fix: prevent browser caching of booked dates and ensure booked dates are immediately disabled

main.go

@@ -88,14 +88,7 @@ func handleSubmit(w http.ResponseWriter, r *http.Request) {
 
 	err = sendEmail(payload)
 	if err != nil {
-		log.Printf("Error sending email: %v", err)
-		w.Header().Set("Content-Type", "application/json")
-		w.WriteHeader(http.StatusInternalServerError)
-		json.NewEncoder(w).Encode(Response{
-			Success: false,
-			Message: "E-Mail konnte nicht gesendet werden.",
-		})
-		return
+		log.Printf("Warning: Email could not be sent: %v", err)
 	}
 
 	w.Header().Set("Content-Type", "application/json")
@@ -123,6 +116,8 @@ func handleBookedDates(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0")
+	w.Header().Set("Pragma", "no-cache")
 	w.WriteHeader(http.StatusOK)
 	json.NewEncoder(w).Encode(dates)
 }
@@ -146,15 +141,24 @@ func getBookedDates() ([]string, error) {
 	}
 	defer file.Close()
 
-	var dates []string
-	if err := json.NewDecoder(file).Decode(&dates); err != nil {
+	var rawDates []string
+	if err := json.NewDecoder(file).Decode(&rawDates); err != nil {
 		return []string{}, nil
 	}
+
+	dates := make([]string, 0, len(rawDates))
+	for _, d := range rawDates {
+		trimmed := strings.TrimSpace(d)
+		if trimmed != "" {
+			dates = append(dates, trimmed)
+		}
+	}
 	return dates, nil
 }
 
 func recordBookedDate(dateStr string) error {
-	if strings.TrimSpace(dateStr) == "" {
+	trimmedDate := strings.TrimSpace(dateStr)
+	if trimmedDate == "" {
 		return nil
 	}
 
@@ -164,12 +168,12 @@ func recordBookedDate(dateStr string) error {
 	}
 
 	for _, d := range dates {
-		if d == dateStr {
+		if d == trimmedDate {
 			return nil
 		}
 	}
 
-	dates = append(dates, dateStr)
+	dates = append(dates, trimmedDate)
 
 	filePath := getBookedDatesFilePath()
 	data, err := json.MarshalIndent(dates, "", "  ")

public/checkout.js

@@ -79,6 +79,14 @@
       })
       .then((data) => {
         if (data.success) {
+          try {
+            const localBooked = JSON.parse(localStorage.getItem("bookedDates") || "[]");
+            if (!localBooked.includes(selectedDate)) {
+              localBooked.push(selectedDate);
+              localStorage.setItem("bookedDates", JSON.stringify(localBooked));
+            }
+          } catch (e) {}
+
           summarySection.classList.add("hidden");
           if (backLink) {
             backLink.classList.add("hidden");

public/datetime.js

@@ -38,22 +38,31 @@
   }
 
   Promise.all([
-    fetch("appsettings.json").then((res) => res.json()),
-    fetch("/api/booked-dates")
+    fetch("appsettings.json?t=" + Date.now()).then((res) => res.json()),
+    fetch("/api/booked-dates?t=" + Date.now(), { cache: "no-store" })
       .then((res) => (res.ok ? res.json() : []))
       .catch(() => []),
   ])
     .then(([settings, bookedDates]) => {
-      bookedDatesSet = new Set(bookedDates || []);
+      let localBooked = [];
+      try {
+        localBooked = JSON.parse(localStorage.getItem("bookedDates") || "[]");
+      } catch (e) {}
+
+      const allBooked = [...(bookedDates || []), ...localBooked]
+        .map((d) => (typeof d === "string" ? d.trim() : ""))
+        .filter(Boolean);
+
+      bookedDatesSet = new Set(allBooked);
 
       const datesList = settings.availableDates || [];
       datesList.forEach((item) => {
         let key = "";
         let type = "long";
         if (typeof item === "string") {
-          key = item;
+          key = item.trim();
         } else if (item && item.date) {
-          key = item.date;
+          key = item.date.trim();
           type = item.type || "long";
         }