feat: added versionning & About window

internal/cat/flexdiscover.go

@@ -0,0 +1,112 @@
+//go:build windows
+
+package cat
+
+import (
+	"context"
+	"net"
+	"regexp"
+	"strconv"
+	"syscall"
+	"time"
+
+	"golang.org/x/sys/windows"
+)
+
+// FlexRadio is one radio found by discovery.
+type FlexRadio struct {
+	IP       string `json:"ip"`
+	Port     int    `json:"port"`
+	Model    string `json:"model"`
+	Nickname string `json:"nickname"`
+	Serial   string `json:"serial"`
+	Callsign string `json:"callsign"`
+}
+
+// FlexRadios on the LAN broadcast a discovery datagram to UDP :4992 about once a
+// second. DiscoverFlex listens for that broadcast for the given duration and
+// returns the unique radios seen. Best effort: if the port can't be bound
+// (SmartSDR running, firewall…), it returns what it has (often nothing) and the
+// user falls back to entering the IP by hand.
+func DiscoverFlex(timeout time.Duration) ([]FlexRadio, error) {
+	if timeout <= 0 {
+		timeout = 2 * time.Second
+	}
+	// Bind :4992 with SO_REUSEADDR so we coexist with SmartSDR, which also
+	// listens for the same broadcast.
+	lc := net.ListenConfig{
+		Control: func(_, _ string, c syscall.RawConn) error {
+			var serr error
+			_ = c.Control(func(fd uintptr) {
+				serr = windows.SetsockoptInt(windows.Handle(fd), windows.SOL_SOCKET, windows.SO_REUSEADDR, 1)
+			})
+			return serr
+		},
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	pc, err := lc.ListenPacket(ctx, "udp4", ":4992")
+	if err != nil {
+		return nil, err
+	}
+	defer pc.Close()
+
+	_ = pc.SetReadDeadline(time.Now().Add(timeout))
+	found := map[string]FlexRadio{}
+	buf := make([]byte, 2048)
+	for {
+		n, _, err := pc.ReadFrom(buf)
+		if err != nil {
+			break // deadline reached or socket closed
+		}
+		if r, ok := parseFlexDiscovery(buf[:n]); ok && r.IP != "" {
+			if _, dup := found[r.IP]; !dup {
+				found[r.IP] = r
+			}
+		}
+	}
+	out := make([]FlexRadio, 0, len(found))
+	for _, r := range found {
+		out = append(out, r)
+	}
+	return out, nil
+}
+
+var (
+	reFlexModel    = regexp.MustCompile(`model=(\S+)`)
+	reFlexIP       = regexp.MustCompile(`ip=(\S+)`)
+	reFlexPort     = regexp.MustCompile(`port=(\d+)`)
+	reFlexSerial   = regexp.MustCompile(`serial=(\S+)`)
+	reFlexNickname = regexp.MustCompile(`nickname=(\S+)`)
+	reFlexCallsign = regexp.MustCompile(`callsign=(\S+)`)
+)
+
+// parseFlexDiscovery extracts radio fields from a VITA-49 discovery datagram.
+// The payload carries a space-separated key=value ASCII blob after a binary
+// header, so we scan the whole packet text for the keys we need.
+func parseFlexDiscovery(pkt []byte) (FlexRadio, bool) {
+	s := string(pkt)
+	m := reFlexIP.FindStringSubmatch(s)
+	if m == nil {
+		return FlexRadio{}, false
+	}
+	r := FlexRadio{IP: m[1], Port: 4992}
+	if mm := reFlexPort.FindStringSubmatch(s); mm != nil {
+		if p, err := strconv.Atoi(mm[1]); err == nil && p > 0 {
+			r.Port = p
+		}
+	}
+	if mm := reFlexModel.FindStringSubmatch(s); mm != nil {
+		r.Model = mm[1]
+	}
+	if mm := reFlexSerial.FindStringSubmatch(s); mm != nil {
+		r.Serial = mm[1]
+	}
+	if mm := reFlexNickname.FindStringSubmatch(s); mm != nil {
+		r.Nickname = mm[1]
+	}
+	if mm := reFlexCallsign.FindStringSubmatch(s); mm != nil {
+		r.Callsign = mm[1]
+	}
+	return r, true
+}