protocol/aprs: refactored

protocol/aprs/status.go

@@ -0,0 +1,92 @@
+package aprs
+
+import (
+	"strings"
+	"time"
+
+	"git.maze.io/go/ham/util/maidenhead"
+)
+
+type Status struct {
+	Time        time.Time
+	Latitude    float64
+	Longitude   float64
+	BeamHeading int
+	ERP         int
+	Symbol      string
+	Text        string
+}
+
+func (s Status) String() string {
+	return s.Text
+}
+
+type statusReportDecoder struct{}
+
+func (statusReportDecoder) CanDecode(frame Frame) bool {
+	return frame.Raw.Type() == '>'
+}
+
+func (statusReportDecoder) Decode(frame Frame) (data Data, err error) {
+	var (
+		text   = string(frame.Raw[1:])
+		status = new(Status)
+	)
+	if hasTimestamp(text) {
+		if status.Time, text, err = parseTimestamp(text); err != nil {
+			return
+		}
+	}
+
+	if len(text) > 3 && text[len(text)-3] == '^' {
+		var (
+			h = text[len(text)-2]
+			p = text[len(text)-1]
+		)
+		if h >= '0' && h <= '9' {
+			status.BeamHeading = int(h-'0') * 10
+		} else if h >= 'A' && h <= 'Z' {
+			status.BeamHeading = 100 + int(h-'A')*10
+		}
+		if p >= '0' && p <= 'Z' {
+			status.ERP = int(p-'0') * int(p-'0') * 10
+		}
+		text = text[:len(text)-3]
+	}
+
+	here := text
+	if i := strings.IndexByte(here, ' '); i != -1 {
+		here = here[:i]
+	}
+	switch len(here) {
+	case 6:
+		var point maidenhead.Point
+		if point, err = maidenhead.ParseLocator(here[:4]); err != nil {
+			return
+		}
+		status.Latitude = point.Latitude
+		status.Longitude = point.Longitude
+		status.Symbol = here[4:]
+		if len(text) > 6 {
+			text = text[7:]
+		} else {
+			text = text[6:]
+		}
+	case 8:
+		var point maidenhead.Point
+		if point, err = maidenhead.ParseLocator(here[:6]); err != nil {
+			return
+		}
+		status.Latitude = point.Latitude
+		status.Longitude = point.Longitude
+		status.Symbol = here[6:]
+		if len(text) > 8 {
+			text = text[9:]
+		} else {
+			text = text[8:]
+		}
+	}
+
+	status.Text = text
+	return status, nil
+}