Improve row/column safety

if you need an unsafe slot, use Slot.ofUnsafe, but you should now use Slot.of.

Constructor will be made private on 2.1.0 to avoid boilerplate and safety issues (like for example, row being 7, column being 10, etc.)

Author: coderFlameyosFlow

core/src/main/java/me/flame/menus/menu/Slot.java

@@ -47,18 +47,79 @@ public final class Slot {
     @CompileTimeConstant
     public static final Slot NaS = getNaS();
 
+    /**
+     * Creates a new slot with the specified row and column.
+     * @param row the row
+     * @param column the col
+     * @deprecated Use {@link #of(int, int)}, constructor will be private in 2.1.0
+     */
+    @Deprecated
     public Slot(final int row, final int column) {
-        this.row = row;
-        this.column = column;
+        this(row, column, false);
+        checkRowColumnSafety(slot, row, column);
 
         this.slot = (column + (row - 1) * 9) - 1;
         this.slot = this.slot >= 54 ? -1 : this.slot;
     }
 
+    private Slot(final int row, final int column, final int slot) {
+        this(row, column, false);
+        this.slot = slot >= 54 ? -1 : slot;
+        checkRowColumnSafety(slot, row, column);
+    }
+
+    /**
+     * Creates a new slot with the specified row and column.
+     * @param slot the slot
+     * @deprecated Use {@link #of(int)}, constructor will be private in 2.1.0
+     */
+    @Deprecated
     public Slot(final int slot) {
+        this(slot / 9 + 1, slot % 9 + 1, false);
+        checkRowColumnSafety(slot, row, column);
+
         this.slot = slot >= 54 ? -1 : slot;
-        this.row = (slot / 9) + 1;
-        this.column = (slot % 9) + 1;
+    }
+
+    private static void checkRowColumnSafety(int slot, int row, int column) {
+        if (row > 6) {
+            throw new IllegalArgumentException(
+                    "Row expected to be between 1 and 6, got " + row +
+                    "\nFix: slot = (column + (row - 1) * 9) - 1, slot = " + slot
+            );
+        }
+        if (column > 9) {
+            throw new IllegalArgumentException(
+                    "Column expected to be between 1 and 9, got " + column +
+                    "\nFix: slot = (column + (row - 1) * 9) - 1, slot = " + slot
+            );
+        }
+    }
+
+    @Contract("_ -> new")
+    public static @NotNull Slot of(int slot) {
+        return new Slot(slot / 9 + 1, slot % 9 + 1, slot);
+    }
+
+    @Contract("_, _ -> new")
+    public static @NotNull Slot of(int row, int column) {
+        return new Slot(row, column, (column + (row - 1) * 9) - 1);
+    }
+
+    public static @NotNull Slot ofUnsafe(int slot) {
+        Slot position = new Slot((slot / 9) + 1, (slot % 9) + 1, true);
+
+        int positionSlot = (position.column + (position.row - 1) * 9) - 1;
+        position.slot = positionSlot >= 54 ? -1 : positionSlot;
+        return position;
+    }
+
+    public static Slot ofUnsafe(int row, int column) {
+        if (column > 9 || row > 6) return Slot.NaS;
+        Slot position = new Slot(row, column, true);
+        int positionSlot = (column + (row - 1) * 9) - 1;
+        position.slot = positionSlot >= 54 ? -1 : positionSlot;
+        return position;
     }
 
     // fast copy constructor
@@ -121,9 +182,7 @@ public Slot setSlot(final int slot) {
      */
     @NotNull
     public Slot copy() {
-        final Slot slot = new Slot(row, column, true);
-        slot.slot = this.slot;
-        return slot;
+        return new Slot(row, column, slot);
     }
 
     /**
@@ -138,7 +197,7 @@ public boolean isSlot() {
     }
 
     /**
-     * Check if the slot is a valid slot.
+     * Check if the slot is valid.
      * @apiNote If the slot is equal to -1, it's invalid; fast check.
      * @return true if the slot does not equal -1.
      */
@@ -149,17 +208,13 @@ public boolean isValid() {
     // faster NaS (Not A Slot) alternative to creating a Slot like new Slot(8, 1);
     @NotNull
     private static Slot getNaS() {
-        Slot slot = new Slot(-1, -1, true);
-        slot.slot = -1;
-        return slot;
+        return new Slot(-1, -1, -1);
     }
 
     // faster FIRST slot compared to doing "new Slot(1, 1)"
     @NotNull
     public static Slot getFirst() {
-        Slot slot = new Slot(1, 1, true);
-        slot.slot = 0;
-        return slot;
+        return new Slot(1, 1, 0);
     }
 
     @Override