from pypdf import PdfReader
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_core.documents import Document
from langchain_openai import OpenAIEmbeddings
from langchain_chroma import Chroma
import re
import os

def extract_text_from_pdf(file_path:str) -> str:
    reader = PdfReader(file_path)
    text = ""
    for page in reader.pages:
        text += page.extract_text() or ""
    return text

def pdf_to_documents(file_path:str,database_name:str,collection_name:str,embeddings:OpenAIEmbeddings,chunk_size=1000,chunk_overlap=200,metadata:dict=None):
    text = extract_text_from_pdf(file_path)
    text = re.sub(r"[^a-zA-Z0-9.,!?;:'\"()\s]", "", text)
    if not text.strip():
        return []

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

    chunks = splitter.split_text(text)
    docs = []
    for i,chunk in enumerate(chunks):
        #print(f"index: {i} , {chunk}")
        meta = metadata.copy() if metadata else {}
        meta.update({"chunk":i})
        docs.append(Document(page_content=chunk, metadata=meta))

    if os.path.exists(database_name):
        Chroma(persist_directory=database_name, embedding_function=embeddings,collection_name=collection_name).delete_collection()

    vectorstore = Chroma.from_documents(documents=docs, embedding=embeddings, persist_directory=database_name,collection_name=collection_name)

    return docs,vectorstore



def store_data(text:str,database_name:str,collection_name:str,embeddings:OpenAIEmbeddings):
    
    text_splitter = RecursiveCharacterTextSplitter(
        chunk_size = 1000,
        chunk_overlap  = 0,
        separators = [" ", ",", "\n"]
    )

    #with open(file_path) as f:
    #    text = f.read()

    texts = text_splitter.split_text(text)

    #print(f"split: {texts}")
    docs = [Document(page_content=t) for t in texts]


    if os.path.exists(database_name):
        Chroma(persist_directory=database_name, embedding_function=embeddings,collection_name=collection_name).delete_collection()

    vectorstore = Chroma.from_documents(documents=docs, embedding=embeddings, persist_directory=database_name,collection_name=collection_name)
    return vectorstore