Better "Withdraws before melee combat" unique

core/src/com/unciv/logic/battle/Battle.kt

@@ -125,11 +125,21 @@ object Battle {
 
         // Withdraw from melee ability
         if (attacker is MapUnitCombatant && attacker.isMelee() && defender is MapUnitCombatant) {
-            val withdrawUniques = defender.unit.getMatchingUniques(UniqueType.MayWithdraw)
-            val combinedProbabilityToStayPut = withdrawUniques.fold(100) { probabilityToStayPut, unique -> probabilityToStayPut * (100-unique.params[0].toInt()) / 100 }
-            val baseWithdrawChance = 100 - combinedProbabilityToStayPut
-            // If a mod allows multiple withdraw properties, they stack multiplicatively
-            if (baseWithdrawChance != 0 && doWithdrawFromMeleeAbility(attacker, defender, baseWithdrawChance))
+            val withdrawChance =
+                if (defender.unit.hasUnique(UniqueType.WithdrawsBeforeMeleeCombat, stateForConditionals = StateForConditionals(
+                        civInfo = defender.getCivInfo(),
+                        ourCombatant = defender,
+                        theirCombatant = attacker,
+                        tile = attackedTile
+                    ))
+                ) 100
+
+                else 100 - defender.unit.getMatchingUniques(UniqueType.MayWithdraw)
+                    .fold(100) { probabilityToWithdraw, unique ->
+                        probabilityToWithdraw * (100 - unique.params[0].toInt()) / 100
+                    }
+
+            if (withdrawChance != 0 && doWithdrawFromMeleeAbility(attacker, defender, withdrawChance))
                 return DamageDealt.None
         }
 
@@ -615,44 +625,29 @@ object Battle {
         }
     }
 
-    private fun doWithdrawFromMeleeAbility(attacker: ICombatant, defender: ICombatant, baseWithdrawChance: Int): Boolean {
-        if (baseWithdrawChance == 0) return false
-        // Some notes...
-        // unit.getUniques() is a union of BaseUnit uniques and Promotion effects.
-        // according to some strategy guide the Slinger's withdraw ability is inherited on upgrade,
-        // according to the Ironclad entry of the wiki the Caravel's is lost on upgrade.
-        // therefore: Implement the flag as unique for the Caravel and Destroyer, as promotion for the Slinger.
-        if (attacker !is MapUnitCombatant) return false         // allow simple access to unit property
-        if (defender !is MapUnitCombatant) return false
+    private fun doWithdrawFromMeleeAbility(attacker: MapUnitCombatant, defender: MapUnitCombatant, withdrawChance: Int): Boolean {
+        if (withdrawChance == 0) return false
         if (defender.unit.isEmbarked()) return false
         if (defender.unit.cache.cannotMove) return false
+
+        // This is where the chance comes into play
+        if (Random( // 'randomness' is consistent for turn and tile, to avoid save-scumming
+                attacker.getCivInfo().gameInfo.turns * defender.getTile().position.hashCode().toLong()
+            ).nextInt(100) > withdrawChance) return false
+
         // Promotions have no effect as per what I could find in available documentation
-        val attackBaseUnit = attacker.unit.baseUnit
-        val defendBaseUnit = defender.unit.baseUnit
         val fromTile = defender.getTile()
-        val attTile = attacker.getTile()
+        val attackerTile = attacker.getTile()
+
         fun canNotWithdrawTo(tile: Tile): Boolean { // if the tile is what the defender can't withdraw to, this fun will return true
            return !defender.unit.movement.canMoveTo(tile)
-                   || defendBaseUnit.isLandUnit() && !tile.isLand // forbid retreat from land to sea - embarked already excluded
+                   || defender.isLandUnit() && !tile.isLand // forbid retreat from land to sea - embarked already excluded
                    || tile.isCityCenter() && tile.getOwner() != defender.getCivInfo() // forbid retreat into the city which doesn't belong to the defender
         }
-        /* Calculate success chance: Base chance from json, calculation method from https://www.bilibili.com/read/cv2216728
-        In general, except attacker's tile, 5 tiles neighbors the defender :
-        2 of which are also attacker's neighbors ( we call them 2-Tiles) and the other 3 aren't (we call them 3-Tiles).
-        Withdraw chance depends on 2 factors : attacker's movement and how many tiles in 3-Tiles the defender can't withdraw to.
-        If the defender can withdraw, at first we choose a tile as toTile from 3-Tiles the defender can withdraw to.
-        If 3-Tiles the defender can withdraw to is null, we choose this from 2-Tiles the defender can withdraw to.
-        If 2-Tiles the defender can withdraw to is also null, we return false.
-        */
-        val percentChance = baseWithdrawChance - max(0, (attackBaseUnit.movement-2)) * 20 -
-                fromTile.neighbors.filterNot { it == attTile || it in attTile.neighbors }.count { canNotWithdrawTo(it) } * 20
-        // Get a random number in [0,100) : if the number <= percentChance, defender will withdraw from melee
-        if (Random( // 'randomness' is consistent for turn and tile, to avoid save-scumming
-                    (attacker.getCivInfo().gameInfo.turns * defender.getTile().hashCode()).toLong()
-        ).nextInt(100) > percentChance) return false
-        val firstCandidateTiles = fromTile.neighbors.filterNot { it == attTile || it in attTile.neighbors }
+
+        val firstCandidateTiles = fromTile.neighbors.filterNot { it == attackerTile || it in attackerTile.neighbors }
                 .filterNot { canNotWithdrawTo(it) }
-        val secondCandidateTiles = fromTile.neighbors.filter { it in attTile.neighbors }
+        val secondCandidateTiles = fromTile.neighbors.filter { it in attackerTile.neighbors }
                 .filterNot { canNotWithdrawTo(it) }
         val toTile: Tile = when {
             firstCandidateTiles.any() -> firstCandidateTiles.toList().random()
@@ -667,11 +662,12 @@ object Battle {
         // and count 1 attack for attacker but leave it in place
         reduceAttackerMovementPointsAndAttacks(attacker, defender)
 
