<reponame>st3107/pdfstream
"""The tools to read, write, audit, transform, wash the data."""
from typing import Any
from typing import Callable
from typing import Generator


def paths(dct: Any, path=()) -> Generator:
    """Yield paths to the leafs of a nested dictionary."""
    if isinstance(dct, dict):
        for key, value in dct.items():
            yield from paths(value, path + (key,))
    elif isinstance(dct, (tuple, list)):
        for ind, elem in enumerate(dct):
            yield from paths(elem, path + (ind,))
    else:
        yield path + (dct,)


def iter_dct(dct: dict, operation: Callable):
    """Recursively iterate the dictionary and operate on the leaf nodes. Return the processed dictionary."""
    dct2 = dict()
    for key, value in dct.items():
        if isinstance(value, dict):
            dct2[key] = iter_dct(value, operation)
        else:
            dct2[key] = operation(value)
    return dct2


def to_dict(obj: object, exclude: Callable[[str], bool] = None) -> dict:
    """Convert an object to a dictionary by keeping import attribute information."""

    def pdfconfig_exclude(attr: str) -> bool:
        """Whether to exclude an attribute in pdfconfig."""
        if attr.startswith("_"):
            return True
        if attr in ("inputfiles", "output", "interact"):
            return True
        return False

    dct = {}
    if exclude is None:
        exclude = pdfconfig_exclude
    for attr_key, attr_val in obj.__dict__.items():
        if not exclude(attr_key):
            dct[attr_key] = attr_val
    return dct


def get_value(dct: dict, keys: tuple) -> Any:
    """Get the value by walking along a key chain."""
    result = dct
    for key in keys:
        result = result[key]
    return result
