import uuid
import re
import logging
from typing import Dict, Any, List, Optional
from dataclasses import dataclass
import tiktoken

logger = logging.getLogger(__name__)

@dataclass
class Chunk:
    """Data class for document chunks"""
    doc_id: str
    chunk_id: str
    content: str
    metadata: Dict[str, Any]
    embeddings: Optional[List[float]] = None

class TextProcessor:
    """Text processing utilities"""
    
    def __init__(self):
        self.encoding = tiktoken.get_encoding("cl100k_base")
    
    def count_tokens(self, text: str) -> int:
        """Count tokens in text"""
        return len(self.encoding.encode(text))
    
    def mask_pii(self, text: str) -> str:
        """Mask personally identifiable information"""
        # Email addresses
        text = re.sub(r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b', '[EMAIL]', text)
        # Phone numbers
        text = re.sub(r'\b\d{3}[-.]?\d{3}[-.]?\d{4}\b', '[PHONE]', text)
        # Credit card numbers
        text = re.sub(r'\b\d{4}[- ]?\d{4}[- ]?\d{4}[- ]?\d{4}\b', '[CREDIT_CARD]', text)
        # SSN
        text = re.sub(r'\b\d{3}-\d{2}-\d{4}\b', '[SSN]', text)
        return text
    
    def clean_text(self, text: str) -> str:
        """Clean and normalize text"""
        # Remove extra whitespace
        text = re.sub(r'\s+', ' ', text)
        # Remove special characters but keep basic punctuation
        text = re.sub(r'[^\w\s.,!?;:()\-]', '', text)
        return text.strip()

    def clean_text_preserve_newlines(self, text: str) -> str:
        """Normalize text but preserve paragraph breaks for chunking.
        - Normalize Windows newlines to \n
        - Trim spaces on each line
        - Collapse 3+ newlines -> 2 newlines (keep blank lines as separators)
        - Collapse multiple spaces within lines
        - Keep basic punctuation
        """
        # Normalize line endings
        text = text.replace('\r\n', '\n').replace('\r', '\n')
        # Trim spaces on each line
        text = '\n'.join(line.strip() for line in text.split('\n'))
        # Collapse 3+ newlines to 2 newlines
        text = re.sub(r'\n{3,}', '\n\n', text)
        # Collapse multiple spaces within lines
        text = re.sub(r'[ \t]+', ' ', text)
        # Remove disallowed characters but keep punctuation and newlines
        text = re.sub(r'[^\w\s\n.,!?;:()\-]', '', text)
        return text.strip()

def generate_id() -> str:
    """Generate unique ID"""
    return str(uuid.uuid4())