-        val attackingUnit = attackBaseUnit.name; val defendingUnit = defendBaseUnit.name
-        val notificationString = "[$defendingUnit] withdrew from a [$attackingUnit]"
+        val attackerName = attacker.getName()
+        val defenderName = defender.getName()
+        val notificationString = "[$defenderName] withdrew from a [$attackerName]"
         val locations = LocationAction(toTile.position, attacker.getTile().position)
-        defender.getCivInfo().addNotification(notificationString, locations, NotificationCategory.War, defendingUnit, NotificationIcon.War, attackingUnit)
-        attacker.getCivInfo().addNotification(notificationString, locations, NotificationCategory.War, defendingUnit, NotificationIcon.War, attackingUnit)
+        defender.getCivInfo().addNotification(notificationString, locations, NotificationCategory.War, defenderName, NotificationIcon.War, attackerName)
+        attacker.getCivInfo().addNotification(notificationString, locations, NotificationCategory.War, defenderName, NotificationIcon.War, attackerName)
         return true
     }
 

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

@@ -411,7 +411,8 @@ enum class UniqueType(
     @Deprecated("As of 4.12.4", ReplaceWith("No damage penalty for wounded units"))
     NoDamagePenalty("Damage is ignored when determining unit Strength", UniqueTarget.Unit, UniqueTarget.Global),
     Uncapturable("Uncapturable", UniqueTarget.Unit),
-    // Replace with "Withdraws before melee combat <with [amount]% chance>"?
+    WithdrawsBeforeMeleeCombat("Withdraws before melee combat", UniqueTarget.Unit),
+    @Deprecated("As of 4.12.4", ReplaceWith("Withdraws before melee combat <with [amount]% chance>"))
     MayWithdraw("May withdraw before melee ([amount]%)", UniqueTarget.Unit),
     CannotCaptureCities("Unable to capture cities", UniqueTarget.Unit),
     CannotPillage("Unable to pillage tiles", UniqueTarget.Unit),

docs/Modders/uniques.md

@@ -876,7 +876,7 @@ Simple unique parameters are explained by mouseover. Complex parameters are expl
 ??? example  "No defensive terrain penalty"
 	Applicable to: Global, Unit
 
-??? example  "Damage is ignored when determining unit Strength"
+??? example  "No damage penalty for wounded units"
 	Applicable to: Global, Unit
 
 ??? example  "No movement cost to pillage"
@@ -1343,9 +1343,7 @@ Simple unique parameters are explained by mouseover. Complex parameters are expl
 ??? example  "Uncapturable"
 	Applicable to: Unit
 
-??? example  "May withdraw before melee ([amount]%)"
-	Example: "May withdraw before melee ([3]%)"
-
+??? example  "Withdraws before melee combat"
 	Applicable to: Unit
 
 ??? example  "Unable to capture cities"