import re

def extract_latest_message(email):
    """Extract only the most recent message from an email thread."""
    text = email
    
    # Define reply separators (ordered by specificity)
    separators = [
        # Outlook style - most common
        r'From:.*?Sent:.*?(?:To:|Subject:)',
        # Horizontal rules
        r'_{40,}',
        r'-{40,}',
        # "Original Message" variants
        r'[-]+\s*Original Message\s*[-]+',
        # Gmail/generic style
        r'On\s+.{0,100}?\s+wrote:',
        # Forwarded message
        r'[-]+\s*Forwarded [Mm]essage\s*[-]+',
    ]
    
    # Try each separator and take the earliest match
    earliest_match = None
    earliest_pos = len(text)
    
    for pattern in separators:
        match = re.search(pattern, text, re.IGNORECASE | re.DOTALL)
        if match and match.start() < earliest_pos:
            earliest_pos = match.start()
            earliest_match = match
    
    # Extract everything before the separator
    if earliest_match:
        latest_text = text[:earliest_pos].strip()
    else:
        latest_text = text
    
    # Remove excessive whitespace
    latest_text = re.sub(r'\n{3,}', '\n\n', latest_text)
    latest_text = re.sub(r' {2,}', ' ', latest_text)
    
    # Limit to reasonable length (adjust as needed)
    if len(latest_text) > 2000:
        latest_text = latest_text[:2000] + "..."
    
    return latest_text