"""Document processing module for loading and splitting documents"""

from typing import List, Union
from langchain_community.document_loaders import WebBaseLoader
from langchain_text_splitters import RecursiveCharacterTextSplitter
# from langchain.schema import Document
from langchain_core.documents import Document
from pathlib import Path
from langchain_community.document_loaders import (
    WebBaseLoader,
    PyPDFLoader,
    TextLoader,
    PyPDFDirectoryLoader
)

class DocumentProcessor:
    """Handles document loading and processing"""
    
    def __init__(self, chunk_size: int = 500, chunk_overlap: int = 50):
        """
        Initialize document processor
        
        Args:
            chunk_size: Size of text chunks
            chunk_overlap: Overlap between chunks
        """
        self.chunk_size = chunk_size
        self.chunk_overlap = chunk_overlap
        self.splitter = RecursiveCharacterTextSplitter(
            chunk_size=chunk_size,
            chunk_overlap=chunk_overlap
        )

    def process_pdf(self, file_paths: List[str]):
        """Load multiple PDFs and return a combined list of chunks"""
        all_documents = []
        
        for path in file_paths:
            try:
                loader = PyPDFLoader(path)
                # This splits the specific PDF into chunks
                chunks = loader.load_and_split(text_splitter=self.text_splitter)
                # We add those chunks to our master list
                all_documents.extend(chunks)
            except Exception as e:
                print(f"Error loading PDF {path}: {e}")
                
        return all_documents

    # def process_pdf(self, file_path: str):
    #     """Load a PDF from a file path and split into chunks"""
    #     try:
    #         loader = PyPDFLoader(file_path)
    #         # Load and split in one go
    #         documents = loader.load_and_split(text_splitter=self.text_splitter)
    #         return documents
    #     except Exception as e:
    #         print(f"Error loading PDF {file_path}: {e}")
    #         return []
        
    def load_from_url(self, url: str) -> List[Document]:
        """Load document(s) from a URL"""
        loader = WebBaseLoader(url)
        return loader.load()

    def load_from_pdf_dir(self, directory: Union[str, Path]) -> List[Document]:
        """Load documents from all PDFs inside a directory"""
        loader = PyPDFDirectoryLoader(str(directory))
        return loader.load()

    def load_from_txt(self, file_path: Union[str, Path]) -> List[Document]:
        """Load document(s) from a TXT file"""
        loader = TextLoader(str(file_path), encoding="utf-8")
        return loader.load()

    def load_from_pdf(self, file_path: Union[str, Path]) -> List[Document]:
        """Load document(s) from a PDF file"""
        loader = PyPDFDirectoryLoader(str("data"))
        return loader.load()
    
    def load_documents(self, sources: List[str]) -> List[Document]:
        """
        Load documents from URLs, PDF directories, or TXT files

        Args:
            sources: List of URLs, PDF folder paths, or TXT file paths

        Returns:
            List of loaded documents
        """
        docs: List[Document] = []
        for src in sources:
            if src.startswith("http://") or src.startswith("https://"):
                docs.extend(self.load_from_url(src))
           
            path = Path("data")
            if path.is_dir():  # PDF directory
                docs.extend(self.load_from_pdf_dir(path))
            elif path.suffix.lower() == ".txt":
                docs.extend(self.load_from_txt(path))
            else:
                raise ValueError(
                    f"Unsupported source type: {src}. "
                    "Use URL, .txt file, or PDF directory."
                )
        return docs
    
    def split_documents(self, documents: List[Document]) -> List[Document]:
        """
        Split documents into chunks
        
        Args:
            documents: List of documents to split
            
        Returns:
            List of split documents
        """
        return self.splitter.split_documents(documents)
    
    def process_urls(self, urls: List[str]) -> List[Document]:
        """
        Complete pipeline to load and split documents
        
        Args:
            urls: List of URLs to process
            
        Returns:
            List of processed document chunks
        """
        docs = self.load_documents(urls)
        return self.split_documents(docs)