update

internal/rotator/pst/pst.go

@@ -0,0 +1,68 @@
+// Package pst sends commands to PstRotator over its UDP listener.
+//
+// PstRotator (Codrut Buda YO3DMU) exposes a simple text/XML protocol on
+// a configurable UDP port (default 12000 on localhost). Each command is a
+// single fire-and-forget datagram — no handshake, no response. This keeps
+// us connectionless and means a misconfigured port silently no-ops rather
+// than hanging the UI. Run the matching "Test" action to confirm the link.
+package pst
+
+import (
+	"fmt"
+	"net"
+	"time"
+)
+
+// Client is a stateless UDP sender. Safe to construct cheaply per call —
+// the underlying socket only lives for the length of one Write.
+type Client struct {
+	Host string // hostname or IP of the PstRotator host (usually "127.0.0.1")
+	Port int    // UDP port (PstRotator default = 12000)
+}
+
+// New returns a Client with sane defaults applied for empty fields.
+func New(host string, port int) *Client {
+	if host == "" {
+		host = "127.0.0.1"
+	}
+	if port <= 0 || port > 65535 {
+		port = 12000
+	}
+	return &Client{Host: host, Port: port}
+}
+
+// GoTo points the antenna at azimuth (0-359°). If hasElevation is true
+// and el >= 0 the elevation field is included too (VHF/satellite setups);
+// otherwise PstRotator just turns in azimuth.
+func (c *Client) GoTo(az int, hasElevation bool, el int) error {
+	az = ((az % 360) + 360) % 360 // normalise to [0,360)
+	if hasElevation && el >= 0 && el <= 180 {
+		return c.send(fmt.Sprintf("<PST><AZIMUTH>%d</AZIMUTH><ELEVATION>%d</ELEVATION></PST>", az, el))
+	}
+	return c.send(fmt.Sprintf("<PST><AZIMUTH>%d</AZIMUTH></PST>", az))
+}
+
+// Stop interrupts any in-progress rotation.
+func (c *Client) Stop() error {
+	return c.send("<PST><STOP>1</STOP></PST>")
+}
+
+// Park sends the rotator to its parked position (configured inside
+// PstRotator itself — we just trigger it).
+func (c *Client) Park() error {
+	return c.send("<PST><PARK>1</PARK></PST>")
+}
+
+func (c *Client) send(payload string) error {
+	addr := fmt.Sprintf("%s:%d", c.Host, c.Port)
+	conn, err := net.DialTimeout("udp", addr, 2*time.Second)
+	if err != nil {
+		return fmt.Errorf("dial PstRotator at %s: %w", addr, err)
+	}
+	defer conn.Close()
+	_ = conn.SetWriteDeadline(time.Now().Add(2 * time.Second))
+	if _, err := conn.Write([]byte(payload)); err != nil {
+		return fmt.Errorf("send to PstRotator: %w", err)
+	}
+	return nil
+}