import re
from typing import Optional
from datetime import datetime
from dateutil import parser

def sanitize_amount(text: str) -> Optional[float]:
    """
    Sanitizes a string representing an amount/number (e.g., "$1,234.56", "€ 50,000", "50 USD")
    by removing currency symbols, commas, and other non-numeric characters (except for the decimal separator),
    and casts it to a float.
    
    Args:
        text (str): The raw extracted text from the document.
        
    Returns:
        Optional[float]: The sanitized numeric value, or None if no number could be extracted.
    """
    if not text:
        return None
        
    # Remove obvious alphabetic currency codes, spaces, and commas
    # We keep digits, period, and minus sign
    cleaned_text = re.sub(r'[^\d\.-]', '', text)
    
    if not cleaned_text:
        return None
        
    try:
        # Handle cases where multiple periods or dashes might exist incorrectly
        # We just try to cast to float. If the OCR produced something like "1.23.45", this will fail.
        # A more robust regex can handle exact capture if needed.
        # But this basic cast covers 95% of standard sanitized strings.
        return float(cleaned_text)
    except ValueError:
        return None

def sanitize_date(text: str, field_type: str = 'DATE') -> Optional[str]:
    """
    Sanitizes a string representing a date or datetime and converts it to ISO 8601 format.
    
    Args:
        text (str): The raw extracted text from the document.
        field_type (str): 'DATE' or 'DATETIME'. Determines the output format.
        
    Returns:
        Optional[str]: The sanitized date string in ISO format, or None if it could not be parsed.
    """
    if not text:
        return None
        
    try:
        # dateutil.parser is very robust at handling formats like "Dec 11, 2020", "11/12/2020", etc.
        # fuzzy=True allows it to ignore extra words/characters around the date
        parsed_date = parser.parse(text, fuzzy=True)
        
        if field_type == 'DATETIME':
            return parsed_date.strftime('%Y-%m-%dT%H:%M:%S')
        else:
            return parsed_date.strftime('%Y-%m-%d')
    except (ValueError, TypeError, OverflowError):
        return None