package hub

import "context"

// Authorize is the §2.5 last-row check on its own: a participation
// bound to this session, in this room, admitted. A member-kind
// participation re-derives standing first (§15.12), exactly as Relay
// does, through memberStandingGone; one whose standing is gone is ended
// here with lost{standing} and answered ErrNotYours. A guest never
// consults standing at all (ruling 14): memberStandingGone returns
// immediately for a non-member kind, without a StandingFor call.
//
// A nil return is not "nothing happened": memberStandingGone still
// records a kind that changed (setKindLocked), which — for an admitted
// member — broadcasts a fresh roster to the room, the same side effect
// Relay's own re-derivation has. What a nil return promises is only
// that no *participation* ended and nothing was relayed; it is not a
// pure read the way CanResume's probe is (that one never writes at
// all). GET /m/{sqid}/ice is its caller.
func (h *Hub) Authorize(ctx context.Context, sqid, session string, peer PeerID) error {
	gone, err := h.memberStandingGone(ctx, sqid, session, peer, true)
	if err != nil {
		return err
	}
	if gone {
		return ErrNotYours
	}
	h.mu.Lock()
	defer h.mu.Unlock()
	p, ok := h.findLocked(sqid, session, peer)
	if !ok {
		return ErrUnknownPeer
	}
	if !p.Admitted {
		return ErrNotAdmitted
	}
	return nil
}