from typing import Any, List

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session

from app import crud, models, schemas
from app.api import deps

router = APIRouter()


@router.get("/", response_model=List[schemas.Category])
def read_categories(
    db: Session = Depends(deps.get_db),
    skip: int = 0,
    limit: int = 100,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Retrieve categories.
    """
    categories = crud.category.get_multi(db, skip=skip, limit=limit)
    return categories


@router.post("/", response_model=schemas.Category)
def create_category(
    *,
    db: Session = Depends(deps.get_db),
    category_in: schemas.CategoryCreate,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Create new category.
    """
    category = crud.category.get_by_name(db, name=category_in.name)
    if category:
        raise HTTPException(
            status_code=400,
            detail="The category with this name already exists in the system.",
        )
    category = crud.category.create(db, obj_in=category_in)
    return category


@router.get("/{id}", response_model=schemas.Category)
def read_category(
    *,
    db: Session = Depends(deps.get_db),
    id: int,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Get category by ID.
    """
    category = crud.category.get(db, id=id)
    if not category:
        raise HTTPException(status_code=404, detail="Category not found")
    return category


@router.put("/{id}", response_model=schemas.Category)
def update_category(
    *,
    db: Session = Depends(deps.get_db),
    id: int,
    category_in: schemas.CategoryUpdate,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Update a category.
    """
    category = crud.category.get(db, id=id)
    if not category:
        raise HTTPException(status_code=404, detail="Category not found")
    
    # Check if the updated name conflicts with an existing category
    if category_in.name and category_in.name != category.name:
        existing_category = crud.category.get_by_name(db, name=category_in.name)
        if existing_category:
            raise HTTPException(
                status_code=400,
                detail="The category with this name already exists in the system.",
            )
    
    category = crud.category.update(db, db_obj=category, obj_in=category_in)
    return category


@router.delete("/{id}", status_code=204, response_model=None)
def delete_category(
    *,
    db: Session = Depends(deps.get_db),
    id: int,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Delete a category.
    """
    category = crud.category.get(db, id=id)
    if not category:
        raise HTTPException(status_code=404, detail="Category not found")
    
    # Check if the category has products
    if category.products:
        raise HTTPException(
            status_code=400,
            detail="Cannot delete category with associated products. Reassign or delete the products first.",
        )
    
    crud.category.remove(db, id=id)
    return None