# ==============================================================================
# Project Name: RAG LLM
# Script Name: documents.py
# Authors: Abraham Sánchez, Ulises Moya, Alejandro Zarate  
# Description:
#   This Python application provides an API service that retrieves answers to 
#   user queries based on the given context.
#
# License: MIT
# ==============================================================================


import re

from ..exceptions.app import InvalidFile
from io import BytesIO
from base64 import b64decode


def extract(data_bytes: str, data_type: str) -> BytesIO | None:
    data = None
    if not data_type:
        return data_bytes
    rcomp = re.compile('application|pdf|text')
    if rcomp.findall(data_type):
        encoded = data_bytes.encode('utf-8')
        data_bytes = b64decode(encoded)
        bytesio = BytesIO(data_bytes)
        data = bytesio
    else:
        raise InvalidFile
    return data