# coding=utf-8
# Copyright 2018 The HuggingFace Inc. team.
#
# 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.
"""Convert OpenAI GPT checkpoint."""

from __future__ import absolute_import, division, print_function

import argparse
from io import open

import torch

from transformers import (
    CONFIG_NAME,
    WEIGHTS_NAME,
    GPT2Config,
    GPT2Model,
    load_tf_weights_in_gpt2,
)

import logging

logging.basicConfig(level=logging.INFO)


def convert_gpt2_checkpoint_to_pytorch(
    gpt2_checkpoint_path, gpt2_config_file, pytorch_dump_folder_path
):
    # Construct model
    if gpt2_config_file == "":
        config = GPT2Config()
    else:
        config = GPT2Config.from_json_file(gpt2_config_file)
    model = GPT2Model(config)

    # Load weights from numpy
    load_tf_weights_in_gpt2(model, config, gpt2_checkpoint_path)

    # Save pytorch-model
    pytorch_weights_dump_path = pytorch_dump_folder_path + "/" + WEIGHTS_NAME
    pytorch_config_dump_path = pytorch_dump_folder_path + "/" + CONFIG_NAME
    print("Save PyTorch model to {}".format(pytorch_weights_dump_path))
    torch.save(model.state_dict(), pytorch_weights_dump_path)

    print("Save configuration file to {}".format(pytorch_config_dump_path))
    with open(pytorch_config_dump_path, "w", encoding="utf-8") as f:
        f.write(config.to_json_string())

    # Also save as half precision to save transfer, loading, and inference time and memory
    pytorch_weights_dump_path += 'half'
    model.half()
    torch.save(model.state_dict(), pytorch_weights_dump_path)
    with open(pytorch_config_dump_path "w", encoding="utf-8") as f:
        f.write(config.to_json_string())
    print("Save configuration file to {}".format(pytorch_config_dump_path))


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    ## Required parameters
    parser.add_argument(
        "--gpt2_checkpoint_path",
        default=None,
        type=str,
        required=True,
        help="Path to the TensorFlow checkpoint path.",
    )
    parser.add_argument(
        "--pytorch_dump_folder_path",
        default=None,
        type=str,
        required=True,
        help="Path to the output PyTorch model.",
    )
    parser.add_argument(
        "--gpt2_config_file",
        default="",
        type=str,
        help="An optional config json file corresponding to the pre-trained OpenAI model. \n"
        "This specifies the model architecture.",
    )
    args = parser.parse_args()
    convert_gpt2_checkpoint_to_pytorch(
        args.gpt2_checkpoint_path, args.gpt2_config_file, args.pytorch_dump_folder_path
    )


"""
download aidungeon2 v5 model from this torrent or elsewhere
-  magnet:?xt=urn:btih:b343b83b35bff774dab13e0281ce13b3daf37d3e&dn=model_v5&tr=udp%3a%2f%2ftracker.coppersurfer.tk%3a6969%2fannounce&tr=udp%3a%2f%2ftracker.leechers-paradise.org%3a6969%2fannounce
export OPENAI_GPT2_CHECKPOINT_PATH=../generator/gpt2/models/model_v5
export PYTORCH_DUMP_OUTPUT=../generator/gpt2/models/model_v5_pytorch
python convert_gpt2_model.py \
    --gpt2_checkpoint_path $OPENAI_GPT2_CHECKPOINT_PATH \
    --pytorch_dump_folder_path $PYTORCH_DUMP_OUTPUT \
    --gpt2_config_file ./aidungeonv2_model_v5_config.json
wget https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-xl-merges.txt -o $PYTORCH_DUMP_OUTPUT/merges.txt
wget https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-xl-vocab.json -o $PYTORCH_DUMP_OUTPUT/vocab.json
"""