app/services/link_service.py

"""Author RAG — Link Service.

Business logic for smart links: buy/preview URL sync between books and links tables.
"""

from fastapi import HTTPException
from sqlalchemy.ext.asyncio import AsyncSession

from app.repositories.book_repo import BookRepository
from app.repositories.link_repo import LinkRepository
from app.schemas.admin import SmartLinkUpdate


class LinkService:
    """Orchestrates smart link updates for admin books."""

    def __init__(self, db: AsyncSession) -> None:
        self._db = db
        self._books = BookRepository(db)
        self._links = LinkRepository(db)

    async def update_smart_link(
        self, author_id: str, book_id: str, body: SmartLinkUpdate
    ) -> dict:
        """Update buy/preview URLs on book and sync to links table (R-074)."""
        book = await self._books.get_by_id(book_id)
        if not book or book.author_id != author_id:
            raise HTTPException(404, "Book not found")

        if body.buy_url is not None:
            book.buy_url = body.buy_url[:1000] if body.buy_url else None
        if body.preview_url is not None:
            book.preview_url = body.preview_url[:1000] if body.preview_url else None

        await self._links.upsert_for_book(
            author_id,
            book_id,
            {
                "purchase_url": book.buy_url,
                "preview_url": book.preview_url,
            },
        )
        await self._db.commit()
        return {"message": "Smart link updated"}