Fixed bug where units could still be purchased if they used a depleted resource (#4798)

core/src/com/unciv/logic/city/CityConstructions.kt

@@ -365,12 +365,11 @@ class CityConstructions {
         val inProgressSnapshot = inProgressConstructions.keys.filter { it != currentConstructionFromQueue }
         for (constructionName in inProgressSnapshot) {
             val construction = getConstruction(constructionName)
-            val rejectionReason: String =
-                    when (construction) {
-                        is Building -> construction.getRejectionReason(this)
-                        is BaseUnit -> construction.getRejectionReason(this)
-                        else -> ""
-                    }
+            // Perpetual constructions should always still be valid (I hope)
+            if (construction is PerpetualConstruction) continue
+            
+            val rejectionReason = 
+                (construction as INonPerpetualConstruction).getRejectionReason(this)
 
             if (rejectionReason.endsWith("lready built")
                     || rejectionReason.startsWith("Cannot be built with")

core/src/com/unciv/logic/city/IConstruction.kt

@@ -22,6 +22,7 @@ interface INonPerpetualConstruction : IConstruction, INamed {
 
     fun getProductionCost(civInfo: CivilizationInfo): Int
     fun getStatBuyCost(cityInfo: CityInfo, stat: Stat): Int?
+    fun getRejectionReason(cityConstructions: CityConstructions): String
     
     private fun getMatchingUniques(uniqueTemplate: String): Sequence<Unique> {
         return uniqueObjects.asSequence().filter { it.placeholderText == uniqueTemplate }
@@ -41,6 +42,13 @@ interface INonPerpetualConstruction : IConstruction, INamed {
         ) return true
         return false
     }
+
+    /** Checks if the construction should be purchasable, not whether it can be bought with a stat at all */
+    fun isPurchasable(cityConstructions: CityConstructions): Boolean {
+        val rejectionReason = getRejectionReason(cityConstructions)
+        return rejectionReason == ""
+                || rejectionReason == "Can only be purchased"
+    }
     
     fun canBePurchasedWithAnyStat(cityInfo: CityInfo): Boolean {
         return Stat.values().any { canBePurchasedWithStat(cityInfo, it) }
@@ -107,7 +115,7 @@ open class PerpetualConstruction(override var name: String, val description: Str
 
     override fun isBuildable(cityConstructions: CityConstructions): Boolean =
             throw Exception("Impossible!")
-
+    
     override fun postBuildEvent(cityConstructions: CityConstructions, wasBought: Boolean) =
             throw Exception("Impossible!")
 

core/src/com/unciv/models/ruleset/Building.kt

@@ -392,7 +392,7 @@ class Building : NamedStats(), INonPerpetualConstruction, ICivilopediaText {
                 || rejectionReason == "Can only be purchased"
     }
 
-    fun getRejectionReason(construction: CityConstructions): String {
+    override fun getRejectionReason(construction: CityConstructions): String {
         if (construction.isBuilt(name)) return "Already built"
         // for buildings that are created as side effects of other things, and not directly built
         // unless they can be bought with faith

core/src/com/unciv/models/ruleset/unit/BaseUnit.kt

@@ -240,7 +240,7 @@ class BaseUnit : INamed, INonPerpetualConstruction, CivilopediaText() {
                 || rejectionReason == "Can only be purchased"
     }
 
-    fun getRejectionReason(cityConstructions: CityConstructions): String {
+    override fun getRejectionReason(cityConstructions: CityConstructions): String {
         if (isWaterUnit() && !cityConstructions.cityInfo.isCoastal())
             return "Can only build water units in coastal cities"
         val civInfo = cityConstructions.cityInfo.civInfo

core/src/com/unciv/ui/cityscreen/CityConstructionsTable.kt

@@ -429,11 +429,12 @@ class CityConstructionsTable(val cityScreen: CityScreen) : Table(CameraStageBase
             }
             
             if (!cityScreen.canChangeState
-                    || city.isPuppet 
-                    || city.isInResistance()
-                    || !city.canPurchase(construction)
-                    || (constructionBuyCost > city.getStatReserve(stat) && !city.civInfo.gameInfo.gameParameters.godMode))
-                button.disable()
+                || !construction.isPurchasable(city.cityConstructions)
+                || city.isPuppet 
+                || city.isInResistance()
+                || !city.canPurchase(construction)
+                || (constructionBuyCost > city.getStatReserve(stat) && !city.civInfo.gameInfo.gameParameters.godMode)
+            ) button.disable()
         }
 
         button.labelCell.pad(5f)