"""
PDF ingestion.
WHY: Local embeddings remove paid API dependency entirely.
"""

import os
from langchain_community.document_loaders import PyPDFLoader
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import FAISS
from langchain_community.embeddings import HuggingFaceEmbeddings
from app.config import PDF_DIR, FAISS_DIR, CHUNK_SIZE, CHUNK_OVERLAP, EMBEDDING_MODEL


def ingest_pdfs():
    documents = []

    for file in os.listdir(PDF_DIR):
        if file.endswith(".pdf"):
            loader = PyPDFLoader(os.path.join(PDF_DIR, file))
            documents.extend(loader.load())

    splitter = RecursiveCharacterTextSplitter(
        chunk_size=CHUNK_SIZE,
        chunk_overlap=CHUNK_OVERLAP
    )

    chunks = splitter.split_documents(documents)

    embeddings = HuggingFaceEmbeddings(
        model_name=EMBEDDING_MODEL
    )

    vectorstore = FAISS.from_documents(chunks, embeddings)
    vectorstore.save_local(FAISS_DIR)