# coding=utf-8
# Copyright 2021 NVIDIA Corporation. 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.
""" Finetuning the library models for question-answering on SQuAD (DistilBERT, Bert, XLM, XLNet)."""
import argparse
import logging
import os
import time
import timeit

import datasets
import numpy as np
import torch
from absl import logging as absl_logging
from datasets import load_dataset, load_metric
from torch.utils.data import DataLoader

import pycuda.autoinit  # noqa: F401
import pycuda.driver as cuda
import tensorrt as trt
import transformers
from accelerate import Accelerator
from transformers import AutoTokenizer, EvalPrediction, default_data_collator, set_seed
from transformers.trainer_pt_utils import nested_concat, nested_truncate
from utils_qa import postprocess_qa_predictions


TRT_LOGGER = trt.Logger(trt.Logger.WARNING)
absl_logger = absl_logging.get_absl_logger()
absl_logger.setLevel(logging.WARNING)

logger = logging.getLogger(__name__)

parser = argparse.ArgumentParser()

# Required parameters
parser.add_argument(
    "--onnx_model_path",
    default=None,
    type=str,
    required=True,
    help="Path to ONNX model: ",
)

parser.add_argument(
    "--output_dir",
    default=None,
    type=str,
    required=True,
    help="The output directory where the model checkpoints and predictions will be written.",
)

# Other parameters

parser.add_argument(
    "--tokenizer_name",
    default="",
    type=str,
    required=True,
    help="Pretrained tokenizer name or path if not the same as model_name",
)

parser.add_argument(
    "--version_2_with_negative",
    action="store_true",
    help="If true, the SQuAD examples contain some that do not have an answer.",
)
parser.add_argument(
    "--null_score_diff_threshold",
    type=float,
    default=0.0,
    help="If null_score - best_non_null is greater than the threshold predict null.",
)

parser.add_argument(
    "--max_seq_length",
    default=384,
    type=int,
    help=(
        "The maximum total input sequence length after WordPiece tokenization. Sequences "
        "longer than this will be truncated, and sequences shorter than this will be padded."
    ),
)
parser.add_argument(
    "--doc_stride",
    default=128,
    type=int,
    help="When splitting up a long document into chunks, how much stride to take between chunks.",
)

parser.add_argument("--per_device_eval_batch_size", default=8, type=int, help="Batch size per GPU/CPU for evaluation.")

parser.add_argument(
    "--n_best_size",
    default=20,
    type=int,
    help="The total number of n-best predictions to generate in the nbest_predictions.json output file.",
)
parser.add_argument(
    "--max_answer_length",
    default=30,
    type=int,
    help=(
        "The maximum length of an answer that can be generated. This is needed because the start "
        "and end predictions are not conditioned on one another."
    ),
)

parser.add_argument("--seed", type=int, default=42, help="random seed for initialization")

parser.add_argument(
    "--dataset_name",
    type=str,
    default=None,
    required=True,
    help="The name of the dataset to use (via the datasets library).",
)
parser.add_argument(
    "--dataset_config_name",
    type=str,
    default=None,
    help="The configuration name of the dataset to use (via the datasets library).",
)
parser.add_argument(
    "--preprocessing_num_workers", type=int, default=4, help="A csv or a json file containing the training data."
)
parser.add_argument(
    "--overwrite_cache", type=bool, default=False, help="Overwrite the cached training and evaluation sets"
)
parser.add_argument(
    "--fp16",
    action="store_true",
    help="Whether to use 16-bit (mixed) precision instead of 32-bit",
)
parser.add_argument(
    "--int8",
    action="store_true",
    help="Whether to use INT8",
)

args = parser.parse_args()

if args.tokenizer_name:
    tokenizer = AutoTokenizer.from_pretrained(args.tokenizer_name, use_fast=True)
else:
    raise ValueError(
        "You are instantiating a new tokenizer from scratch. This is not supported by this script."
        "You can do it from another script, save it, and load it from here, using --tokenizer_name."
    )

logger.info("Training/evaluation parameters %s", args)

args.eval_batch_size = args.per_device_eval_batch_size

INPUT_SHAPE = (args.eval_batch_size, args.max_seq_length)

