Add the SellBuilding Unique (#10514)

* Restored the SellBuilding Unique

* Rephrased SellBuilding unique

core/src/com/unciv/models/ruleset/unique/UniqueTriggerActivation.kt

@@ -687,6 +687,26 @@ object UniqueTriggerActivation {
                 return true
             }
 
+            UniqueType.SellBuilding -> {
+
+                val applicableCities = civInfo.cities.asSequence().filter {
+                    it.matchesFilter(unique.params[1])
+                }
+
+                for (applicableCity in applicableCities) {
+                    val buildingsToSell = applicableCity.cityConstructions.getBuiltBuildings().filter {
+                        it.matchesFilter(unique.params[0]) && it.isSellable()
+                    }
+
+                    for (building in buildingsToSell) {
+                        applicableCity.sellBuilding(building)
+                    }
+
+                }
+
+                return true
+            }
+
             else -> {}
         }
         return false

core/src/com/unciv/models/ruleset/unique/UniqueType.kt

@@ -133,6 +133,7 @@ enum class UniqueType(val text: String, vararg targets: UniqueTarget, val flags:
     GainFreeBuildings("Gain a free [buildingName] [cityFilter]", UniqueTarget.Global, UniqueTarget.Triggerable),
     BuildingMaintenance("[relativeAmount]% maintenance cost for buildings [cityFilter]", UniqueTarget.Global, UniqueTarget.FollowerBelief),
     RemoveBuilding("Remove [buildingFilter] [cityFilter]", UniqueTarget.Global, UniqueTarget.Triggerable),
+    SellBuilding("Sell [buildingFilter] buildings [cityFilter]", UniqueTarget.Global, UniqueTarget.Triggerable),
 
     /// Border growth
     BorderGrowthPercentage("[relativeAmount]% Culture cost of natural border growth [cityFilter]", UniqueTarget.Global, UniqueTarget.FollowerBelief),

docs/Modders/uniques.md

@@ -18,6 +18,11 @@ Simple unique parameters are explained by mouseover. Complex parameters are expl
 
 	Applicable to: Triggerable, Global
 
+??? example  "Sell [buildingFilter] [cityFilter]"
+	Example: "Sell [Culture] [in all cities]"
+
+	Applicable to: Triggerable, Global
+
 ??? example  "Free [unit] appears"
 	Example: "Free [Musketman] appears"