feat: balancer dashboard metrics + fix WebSocket Hijacker

internal/esl/client.go

@@ -401,3 +401,70 @@ func (c *Client) GetStats() Stats {
 func (c *Client) IncGatewayOps() {
 	c.gatewayOps.Add(1)
 }
+
+// --- FS stats ---
+
+// FsStats — показатели FreeSWITCH балансировщика.
+type FsStats struct {
+	ActiveCalls int
+	MaxSessions int
+	FsUptime    string
+}
+
+// FetchFsStats запрашивает метрики FreeSWITCH через api команды.
+func (c *Client) FetchFsStats() (FsStats, error) {
+	if !c.connected.Load() {
+		return FsStats{}, fmt.Errorf("esl не подключён")
+	}
+	var stats FsStats
+
+	_, body, err := c.Send("api show calls count")
+	if err != nil {
+		return FsStats{}, err
+	}
+	stats.ActiveCalls = parseFirstInt(body)
+
+	_, body, err = c.Send("api status")
+	if err != nil {
+		return stats, err
+	}
+	stats.MaxSessions = parseMaxSessions(body)
+	stats.FsUptime = parseUptime(body)
+
+	return stats, nil
+}
+
+func parseFirstInt(s string) int {
+	s = strings.TrimSpace(s)
+	for i, c := range s {
+		if c < '0' || c > '9' {
+			if i == 0 {
+				return 0
+			}
+			v, err := strconv.Atoi(s[:i])
+			if err != nil {
+				return 0
+			}
+			return v
+		}
+	}
+	return 0
+}
+
+func parseMaxSessions(body string) int {
+	for _, line := range strings.Split(body, "\n") {
+		if strings.Contains(line, "session(s) max") {
+			return parseFirstInt(line)
+		}
+	}
+	return 0
+}
+
+func parseUptime(body string) string {
+	for _, line := range strings.Split(body, "\n") {
+		if strings.HasPrefix(line, "UP ") {
+			return strings.TrimPrefix(line, "UP ")
+		}
+	}
+	return ""
+}