import PyPDF2
from datetime import datetime
from typing import Dict, Any
from io import BytesIO

class PDFProcessor:
    """Handles PDF text extraction and metadata creation for the RAG system."""
    
    def extract_text(self, file: BytesIO) -> str:
        """
        Extract text from a PDF file.
        
        Args:
            file: Streamlit uploaded file (BytesIO object).
            
        Returns:
            Extracted text as a string.
        """
        try:
            pdf_reader = PyPDF2.PdfReader(file)
            text = ""
            for page in pdf_reader.pages:
                page_text = page.extract_text() or ""
                text += page_text + "\n"
            return text.strip()
        except Exception as e:
            raise Exception(f"Failed to extract text from PDF: {str(e)}")
    
    def create_document_metadata(self, file: BytesIO, document_type: str) -> Dict[str, Any]:
        """
        Create metadata for a document.
        
        Args:
            file: Streamlit uploaded file (BytesIO object).
            document_type: Category of the document (e.g., 'Research Paper').
            
        Returns:
            Dictionary containing metadata.
        """
        try:
            return {
                'filename': file.name,
                'document_type': document_type,
                'ingestion_timestamp': datetime.now().isoformat()
            }
        except Exception as e:
            raise Exception(f"Failed to create metadata: {str(e)}")