from typing import Union, Optional
from sqlalchemy.ext.asyncio import AsyncSession

from dto.catalogue import CatalogueType, CatalogueView
from misc.mapper import parse_cat_id, serialize_cat_id
from misc.texts import get_breadcrumps_path
from repositories import ProductRepository, CategoriesRepository
from config import PAGE_SIZE


class CatalogueService:
    def __init__(
        self, product_repo: ProductRepository, categories_repo: CategoriesRepository
    ) -> None:
        self.product_repo = product_repo
        self.categories_repo = categories_repo

    async def build_category_view(
        self, session: AsyncSession, cat_id: Optional[Union[int, str]], page: int = 0
    ) -> CatalogueView:
        cat_id = parse_cat_id(cat_id)

        view = CatalogueView(page=page)
        children = await self.categories_repo.get_categories_by_parent_id(
            session, cat_id
        )
        category = await self.categories_repo.get_category_by_id(session, cat_id)

        if not category:  # Root category
            view.category = "root"
            view.show_menu = True
        else:  # Subcategories
            view.category = cat_id
            view.parent_id = serialize_cat_id(category.parent_id)

        if not children:  # Products
            products = await self.product_repo.get_product_by_category(
                session, cat_id, limit=PAGE_SIZE + 1, offset=view.page * PAGE_SIZE
            )
            if products:
                view.view_type = CatalogueType.PRODUCTS
                view.products = products[:PAGE_SIZE]
                view.has_next = len(products) > PAGE_SIZE

                return view
            view.view_type = CatalogueType.EMPTY
            return view

        view.view_type = CatalogueType.CATEGORIES
        view.children = children

        return view

    async def get_path(self, session: AsyncSession, cat_id: Union[int, str]):
        category = int(cat_id) if isinstance(cat_id, int) or cat_id.isdigit() else None
        products = await self.categories_repo.get_category_path(session, category)

        return get_breadcrumps_path(products)