# TRT Engine properties
STRICT_TYPES = True

engine_name = "temp_engine/bert-fp32.engine"
if args.fp16:
    engine_name = "temp_engine/bert-fp16.engine"
if args.int8:
    engine_name = "temp_engine/bert-int8.engine"

# import ONNX file
if not os.path.exists("temp_engine"):
    os.makedirs("temp_engine")

EXPLICIT_BATCH = 1 << (int)(trt.NetworkDefinitionCreationFlag.EXPLICIT_BATCH)
with trt.Builder(TRT_LOGGER) as builder, builder.create_network(EXPLICIT_BATCH) as network, trt.OnnxParser(
    network, TRT_LOGGER
) as parser:
    with open(args.onnx_model_path, "rb") as model:
        if not parser.parse(model.read()):
            for error in range(parser.num_errors):
                print(parser.get_error(error))

    # Query input names and shapes from parsed TensorRT network
    network_inputs = [network.get_input(i) for i in range(network.num_inputs)]
    input_names = [_input.name for _input in network_inputs]  # ex: ["actual_input1"]

    with builder.create_builder_config() as config:
        config.max_workspace_size = 1 << 50
        if STRICT_TYPES:
            config.set_flag(trt.BuilderFlag.STRICT_TYPES)
        if args.fp16:
            config.set_flag(trt.BuilderFlag.FP16)
        if args.int8:
            config.set_flag(trt.BuilderFlag.INT8)
        profile = builder.create_optimization_profile()
        config.add_optimization_profile(profile)
        for i in range(len(input_names)):
            profile.set_shape(input_names[i], INPUT_SHAPE, INPUT_SHAPE, INPUT_SHAPE)
        engine = builder.build_engine(network, config)

        # serialize_engine and store in file (can be directly loaded and deserialized):
        with open(engine_name, "wb") as f:
            f.write(engine.serialize())


# run inference with TRT
def model_infer(inputs, context, d_inputs, h_output0, h_output1, d_output0, d_output1, stream):
    input_ids = np.asarray(inputs["input_ids"], dtype=np.int32)
    attention_mask = np.asarray(inputs["attention_mask"], dtype=np.int32)
    token_type_ids = np.asarray(inputs["token_type_ids"], dtype=np.int32)

    # Copy inputs
    cuda.memcpy_htod_async(d_inputs[0], input_ids.ravel(), stream)
    cuda.memcpy_htod_async(d_inputs[1], attention_mask.ravel(), stream)
    cuda.memcpy_htod_async(d_inputs[2], token_type_ids.ravel(), stream)
    # start time
    start_time = time.time()
    # Run inference
    context.execute_async(
        bindings=[int(d_inp) for d_inp in d_inputs] + [int(d_output0), int(d_output1)], stream_handle=stream.handle
    )
    # Transfer predictions back from GPU
    cuda.memcpy_dtoh_async(h_output0, d_output0, stream)
    cuda.memcpy_dtoh_async(h_output1, d_output1, stream)
    # Synchronize the stream and take time
    stream.synchronize()
    # end time
    end_time = time.time()
    infer_time = end_time - start_time
    outputs = (h_output0, h_output1)
    # print(outputs)
    return outputs, infer_time


# Initialize the accelerator. We will let the accelerator handle device placement for us in this example.
accelerator = Accelerator()
# Make one log on every process with the configuration for debugging.
logging.basicConfig(
    format="%(asctime)s - %(levelname)s - %(name)s - %(message)s",
    datefmt="%m/%d/%Y %H:%M:%S",
    level=logging.INFO,
)

# Setup logging, we only want one process per machine to log things on the screen.
# accelerator.is_local_main_process is only True for one process per machine.
logger.setLevel(logging.INFO if accelerator.is_local_main_process else logging.ERROR)
if accelerator.is_local_main_process:
    datasets.utils.logging.set_verbosity_warning()
    transformers.utils.logging.set_verbosity_info()
else:
    datasets.utils.logging.set_verbosity_error()
    transformers.utils.logging.set_verbosity_error()

