                input_ids = input_ids + [tokenizer.pad_token_id] * pad_len
                labels = labels + [tokenizer.pad_token_id] * pad_len
                if data_args.ignore_pad_token_for_loss:
                    labels = [(l if l != tokenizer.pad_token_id else -100) for l in labels]

                model_inputs["input_ids"].append(input_ids)
                model_inputs["labels"].append(labels)

        return model_inputs
    
    def print_dataset_example(example):
        print("input_ids",example["input_ids"])
        print("inputs", tokenizer.decode(example["input_ids"]))
        print("label_ids", example["labels"])
        print("labels", tokenizer.decode(example["labels"]))

    if training_args.do_train:
        if "train" not in raw_datasets:
            raise ValueError("--do_train requires a train dataset")
        train_dataset = raw_datasets["train"]
        if data_args.max_train_samples is not None:
            max_train_samples = min(len(train_dataset), data_args.max_train_samples)
            train_dataset = train_dataset.select(range(max_train_samples))
        with training_args.main_process_first(desc="train dataset map pre-processing"):
            train_dataset = train_dataset.map(
                preprocess_function_train,
                batched=True,
                num_proc=data_args.preprocessing_num_workers,
                remove_columns=column_names,
                load_from_cache_file=not data_args.overwrite_cache,
                desc="Running tokenizer on train dataset",
            )
        print_dataset_example(train_dataset[0])

    if training_args.do_eval:
        max_target_length = data_args.val_max_target_length
        if "validation" not in raw_datasets:
            raise ValueError("--do_eval requires a validation dataset")
        eval_dataset = raw_datasets["validation"]
        if data_args.max_eval_samples is not None:
            max_eval_samples = min(len(eval_dataset), data_args.max_eval_samples)
            eval_dataset = eval_dataset.select(range(max_eval_samples))
        with training_args.main_process_first(desc="validation dataset map pre-processing"):
            eval_dataset = eval_dataset.map(
                preprocess_function_eval,
                batched=True,
                num_proc=data_args.preprocessing_num_workers,
                remove_columns=column_names,
                load_from_cache_file=not data_args.overwrite_cache,
                desc="Running tokenizer on validation dataset",
            )
        print_dataset_example(eval_dataset[0])

    if training_args.do_predict:
        max_target_length = data_args.val_max_target_length
        if "test" not in raw_datasets:
            raise ValueError("--do_predict requires a test dataset")
        predict_dataset = raw_datasets["test"]
        if data_args.max_predict_samples is not None:
            max_predict_samples = min(len(predict_dataset), data_args.max_predict_samples)
            predict_dataset = predict_dataset.select(range(max_predict_samples))
        with training_args.main_process_first(desc="prediction dataset map pre-processing"):
            predict_dataset = predict_dataset.map(
                preprocess_function_eval,
                batched=True,
                num_proc=data_args.preprocessing_num_workers,
                remove_columns=column_names,
                load_from_cache_file=not data_args.overwrite_cache,
                desc="Running tokenizer on prediction dataset",
            )
        print_dataset_example(predict_dataset[0])

    # Data collator
    label_pad_token_id = -100 if data_args.ignore_pad_token_for_loss else tokenizer.pad_token_id
    data_collator = DataCollatorForSeq2Seq(
        tokenizer,
        model=model,
        label_pad_token_id=label_pad_token_id,
        pad_to_multiple_of=None,
        padding=False
    )

    # Metric
    def compute_metrics(eval_preds):
        preds, labels = eval_preds
        if isinstance(preds, tuple):
            preds = preds[0]
        decoded_preds = tokenizer.batch_decode(preds, skip_special_tokens=True)
        if data_args.ignore_pad_token_for_loss:
            # Replace -100 in the labels as we can't decode them.
            labels = np.where(labels != -100, labels, tokenizer.pad_token_id)
        decoded_labels = tokenizer.batch_decode(labels, skip_special_tokens=True)

        score_dict = {
            "rouge-1": [],
            "rouge-2": [],
            "rouge-l": [],
            "bleu-4": []
        }
        for pred, label in zip(decoded_preds, decoded_labels):
            hypothesis = list(jieba.cut(pred))
            reference = list(jieba.cut(label))
            rouge = Rouge()
            scores = rouge.get_scores(' '.join(hypothesis) , ' '.join(reference))
            result = scores[0]
            
            for k, v in result.items():
                score_dict[k].append(round(v["f"] * 100, 4))
            bleu_score = sentence_bleu([list(label)], list(pred))
            score_dict["bleu-4"].append(round(bleu_score * 100, 4))

        for k, v in score_dict.items():
            score_dict[k] = float(np.mean(v))
        return score_dict

