# 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
from typing import List
from typing import Optional

from paddle.inference import Config
from paddle.inference import create_predictor


def init_predictor(model_dir: Optional[os.PathLike]=None,
                   model_file: Optional[os.PathLike]=None,
                   params_file: Optional[os.PathLike]=None,
                   predictor_conf: dict=None):
    """Create predictor with Paddle inference

    Args:
        model_dir (Optional[os.PathLike], optional): The path of the static model saved in the model layer. Defaults to None.
        model_file (Optional[os.PathLike], optional): *.pdmodel file path. Defaults to None.
        params_file (Optional[os.PathLike], optional): *.pdiparams file path.. Defaults to None.
        predictor_conf (dict, optional): The configuration parameters of predictor. Defaults to None.

    Returns:
        predictor (PaddleInferPredictor): created predictor
    """

    if model_dir is not None:
        config = Config(args.model_dir)
    else:
        config = Config(model_file, params_file)

    config.enable_memory_optim()
    if predictor_conf["use_gpu"]:
        config.enable_use_gpu(1000, 0)
    if predictor_conf["enable_mkldnn"]:
        config.enable_mkldnn()
    if predictor_conf["switch_ir_optim"]:
        config.switch_ir_optim()

    predictor = create_predictor(config)

    return predictor


def run_model(predictor, input: List) -> List:
    """ run predictor

    Args:
        predictor: paddle inference predictor
        input (list): The input of predictor

    Returns:
        list: result list
    """
    input_names = predictor.get_input_names()
    for i, name in enumerate(input_names):
        input_handle = predictor.get_input_handle(name)
        input_handle.copy_from_cpu(input[i])

    # do the inference
    predictor.run()

    results = []
    # get out data from output tensor
    output_names = predictor.get_output_names()
    for i, name in enumerate(output_names):
        output_handle = predictor.get_output_handle(name)
        output_data = output_handle.copy_to_cpu()
        results.append(output_data)

    return results