import joblib
import pandas as pd
from App.schemas import EmployeeFeatures
import json
from pathlib import Path
from huggingface_hub import hf_hub_download


# Import SQLAlchemy uniquement si disponible 
try: 
    from sqlalchemy.orm import Session 
    from App.database import SessionLocal 
    from App.model import Input, Predictions
    SQLALCHEMY_AVAILABLE = True 
except ModuleNotFoundError: 
    SQLALCHEMY_AVAILABLE = False 
    essionLocal = None 
    Input = None 
    Predictions = None
    

MODEL_REPO = "Diaure/xgb_model"

# Variables chargées
model = None
classes_mapping = None
Features = list(EmployeeFeatures.model_fields.keys())


# Chargement des fichiers: fonction pour charger le modèle, le mapping afin de permettre à l'API de démarrer m^me si les éléments ne sont pas présents
def files_load():
    global model, classes_mapping

    if model is None:
        chemin_model = Path(hf_hub_download(repo_id=MODEL_REPO, filename="modele_final_xgb.joblib"))
        # if not chemin_model.exists():
        #     raise RuntimeError("Eléments du modèle introuvable.")
        model =joblib.load(chemin_model)

    if classes_mapping is None:
        chemin_mapping = Path(hf_hub_download(repo_id=MODEL_REPO, filename="mapping_classes.json"))
        # if not chemin_mapping.exists():
        #     raise RuntimeError("Mapping des classes introuvable.")
        with open(chemin_mapping) as f:
            classes_mapping = json.load(f)

# Fonction prédiction
def predict_employee(data: dict):
    files_load()

    df = pd.DataFrame([data])[Features]

    print("Colonnes API :", df.columns.tolist()) 
    print("Nombre colonnes API :", len(df.columns))
    
    pred = model.predict(df)[0]
    proba = model.predict_proba(df)[0][1]

    # DB désactivée si SQLAlchemy indisponible ou SessionLocal = None 
    if SQLALCHEMY_AVAILABLE and SessionLocal is not None:
        db: Session = SessionLocal() 
    else: db = None

    if db is not None:
        try:
            # enregistrer les inputs: à chaque appel de POST/predict, on stocke d'abord les entrées de l'utilisateur
            input_row = Input(**data) 
            db.add(input_row) 
            db.commit() 
            db.refresh(input_row)

            # puis on récupère les ids générés automatiquement et enregistre les prédictions liés aux ids
            pred_row = Predictions(input_id = input_row.id, prediction_label = classes_mapping[str(pred)], prediction_proba = float(proba), model_version = "v1") 
            db.add(pred_row) 
            db.commit()
        
        except Exception as e: 
            print("ERREUR DB:", e) 
            raise e

        finally:
            db.close()

    # puis on renvoie la réponse API
    return {
        "Prediction": classes_mapping[str(pred)],
        "Probabilite_depart": float(proba)}