Add tiny webserver for JSON data

main.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"bytes"
 	"database/sql"
+	"encoding/json"
 	"fmt"
 	"image"
 	"image/jpeg"
@@ -75,6 +76,7 @@ func main() {
 	webcamURL := getEnv("WEBCAM_URL", "http://furnace.service:8082/stream")
 	minBrightness := getEnvInt("MIN_BRIGHTNESS", 150)
 	checkInterval := getEnvDuration("CHECK_INTERVAL", 2*time.Second)
+	webPort := getEnv("FURNACE_WEB_PORT", "8090")
 
 	fmt.Println("Using DB:", dbPath)
 	fmt.Println("Using webcam:", webcamURL)
@@ -83,6 +85,9 @@ func main() {
 
 	db, err := sql.Open("sqlite", dbPath)
 
+	go startWebServer(db, getEnv("HTTP_PORT", webPort))
+	fmt.Println("Starting json data server on port ", webPort)
+
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -254,3 +259,35 @@ func sendNtfyNotification(light Light, on bool) {
 	}
 	resp.Body.Close()
 }
+
+func startWebServer(db *sql.DB, port string) {
+	http.HandleFunc("/lights", func(w http.ResponseWriter, r *http.Request) {
+		rows, err := db.Query(`
+            SELECT name, state, MAX(timestamp) 
+            FROM light_checks 
+            GROUP BY name
+        `)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		defer rows.Close()
+
+		resp := make(map[string]string)
+		for rows.Next() {
+			var key, state string
+			var ts string
+			if err := rows.Scan(&key, &state, &ts); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+			resp[lights[key].Name] = state
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp)
+	})
+
+	log.Println("HTTP server listening on", port)
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}