# If passed along, set the training seed now.
if args.seed is not None:
    set_seed(args.seed)

# Get the datasets: you can either provide your own CSV/JSON/TXT training and evaluation files (see below)
# or just provide the name of one of the public datasets available on the hub at https://huggingface.co/datasets/
# (the dataset will be downloaded automatically from the datasets Hub).
#
# For CSV/JSON files, this script will use the column called 'text' or the first column if no column called
# 'text' is found. You can easily tweak this behavior (see below).
if args.dataset_name is not None:
    # Downloading and loading a dataset from the hub.
    raw_datasets = load_dataset(args.dataset_name, args.dataset_config_name)
else:
    raise ValueError("Evaluation requires a dataset name")
# See more about loading any type of standard or custom dataset (from files, python dict, pandas DataFrame, etc) at
# https://huggingface.co/docs/datasets/loading_datasets.html.

# Preprocessing the datasets.
# Preprocessing is slighlty different for training and evaluation.

column_names = raw_datasets["validation"].column_names

question_column_name = "question" if "question" in column_names else column_names[0]
context_column_name = "context" if "context" in column_names else column_names[1]
answer_column_name = "answers" if "answers" in column_names else column_names[2]

# Padding side determines if we do (question|context) or (context|question).
pad_on_right = tokenizer.padding_side == "right"

if args.max_seq_length > tokenizer.model_max_length:
    logger.warning(
        f"The max_seq_length passed ({args.max_seq_length}) is larger than the maximum length for the"
        f"model ({tokenizer.model_max_length}). Using max_seq_length={tokenizer.model_max_length}."
    )

max_seq_length = min(args.max_seq_length, tokenizer.model_max_length)


# Validation preprocessing
def prepare_validation_features(examples):
    # Some of the questions have lots of whitespace on the left, which is not useful and will make the
    # truncation of the context fail (the tokenized question will take a lots of space). So we remove that
    # left whitespace
    examples[question_column_name] = [q.lstrip() for q in examples[question_column_name]]

    # Tokenize our examples with truncation and maybe padding, but keep the overflows using a stride. This results
    # in one example possible giving several features when a context is long, each of those features having a
    # context that overlaps a bit the context of the previous feature.
    tokenized_examples = tokenizer(
        examples[question_column_name if pad_on_right else context_column_name],
        examples[context_column_name if pad_on_right else question_column_name],
        truncation="only_second" if pad_on_right else "only_first",
        max_length=max_seq_length,
        stride=args.doc_stride,
        return_overflowing_tokens=True,
        return_offsets_mapping=True,
        padding="max_length",
    )

    # Since one example might give us several features if it has a long context, we need a map from a feature to
    # its corresponding example. This key gives us just that.
    sample_mapping = tokenized_examples.pop("overflow_to_sample_mapping")

    # For evaluation, we will need to convert our predictions to substrings of the context, so we keep the
    # corresponding example_id and we will store the offset mappings.
    tokenized_examples["example_id"] = []

    for i in range(len(tokenized_examples["input_ids"])):
        # Grab the sequence corresponding to that example (to know what is the context and what is the question).
        sequence_ids = tokenized_examples.sequence_ids(i)
        context_index = 1 if pad_on_right else 0

        # One example can give several spans, this is the index of the example containing this span of text.
        sample_index = sample_mapping[i]
        tokenized_examples["example_id"].append(examples["id"][sample_index])

        # Set to None the offset_mapping that are not part of the context so it's easy to determine if a token
        # position is part of the context or not.
        tokenized_examples["offset_mapping"][i] = [
            (o if sequence_ids[k] == context_index else None)
            for k, o in enumerate(tokenized_examples["offset_mapping"][i])
        ]

    return tokenized_examples


eval_examples = raw_datasets["validation"]
# Validation Feature Creation
eval_dataset = eval_examples.map(
    prepare_validation_features,
    batched=True,
    num_proc=args.preprocessing_num_workers,
    remove_columns=column_names,
    load_from_cache_file=not args.overwrite_cache,
    desc="Running tokenizer on validation dataset",
)

data_collator = default_data_collator

eval_dataset_for_model = eval_dataset.remove_columns(["example_id", "offset_mapping"])
eval_dataloader = DataLoader(
    eval_dataset_for_model, collate_fn=data_collator, batch_size=args.per_device_eval_batch_size
)


