# Copyright 2026 jCloud

# 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.

'''
The utilities for jcloud_docsgen
'''

import pathlib
import os
import errno
from typing import Union
import types

class ExistingDirectory(pathlib.Path):
    '''
    pathlib.Path subclass that is a directory.

    ExistingDirectory represents a filesystem path but it also checks
    whether the path exists and is not a file but a directory. It
    inherits from pathlib.Path.
    '''
    def __init__(self, path, *args, **kwargs) -> None:
        if not os.path.exists(path):
            raise FileNotFoundError(errno.ENOENT, 'no such file or directory', path)
        if not os.path.isdir(path):
            raise NotADirectoryError(errno.ENOTDIR, 'not a directory', path)
        super().__init__(*(path, *args), **kwargs)

class ExistingFile(pathlib.Path):
    '''
    pathlib.Path subclass that is a file.

    ExistingFile represents a filesystem path but it also checks whether
    the path exists and is not a directory but a file. It inherits from
    pathlib.Path.
    '''
    def __init__(self, path, *args, **kwargs) -> None:
        if not os.path.exists(path):
            raise FileNotFoundError(errno.ENOENT, 'no such file or directory', path)
        if not os.path.isfile(path):
            raise IsADirectoryError(errno.EISDIR, 'is a directory', path)
        super().__init__(*(path, *args), **kwargs)

def _quote(string: str, quotation_mark: str) -> str:
    '''
    Quotes a string.
    
    :param string: The string to quote
    :type string: str
    :param quotation_mark: The quotation mark
    :type quotation_mark: str

    :return: The quoted string
    :rtype: str
    '''

    return quotation_mark + string + quotation_mark

def human_readable_list(ls: list, final_separator: str = 'and', quotation_mark: str = '') -> str:
    '''
    Generates a human-readable list from a list.

    :param ls: The list.
    :type ls: list
    :param final_separator: The seperator between the last and the
                            second-to-last element of the list. Default
                            is 'and'.
    :type final_separator: str
    :param quotation_mark: The characters that are inserted before and
                           after an element. Default is ''.
    
    :return: The human-readable list.
    :rtype: str
    '''

    # empty list
    if not ls:
        return ''
    
    # list with one element
    if len(ls) == 1:
        return _quote(str(ls[0]), quotation_mark)
    
    return ', '.join(
        [
            _quote(str(obj), quotation_mark) # quote the string representation of the object
            for obj in ls[:-1] # do not include the last element of the list
        ]
    ) + ' ' + final_separator + ' ' + _quote(str(ls[-1]), quotation_mark)

def _list_type_names(types: list[type]) -> list[str]:
    '''
    Converts a list of types into a list of their names (``__name__``
    attribute)

    :param types: The list of types
    :type types: list[type]

    :return: The list of the names of the types
    :rtype: list[str]
    '''

    return [tp.__name__ for tp in types]

def assert_that_is_instance(obj: object, class_or_tuple: Union[type, types.UnionType, tuple[type, ...]]) -> None:
    if not isinstance(class_or_tuple, Union[type, types.UnionType, tuple]):
        raise TypeError(f'class_or_tuple: expected \'Union[type, types.UnionType, tuple[type, ...]]\', \'got {type(class_or_tuple).__name__}\'')
    if not isinstance(obj, class_or_tuple):
        if isinstance(class_or_tuple, (tuple, types.UnionType)):
            if isinstance(class_or_tuple, types.UnionType):
                class_or_tuple = class_or_tuple.__args__
            if len(class_or_tuple) > 1:
                exception_message_expected = 'either '
            else:
                exception_message_expected = ''
            exception_message_expected += human_readable_list(_list_type_names(class_or_tuple), 'or', '\'')
        else:
            exception_message_expected = '\'' + class_or_tuple.__name__ + '\''
        raise TypeError(f'expected {exception_message_expected}, got \'{type(obj).__name__}\'')
    
def non_empty_str(value: Union[str, None]) -> Union[str, None]:
    '''
    Returns the value or ``None``.

    Returns the value if it is not empty and not `Ǹone``; otherwise,
    returns ``None``.
    Please note: values are stripped, i. e. if the value consists only
                 of spaces, it is also considered empty.

    :param value: The value.
    :type value: Union[str, None]

    :return: The value or ``None``.
    :rtype: Union[str, None]
    '''

    if value is None:
        return None
    
    if value.strip() == '':
        return None

    return value

def get_relative_path_segments(path: pathlib.Path, root: pathlib.Path) -> list[str]:
    '''
    Returns the path segments relative to ``root``.

    :param path: The path.
    :type path: pathlib.Path
    :param root: The root path.
    :type root: pathlib.Path

    :return: The path segments relative to ``root``.
    :rtype: list[str]
    '''

    return list(
        path.resolve()
        .relative_to(
            root.resolve()
        )
        .parts
    )