Fix enchant scroll applying single-level stats instead of cumulative (#674)

* Fix enchant scroll applying single-level stats instead of cumulative

EnchantScrollHandler.HandleEnchant only called GetEnchant for the target
level, giving e.g. only level 11's bonus instead of the sum of levels
1 through 11. HandlePreview also computed deltas from current enchant
level instead of absolute cumulative values, showing wrong stats when
using a scroll on an already-enchanted item.

Both now use GetCumulativeEnchant which sums per-level rates from 1
through the target level, matching manual Ophelia/Peachy enchanting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: enchant scroll preview floor and in-place enchant update

Clamp preview minimum to item's current enchant level (Math.Max) since
enchant scrolls never decrease enchant level. Update enchant properties
in-place instead of replacing the ItemEnchant object to preserve
persisted fields (EnchantExp, EnchantCharges, Charges, Tradeable).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: AngeloTadeucci

Maple2.Server.Game/PacketHandlers/EnchantScrollHandler.cs

@@ -62,31 +62,17 @@ private void HandlePreview(GameSession session, IByteReader packet) {
             return;
         }
 
-        int minEnchant = Math.Min(item.Enchant?.Enchants ?? 0, metadata.Enchants.Min());
-        int maxEnchant = metadata.Enchants.Max();
-        Dictionary<BasicAttribute, BasicOption> minOptions = [];
-        Dictionary<BasicAttribute, BasicOption> maxOptions = [];
-        for (int i = minEnchant; i < maxEnchant; i++) {
-            // add to dictionaries
-            int targetEnchant = i - 1;
-            ItemEnchant result = ItemEnchantManager.GetEnchant(session, item, i + 1);
-            foreach ((BasicAttribute attribute, BasicOption option) in result.BasicOptions) {
-                if (minOptions.TryGetValue(attribute, out BasicOption currentOption)) {
-                    minOptions[attribute] = currentOption + option;
-                } else {
-                    minOptions[attribute] = option;
-                }
-            }
-
-            result = ItemEnchantManager.GetEnchant(session, item, i - 1);
-            foreach ((BasicAttribute attribute, BasicOption option) in result.BasicOptions) {
-                if (maxOptions.TryGetValue(attribute, out BasicOption currentOption)) {
-                    maxOptions[attribute] = currentOption + option;
-                } else {
-                    maxOptions[attribute] = option;
-                }
-            }
+        Dictionary<BasicAttribute, BasicOption> minOptions;
+        Dictionary<BasicAttribute, BasicOption> maxOptions;
+        if (metadata.Type == EnchantScrollType.Random) {
+            int minRoll = Math.Max(metadata.Enchants.Min(), item.Enchant?.Enchants ?? 0);
+            minOptions = GetCumulativeEnchant(session, item, minRoll).BasicOptions;
+            maxOptions = GetCumulativeEnchant(session, item, metadata.Enchants.Max()).BasicOptions;
+        } else {
+            minOptions = GetCumulativeEnchant(session, item, metadata.Enchants.Max()).BasicOptions;
+            maxOptions = minOptions;
         }
+
         session.Send(EnchantScrollPacket.Preview(item, metadata.Type, minOptions, maxOptions));
     }
 
@@ -122,8 +108,12 @@ private void HandleEnchant(GameSession session, IByteReader packet) {
             // Ensure that you cannot randomize an enchant lower than current item.
             item.Enchant ??= new ItemEnchant();
             if (enchantLevel > item.Enchant.Enchants) {
-                item.Enchant = ItemEnchantManager.GetEnchant(session, item, enchantLevel);
-                item.Enchant.Enchants = enchantLevel;
+                ItemEnchant computed = GetCumulativeEnchant(session, item, enchantLevel);
+                item.Enchant.Enchants = computed.Enchants;
+                item.Enchant.BasicOptions.Clear();
+                foreach ((BasicAttribute attribute, BasicOption option) in computed.BasicOptions) {
+                    item.Enchant.BasicOptions[attribute] = option;
+                }
             }
 
             session.Send(EnchantScrollPacket.Enchant(item));
@@ -151,6 +141,22 @@ private static EnchantScrollError IsCompatibleScroll(Item item, EnchantScrollMet
         return s_enchantscroll_ok;
     }
 
+    private static ItemEnchant GetCumulativeEnchant(GameSession session, Item item, int targetLevel) {
+        var cumulative = new ItemEnchant();
+        for (int i = 1; i <= targetLevel; i++) {
+            ItemEnchant levelEnchant = ItemEnchantManager.GetEnchant(session, item, i);
+            foreach ((BasicAttribute attribute, BasicOption option) in levelEnchant.BasicOptions) {
+                if (cumulative.BasicOptions.TryGetValue(attribute, out BasicOption existing)) {
+                    cumulative.BasicOptions[attribute] = existing + option;
+                } else {
+                    cumulative.BasicOptions[attribute] = option;
+                }
+            }
+        }
+        cumulative.Enchants = targetLevel;
+        return cumulative;
+    }
+
     private bool TryGetMetadata(GameSession session, long scrollUid, [NotNullWhen(true)] out EnchantScrollMetadata? metadata) {
         Item? scroll = session.Item.Inventory.Get(scrollUid);
         if (scroll == null) {