# Post-processing:
def post_processing_function(examples, features, predictions, stage="eval"):
    # Post-processing: we match the start logits and end logits to answers in the original context.
    predictions = postprocess_qa_predictions(
        examples=examples,
        features=features,
        predictions=predictions,
        version_2_with_negative=args.version_2_with_negative,
        n_best_size=args.n_best_size,
        max_answer_length=args.max_answer_length,
        null_score_diff_threshold=args.null_score_diff_threshold,
        output_dir=args.output_dir,
        prefix=stage,
    )
    # Format the result to the format the metric expects.
    if args.version_2_with_negative:
        formatted_predictions = [
            {"id": k, "prediction_text": v, "no_answer_probability": 0.0} for k, v in predictions.items()
        ]
    else:
        formatted_predictions = [{"id": k, "prediction_text": v} for k, v in predictions.items()]

    references = [{"id": ex["id"], "answers": ex[answer_column_name]} for ex in examples]
    return EvalPrediction(predictions=formatted_predictions, label_ids=references)


metric = load_metric("squad_v2" if args.version_2_with_negative else "squad")

# Evaluation!
logger.info("Loading ONNX model %s for evaluation", args.onnx_model_path)
with open(engine_name, "rb") as f, trt.Runtime(TRT_LOGGER) as runtime, runtime.deserialize_cuda_engine(
    f.read()
) as engine, engine.create_execution_context() as context:

    # setup for TRT inferrence
    for i in range(len(input_names)):
        context.set_binding_shape(i, INPUT_SHAPE)
    assert context.all_binding_shapes_specified

    def binding_nbytes(binding):
        return trt.volume(engine.get_binding_shape(binding)) * engine.get_binding_dtype(binding).itemsize

    # Allocate device memory for inputs and outputs.
    d_inputs = [cuda.mem_alloc(binding_nbytes(binding)) for binding in engine if engine.binding_is_input(binding)]

    # Allocate output buffer
    h_output0 = cuda.pagelocked_empty(tuple(context.get_binding_shape(3)), dtype=np.float32)
    h_output1 = cuda.pagelocked_empty(tuple(context.get_binding_shape(4)), dtype=np.float32)
    d_output0 = cuda.mem_alloc(h_output0.nbytes)
    d_output1 = cuda.mem_alloc(h_output1.nbytes)

    # Create a stream in which to copy inputs/outputs and run inference.
    stream = cuda.Stream()

    # Evaluation
    logger.info("***** Running Evaluation *****")
    logger.info(f"  Num examples = {len(eval_dataset)}")
    logger.info(f"  Batch size = {args.per_device_eval_batch_size}")

    total_time = 0.0
    niter = 0
    start_time = timeit.default_timer()

    all_preds = None
    for step, batch in enumerate(eval_dataloader):

        outputs, infer_time = model_infer(batch, context, d_inputs, h_output0, h_output1, d_output0, d_output1, stream)
        total_time += infer_time
        niter += 1

        start_logits, end_logits = outputs
        start_logits = torch.tensor(start_logits)
        end_logits = torch.tensor(end_logits)

        # necessary to pad predictions and labels for being gathered
        start_logits = accelerator.pad_across_processes(start_logits, dim=1, pad_index=-100)
        end_logits = accelerator.pad_across_processes(end_logits, dim=1, pad_index=-100)

        logits = (accelerator.gather(start_logits).cpu().numpy(), accelerator.gather(end_logits).cpu().numpy())
        all_preds = logits if all_preds is None else nested_concat(all_preds, logits, padding_index=-100)

    if all_preds is not None:
        all_preds = nested_truncate(all_preds, len(eval_dataset))

    evalTime = timeit.default_timer() - start_time
    logger.info("  Evaluation done in total %f secs (%f sec per example)", evalTime, evalTime / len(eval_dataset))
    # Inference time from TRT
    logger.info("Average Inference Time = {:.3f} ms".format(total_time * 1000 / niter))
    logger.info("Total Inference Time =  {:.3f} ms".format(total_time * 1000))
    logger.info("Total Number of Inference =  %d", niter)

prediction = post_processing_function(eval_examples, eval_dataset, all_preds)
eval_metric = metric.compute(predictions=prediction.predictions, references=prediction.label_ids)
logger.info(f"Evaluation metrics: {eval_metric}")
