feat: status bar added

internal/rotator/pst/pst.go

@@ -10,6 +10,7 @@ package pst
 import (
 	"fmt"
 	"net"
+	"strconv"
 	"time"
 )
 
@@ -53,6 +54,59 @@ func (c *Client) Park() error {
 	return c.send("<PST><PARK>1</PARK></PST>")
 }
 
+// Heading queries PstRotator for the current azimuth. PstRotator's protocol:
+// send "<PST>AZ?</PST>" to the command port, and it reports the azimuth back
+// on UDP port+1. So we bind a listener on port+1 first, send the query, then
+// read the reply. Returns the raw reply too, for diagnostics. err is non-nil
+// on timeout (no reply) or an unparseable response.
+func (c *Client) Heading() (az int, raw string, err error) {
+	// Listen on port+1 where PstRotator sends its position report.
+	pc, err := net.ListenPacket("udp4", fmt.Sprintf(":%d", c.Port+1))
+	if err != nil {
+		return 0, "", fmt.Errorf("listen :%d for PstRotator reply: %w", c.Port+1, err)
+	}
+	defer pc.Close()
+
+	if err := c.send("<PST>AZ?</PST>"); err != nil {
+		return 0, "", fmt.Errorf("query PstRotator: %w", err)
+	}
+
+	_ = pc.SetReadDeadline(time.Now().Add(1500 * time.Millisecond))
+	buf := make([]byte, 512)
+	n, _, rerr := pc.ReadFrom(buf)
+	if rerr != nil {
+		return 0, "", fmt.Errorf("no reply on :%d: %w", c.Port+1, rerr)
+	}
+	raw = string(buf[:n])
+	a, ok := parseAzimuth(raw)
+	if !ok {
+		return 0, raw, fmt.Errorf("no azimuth in reply %q", raw)
+	}
+	return a, raw, nil
+}
+
+// parseAzimuth extracts the first integer found in a PstRotator reply
+// ("AZ:123", "123", "<PST><AZIMUTH>123</AZIMUTH></PST>", …) and normalises
+// it to [0,360).
+func parseAzimuth(s string) (int, bool) {
+	i := 0
+	for i < len(s) && (s[i] < '0' || s[i] > '9') {
+		i++
+	}
+	if i >= len(s) {
+		return 0, false
+	}
+	j := i
+	for j < len(s) && s[j] >= '0' && s[j] <= '9' {
+		j++
+	}
+	n, err := strconv.Atoi(s[i:j])
+	if err != nil {
+		return 0, false
+	}
+	return ((n % 360) + 360) % 360, true
+}
+
 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)