package httputil

import (
	"fmt"
	"net/http"
)

func HandleSSE(handler func(broadcast, single chan<- string)) http.Handler {
	broadcast := make(chan string)

	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		w.Header().Set("Cache-Control", "no-cache")
		w.Header().Set("Connection", "keep-alive")
		w.Header().Set("Access-Control-Allow-Origin", "*")

		client := make(chan string)
		defer func() {
			close(client)
		}()

		go handler(broadcast, client)

		flusher, _ := w.(http.Flusher)
		for {
			select {
			case message := <-broadcast:
				fmt.Fprintf(w, "%s\n", message)
				flusher.Flush()
			case message := <-client:
				fmt.Fprintf(w, "%s\n", message)
				flusher.Flush()
			case <-r.Context().Done():
				return
			}
		}
	})
}