-rpi-sendspin/cmd/live-server/main.go

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"sort"
	"strconv"
	"syscall"
	"time"

	"github.com/Sendspin/sendspin-go/pkg/sendspin"

	"rpi-sendspin/internal/live"
)

// flagSpec describes one user-facing option. The flag is registered
// under all names; help output (custom Usage below) groups them onto a
// single line so `-s, --source` reads as one option rather than two.
type flagSpec struct {
	long  string
	short string // optional
	usage string
}

var specs []flagSpec

func addStr(target *string, def, long, short, usage string) {
	flag.StringVar(target, long, def, usage)
	if short != "" {
		flag.StringVar(target, short, def, usage)
	}
	specs = append(specs, flagSpec{long, short, usage})
}

func addInt(target *int, def int, long, short, usage string) {
	flag.IntVar(target, long, def, usage)
	if short != "" {
		flag.IntVar(target, short, def, usage)
	}
	specs = append(specs, flagSpec{long, short, usage})
}

func main() {
	var (
		port          int
		name          string
		httpPort      int
		configPath    string
		source        string
		mqttURL       string
		mqttUser      string
		mqttPass      string
		mqttBase      string
		mqttDiscovery string
		rate          int
		channels      int
	)

	addInt(&port, 8927, "port", "p", "Sendspin WebSocket port")
	addStr(&name, "Live Audio", "name", "n", "advertised server name")
	addInt(&httpPort, 8080, "http-port", "", "HTTP/API port")
	addStr(&configPath, defaultConfigPath(), "config", "c", "presets file path")
	addStr(&source, "", "source", "s", "PipeWire source node (e.g. alsa_input.usb-...pro-input-0.monitor); when set, overrides preset.source")
	addStr(&mqttURL, "", "mqtt-url", "", "MQTT broker URL (e.g. tcp://broker.local:1883); empty disables MQTT")
	addStr(&mqttUser, "", "mqtt-username", "", "MQTT username")
	addStr(&mqttPass, "", "mqtt-password", "", "MQTT password")
	addStr(&mqttBase, "sendspin/live", "mqtt-base", "", "MQTT base topic")
	addStr(&mqttDiscovery, "homeassistant", "mqtt-discovery", "", "Home Assistant discovery prefix")
	addInt(&rate, 48000, "rate", "r", "capture sample rate")
	addInt(&channels, 2, "channels", "", "capture channels")

	flag.Usage = usage
	flag.Parse()

	log.SetFlags(log.LstdFlags | log.Lmicroseconds)

	store, err := live.NewStore(configPath)
	if err != nil {
		log.Fatalf("load presets: %v", err)
	}

	src := live.NewSource(rate, channels)
	roster := live.NewRoster()

	var mgr *live.Manager
	server, err := sendspin.NewServer(sendspin.ServerConfig{
		Port:            port,
		Name:            name,
		Source:          src,
		EnableMDNS:      true,
		DiscoverClients: true,
		ClientFilter: func(id string) bool {
			if mgr == nil {
				return false
			}
			return mgr.ClientAllowed(id)
		},
		OnClientHello: roster.Record,
	})
	if err != nil {
		log.Fatalf("create sendspin server: %v", err)
	}
	mgr = live.NewManager(store, server, src)
	mgr.SetSourceOverride(source)
	if source != "" {
		log.Printf("source override: %s (preset.source ignored)", source)
	}

	disc := live.NewDiscovery()
	disc.Start()
	defer disc.Stop()

	httpSrv := &http.Server{
		Addr:         ":" + strconv.Itoa(httpPort),
		Handler:      live.NewHTTPServer(mgr, store, disc, roster, server).Handler(),
		ReadTimeout:  5 * time.Second,
		WriteTimeout: 10 * time.Second,
	}
	go func() {
		log.Printf("HTTP API listening on %s", httpSrv.Addr)
		if err := httpSrv.ListenAndServe(); err != http.ErrServerClosed {
			log.Fatalf("http: %v", err)
		}
	}()

	var bridge *live.MQTTBridge
	if mqttURL != "" {
		bridge = live.NewMQTTBridge(live.MQTTConfig{
			URL:             mqttURL,
			Username:        mqttUser,
			Password:        mqttPass,
			BaseTopic:       mqttBase,
			DiscoveryPrefix: mqttDiscovery,
		}, mgr)
		if err := bridge.Start(); err != nil {
			log.Fatalf("mqtt: %v", err)
		}
	}

	serverDone := make(chan error, 1)
	go func() { serverDone <- server.Start() }()
	log.Printf("Sendspin server %q on :%d", name, port)

	sig := make(chan os.Signal, 1)
	signal.Notify(sig, os.Interrupt, syscall.SIGTERM)
	select {
	case <-sig:
		log.Printf("signal received, shutting down")
	case err := <-serverDone:
		log.Printf("sendspin server exited: %v", err)
	}

	if bridge != nil {
		bridge.Stop()
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_ = httpSrv.Shutdown(ctx)
	server.Stop()
	_ = src.Close()
}

func defaultConfigPath() string {
	home, err := os.UserHomeDir()
	if err != nil {
		return "presets.json"
	}
	return filepath.Join(home, ".config", "sendspin-live", "presets.json")
}

// usage renders one line per logical option, pairing the short alias
// with the long form (e.g. "-s, --source"). The default flag.Usage
// would list each registration separately and double-print everything.
func usage() {
	out := flag.CommandLine.Output()
	fmt.Fprintf(out, "Usage: %s [flags]\n\nFlags:\n", os.Args[0])

	sort.Slice(specs, func(i, j int) bool { return specs[i].long < specs[j].long })

	for _, s := range specs {
		f := flag.Lookup(s.long)
		if f == nil {
			continue
		}
		head := "      --" + s.long
		if s.short != "" {
			head = "  -" + s.short + ", --" + s.long
		}
		if f.DefValue != "" {
			head += "=" + f.DefValue
		}
		fmt.Fprintf(out, "%-44s %s\n", head, s.usage)
	}
}