AI considers liberating city-states from other civilizations (#7157)

* AI will consider liberating a city state on conquest

* Factor in current civ happiness for liberation consideration

* Refactor foundingCiv check into function

core/src/com/unciv/logic/automation/NextTurnAutomation.kt

@@ -299,8 +299,6 @@ object NextTurnAutomation {
 
     private fun valueCityStateAlliance(civInfo: CivilizationInfo, cityState: CivilizationInfo): Int {
         var value = 0
-        if (!cityState.isAlive() || cityState.cities.isEmpty() || civInfo.cities.isEmpty())
-            return value
 
         if (civInfo.wantsToFocusOn(Victory.Focus.Culture) && cityState.canGiveStat(Stat.Culture)) {
             value += 10
@@ -310,24 +308,33 @@ object NextTurnAutomation {
             value += 10
         }
         else if (civInfo.wantsToFocusOn(Victory.Focus.Military)) {
-            // Don't ally close city-states, conquer them instead
-            val distance = getMinDistanceBetweenCities(civInfo, cityState)
-            if (distance < 20)
-                value -= (20 - distance) / 4
+            if (!cityState.isAlive())
+                value -= 5
+            else {
+                // Don't ally close city-states, conquer them instead
+                val distance = getMinDistanceBetweenCities(civInfo, cityState)
+                if (distance < 20)
+                    value -= (20 - distance) / 4
+            }
         }
         else if (civInfo.wantsToFocusOn(Victory.Focus.CityStates)) {
             value += 5  // Generally be friendly
         }
-        if (civInfo.gold < 100) {
-            // Consider bullying for cash
-            value -= 5
-        }
         if (civInfo.getHappiness() < 5 && cityState.canGiveStat(Stat.Happiness)) {
             value += 10 - civInfo.getHappiness()
         }
         if (civInfo.getHappiness() > 5 && cityState.canGiveStat(Stat.Food)) {
             value += 5
         }
+
+        if (!cityState.isAlive() || cityState.cities.isEmpty() || civInfo.cities.isEmpty())
+            return value
+
+        if (civInfo.gold < 100) {
+            // Consider bullying for cash
+            value -= 5
+        }
+
         if (cityState.getAllyCiv() != null && cityState.getAllyCiv() != civInfo.civName) {
             // easier not to compete if a third civ has this locked down
             val thirdCivInfluence = cityState.getDiplomacyManager(cityState.getAllyCiv()!!).getInfluence().toInt()
@@ -936,6 +943,31 @@ object NextTurnAutomation {
         diplomacyManager.removeFlag(DiplomacyFlags.SettledCitiesNearUs)
     }
 
+    /** Handle decision making after city conquest, namely whether the AI should liberate, puppet,
+     * or raze a city */
+    fun onConquerCity(civInfo: CivilizationInfo, city: CityInfo) {
+        if (!city.hasDiplomaticMarriage()) {
+            val foundingCiv = civInfo.gameInfo.getCivilization(city.foundingCiv)
+            var valueAlliance = valueCityStateAlliance(civInfo, foundingCiv)
+            if (civInfo.getHappiness() < 0)
+                valueAlliance -= civInfo.getHappiness() // put extra weight on liberating if unhappy
+            if (foundingCiv.isCityState() && city.civInfo != civInfo && foundingCiv != civInfo
+                    && !civInfo.isAtWarWith(foundingCiv)
+                    && valueAlliance > 0) {
+                city.liberateCity(civInfo)
+                return
+            }
+        }
+
+        city.puppetCity(civInfo)
+        if ((city.population.population < 4 || civInfo.isCityState())
+                && city.foundingCiv != civInfo.civName && city.canBeDestroyed(justCaptured = true)) {
+            // raze if attacker is a city state
+            city.annexCity()
+            city.isBeingRazed = true
+        }
+    }
+
     fun getMinDistanceBetweenCities(civ1: CivilizationInfo, civ2: CivilizationInfo): Int {
         return getClosestCities(civ1, civ2).aerialDistance
     }

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

@@ -3,6 +3,7 @@ package com.unciv.logic.battle
 import com.badlogic.gdx.math.Vector2
 import com.unciv.Constants
 import com.unciv.UncivGame
+import com.unciv.logic.automation.NextTurnAutomation
 import com.unciv.logic.city.CityInfo
 import com.unciv.logic.civilization.AlertType
 import com.unciv.logic.civilization.CivilizationInfo
@@ -540,15 +541,7 @@ object Battle {
             // we're not taking our former capital
             attackerCiv.popupAlerts.add(PopupAlert(AlertType.CityConquered, city.id))
         } else {
-            // ideally here we would do some AI thinking for liberation vs. razing
-            // e.g., valueCityStateAlliance() > 0 to determine if we should liberate a city-state
-            city.puppetCity(attackerCiv)
-            if ((city.population.population < 4 || attackerCiv.isCityState())
-                && city.canBeDestroyed(justCaptured = true)) {
-                // raze if attacker is a city state
-                city.annexCity()
-                city.isBeingRazed = true
-            }
+            NextTurnAutomation.onConquerCity(attackerCiv, city)
         }
 
         if (attackerCiv.isPlayerCivilization())

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

@@ -145,6 +145,8 @@ class CityInfo {
 
     private var flagsCountdown = HashMap<String, Int>()
 
+    fun hasDiplomaticMarriage(): Boolean = foundingCiv == ""
+
     constructor()   // for json parsing, we need to have a default constructor
     constructor(civInfo: CivilizationInfo, cityLocation: Vector2) {  // new city!
         this.civInfo = civInfo