package main

import "context"

// streamChunkSubject is the bus subject the loop's OnStream closure publishes
// each token delta to. The gateway hub subscribes to ws.> and re-broadcasts it
// as a ws.stream_chunk frame to every client.
const streamChunkSubject = "ws.stream_chunk"

// streamChunk is the loop's OnStream callback. It publishes one token delta to
// the gateway's streaming subject so the hub fans it out to every client as a
// ws.stream_chunk frame. It is a no-op when no bus is wired and never blocks the
// loop: bus.Publish is asynchronous and a full per-subscription buffer drops the
// event rather than stalling the model stream.
func (a *app) streamChunk(delta string) {
	if a.bus == nil {
		return
	}
	if err := a.bus.Publish(context.Background(), streamChunkSubject, map[string]any{"delta": delta}); err != nil {
		a.log.Warn("stream chunk publish", "err", err)
	}
}