from fastapi import APIRouter, Depends
from sqlalchemy.orm import Session
from sqlalchemy import func
from app.db.session import get_db
from app.models.product import Product
from app.models.stock_movement import StockMovement, MovementType

router = APIRouter(prefix="/reports", tags=["reports"])


@router.get("/inventory-summary")
def get_inventory_summary(db: Session = Depends(get_db)):
    total_products = db.query(Product).count()
    total_stock_value = (
        db.query(func.sum(Product.price * Product.quantity_in_stock)).scalar() or 0
    )
    low_stock_products = (
        db.query(Product)
        .filter(Product.quantity_in_stock <= Product.minimum_stock_level)
        .count()
    )

    return {
        "total_products": total_products,
        "total_stock_value": round(total_stock_value, 2),
        "low_stock_products": low_stock_products,
    }


@router.get("/low-stock")
def get_low_stock_products(db: Session = Depends(get_db)):
    products = (
        db.query(Product)
        .filter(Product.quantity_in_stock <= Product.minimum_stock_level)
        .all()
    )

    return [
        {
            "id": product.id,
            "name": product.name,
            "sku": product.sku,
            "current_stock": product.quantity_in_stock,
            "minimum_stock": product.minimum_stock_level,
            "shortage": product.minimum_stock_level - product.quantity_in_stock,
        }
        for product in products
    ]


@router.get("/stock-movements-summary")
def get_stock_movements_summary(db: Session = Depends(get_db)):
    stock_in = (
        db.query(func.sum(StockMovement.quantity))
        .filter(StockMovement.movement_type == MovementType.IN)
        .scalar()
        or 0
    )

    stock_out = (
        db.query(func.sum(StockMovement.quantity))
        .filter(StockMovement.movement_type == MovementType.OUT)
        .scalar()
        or 0
    )

    adjustments = (
        db.query(func.sum(StockMovement.quantity))
        .filter(StockMovement.movement_type == MovementType.ADJUSTMENT)
        .scalar()
        or 0
    )

    return {
        "total_stock_in": stock_in,
        "total_stock_out": stock_out,
        "total_adjustments": adjustments,
        "net_movement": stock_in - stock_out + adjustments,
    }