import uuid

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

from app.database import get_db
from app.dependencies import get_current_user
from app.models import User
from app.schemas.user import UserDirectoryRead
from app.storage import UPLOADS_DIR

router = APIRouter(prefix="/api/users", tags=["users"])


@router.get("", response_model=list[UserDirectoryRead])
async def list_users_directory_endpoint(
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    result = await db.execute(
        select(User)
        .where(User.is_active.is_(True), User.is_bot.is_(False))
        .order_by(User.username)
    )
    return list(result.scalars().all())


@router.get("/online", response_model=list[uuid.UUID])
async def list_online_users_endpoint(
    request: Request,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
) -> list[uuid.UUID]:
    """A snapshot, not a live feed -- deliberately simpler than the presence
    dot in chat (which updates live via the existing room-broadcast
    machinery). Used by surfaces where "accurate as of page load" is good
    enough: the admin user list and the room-invite user search."""
    raw_online_ids = await request.app.state.global_presence.all_online_user_ids()
    if not raw_online_ids:
        return []
    result = await db.execute(
        select(User.id).where(User.id.in_(raw_online_ids), User.appear_offline.is_(False))
    )
    return [row[0] for row in result.all()]


@router.get("/{user_id}/avatar")
async def get_user_avatar_endpoint(
    user_id: uuid.UUID,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    user = await db.get(User, user_id)
    if user is None or not user.avatar_filename:
        raise HTTPException(status_code=404, detail="No avatar set")
    return FileResponse(
        UPLOADS_DIR / user.avatar_filename,
        media_type=user.avatar_content_type,
        # Unlike message images (content-addressed, immutable once posted),
        # an avatar URL is identity-addressed and its content can change on
        # re-upload -- a short cache instead of `immutable` so a stale copy
        # doesn't linger. Not room-membership-gated: avatar visibility
        # matches username visibility (anyone logged in), unlike room-scoped
        # message content.
        headers={"Cache-Control": "private, max-age=300"},
    )