feat: implement SQLite storage for state messages and add message retrieval endpoint

cmd/server/main.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os"
 	"os/signal"
+	"strings"
 	"syscall"
 	"time"
 
@@ -18,6 +19,7 @@ import (
 	"git.piskot.si/SeminarM2/lambdaiot-core/internal/handler"
 	"git.piskot.si/SeminarM2/lambdaiot-core/internal/middleware"
 	mqttclient "git.piskot.si/SeminarM2/lambdaiot-core/internal/mqtt"
+	"git.piskot.si/SeminarM2/lambdaiot-core/internal/storage"
 )
 
 func main() {
@@ -52,6 +54,21 @@ func main() {
 
 	// connect to MQTT broker (best-effort)
 	var mq *mqttclient.Client
+	// initialize sqlite for state messages
+	var db *storage.DB
+	{
+		dbPath := os.Getenv("SQLITE_PATH")
+		if dbPath == "" {
+			dbPath = "state_messages.db"
+		}
+		dbInit, err := storage.Init(dbPath)
+		if err != nil {
+			log.Printf("warning: sqlite init failed: %v", err)
+		} else {
+			db = dbInit
+			storage.SetDefault(db)
+		}
+	}
 	if cfg.MQTT.Broker != "" {
 		mqc, err := mqttclient.Connect(cfg.MQTT)
 		if err != nil {
@@ -64,6 +81,12 @@ func main() {
 			if cfg.MQTT.Topic != "" {
 				if err := mq.Subscribe(cfg.MQTT.Topic, func(t string, p []byte) {
 					log.Printf("mqtt recv on %s: %s", t, string(p))
+					// if topic starts with state: -> store in sqlite
+					if strings.HasPrefix(t, "state:") {
+						if storage.Default != nil {
+							_ = storage.Default.InsertMessage(string(p), time.Now())
+						}
+					}
 				}); err != nil {
 					log.Printf("warning: mqtt subscribe failed: %v", err)
 				}
@@ -93,8 +116,7 @@ func main() {
 	r.POST("/login", h.Login)
 	r.GET("/devices", h.GetDevices)
 
-	// mqttping endpoint handled by internal/handler
-	r.POST("/mqttping", h.MQTTPing)
+	// mqttping endpoint handled by internal/handler (protected)
 
 	// Protected routes
 	auth := r.Group("/")
@@ -130,6 +152,9 @@ func main() {
 	if mq != nil {
 		mq.Close()
 	}
+	if db != nil {
+		db.Close()
+	}
 	log.Println("server exiting")
 }