From d4175567207e0e3b5abbe1f03ba50944a303ed91 Mon Sep 17 00:00:00 2001
From: Xander Lenstra <71121390+xlenstra@users.noreply.github.com>
Date: Thu, 31 Mar 2022 22:06:42 +0200
Subject: [PATCH] Added a unique for attacking when embarked (#6464)

* Added a unique for attacking when embarked

* Implemented requested changes

* Fixed withdrawel probability
---
 core/src/com/unciv/logic/automation/BattleHelper.kt    | 4 ++--
 core/src/com/unciv/logic/battle/Battle.kt              | 8 +++++---
 core/src/com/unciv/models/ruleset/unique/UniqueType.kt | 1 +
 docs/Modders/uniques.md                                | 3 +++
 4 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/core/src/com/unciv/logic/automation/BattleHelper.kt b/core/src/com/unciv/logic/automation/BattleHelper.kt
index 379449593d..6bbf151c25 100644
--- a/core/src/com/unciv/logic/automation/BattleHelper.kt
+++ b/core/src/com/unciv/logic/automation/BattleHelper.kt
@@ -92,8 +92,8 @@ object BattleHelper {
 
     fun containsAttackableEnemy(tile: TileInfo, combatant: ICombatant): Boolean {
         if (combatant is MapUnitCombatant && combatant.unit.isEmbarked()) {
-            if (tile.isWater) return false // can't attack water units while embarked, only land
-            if (combatant.isRanged()) return false
+            // Can't attack water units while embarked, only land
+            if (tile.isWater || combatant.isRanged()) return combatant.hasUnique(UniqueType.AttackOnSea) 
         }
 
         val tileCombatant = Battle.getMapCombatantOfTile(tile) ?: return false
diff --git a/core/src/com/unciv/logic/battle/Battle.kt b/core/src/com/unciv/logic/battle/Battle.kt
index 11f12fee6c..73310d1ae3 100644
--- a/core/src/com/unciv/logic/battle/Battle.kt
+++ b/core/src/com/unciv/logic/battle/Battle.kt
@@ -76,9 +76,10 @@ object Battle {
 
         // Withdraw from melee ability
         if (attacker is MapUnitCombatant && attacker.isMelee() && defender is MapUnitCombatant) {
-            val withdraw = defender.unit.getMatchingUniques(UniqueType.MayWithdraw)
-                .sumOf{ it.params[0].toInt() }  // If a mod allows multiple withdraw properties, ensure the best is used
-            if (withdraw != 0 && doWithdrawFromMeleeAbility(attacker, defender, withdraw)) return
+            val withdrawUniques = defender.unit.getMatchingUniques(UniqueType.MayWithdraw)
+            val baseWithdrawChance = 100-withdrawUniques.fold(100) { probability, unique -> probability * (100-unique.params[0].toInt()) }
+            // If a mod allows multiple withdraw properties, they stack multiplicatively
+            if (baseWithdrawChance != 0 && doWithdrawFromMeleeAbility(attacker, defender, baseWithdrawChance)) return
         }
 
         val isAlreadyDefeatedCity = defender is CityCombatant && defender.isDefeated()
@@ -820,6 +821,7 @@ 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,
diff --git a/core/src/com/unciv/models/ruleset/unique/UniqueType.kt b/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
index c2379340ad..fcce6d981e 100644
--- a/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
+++ b/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
@@ -448,6 +448,7 @@ enum class UniqueType(val text: String, vararg targets: UniqueTarget, val flags:
     @Deprecated("as of 3.19.8", ReplaceWith("Eliminates combat penalty for attacking across a coast"))
     AttackFromSea("Eliminates combat penalty for attacking from the sea", UniqueTarget.Unit),
     AttackAcrossCoast("Eliminates combat penalty for attacking across a coast", UniqueTarget.Unit),
+    AttackOnSea("May attack when embarked", UniqueTarget.Unit),
 
     NoSight("No Sight", UniqueTarget.Unit),
     CanSeeOverObstacles("Can see over obstacles", UniqueTarget.Unit),
diff --git a/docs/Modders/uniques.md b/docs/Modders/uniques.md
index abea6afbc6..26fd6a2746 100644
--- a/docs/Modders/uniques.md
+++ b/docs/Modders/uniques.md
@@ -1010,6 +1010,9 @@ Simple unique parameters are explained by mouseover. Complex parameters are expl
 ??? example  "Eliminates combat penalty for attacking across a coast"
 	Applicable to: Unit
 
+??? example  "May attack when embarked"
+	Applicable to: Unit
+
 ??? example  "No Sight"
 	Applicable to: Unit