package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"net/http"
	"time"
)

func sseHandler(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", "*")
	clientGone := r.Context().Done()

	rc := http.NewResponseController(w)

	body, err := io.ReadAll(r.Body)
	if err != nil {
		body = []byte("Error reading body")
	}
	defer r.Body.Close()

	_, err = fmt.Fprintf(w, "data: === Initial Request Details ===\n")
	if err != nil {
		return
	}
	_, err = fmt.Fprintf(w, "data: Method: %s\n", r.Method)
	if err != nil {
		return
	}
	_, err = fmt.Fprintf(w, "data: URL: %s\n", r.URL.String())
	if err != nil {
		return
	}
	_, err = fmt.Fprintf(w, "data: Headers:\n")
	if err != nil {
		return
	}
	for key, values := range r.Header {
		for _, value := range values {
			_, err = fmt.Fprintf(w, "data:   %s: %s\n", key, value)
			if err != nil {
				return
			}
		}
	}
	_, err = fmt.Fprintf(w, "data: Body: %s\n\n", string(body))
	if err != nil {
		return
	}
	err = rc.Flush()
	if err != nil {
		return
	}

	for i := 1; i <= 3; i++ {
		select {
		case <-clientGone:
			fmt.Println("Client disconnected")
			return
		case <-time.After(time.Second * 3):
			_, err := fmt.Fprintf(w, "data: Chunk %d at %s\n\n", i, time.Now().Format(time.UnixDate))
			if err != nil {
				return
			}
			err = rc.Flush()
			if err != nil {
				return
			}
		}
	}
}

func main() {
	var (
		port     = flag.String("port", "8081", "Port to listen on")
		useHTTPS = flag.Bool("https", false, "Enable HTTPS")
		certFile = flag.String("cert", "", "Path to TLS certificate file (required for HTTPS)")
		keyFile  = flag.String("key", "", "Path to TLS key file (required for HTTPS)")
	)
	flag.Parse()

	http.HandleFunc("/events", sseHandler)

	addr := ":" + *port

	if *useHTTPS {
		if *certFile == "" || *keyFile == "" {
			log.Fatal("Both -cert and -key are required when using HTTPS")
		}
		fmt.Printf("Server is running on https://localhost:%s\n", *port)
		if err := http.ListenAndServeTLS(addr, *certFile, *keyFile, nil); err != nil {
			log.Fatal(err)
		}
	} else {
		fmt.Printf("Server is running on http://localhost:%s\n", *port)
		if err := http.ListenAndServe(addr, nil); err != nil {
			log.Fatal(err)
		}
	}
}