restructured the project to comply community guideline, for others check release note

internal/proxy/fields/port.go

@@ -0,0 +1,41 @@
+package fields
+
+import (
+	"strconv"
+
+	E "github.com/yusing/go-proxy/internal/error"
+)
+
+type Port int
+
+func ValidatePort[String ~string](v String) (Port, E.NestedError) {
+	p, err := strconv.Atoi(string(v))
+	if err != nil {
+		return ErrPort, E.Invalid("port number", v).With(err)
+	}
+	return ValidatePortInt(p)
+}
+
+func ValidatePortInt[Int int | uint16](v Int) (Port, E.NestedError) {
+	p := Port(v)
+	if !p.inBound() {
+		return ErrPort, E.OutOfRange("port", p)
+	}
+	return p, nil
+}
+
+func (p Port) inBound() bool {
+	return p >= MinPort && p <= MaxPort
+}
+
+func (p Port) String() string {
+	return strconv.Itoa(int(p))
+}
+
+const (
+	MinPort  = 0
+	MaxPort  = 65535
+	ErrPort  = Port(-1)
+	NoPort   = Port(-1)
+	ZeroPort = Port(0)
+)