from typing import Any, List, Optional

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

from app import crud, schemas
from app.db.session import get_db

router = APIRouter()


@router.get("/", response_model=List[schemas.Category])
def read_categories(
    db: Session = Depends(get_db),
    skip: int = 0,
    limit: int = 100,
    name: Optional[str] = None,
) -> Any:
    """
    Retrieve categories with optional filtering by name.
    """
    categories = crud.category.get_multi(db, skip=skip, limit=limit, name=name)
    return categories


@router.post("/", response_model=schemas.Category, status_code=status.HTTP_201_CREATED)
def create_category(
    *,
    db: Session = Depends(get_db),
    category_in: schemas.CategoryCreate,
) -> Any:
    """
    Create new category.
    """
    # Check if category with the same name already exists
    category = crud.category.get_by_name(db, name=category_in.name)
    if category:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Category with this name already exists.",
        )

    category = crud.category.create(db, obj_in=category_in)
    return category


@router.get("/{category_id}", response_model=schemas.Category)
def read_category(
    *,
    db: Session = Depends(get_db),
    category_id: str,
) -> Any:
    """
    Get category by ID.
    """
    category = crud.category.get(db, category_id=category_id)
    if not category:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Category not found",
        )
    return category


@router.put("/{category_id}", response_model=schemas.Category)
def update_category(
    *,
    db: Session = Depends(get_db),
    category_id: str,
    category_in: schemas.CategoryUpdate,
) -> Any:
    """
    Update a category.
    """
    category = crud.category.get(db, category_id=category_id)
    if not category:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Category not found",
        )

    # Check if trying to update to existing name
    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 and existing_category.id != category_id:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Category with this name already exists",
            )

    category = crud.category.update(db, db_obj=category, obj_in=category_in)
    return category


@router.delete("/{category_id}", status_code=status.HTTP_204_NO_CONTENT, response_model=None)
def delete_category(
    *,
    db: Session = Depends(get_db),
    category_id: str,
) -> Any:
    """
    Delete a category.
    """
    category = crud.category.get(db, category_id=category_id)
    if not category:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Category not found",
        )

    # Check if category has products before deleting
    if category.products and len(category.products) > 0:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Cannot delete category with products. Remove or reassign products first.",
        )

    crud.category.remove(db, category_id=category_id)
    return None