platform: modularize api/gui, add docs-tests-web foundation, and refresh root config

selective-vpn-api/app/trafficmode/interfaces.go

@@ -0,0 +1,156 @@
+package trafficmode
+
+import (
+	"sort"
+	"strings"
+)
+
+func NormalizePreferredIface(raw string) string {
+	v := strings.TrimSpace(raw)
+	l := strings.ToLower(v)
+	if l == "" || l == "auto" || l == "-" || l == "default" {
+		return ""
+	}
+	return v
+}
+
+func IfaceExists(iface string, run RunCommandSimpleFunc) bool {
+	iface = strings.TrimSpace(iface)
+	if iface == "" || run == nil {
+		return false
+	}
+	_, _, code, _ := run("ip", "link", "show", iface)
+	return code == 0
+}
+
+func ParseUpIfaces(ipLinkOutput string) []string {
+	seen := map[string]struct{}{}
+	outIfaces := make([]string, 0, 8)
+	for _, line := range strings.Split(ipLinkOutput, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		parts := strings.SplitN(line, ":", 3)
+		if len(parts) < 3 {
+			continue
+		}
+		name := strings.TrimSpace(parts[1])
+		name = strings.SplitN(name, "@", 2)[0]
+		name = strings.TrimSpace(name)
+		if name == "" || name == "lo" {
+			continue
+		}
+		if _, ok := seen[name]; ok {
+			continue
+		}
+		seen[name] = struct{}{}
+		outIfaces = append(outIfaces, name)
+	}
+	return outIfaces
+}
+
+func ListUpIfaces(run RunCommandSimpleFunc) []string {
+	if run == nil {
+		return nil
+	}
+	out, _, code, _ := run("ip", "-o", "link", "show", "up")
+	if code != 0 {
+		return nil
+	}
+	return ParseUpIfaces(out)
+}
+
+func IsVPNLikeIface(iface string) bool {
+	l := strings.ToLower(strings.TrimSpace(iface))
+	return strings.HasPrefix(l, "tun") ||
+		strings.HasPrefix(l, "wg") ||
+		strings.HasPrefix(l, "ppp") ||
+		strings.HasPrefix(l, "tap") ||
+		strings.HasPrefix(l, "utun") ||
+		strings.HasPrefix(l, "vpn")
+}
+
+func ListSelectableIfaces(up []string, preferred string) []string {
+	seen := map[string]struct{}{}
+	var vpnLike []string
+	var other []string
+
+	add := func(dst *[]string, iface string) {
+		iface = strings.TrimSpace(iface)
+		if iface == "" {
+			return
+		}
+		if _, ok := seen[iface]; ok {
+			return
+		}
+		seen[iface] = struct{}{}
+		*dst = append(*dst, iface)
+	}
+
+	for _, iface := range up {
+		if IsVPNLikeIface(iface) {
+			add(&vpnLike, iface)
+		}
+	}
+	for _, iface := range up {
+		if !IsVPNLikeIface(iface) {
+			add(&other, iface)
+		}
+	}
+	sort.Strings(vpnLike)
+	sort.Strings(other)
+
+	selected := make([]string, 0, len(vpnLike)+len(other)+1)
+	selected = append(selected, vpnLike...)
+	selected = append(selected, other...)
+
+	pref := NormalizePreferredIface(preferred)
+	if pref != "" {
+		if _, ok := seen[pref]; !ok {
+			selected = append([]string{pref}, selected...)
+		}
+	}
+	return selected
+}
+
+func ResolveTrafficIface(
+	preferred string,
+	ifaceExists func(string) bool,
+	statusIface func() string,
+	listUp func() []string,
+) (string, string) {
+	exists := ifaceExists
+	if exists == nil {
+		exists = func(string) bool { return false }
+	}
+	status := statusIface
+	if status == nil {
+		status = func() string { return "" }
+	}
+	upIfaces := listUp
+	if upIfaces == nil {
+		upIfaces = func() []string { return nil }
+	}
+
+	pref := NormalizePreferredIface(preferred)
+	if pref != "" && exists(pref) {
+		return pref, "preferred"
+	}
+
+	statusResolved := strings.TrimSpace(status())
+	if statusResolved != "" && exists(statusResolved) {
+		return statusResolved, "status"
+	}
+
+	for _, iface := range upIfaces() {
+		if IsVPNLikeIface(iface) {
+			return iface, "auto-vpn-like"
+		}
+	}
+
+	if pref != "" {
+		return "", "preferred-not-found"
+	}
+	return "", "iface-not-found"
+}