Fixed creation of users + better frontend handling of permissions

backend/utils/get_diff.go

@@ -0,0 +1,42 @@
+package utils
+
+import (
+	"log"
+)
+
+// GetDiff returns two slices: elements to add and elements to remove
+func GetDiff[T comparable](current, newm []T) ([]T, []T) {
+	log.Println(current, newm)
+	// Use a single map with an int to track state:
+	// 1: only in current, 2: only in new, 3: in both
+	presence := make(map[T]int)
+
+	// Mark all items in current as 1
+	for _, item := range current {
+		presence[item] = 1
+	}
+
+	// Update map based on newm: add 2 if not present, set to 3 if present
+	for _, item := range newm {
+		if val, exists := presence[item]; exists {
+			presence[item] = val + 2 // 1 -> 3 (both)
+		} else {
+			presence[item] = 2 // only in new
+		}
+	}
+
+	var toAdd, toRemove []T
+
+	// Iterate once over the map to build results
+	for item, state := range presence {
+		switch state {
+		case 1: // Only in current -> remove
+			toRemove = append(toRemove, item)
+		case 2: // Only in new -> add
+			toAdd = append(toAdd, item)
+			// case 3: in both, do nothing
+		}
+	}
+
+	return toAdd, toRemove
+}