"""Символьные признаки: частоты букв, регистр, цифры, пунктуация."""

from __future__ import annotations

import string

import pandas as pd

from .base import safe_div


def extract(row: pd.Series) -> dict[str, float]:
    text = str(row.get("text", ""))
    lower = text.lower()
    letters = [char for char in lower if "a" <= char <= "z"]
    n_letters = max(len(letters), 1)
    n_chars = max(len(text), 1)

    features: dict[str, float] = {}
    for char in string.ascii_lowercase:
        features[f"char_freq_{char}"] = safe_div(letters.count(char), n_letters)

    upper = sum(1 for char in text if char.isupper())
    digits = sum(1 for char in text if char.isdigit())
    spaces = sum(1 for char in text if char.isspace())
    punctuation = sum(1 for char in text if not char.isalnum() and not char.isspace())
    features.update(
        {
            "char_letter_count": float(len(letters)),
            "char_upper_rate": safe_div(upper, n_letters),
            "char_digit_rate": safe_div(digits, n_chars),
            "char_space_rate": safe_div(spaces, n_chars),
            "char_punctuation_rate": safe_div(punctuation, n_chars),
            "char_apostrophe_rate": safe_div(text.count("'"), n_chars),
            "char_quote_rate": safe_div(text.count('"'), n_chars),
        }
    )
    return features