import asyncio
import sys
from app.services.dependencies import get_file_service, get_faiss_service
from app.config import get_config
from langchain_openai import ChatOpenAI
from langchain.schema import Document
from langchain.prompts import PromptTemplate


async def main():
    """
    Entry point for the XBO product assistant.
    """
    config = get_config(env_name="development")
    file_service = get_file_service(config=config)

    openai_api_key = config.OPENAI_API_KEY
    create_faiss_index = config.CREATE_FAISS_INDEX
    print ("Create FAISS Index: ", create_faiss_index)
    print("Wilkommen zum XBO Kaufberater!")
    faiss_service = get_faiss_service(openai_api_key)

    try:
        if create_faiss_index:
            print("[INFO] Creating a new FAISS index...")
            pdfs = file_service.load_pdfs()
            if not pdfs:
                print("[ERROR] No PDFs found.")
                sys.exit(1)

            all_documents = []
            for pdf in pdfs:
                print(f"Processing PDF: {pdf}")
                text = file_service.extract_text_from_pdf(pdf)
                all_documents.append(Document(page_content=text, metadata={"source": pdf}))

            vectorstore = faiss_service.create_faiss_index(all_documents)
        else:
            vectorstore = faiss_service.load_faiss_index()
    except Exception as e:
        print(f"[ERROR] {e}")
        sys.exit(1)

    llm = ChatOpenAI(model="gpt-4o", openai_api_key=openai_api_key)
    retriever = vectorstore.as_retriever(search_kwargs={"k": 21}, search_type="mmr")

    while True:
        user_input = input("\nWas möchten Sie wissen? (type 'exit' to quit): ").strip()
        if user_input.lower() == "exit":
            print("Auf Wiedersehen!")
            break

        try:
            print("[INFO] Retrieving relevant documents...")
            docs = retriever.invoke(user_input)

            if not docs:
                print("\n[ANSWER]: Keine passenden Informationen gefunden.")
                continue

            context = "\n\n".join([doc.page_content for doc in docs])

            prompt = PromptTemplate(
                template="""
                Du bist ein Assistent, der Fragen zu Produktinformationen beantwortet.

                Kontext:
                {context}

                Frage:
                {question}

                Antwort:
                """,
                input_variables=["context", "question"]
            )

            response = llm.invoke(prompt.format(context=context, question=user_input))

            print("\n[ANSWER]:")
            print(response.content)
        except Exception as e:
            print(f"[ERROR] Failed to process query: {e}")


if __name__ == "__main__":
    asyncio.run(main())