package api

import (
	"net/http"

	"github.com/local-mcp/local-mcp-go/internal/events"
)

// handleSSE streams server-sent events to browser clients.
func handleSSE(broker *events.Broker) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		// Set SSE headers
		w.Header().Set("Content-Type", "text/event-stream")
		w.Header().Set("Cache-Control", "no-cache")
		w.Header().Set("Connection", "keep-alive")
		w.Header().Set("X-Accel-Buffering", "no")

		flusher, ok := w.(http.Flusher)
		if !ok {
			writeError(w, http.StatusInternalServerError, "Streaming not supported")
			return
		}

		// Subscribe to event broker
		ch := broker.Subscribe()
		defer broker.Unsubscribe(ch)

		// Send initial connection event
		w.Write([]byte("data: {\"type\":\"connected\"}\n\n"))
		flusher.Flush()

		// Stream events until client disconnects
		for {
			select {
			case msg, ok := <-ch:
				if !ok {
					return // broker closed
				}
				w.Write(msg)
				flusher.Flush()
			case <-r.Context().Done():
				return // client disconnected
			}
		}
	}
}