app.py

from transformers import AutoTokenizer, AutoModelForCausalLM, pipeline
from langchain_core.prompts import ChatPromptTemplate
from langchain.prompts import PromptTemplate
from langchain_core.output_parsers import StrOutputParser
from langchain.memory import ConversationSummaryMemory
from langchain_huggingface import HuggingFacePipeline
from langchain_core.runnables import RunnableSequence
import gradio as gr

# Load model
model_id = "google/gemma-2b"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id)

# Text generation pipeline
generator = pipeline(
    "text-generation",
    model=model,
    tokenizer=tokenizer,
    max_new_tokens=100,
    do_sample=True,
    temperature=0.7
)



# LangChain wrapper
llm = HuggingFacePipeline(pipeline=generator)

# Prompt template
prompt = ChatPromptTemplate.from_messages([
     ("system", "You are a helpful assistant. Explain the following code clearly:\n\n{code}")
])

# Runnable sequence instead of LLMChain
chain = prompt | llm | StrOutputParser()


# Gradio interface
def generate_answer(input_code):
    result = chain.invoke({"code":input_code })
    return result

gr.Interface(fn=generate_answer, inputs="text", outputs="text", title="Gemma 2B Code Explainer").launch()