import os
import sys
import logging
import shutil
from datetime import datetime
from typing import List, Dict, Any

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

def sanitize_filename(filename: str) -> str:
    """Sanitize a filename by removing invalid characters."""
    # Replace invalid characters with underscores
    invalid_chars = '<>:"/\\|?*'
    for char in invalid_chars:
        filename = filename.replace(char, '_')
    # Limit filename length to avoid issues
    if len(filename) > 200:
        base, ext = os.path.splitext(filename)
        filename = base[:195] + ext
    return filename

def get_document_path(filename: str) -> str:
    """Get the path to store a document."""
    try:
        # Get the documents directory
        docs_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))), 'data', 'documents')
        
        # Create the directory if it doesn't exist
        os.makedirs(docs_dir, exist_ok=True)
        
        # Try to ensure the directory has write permissions
        try:
            # Test file to check write permissions
            test_file = os.path.join(docs_dir, '.test_write_access')
            with open(test_file, 'w') as f:
                f.write('test')
            os.remove(test_file)
        except Exception as e:
            logger.warning(f"Document directory may not be writable: {e}")
            # Try alternative location
            docs_dir = '/tmp/documents' if os.name != 'nt' else os.path.join(os.environ.get('TEMP', 'C:\\Temp'), 'documents')
            os.makedirs(docs_dir, exist_ok=True)
        
        # Sanitize the filename
        filename = sanitize_filename(filename)
        
        # Add a timestamp to make the filename unique
        timestamp = datetime.now().strftime('%Y%m%d%H%M%S')
        base, ext = os.path.splitext(filename)
        unique_filename = f"{base}_{timestamp}{ext}"
        
        filepath = os.path.join(docs_dir, unique_filename)
        logger.info(f"Document will be stored at: {filepath}")
        return filepath
    except Exception as e:
        logger.error(f"Error getting document path: {e}")
        # Fallback to a simple path in /tmp or temp directory
        fallback_dir = '/tmp' if os.name != 'nt' else os.environ.get('TEMP', 'C:\\Temp')
        os.makedirs(fallback_dir, exist_ok=True)
        return os.path.join(fallback_dir, f"doc_{datetime.now().strftime('%Y%m%d%H%M%S')}")

def copy_uploaded_file(source_path: str, destination_path: str) -> bool:
    """Copy an uploaded file with proper error handling."""
    try:
        shutil.copy2(source_path, destination_path)
        logger.info(f"File copied from {source_path} to {destination_path}")
        return True
    except Exception as e:
        logger.error(f"Error copying file: {e}")
        # Try alternate approach
        try:
            with open(source_path, 'rb') as src, open(destination_path, 'wb') as dst:
                dst.write(src.read())
            logger.info(f"File copied using alternate method")
            return True
        except Exception as e2:
            logger.error(f"All methods of copying file failed: {e2}")
            return False

def format_sources(sources: List[Dict[str, Any]]) -> str:
    """Format source documents for display."""
    try:
        if not sources:
            return "No sources found."
        
        formatted = []
        for i, source in enumerate(sources, 1):
            source_str = f"{i}. {source.get('file_name', 'Unknown Source')} "
            if source.get('page'):
                source_str += f"(Page {source['page']}) "
            formatted.append(source_str)
        
        return "\n".join(formatted)
    except Exception as e:
        logger.error(f"Error formatting sources: {e}")
        return "Error displaying sources."

def save_conversation(question: str, answer: str, sources: List[Dict[str, Any]]) -> str:
    """Save a conversation to a file."""
    try:
        # Create a directory for conversations
        conv_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))), 'data', 'conversations')
        try:
            os.makedirs(conv_dir, exist_ok=True)
        except Exception as e:
            logger.warning(f"Could not create conversation directory: {e}")
            # Use alternative directory
            conv_dir = '/tmp/conversations' if os.name != 'nt' else os.path.join(os.environ.get('TEMP', 'C:\\Temp'), 'conversations')
            os.makedirs(conv_dir, exist_ok=True)
        
        # Create a filename based on the timestamp and first few words of the question
        timestamp = datetime.now().strftime('%Y%m%d%H%M%S')
        question_slug = "_".join((question or "empty_question").split()[:5]).lower()
        question_slug = sanitize_filename(question_slug)
        filename = f"{timestamp}_{question_slug}.txt"
        
        # Format the conversation
        formatted_sources = format_sources(sources)
        content = f"Question: {question}\n\nAnswer: {answer}\n\nSources:\n{formatted_sources}\n"
        
        # Save the conversation
        filepath = os.path.join(conv_dir, filename)
        with open(filepath, 'w') as f:
            f.write(content)
        
        logger.info(f"Conversation saved to {filepath}")
        return filepath
    except Exception as e:
        logger.error(f"Error saving conversation: {e}")
        return ""