feat: v6 rewrite

progress.go

@@ -0,0 +1,40 @@
+package cameradar
+
+import (
+	"strconv"
+	"strings"
+)
+
+const progressMessagePrefix = "\x00progress:"
+
+// ProgressTotalMessage returns a progress control message that sets the total units for a step.
+func ProgressTotalMessage(total int) string {
+	return progressMessagePrefix + "total=" + strconv.Itoa(total)
+}
+
+// ProgressTickMessage returns a progress control message that increments a step's progress by one unit.
+func ProgressTickMessage() string {
+	return progressMessagePrefix + "tick"
+}
+
+// ParseProgressMessage parses a progress control message.
+// It returns a kind of "total" or "tick" and an optional value.
+func ParseProgressMessage(message string) (string, int, bool) {
+	if !strings.HasPrefix(message, progressMessagePrefix) {
+		return "", 0, false
+	}
+
+	payload := strings.TrimPrefix(message, progressMessagePrefix)
+	if payload == "tick" {
+		return "tick", 1, true
+	}
+	if valuePart, ok := strings.CutPrefix(payload, "total="); ok {
+		value, err := strconv.Atoi(valuePart)
+		if err != nil {
+			return "", 0, false
+		}
+		return "total", value, true
+	}
+
+	return "", 0, false
+}