from utils.file_loader import extract_text
from prompts.summarize_prompt import SUMMARY_PROMPT
from llm.hf_llm import get_chat_model

chat_model = get_chat_model()
summarize_chain = SUMMARY_PROMPT | chat_model

MAX_CHARS = 18_000

def summarize_document(file):
    if not file:
        return "Please upload a document."

    text = extract_text(file)

    if text.startswith("❌"):
        return text

    if len(text.strip()) < 80:
        return "Not enough meaningful text extracted."

    warning = ""
    if len(text) > MAX_CHARS:
        text = text[:MAX_CHARS]
        warning = "⚠️ Document truncated for processing.\n\n"

    try:
        response = summarize_chain.invoke({"text": text})
        return warning + response.content.strip()

    except Exception as e:
        msg = str(e).lower()
        if "token" in msg:
            return "❌ Invalid or missing Hugging Face token."
        if "rate" in msg:
            return "❌ Rate limit exceeded. Try later."
        return f"❌ Error: {str(e)}"