feat: #26107 uplink discounts for traitors (no nukies for now) (#26297)

* feat: #26107 uplink discounts for traitors and nukies

* refactor: #26107 extracted discount label from price of StoreListingControl

* refactor: minor renaming

* refactor: parametrized adding discounts to uplink store

* fix: #26107 prevent exception on empty discountOptions

* feat: uplink now have 'Discounted' category which contains all discounted items on this session.

* after merge fixups

* rename discount categories according to common sense

* refactor: DiscountOptions is now optional (nullable) on ListingData

* add nullability check ignore for already checked listingData.DiscountOptions

* fix after merge store menu ui

* remove unused using

* final fix after merge conflicts

* [refactor]: #26107 fix variables naming in UplinkSystem

* fix: #26107 fix after merge

* refactor: #26107 now supports discountDownUntil on ListingItem, instead of % of discount

* feat: #26107 support multiple currency discount in store on side of discount message label

* refactor: #26107 extracted discounts initialization to separate system. StoreDiscountData are spread as array and not list now

* refactor: #26107 move more code from storesystem to StoreDiscountComponent

* refactor: #26107 separated StoreSystem and StoreDiscountSystem using events

* fix: #26107 placed not-nullable variable initialization in ListingData for tests

* refactor: #26107 minor renaming, xml-docs

* fix: #26107 changed most of discounts to be down to half price for balance purposes

* ids used in with discounts are now ProtoIds, dicountCategories are now prototypes, code with weights simplified

* decoupled storesystem and store discount system

* xml-docs

* refactor:  #26107 xml-doc for StoreDiscountSystem

* is now a thing (tmp)

* fix: compilation errors + StoreDiscountData.DiscountCategoryId

* refactor: rename ListingDataWithCostModifiers, fix all cost related code, enpittyfy performance, uglify uplink_catalog

* refactor: removed unused code, more StoreDiscountSystem docs, simplify code

* refactor: moved discount category logic to respective system, now creating ListingData c-tor clones all mutable fields as expected

* refactor: rename back (its not prototype)

* refactor: move ListingItemsInitializingEvent to file with handling logic

* refactor: comments for StoreBuyFinishedEvent handling, more logging

* refactor: moved StoreInitializedEvent, xml-doc

* refactor: simplify StoreDiscountSystem code  (reduce nesting) + xml-doc

* refactor: restore old listing data cost field name

* refactor: fix linter in uplink_catalog.yml

* refactor: xml-doc for ListingDataWithCostModifiers

* refactor: limit usage of ListingData in favour of ListingDataWithCostModifiers

* refactor: purged linq, removed custom datafield names, minor cleanup

* refactor: removed double-allocation on getting available listings

* refactor: StoreSystem.OnBuyRequest now uses component.FullListingsCatalog as reference point (as it was in original code)

* fix: minor discount categories on uplink items changes following design overview

* refactor: StoreBuyListingMessage now uses protoId and not whole object

* refactor: store refund and discount integration test, RefreshAllListings now translates previous cost modifiers to refreshed list, if state previous to refresh had any listing items

---------

Co-authored-by: pa.pecherskij <pa.pecherskij@interfax.ru>

Content.Server/Store/Systems/StoreSystem.Ui.cs

@@ -91,7 +91,8 @@ public sealed partial class StoreSystem
         //this is the person who will be passed into logic for all listing filtering.
         if (user != null) //if we have no "buyer" for this update, then don't update the listings
         {
-            component.LastAvailableListings = GetAvailableListings(component.AccountOwner ?? user.Value, store, component).ToHashSet();
+            component.LastAvailableListings = GetAvailableListings(component.AccountOwner ?? user.Value, store, component)
+                .ToHashSet();
         }
 
         //dictionary for all currencies, including 0 values for currencies on the whitelist
@@ -109,6 +110,7 @@ public sealed partial class StoreSystem
 
         // only tell operatives to lock their uplink if it can be locked
         var showFooter = HasComp<RingerUplinkComponent>(store);
+
         var state = new StoreUpdateState(component.LastAvailableListings, allCurrency, showFooter, component.RefundAllowed);
         _ui.SetUiState(store, StoreUiKey.Key, state);
     }
@@ -128,7 +130,7 @@ public sealed partial class StoreSystem
     /// </summary>
     private void OnBuyRequest(EntityUid uid, StoreComponent component, StoreBuyListingMessage msg)
     {
-        var listing = component.Listings.FirstOrDefault(x => x.Equals(msg.Listing));
+        var listing = component.FullListingsCatalog.FirstOrDefault(x => x.ID.Equals(msg.Listing.Id));
 
         if (listing == null) //make sure this listing actually exists
         {
@@ -153,9 +155,10 @@ public sealed partial class StoreSystem
         }
 
         //check that we have enough money
-        foreach (var currency in listing.Cost)
+        var cost = listing.Cost;
+        foreach (var (currency, amount) in cost)
         {
-            if (!component.Balance.TryGetValue(currency.Key, out var balance) || balance < currency.Value)
+            if (!component.Balance.TryGetValue(currency, out var balance) || balance < amount)
             {
                 return;
             }
@@ -165,13 +168,13 @@ public sealed partial class StoreSystem
             component.RefundAllowed = false;
 
         //subtract the cash
-        foreach (var (currency, value) in listing.Cost)
+        foreach (var (currency, amount) in cost)
         {
-            component.Balance[currency] -= value;
+            component.Balance[currency] -= amount;
 
             component.BalanceSpent.TryAdd(currency, FixedPoint2.Zero);
 
-            component.BalanceSpent[currency] += value;
+            component.BalanceSpent[currency] += amount;
         }
 
         //spawn entity
@@ -213,7 +216,7 @@ public sealed partial class StoreSystem
 
                 if (listing.ProductUpgradeId != null)
                 {
-                    foreach (var upgradeListing in component.Listings)
+                    foreach (var upgradeListing in component.FullListingsCatalog)
                     {
                         if (upgradeListing.ID == listing.ProductUpgradeId)
                         {
@@ -262,6 +265,13 @@ public sealed partial class StoreSystem
         listing.PurchaseAmount++; //track how many times something has been purchased
         _audio.PlayEntity(component.BuySuccessSound, msg.Actor, uid); //cha-ching!
 
+        var buyFinished = new StoreBuyFinishedEvent
+        {
+            PurchasedItem = listing,
+            StoreUid = uid
+        };
+        RaiseLocalEvent(ref buyFinished);
+
         UpdateUserInterface(buyer, uid, component);
     }
 
@@ -346,6 +356,7 @@ public sealed partial class StoreSystem
         {
             component.Balance[currency] += value;
         }
+
         // Reset store back to its original state
         RefreshAllListings(component);
         component.BalanceSpent = new();
@@ -376,3 +387,14 @@ public sealed partial class StoreSystem
         component.RefundAllowed = false;
     }
 }
+
+/// <summary>
+/// Event of successfully finishing purchase in store (<see cref="StoreSystem"/>.
+/// </summary>
+/// <param name="StoreUid">EntityUid on which store is placed.</param>
+/// <param name="PurchasedItem">ListingItem that was purchased.</param>
+[ByRefEvent]
+public readonly record struct StoreBuyFinishedEvent(
+    EntityUid StoreUid,
+    ListingDataWithCostModifiers PurchasedItem
+);