from typing import List, Optional
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session

from app.db.session import get_db
from app.models.item import Item as ItemModel
from app.schemas.item import Item, ItemCreate, ItemUpdate

router = APIRouter()

@router.get("/", response_model=List[Item])
def read_items(
    skip: int = 0,
    limit: int = 100,
    category: Optional[str] = None,
    db: Session = Depends(get_db)
):
    """
    Retrieve all items with optional filtering by category.
    """
    query = db.query(ItemModel)
    if category:
        query = query.filter(ItemModel.category == category)
    return query.offset(skip).limit(limit).all()


@router.post("/", response_model=Item, status_code=status.HTTP_201_CREATED)
def create_item(
    item_in: ItemCreate,
    db: Session = Depends(get_db)
):
    """
    Create a new inventory item.
    """
    db_item = ItemModel(**item_in.model_dump())
    db.add(db_item)
    db.commit()
    db.refresh(db_item)
    return db_item


@router.get("/{item_id}", response_model=Item)
def read_item(
    item_id: int,
    db: Session = Depends(get_db)
):
    """
    Get a specific item by ID.
    """
    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
    if db_item is None:
        raise HTTPException(status_code=404, detail="Item not found")
    return db_item


@router.put("/{item_id}", response_model=Item)
def update_item(
    item_id: int,
    item_in: ItemUpdate,
    db: Session = Depends(get_db)
):
    """
    Update an existing item.
    """
    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
    if db_item is None:
        raise HTTPException(status_code=404, detail="Item not found")
    
    update_data = item_in.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        setattr(db_item, field, value)
    
    db.commit()
    db.refresh(db_item)
    return db_item


@router.delete("/{item_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
def delete_item(
    item_id: int,
    db: Session = Depends(get_db)
):
    """
    Delete an item.
    """
    db_item = db.query(ItemModel).filter(ItemModel.id == item_id).first()
    if db_item is None:
        raise HTTPException(status_code=404, detail="Item not found")
    
    db.delete(db_item)
    db.commit()
    return None