back/server.py

from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from dotenv import load_dotenv
import google.generativeai as genai
import os

# Load .env
load_dotenv()

API_KEY = os.getenv("GEMINI_API_KEY")
if not API_KEY:
    raise RuntimeError("GEMINI_API_KEY not found in .env")

# Gemini config
genai.configure(api_key=API_KEY)

SYSTEM_INSTRUCTION = """
You are a senior software engineer.
Provide structured, technical, and accurate answers.
Explain reasoning step by step when needed.
Focus on best practices and real-world solutions.
Avoid unnecessary explanations.
"""

model = genai.GenerativeModel(
    model_name="gemini-2.5-flash",
    system_instruction=SYSTEM_INSTRUCTION,
)

app = FastAPI()

# CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

class TextRequest(BaseModel):
    text: str

@app.post("/summarize")
async def summarize(req: TextRequest):
    text = req.text.strip()
    if not text:
        raise HTTPException(status_code=400, detail="Text is required")

    try:
        response = model.generate_content(text)
        return {"summary": response.text.strip()}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


if __name__ == "__main__":
    import uvicorn
    uvicorn.run("server:app", host="0.0.0.0", port=4000, reload=True)