"""
Helper functions for file reading and writing
"""
import re
import pathlib
import logging

from .. import Pattern, PatternError
from ..shapes import Polygon, Path


logger = logging.getLogger(__name__)


def mangle_name(name: str) -> str:
    """
    Sanitize a name.

    Args:
        name: Name we want to mangle.

    Returns:
        Mangled name.
    """
    expression = re.compile(r'[^A-Za-z0-9_\?\$]')
    sanitized_name = expression.sub('_', name)
    return sanitized_name


def clean_pattern_vertices(pat: Pattern) -> Pattern:
    """
    Given a pattern, remove any redundant vertices in its polygons and paths.
    The cleaning process completely removes any polygons with zero area or <3 vertices.

    Args:
        pat: Pattern to clean

    Returns:
        pat
    """
    remove_inds = []
    for ii, shape in enumerate(pat.shapes):
        if not isinstance(shape, (Polygon, Path)):
            continue
        try:
            shape.clean_vertices()
        except PatternError:
            remove_inds.append(ii)
    for ii in sorted(remove_inds, reverse=True):
        del pat.shapes[ii]
    return pat


def is_gzipped(path: pathlib.Path) -> bool:
    with open(path, 'rb') as stream:
        magic_bytes = stream.read(2)
        return magic_bytes == b'\x1f\x8b'