"""Get post use case."""

from uuid import UUID

from app.application.dtos.post import PostResponseDTO
from app.application.interfaces import TransactionManager
from app.domain.entities import Post
from app.domain.exceptions import NotFoundException
from app.domain.repositories import PostRepository


class GetPostUseCase:
    """Use case for retrieving a post by ID or slug."""

    def __init__(
        self,
        post_repo: PostRepository,
        tx_manager: TransactionManager,
    ) -> None:
        self._post_repo = post_repo
        self._tx_manager = tx_manager

    async def by_id(self, post_id: UUID) -> PostResponseDTO:
        """Get post by ID."""
        post = await self._post_repo.get_by_id(post_id)
        if not post:
            raise NotFoundException(f"Post with id '{post_id}' not found")
        return self._map_to_dto(post)

    async def by_slug(self, slug: str) -> PostResponseDTO:
        """Get post by slug."""
        post = await self._post_repo.get_by_slug(slug)
        if not post:
            raise NotFoundException(f"Post with slug '{slug}' not found")
        return self._map_to_dto(post)

    def _map_to_dto(self, post: Post) -> PostResponseDTO:
        """Map domain entity to response DTO."""
        return PostResponseDTO(
            id=post.id,
            title=post.title.value,
            content=post.content.value,
            slug=post.slug.value,
            author_id=post.author_id,
            published=post.published,
            tags=post.tags.copy(),
            created_at=post.created_at,
            updated_at=post.updated_at,
        )