# Copyright 2019 Huawei Technologies Co., Ltd
#
# 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.
# ============================================================================
"""Common Tools."""
import imghdr
import math
import os

from numbers import Number
from urllib.parse import unquote

from mindinsight.datavisual.common.exceptions import MaxCountExceededError
from mindinsight.utils import exceptions

_IMG_EXT_TO_MIMETYPE = {
    'bmp': 'image/bmp',
    'gif': 'image/gif',
    'jpeg': 'image/jpeg',
    'png': 'image/png',
}
_DEFAULT_IMAGE_MIMETYPE = 'application/octet-stream'


def find_app_package():
    """Find package in current directory."""
    backend_dir = os.path.realpath(os.path.join(__file__, os.pardir, os.pardir, os.pardir, "backend"))
    packages = []
    for file in os.listdir(backend_dir):
        file_path = os.path.join(backend_dir, file)
        if os.path.isfile(file_path):
            continue
        if not os.path.isfile(os.path.join(file_path, '__init__.py')):
            continue
        rel_path = os.path.relpath(file_path, backend_dir)
        package = rel_path.replace(os.path.sep, '.')
        package = f"mindinsight.backend.{package}"
        packages.append(package)
    return packages


def to_str(bytes_or_text, encode="utf-8"):
    """Bytes transform string."""
    if isinstance(bytes_or_text, bytes):
        return bytes_or_text.decode(encode)
    if isinstance(bytes_or_text, str):
        return bytes_or_text

    raise TypeError("Param isn't str or bytes type, param={}".format(bytes_or_text))


def to_int(param, param_name):
    """
    Transfer param to int type.

    Args:
        param (Any): A param transformed.
        param_name (str): Param name.

    Returns:
        int, value after transformed.

    """
    try:
        param = int(param)
    except ValueError:
        raise exceptions.ParamTypeError(param_name, 'Integer')
    return param


def str_to_bool(param, param_name):
    """
    Check param and transform it to bool.

    Args:
        param (str): 'true' or 'false' is valid.
        param_name (str): Param name.

    Returns:
        bool, if param is 'true', case insensitive.

    Raises:
        ParamValueError: If the value of param is not 'false' and 'true'.

    """
    if not isinstance(param, str):
        raise exceptions.ParamTypeError(param_name, 'str')

    if param.lower() not in ['false', 'true']:
        raise exceptions.ParamValueError("The value of %s must be 'false' or 'true'." % param_name)
    param = (param.lower() == 'true')

    return param


def get_img_mimetype(img_data):
    """
    Recognize image headers and generate image MIMETYPE.

    Args:
        img_data (bin): Binary character stream of image.

    Returns:
        str, a MIMETYPE of the give image.
    """
    image_type = imghdr.what(None, img_data)
    mimetype = _IMG_EXT_TO_MIMETYPE.get(image_type, _DEFAULT_IMAGE_MIMETYPE)
    return mimetype


def get_train_id(request):
    """
    Get train ID from requst query string and unquote content.

    Args:
        request (FlaskRequest): Http request instance.

    Returns:
        str, unquoted train ID.
    """
    train_id = request.args.get('train_id')
    if train_id is not None:
        try:
            train_id = unquote(train_id, errors='strict')
        except UnicodeDecodeError:
            raise exceptions.UrlDecodeError('Unquote train id error with strict mode')
    return train_id


def if_nan_inf_to_none(name, value):
    """
    Transform value to None if it is NaN or Inf.

    Args:
        name (str): Name of value.
        value (float): A number transformed.

    Returns:
        float, if value is NaN or Inf, return None.

    """
    if not isinstance(value, Number):
        raise exceptions.ParamTypeError(name, 'number')
    if math.isnan(value) or math.isinf(value):
        value = None
    return value


class Counter:
    """Count accumulator with limit checking."""
    def __init__(self, max_count=None, init_count=0):
        self._count = init_count
        self._max_count = max_count

    def add(self, value=1):
        """Add value."""
        if self._max_count is not None and self._count + value > self._max_count:
            raise MaxCountExceededError()
        self._count += value