"""Update post use case."""

from uuid import UUID

from app.application.dtos.post import PostResponseDTO, UpdatePostDTO
from app.application.interfaces import TransactionManager
from app.domain.entities import Post
from app.domain.exceptions import ForbiddenException, NotFoundException
from app.domain.repositories import PostRepository
from app.domain.value_objects import Content, Title


class UpdatePostUseCase:
    """Use case for updating a blog post."""

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

    async def execute(
        self,
        post_id: UUID,
        dto: UpdatePostDTO,
        current_user_id: str,
    ) -> PostResponseDTO:
        """Execute the use case."""
        post = await self._post_repo.get_by_id(post_id)
        if not post:
            raise NotFoundException(f"Post with id '{post_id}' not found")

        # Check authorization
        if post.author_id != current_user_id:
            raise ForbiddenException("You can only update your own posts")

        # Update fields
        if dto.title is not None:
            post.update_title(Title(dto.title))

        if dto.content is not None:
            post.update_content(Content(dto.content))

        if dto.tags is not None:
            # Replace all tags
            for tag in post.tags[:]:
                post.remove_tag(tag)
            for tag in dto.tags:
                post.add_tag(tag)

        # Persist changes
        await self._post_repo.update(post)

        # Commit transaction
        await self._tx_manager.commit()

        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,
        )