app.py

import io
import json
import joblib
import pandas as pd
from fastapi import FastAPI, File, UploadFile, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel

MODEL_PATH = "SuperKart_prediction_model_v1_0.joblib"

EXPECTED_COLS = [
    "Product_Weight",
    "Product_Allocated_Area",
    "Product_MRP",
    "Store_Age",
    "Product_Sugar_Content",
    "Product_Type",
    "Store_Type",
    "Store_Size",
    "Store_Location_City_Type",
]

app = FastAPI(title="SuperKart Backend", version="1.0")

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

model = None

@app.on_event("startup")
def load_model():
    global model
    model = joblib.load(MODEL_PATH)

class Payload(BaseModel):
    Product_Weight: float
    Product_Allocated_Area: float
    Product_MRP: float
    Store_Age: int
    Product_Sugar_Content: str
    Product_Type: str
    Store_Type: str
    Store_Size: int
    Store_Location_City_Type: int

def validate_and_order(df: pd.DataFrame) -> pd.DataFrame:
    missing = [c for c in EXPECTED_COLS if c not in df.columns]
    if missing:
        raise HTTPException(status_code=422, detail=f"Missing columns: {missing}")
    return df[EXPECTED_COLS].copy()

@app.get("/health")
def health():
    return {"status": "ok"}

@app.post("/v1/salesprice")
def predict_single(payload: Payload):
    try:
        df = pd.DataFrame([payload.dict()])
        X = validate_and_order(df)
        y = model.predict(X)
        return {"Predicted Price": float(y[0])}
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@app.post("/v1/salespricebatch")
def predict_batch(file: UploadFile = File(...)):
    try:
        content = file.file.read()
        df = pd.read_csv(io.BytesIO(content))
        X = validate_and_order(df)
        y = model.predict(X)
        df["Predicted Price"] = y
        return json.loads(df.to_json(orient="records"))
    except HTTPException:
        raise
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))