"""
MediGenius — tools/pdf_loader.py
PDF document loading and text splitting utilities.
"""

from typing import List

from langchain_core.documents import Document

from app.core.logging_config import logger


def load_pdf(pdf_path: str) -> List[Document]:
    """Load all pages from a PDF file using PyPDFLoader."""
    from langchain_community.document_loaders import PyPDFLoader

    loader = PyPDFLoader(pdf_path)
    docs = loader.load()
    logger.info("Loaded %d pages from PDF: %s", len(docs), pdf_path)
    return docs


def split_documents(docs: List[Document]) -> List[Document]:
    """Split documents into overlapping chunks using tiktoken-aware splitter."""
    from langchain_text_splitters import RecursiveCharacterTextSplitter

    splitter = RecursiveCharacterTextSplitter.from_tiktoken_encoder(
        chunk_size=512,
        chunk_overlap=128,
        separators=["\n\n", ". ", "\n", " "],
    )
    splits = splitter.split_documents(docs)
    logger.info("Split into %d chunks", len(splits))
    return splits


def process_pdf(pdf_path: str) -> List[Document]:
    """Load a PDF and split it into chunks. Convenience wrapper."""
    return split_documents(load_pdf(pdf_path))