import re
from typing import Dict, Optional


class TextNormalizer:
    """Text normalization."""

    DEFAULT_REPLACEMENTS = {
        "\\[": "$$", "\\]": "$$", "\\(": "$", "\\)": "$",
        '\u2018': "'", '\u2019': "'", '\u0060': "'",
        '\u201C': '"', '\u201D': '"',
        '\u2013': '-', '\u2014': '--', '\u2212': '-',
        '\u00A0': ' ', '\u2026': '...'
    }

    def __init__(self, custom_rules: Optional[Dict[str, str]] = None):
        self.replacements = {**self.DEFAULT_REPLACEMENTS, **(custom_rules or {})}
        self._pattern = re.compile('|'.join(re.escape(k) for k in self.replacements))

    def normalize(self, text: str) -> str:
        return self._pattern.sub(lambda m: self.replacements[m.group()], text)