Agent-Status und Inaktivitaets-Erkennung implementiert

- Status wird aus last_heartbeat berechnet (online/stale/offline/unknown)
- GET /agents und GET /agents/{id} liefern status Feld
- agent_events Tabelle fuer Event-Tracking (Migration automatisch)
- Inaktivitaets-Monitor als Goroutine (prueft alle 60s, schreibt Events bei Statuswechsel)
- WebSocket Connect/Disconnect Events werden automatisch geschrieben
- API-Endpoints: GET /agents/events und GET /agents/{id}/events (?limit=N&type=X)
- DB-Methoden: InsertAgentEvent, GetAgentEvents, GetAllAgentEvents, GetAgentStatus
- README aktualisiert (Status-Doku, Events API, Dateistruktur)

backend/api/handlers.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"log"
 	"net/http"
+	"strconv"
 	"strings"
 	"time"
 
@@ -28,7 +29,9 @@ func (h *Handler) SetupRoutes(mux *http.ServeMux, hub *ws.Hub) {
 	mux.HandleFunc("POST /api/v1/agent/register", h.registerAgent)
 	mux.HandleFunc("POST /api/v1/agent/heartbeat", h.heartbeat)
 	mux.HandleFunc("GET /api/v1/agents", h.listAgents)
+	mux.HandleFunc("GET /api/v1/agents/events", h.getAllAgentEvents)
 	mux.HandleFunc("GET /api/v1/agents/{id}", h.getAgent)
+	mux.HandleFunc("GET /api/v1/agents/{id}/events", h.getAgentEvents)
 	mux.HandleFunc("GET /api/v1/agents/{id}/system", h.getSystemData)
 	mux.HandleFunc("DELETE /api/v1/agents/{id}", h.deleteAgent)
 	
@@ -151,7 +154,19 @@ func (h *Handler) listAgents(w http.ResponseWriter, r *http.Request) {
 	if agents == nil {
 		agents = []models.Agent{}
 	}
-	writeJSON(w, http.StatusOK, agents)
+
+	// Status fuer jeden Agent berechnen
+	var response []models.AgentResponse
+	for _, a := range agents {
+		response = append(response, models.AgentResponse{
+			Agent:  a,
+			Status: models.CalculateAgentStatus(a.LastHeartbeat),
+		})
+	}
+	if response == nil {
+		response = []models.AgentResponse{}
+	}
+	writeJSON(w, http.StatusOK, response)
 }
 
 // GET /api/v1/agents/{id}
@@ -170,6 +185,7 @@ func (h *Handler) getAgent(w http.ResponseWriter, r *http.Request) {
 
 	result := map[string]interface{}{
 		"agent":       agent,
+		"status":      models.CalculateAgentStatus(agent.LastHeartbeat),
 		"system_data": sysData,
 	}
 	writeJSON(w, http.StatusOK, result)
@@ -207,3 +223,42 @@ func (h *Handler) deleteAgent(w http.ResponseWriter, r *http.Request) {
 	log.Printf("Agent geloescht: %s", id)
 	writeJSON(w, http.StatusOK, map[string]string{"message": "Agent geloescht"})
 }
+
+// GET /api/v1/agents/{id}/events
+func (h *Handler) getAgentEvents(w http.ResponseWriter, r *http.Request) {
+	agentID := r.PathValue("id")
+	eventType := r.URL.Query().Get("type")
+	limit := 100
+	if l := r.URL.Query().Get("limit"); l != "" {
+		if n, err := strconv.Atoi(l); err == nil && n > 0 {
+			limit = n
+		}
+	}
+
+	events, err := h.db.GetAgentEvents(agentID, eventType, limit)
+	if err != nil {
+		log.Printf("Fehler beim Laden der Events: %v", err)
+		writeError(w, http.StatusInternalServerError, "Fehler beim Laden")
+		return
+	}
+	writeJSON(w, http.StatusOK, events)
+}
+
+// GET /api/v1/agents/events
+func (h *Handler) getAllAgentEvents(w http.ResponseWriter, r *http.Request) {
+	eventType := r.URL.Query().Get("type")
+	limit := 100
+	if l := r.URL.Query().Get("limit"); l != "" {
+		if n, err := strconv.Atoi(l); err == nil && n > 0 {
+			limit = n
+		}
+	}
+
+	events, err := h.db.GetAllAgentEvents(eventType, limit)
+	if err != nil {
+		log.Printf("Fehler beim Laden der Events: %v", err)
+		writeError(w, http.StatusInternalServerError, "Fehler beim Laden")
+		return
+	}
+	writeJSON(w, http.StatusOK, events)
+}