Join one FM-Funknetz talk group from a headset window.

The station reads ~/.funknetz.json, speaks protocol 2.0, and builds an unsigned funknetz.app. Co-authored-by: Cursor <cursoragent@cursor.com>
2026-10-03 16:21:41 +02:00
parent 8e75515460
commit 9c4f6621fc
23 changed files with 2933 additions and 0 deletions
@@ -0,0 +1,155 @@
+package station
+
+import (
+	"fmt"
+	"math"
+	"os"
+	"regexp"
+	"strings"
+
+	"encoding/json/jsontext"
+	jsonv2 "encoding/json/v2"
+)
+
+type loaded struct {
+	host      string
+	port      int
+	callsign  string
+	authKey   string
+	talkGroup int
+}
+
+type fileShape struct {
+	Host      jsontext.Value `json:"host"`
+	Port      jsontext.Value `json:"port"`
+	Callsign  jsontext.Value `json:"callsign"`
+	AuthKey   jsontext.Value `json:"authKey"`
+	TalkGroup jsontext.Value `json:"talkGroup"`
+}
+
+type templateFile struct {
+	Host      string `json:"host"`
+	Port      int    `json:"port"`
+	Callsign  string `json:"callsign"`
+	AuthKey   string `json:"authKey"`
+	TalkGroup int    `json:"talkGroup"`
+}
+
+var callsignPattern = regexp.MustCompile(`^[A-Z0-9][A-Z]{0,2}\d[A-Z0-9]{0,3}[A-Z](?:-[A-Z0-9]{1,3})?$`)
+
+func loadConfig(path string) (loaded, error) {
+	body, err := os.ReadFile(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			if err := writeTemplate(path); err != nil {
+				return loaded{}, err
+			}
+			return loaded{}, fmt.Errorf("created %s", path)
+		}
+		return loaded{}, fmt.Errorf("could not be read")
+	}
+	return parseConfig(body)
+}
+
+func writeTemplate(path string) error {
+	body, err := jsonv2.Marshal(templateFile{})
+	if err != nil {
+		return err
+	}
+	body = append(body, '\n')
+	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
+	if err != nil {
+		return err
+	}
+	_, werr := f.Write(body)
+	cerr := f.Close()
+	if werr != nil {
+		return werr
+	}
+	if cerr != nil {
+		return cerr
+	}
+	return os.Chmod(path, 0o600)
+}
+
+func parseConfig(body []byte) (loaded, error) {
+	var shape fileShape
+	if err := jsonv2.Unmarshal(body, &shape); err != nil {
+		return loaded{}, fmt.Errorf("could not be read")
+	}
+	host, err := stringField("host", shape.Host)
+	if err != nil {
+		return loaded{}, err
+	}
+	port, err := intField("port", shape.Port, 1, 65535)
+	if err != nil {
+		return loaded{}, err
+	}
+	call, err := stringField("callsign", shape.Callsign)
+	if err != nil {
+		return loaded{}, err
+	}
+	key, err := authField(shape.AuthKey)
+	if err != nil {
+		return loaded{}, err
+	}
+	tg, err := intField("talkGroup", shape.TalkGroup, 1, int(math.MaxUint32))
+	if err != nil {
+		return loaded{}, err
+	}
+
+	host = strings.TrimSpace(host)
+	if host == "" {
+		return loaded{}, fmt.Errorf("host is empty")
+	}
+	call = strings.ToUpper(strings.TrimSpace(call))
+	if call == "" {
+		return loaded{}, fmt.Errorf("callsign is empty")
+	}
+	if !callsignPattern.MatchString(call) {
+		return loaded{}, fmt.Errorf("callsign is invalid")
+	}
+	return loaded{host: host, port: port, callsign: call, authKey: key, talkGroup: tg}, nil
+}
+
+func stringField(name string, v jsontext.Value) (string, error) {
+	if len(v) == 0 {
+		return "", nil
+	}
+	if v.Kind() != jsontext.KindString {
+		return "", fmt.Errorf("%s has the wrong type", name)
+	}
+	var s string
+	if err := jsonv2.Unmarshal(v, &s); err != nil {
+		return "", fmt.Errorf("%s has the wrong type", name)
+	}
+	return s, nil
+}
+
+func authField(v jsontext.Value) (string, error) {
+	s, err := stringField("authKey", v)
+	if err != nil {
+		return "", err
+	}
+	if strings.TrimSpace(s) == "" {
+		return "", fmt.Errorf("authKey is empty")
+	}
+	return s, nil
+}
+
+func intField(name string, v jsontext.Value, min, max int) (int, error) {
+	if len(v) == 0 {
+		return 0, fmt.Errorf("%s is invalid", name)
+	}
+	if v.Kind() != jsontext.KindNumber {
+		return 0, fmt.Errorf("%s has the wrong type", name)
+	}
+	var n int
+	if err := jsonv2.Unmarshal(v, &n); err != nil {
+		return 0, fmt.Errorf("%s is invalid", name)
+	}
+	if n < min || n > max {
+		return 0, fmt.Errorf("%s is invalid", name)
+	}
+	return n, nil
+}