    # Override the decoding parameters of Seq2SeqTrainer
    training_args.generation_max_length = (
        training_args.generation_max_length
        if training_args.generation_max_length is not None
        else data_args.val_max_target_length
    )
    training_args.generation_num_beams = (
        data_args.num_beams if data_args.num_beams is not None else training_args.generation_num_beams
    )
    # Initialize our Trainer
    trainer = Seq2SeqTrainer(
        model=model,
        args=training_args,
        train_dataset=train_dataset if training_args.do_train else None,
        eval_dataset=eval_dataset if training_args.do_eval else None,
        tokenizer=tokenizer,
        data_collator=data_collator,
        compute_metrics=compute_metrics if training_args.predict_with_generate else None,
    )

    # Training
    if training_args.do_train:
        checkpoint = None
        if training_args.resume_from_checkpoint is not None:
            checkpoint = training_args.resume_from_checkpoint
        # elif last_checkpoint is not None:
        #     checkpoint = last_checkpoint
        model.gradient_checkpointing_enable()
        model.enable_input_require_grads()
        train_result = trainer.train(resume_from_checkpoint=checkpoint)
        # trainer.save_model()  # Saves the tokenizer too for easy upload

        metrics = train_result.metrics
        max_train_samples = (
            data_args.max_train_samples if data_args.max_train_samples is not None else len(train_dataset)
        )
        metrics["train_samples"] = min(max_train_samples, len(train_dataset))

        trainer.log_metrics("train", metrics)
        trainer.save_metrics("train", metrics)
        trainer.save_state()

    # Evaluation
    results = {}
    if training_args.do_eval:
        logger.info("*** Evaluate ***")
        metrics = trainer.evaluate(metric_key_prefix="eval", do_sample=True, top_p=0.7, max_length=512, temperature=0.95)
        max_eval_samples = data_args.max_eval_samples if data_args.max_eval_samples is not None else len(eval_dataset)
        metrics["eval_samples"] = min(max_eval_samples, len(eval_dataset))

        trainer.log_metrics("eval", metrics)
        trainer.save_metrics("eval", metrics)

    if training_args.do_predict:
        logger.info("*** Predict ***")

        predict_results = trainer.predict(predict_dataset, metric_key_prefix="predict", max_length=512, do_sample=True, top_p=0.7, temperature=0.95)
        metrics = predict_results.metrics
        max_predict_samples = (
            data_args.max_predict_samples if data_args.max_predict_samples is not None else len(predict_dataset)
        )
        metrics["predict_samples"] = min(max_predict_samples, len(predict_dataset))

        trainer.log_metrics("predict", metrics)
        trainer.save_metrics("predict", metrics)

        if trainer.is_world_process_zero():
            if training_args.predict_with_generate:
                predictions = tokenizer.batch_decode(
                    predict_results.predictions, skip_special_tokens=True, clean_up_tokenization_spaces=True
                )
                predictions = [pred.strip() for pred in predictions]
                labels = tokenizer.batch_decode(
                    predict_results.label_ids, skip_special_tokens=True, clean_up_tokenization_spaces=True
                )
                labels = [label.strip() for label in labels]
                output_prediction_file = os.path.join(training_args.output_dir, "generated_predictions.txt")
                with open(output_prediction_file, "w", encoding="utf-8") as writer:
                    for p, l in zip(predictions, labels):
                        res = json.dumps({"labels": l, "predict": p}, ensure_ascii=False)
                        writer.write(f"{res}\n")
    return results


def _mp_fn(index):
    # For xla_spawn (TPUs)
    main()


if __name__ == "__main__":
    main()