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

selective-vpn-api/app/traffic_mode_handlers.go

@@ -0,0 +1,61 @@
+package app
+
+import (
+	"net/http"
+	"os"
+	"syscall"
+)
+
+func handleTrafficInterfaces(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	st := loadTrafficModeState()
+	active, reason := resolveTrafficIface(st.PreferredIface)
+	resp := TrafficInterfacesResponse{
+		Interfaces:     listSelectableIfaces(st.PreferredIface),
+		PreferredIface: normalizePreferredIface(st.PreferredIface),
+		ActiveIface:    active,
+		IfaceReason:    reason,
+	}
+	writeJSON(w, http.StatusOK, resp)
+}
+
+func handleTrafficModeTest(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet && r.Method != http.MethodPost {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	st := loadTrafficModeState()
+	writeJSON(w, http.StatusOK, evaluateTrafficMode(st))
+}
+
+func acquireTrafficApplyLock() (*os.File, *TrafficModeStatusResponse) {
+	lock, err := os.OpenFile(lockFile, os.O_CREATE|os.O_RDWR, 0o644)
+	if err != nil {
+		msg := evaluateTrafficMode(loadTrafficModeState())
+		msg.Message = "traffic lock open failed: " + err.Error()
+		return nil, &msg
+	}
+	if err := syscall.Flock(int(lock.Fd()), syscall.LOCK_EX|syscall.LOCK_NB); err != nil {
+		_ = lock.Close()
+		msg := evaluateTrafficMode(loadTrafficModeState())
+		msg.Message = "traffic apply skipped: routes operation already running"
+		return nil, &msg
+	}
+	return lock, nil
+}
+
+func handleTrafficMode(w http.ResponseWriter, r *http.Request) {
+	switch r.Method {
+	case http.MethodGet:
+		st := loadTrafficModeState()
+		writeJSON(w, http.StatusOK, evaluateTrafficMode(st))
+	case http.MethodPost:
+		handleTrafficModePost(w, r)
+	default:
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+	}
+}