"""Author RAG — Public Chat API (Vanity URL Support).

Serves data needed by the Next.js vanity chat pages:
  chat.yourdomain.com/jane-smith → full-page chatbot for author "jane-smith"

Routes (no auth — fully public):
  GET /api/public/{author_slug}/profile        → name, avatar, bio for OG tags
  GET /api/public/{author_slug}/widget-config  → bot name, colors, welcome message
  GET /api/public/{author_slug}/books          → public book list for selector UI
"""

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.dependencies import get_db
from app.models.user import User
from app.models.book import Book
from app.models.client_access import ClientAccess
from datetime import datetime, timezone

router = APIRouter(prefix="/public", tags=["Public Chat"])


async def _get_active_author(slug: str, db: AsyncSession) -> User:
    """Fetch author by slug (ID), verify they have active access."""
    user = await db.get(User, slug)
    if not user or not user.is_active or user.role != "author":
        raise HTTPException(404, "Author not found")

    # Check active subscription
    result = await db.execute(
        select(ClientAccess).where(
            ClientAccess.author_id == slug,
            ClientAccess.is_revoked == False,  # noqa: E712
            ClientAccess.expires_at > datetime.now(timezone.utc),
        )
    )
    access = result.scalar_one_or_none()
    if not access:
        raise HTTPException(404, "Author not found")  # Don't reveal subscription status

    return user


@router.get("/{author_slug}/profile")
async def get_public_profile(
    author_slug: str,
    db: AsyncSession = Depends(get_db),
):
    """Public author profile — used for Open Graph meta tags on vanity chat pages.

    Powers the rich link previews when authors share their chat links on social media:
      Title: "Chat with Jane Smith about her books"
      Description: Author's bio
      Image: Author's avatar
    """
    user = await _get_active_author(author_slug, db)

    # Count published books for the description
    books_result = await db.execute(
        select(Book).where(Book.author_id == author_slug, Book.is_active == True)  # noqa: E712
    )
    books = books_result.scalars().all()

    return {
        "slug": author_slug,
        "full_name": user.full_name or "Author",
        "bio": user.bio if user.bio and not user.bio.startswith("__meta__") else None,
        "avatar_url": user.bot_avatar_path,
        "website_url": user.website_url,
        "book_count": len(books),
        "og_title": f"Chat with {user.full_name or 'this author'} about their books",
        "og_description": (
            f"{user.full_name or 'An author'} uses AI to answer your questions about "
            f"their {len(books)} book{'s' if len(books) != 1 else ''}. Ask anything!"
        ),
    }


@router.get("/{author_slug}/widget-config")
async def get_widget_config(
    author_slug: str,
    db: AsyncSession = Depends(get_db),
):
    """Return widget configuration for the vanity chat page.

    The Next.js page uses this to initialize the chatbot with the correct
    bot name, colors, welcome message, and styling.
    """
    user = await _get_active_author(author_slug, db)
    return {
        "slug": author_slug,
        "bot_name": user.bot_name,
        "welcome_message": user.welcome_message,
        "widget_theme": user.widget_theme,
        "widget_position": user.widget_position,
        "chatbot_is_active": user.chatbot_is_active,
        "remove_branding": user.remove_branding,
        "custom_widget_css": user.custom_widget_css,
        "response_style": user.response_style,
    }


@router.get("/{author_slug}/books")
async def get_public_books(
    author_slug: str,
    db: AsyncSession = Depends(get_db),
):
    """Return public book list for the chat page's book selector UI."""
    await _get_active_author(author_slug, db)

    result = await db.execute(
        select(Book).where(
            Book.author_id == author_slug,
            Book.is_active == True,  # noqa: E712
        ).order_by(Book.created_at.desc())
    )
    books = result.scalars().all()

    return {
        "books": [
            {
                "id": b.id,
                "title": b.title,
                "cover_image_path": b.cover_image_path if hasattr(b, "cover_image_path") else None,
                "buy_link": b.buy_link if hasattr(b, "buy_link") else None,
                "genre": b.genre if hasattr(b, "genre") else None,
            }
            for b in books
        ]
    }