from pydantic import BaseModel
from fastapi.middleware.cors import CORSMiddleware
from fastapi import FastAPI, HTTPException

from happytransformer import HappyTextToText, TTSettings

app = FastAPI()

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

class GenerateInput(BaseModel):
    prompt: str

happy_tt = HappyTextToText("T5", "vennify/t5-base-grammar-correction")
args = TTSettings(num_beams=5, min_length=1, max_length=100000)

def generate_text(prompt: str):
    if not prompt.strip():
        raise HTTPException(status_code=400, detail="Please provide a non-empty prompt.")
    
    result = happy_tt.generate_text(f"grammar: {prompt}", args=args)
    return result.text

@app.get("/", tags=["Home"])
def api_home():
    return {'detail': 'Welcome to FastAPI TextGen by Knowde!'}

@app.post("/api/generate", tags=["Generate"])
def inference(data: GenerateInput):
    return generate_text(data.prompt)