from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, Field
from typing import Optional
from app.handler import FastApiHandler

app = FastAPI(title="Effici EPC Energy Prediction API")

handler = None


# ---------- EPC Request Schema ----------
class EPCPredictRequest(BaseModel):
    model_params: dict = Field(
        ...,
        json_schema_extra={
            "example": {
                "PROPERTY_TYPE": "Flat",
                "BUILT_FORM": "Enclosed End-Terrace",
                "CONSTRUCTION_AGE_BAND": "England and Wales: 1996-2002",

                "TOTAL_FLOOR_AREA": 70.12,
                "FLOOR_HEIGHT": 2.32,
                "FLAT_TOP_STOREY": "N",
                "FLAT_STOREY_COUNT": 23.0,

                "WINDOWS_DESCRIPTION": "Fully triple glazed",
                "WALLS_DESCRIPTION": "System built, as built, insulated (assumed)",
                "ROOF_DESCRIPTION": "(another dwelling above)",
                "FLOOR_DESCRIPTION": "(other premises below)",

                "MAINHEAT_DESCRIPTION": "Air source heat pump, warm air, electric",
                "MAINHEAT_ENERGY_EFF": "Average",

                "SECONDHEAT_DESCRIPTION": "Room heaters, electric",

                "HOTWATER_DESCRIPTION": "Electric immersion, standard tariff, no cylinderstat",
                "HOT_WATER_ENERGY_EFF": "Very Poor",

                "LIGHTING_DESCRIPTION": "No low energy lighting",

                "MECHANICAL_VENTILATION": "natural",
                "PHOTO_SUPPLY": 0.0
            }
        },
    )



# ---------- Startup ----------
@app.on_event("startup")
def load_model_once():
    global handler
    handler = FastApiHandler()
    print("✅ EPC MLflow model loaded at startup")


# ---------- Routes ----------
@app.get("/")
def root():
    return {
        "message": "🏠 Effici EPC Energy Prediction API is running",
    }


@app.post("/predict")
def predict(req: EPCPredictRequest):
    try:
        result = handler.handle(req.dict())
        if "error" in result:
            raise HTTPException(status_code=400, detail=result["error"])
        return result
    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))


@app.post("/explain")
def explain(req: EPCPredictRequest):
    try:
        explanation = handler.explain_prediction(req.model_params)
        return explanation
    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))