from typing import Any, Dict, List, Optional, Union

from fastapi.encoders import jsonable_encoder
from sqlalchemy.orm import Session

from app.models.product import Product
from app.schemas.product import ProductCreate, ProductUpdate
from app.utils.uuid import generate_uuid


def get(db: Session, product_id: str) -> Optional[Product]:
    """
    Get a product by ID.
    """
    return db.query(Product).filter(Product.id == product_id).first()


def get_by_sku(db: Session, sku: str) -> Optional[Product]:
    """
    Get a product by SKU.
    """
    return db.query(Product).filter(Product.sku == sku).first()


def get_by_barcode(db: Session, barcode: str) -> Optional[Product]:
    """
    Get a product by barcode.
    """
    return db.query(Product).filter(Product.barcode == barcode).first()


def get_multi(
    db: Session, *, skip: int = 0, limit: int = 100, filters: Optional[Dict[str, Any]] = None
) -> List[Product]:
    """
    Get multiple products with optional filtering.
    """
    query = db.query(Product)

    # Apply filters if provided
    if filters:
        if "name" in filters and filters["name"]:
            query = query.filter(Product.name.ilike(f"%{filters['name']}%"))
        if "category_id" in filters and filters["category_id"]:
            query = query.filter(Product.category_id == filters["category_id"])
        if "supplier_id" in filters and filters["supplier_id"]:
            query = query.filter(Product.supplier_id == filters["supplier_id"])
        if "is_active" in filters and filters["is_active"] is not None:
            query = query.filter(Product.is_active == filters["is_active"])
        if "low_stock" in filters and filters["low_stock"] is True:
            query = query.filter(Product.current_stock <= Product.min_stock_level)

    return query.offset(skip).limit(limit).all()


def create(db: Session, *, obj_in: ProductCreate) -> Product:
    """
    Create a new product.
    """
    obj_in_data = jsonable_encoder(obj_in)
    db_obj = Product(**obj_in_data, id=generate_uuid())
    db.add(db_obj)
    db.commit()
    db.refresh(db_obj)
    return db_obj


def update(
    db: Session, *, db_obj: Product, obj_in: Union[ProductUpdate, Dict[str, Any]]
) -> Product:
    """
    Update a product.
    """
    obj_data = jsonable_encoder(db_obj)
    if isinstance(obj_in, dict):
        update_data = obj_in
    else:
        update_data = obj_in.model_dump(exclude_unset=True)

    for field in obj_data:
        if field in update_data:
            setattr(db_obj, field, update_data[field])

    db.add(db_obj)
    db.commit()
    db.refresh(db_obj)
    return db_obj


def remove(db: Session, *, product_id: str) -> Optional[Product]:
    """
    Delete a product.
    """
    obj = db.query(Product).get(product_id)
    if obj:
        db.delete(obj)
        db.commit()
    return obj


def update_stock(db: Session, *, db_obj: Product, quantity: int) -> Product:
    """
    Update product stock quantity.
    """
    db_obj.current_stock += quantity
    db.add(db_obj)
    db.commit()
    db.refresh(db_obj)
    return db_obj