from fastapi import APIRouter, Depends, HTTPException, Query
from sqlalchemy import select
from sqlalchemy.orm import Session, selectinload

from ..database import get_db
from ..models import PriceSnapshot, Product
from ..schemas import PriceSnapshot as PriceSnapshotSchema, ProductWithLatestPrice

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


def _attach_latest_price(product: Product, db: Session) -> ProductWithLatestPrice:
    p = ProductWithLatestPrice.model_validate(product)
    latest = db.scalar(
        select(PriceSnapshot)
        .where(PriceSnapshot.product_id == product.id)
        .order_by(PriceSnapshot.timestamp.desc())
        .limit(1)
    )
    if latest:
        p.latest_price = latest.price
        p.latest_price_timestamp = latest.timestamp
        p.is_on_sale = latest.is_on_sale
    return p


@router.get("", response_model=list[ProductWithLatestPrice])
def search_products(
    search: str = Query(default=""),
    limit: int = Query(default=20, le=100),
    db: Session = Depends(get_db),
):
    q = select(Product).options(selectinload(Product.store))
    if search:
        q = q.where(Product.name.ilike(f"%{search}%"))
    q = q.order_by(Product.name).limit(limit)
    products = db.scalars(q).all()
    return [_attach_latest_price(p, db) for p in products]


@router.get("/{product_id}", response_model=ProductWithLatestPrice)
def get_product(product_id: int, db: Session = Depends(get_db)):
    product = db.scalar(
        select(Product)
        .where(Product.id == product_id)
        .options(selectinload(Product.store))
    )
    if not product:
        raise HTTPException(status_code=404, detail="Product not found")
    return _attach_latest_price(product, db)


@router.get("/{product_id}/prices", response_model=list[PriceSnapshotSchema])
def get_product_prices(
    product_id: int,
    limit: int = Query(default=200, le=1000),
    db: Session = Depends(get_db),
):
    return db.scalars(
        select(PriceSnapshot)
        .where(PriceSnapshot.product_id == product_id)
        .order_by(PriceSnapshot.timestamp.asc())
        .limit(limit)
    ).all()