app.py

from fastapi import FastAPI, Request
from transformers import AutoTokenizer, AutoModelForSequenceClassification
import torch
import uvicorn
import os

# ✅ Fix permission issue on Hugging Face Spaces
os.environ["TRANSFORMERS_CACHE"] = "/tmp/huggingface"

app = FastAPI(title="AI Detector API")

MODEL_NAME = "roberta-base-openai-detector"
tokenizer = AutoTokenizer.from_pretrained(MODEL_NAME)
model = AutoModelForSequenceClassification.from_pretrained(MODEL_NAME)
model.eval()

def get_ai_probability(text: str) -> float:
    inputs = tokenizer(text, return_tensors="pt", truncation=True, max_length=512)
    with torch.no_grad():
        logits = model(**inputs).logits
        probs = torch.softmax(logits, dim=1)
    ai_score = probs[0][1].item() * 100
    return round(ai_score, 2)

@app.post("/analyze")
async def analyze_text(request: Request):
    data = await request.json()
    text = data.get("text", "").strip()
    if not text:
        return {"error": "No text provided"}

    paragraphs = [p.strip() for p in text.split("\n") if p.strip()]
    results = []

    for i, para in enumerate(paragraphs, start=1):
        ai_score = get_ai_probability(para)
        results.append({